Environmental Benefits of Tree Trees alter the environment in which we live by moderating climate, improving air quality, conserving water, and harboring wildlife. Climate control is obtained by moderating the effects of sun, wind, and rain. Radiant energy from the sun is absorbed or deflected by leaves on deciduous trees in the summer and is only filtered by branches of deciduous trees in winter. We are cooler when we stand in the shade of trees and are not exposed to direct sunlight. In winter, we value the sun radiant energy. Therefore, we should plant only small or deciduous trees on the south side of homes. Wind speed and direction can be affected by trees. The more compact the foliage on the tree or group of trees, the greater the influence of the windbreak. The downward fall of rain, sleet, and hail is initially absorbed or deflected by trees, which provides some protection for people, pets, and buildings. Trees intercept water, store some of it, and reduce storm runoff and the possibility of flooding. Dew and frost are less common under trees because less radiant energy is released from the soil in those areas at night. Temperature in the vicinity of trees is cooler than that away from trees. The larger the tree, the greater the cooling. By using trees in the cities, we are able to moderate the heat-island effect caused by pavement and buildings in commercial areas. Air quality can be improved through the use of trees, shrubs, and turf. Leaves filter the air we breathe by removing dust and other particulates. Rain then washes the pollutants to the ground. Leaves absorb carbon dioxide from the air to form carbohydrates that are used in the plant structure and function. In this process, leaves also absorb other air pollutants such as ozone, carbon monoxide, and sulfur dioxide and give off oxygen. By planting trees and shrubs, we return to a more natural, less artificial environment. Birds and other wildlife are attracted to the area. The natural cycles of plant growth, reproduction, and decomposition are again present, both above and below ground. Natural harmony is restored to the urban environment.
10 Best Trees You Should Plant Consider Planting These Trees in Your Yard By Steve Nix, About.com Guide I've reviewed the popular literature for you, polled my About Forestry forum and the Internet for the most popular trees and compiled these frequently requested trees to use as a starting place. By further studying the commercial appeal of each of these individual species and taking into account horticulturists' praise I selected my ten best. No Tree Is Perfect Remember, all yard trees have good and bad characteristics. It is a rare tree that will satisfy your needs throughout its entire life span. A tree can outgrow its original purpose very quickly or grow into its intended purpose very slowly. Understanding this concept is the key to proper tree planting in your yard.
Tree Roots Effects on Soil Full of benefits, trees have an enviable position in any landscape, shade, controlling soil erosion, home to many birds, fruits and flowers. Of all the parts of a tree, the roots are perhaps the most unappreciated, as they are unseen. Roots There are two types of roots; primary roots that grow deep down vertically into the soil and secondary roots that branch out horizontally. The architecture of the root system is to absorb water and inorganic nutrients and anchor the plant to the ground. Effects The roots affect the soil , depending on the type of the tree and the soil. These effects have a direct impact on all the plants grown near the tree. Normally a healthy tree represents healthy soil. A big tree takes up most of the water available in the soil, leaving the other plants dry. Growing as well as mowing lawn grass is another difficulty around a large tree, especially if the roots are protruding outside. Tree roots help control soil erosion , however in some cases the roots have a negative effect on the soil by causing a phenomenon called allelopathy. Allelopathy Derived from two words; allelon which means of each other and pathos which means to suffer. It refers to the chemical inhibition of one species by another, by releasing a chemical affecting the development and growth of surrounding plants. In other words, plants try to get their own space, by restricting other plants from growing too close to them. Allelopathic chemicals secretion are not just restricted to the roots, they are also found in branches, leaves, flowers and fruits . The decomposed leaves and bark affect the top layer of soil, while the roots affect the surrounding soil. The chemical curtails the root growth of other plants by inhibiting their nutrient source, thus influencing their evolution and distribution. Juglone It is an aromatic organic allelopathic compound occurring naturally in the roots, bark and leaves of trees in the Juglandaceae family. It releases certain enzymes that inhibits the metabolic function, stunting the growth of many plants and at times even killing an allelopathy intolerant plant. The quantity of Juglone released depends on the weather and soil conditions. The black walnut is the most commonly known for its allelopathic properties. When Juglone sensitive plants come within 0.5 to 0.25 inches of the tree roots, they turn yellow, wilt and die. This in turn, also infects the soil.
Their leaves and roots clean the air we breathe and the water we drink
Top 10 Reasons Why Trees Are Valuable and Important Trees are important, valuable and necessary to our very existence. It's not too hard to believe that, without trees we humans would not exist on this beautiful planet. In fact, some claim can be made that our mother's and father's ancestors climbed trees - another debate for another site. Still, trees are essential to life as we know it and are the ground troops on an environmental frontline. Our existing forest and the trees we plant work in tandem to make a better world.
Studi Pengaruh Kualitas Vegetasi pada Lingkungan Termal Kawasan Kota di Bandung Menggunakan Data Citra Satelit Surjamanto Wonorahardjo, Suwardi Tedja, Benedictus Edward Laboratorium Teknologi Bangunan Sekolah Arsitektur, Perencanaan dan Pengembangan Kebijakan Institut Teknologi Bandung E-mail : email@example.com Tulisan ini membahas lingkungan termal kawasan perkotaan yang dipengaruhi oleh berbagai aspek antara lain bentuk permukaan kawasan, kepadatan dan penggunaan bahan bangunan. Salah satu aspek fisik permukan kawasan yang diyakini para ahli dapat mempengaruhi suhu udara adalah vegetasi seperti taman kota, pohon di tepi jalan dll. Konsep zoning pada kota membentuk kawasan dengan keunikan karakteristik fisik permukaan dan vegetasinya sehingga membentuk kenikan lingkungan termal seperti terbentuknya pulau-pulau panas ( heat island ). Penelitian ini memanfaatkan data satelit Landsat ETM yang mengambil citranya dalam 7 band termasuk di dalamnya citra termal. Metoda ini cukup akurat karena citra (termal) satelit mempunyai resolusi 1 pixel = 60mx 60 m. Pendataan suhu udara lingkungan juga dilakukan dengan pengukuran lapangan untuk pembanding data citra satelit tersebut. Analisis dilakukan terhadap pengaruh tipe vegetasi (pohon, perdu, rumput di lahan terbuka dll) terhadap fisik permukaan kawasan (bentuk permukaan kawasan, kepadatan, penggunaan bahan bangunan) dari aspek pembentukan lingkungan termalnya. Hasil penelitian menunjukkan lingkungan termal kawasan kota sangat dipengaruhi oleh karakteristik vegetasinya.
1. Trees Produce Oxygen Let's face it, we could not exist as we do if there were no trees. A mature leafy tree produces as much oxygen in a season as 10 people inhale in a year. What many people don't realize is the forest also acts as a giant filter that cleans the air we breath.
Urbanization dramatically alters the hydrologic cycle
Increases flooding frequency
Decreases infiltration and groundwater recharge
Nationwide impervious surfaces have increased by 20% in the past 20 years
Lesovedenie Effect of vibrations of tree roots on soil permeability. Danilik, V. N. , Makarenko, G. P. , Tolkach, O. V. Ural'skaya Lesnaya Opytnaya Stantsiya, VNIILM, Russia. Measurements were made in the Urals of the wind-induced movements of 33 roots of Scots pine [ Pinus sylvestris ] and Norway spruce [ Picea abies ] trees, and of the effect of these root movements on soil permeability. Details are given of the procedure; measurements were made when the amplitude of crown tip swaying was 1.4-3.0 m, which corresponded to a strong wind of 11-13 m/s. Root movement occurred in the vertical and the horizontal planes, both perpendicularly and along the root. The amplitude of the root vibrations depended on the structure of the root system, soil mechanical composition, distance from the stem, amplitude of stem sway, and root diameter. The greatest vibrations (0.05-1.11 mm) were those vertical and horizontal across the roots, but they rapidly decreased with increasing distance from the stem. Wind-sway of the stems, leading to vibration of the roots and the ball of soil, increased water permeability along the roots on average by a factor of 3.7, and of the soil within the root system by a factor of 1.2-1.9. Swaying trees accelerated the movement of water along the vibrating roots much more on light than on heavy soils.
Journal of Arboriculture Fill soil effects on soil aeration and tree growth. MacDonald, J. D. , Costello, L. R. , Lichter, J. M. , Quickert, D. Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA. A 4-year study was conducted to evaluate the effects of fill soil on tree growth and soil aeration. Cherry trees ( Prunus × yedoensis 'Afterglow') were grown for 3 years in a test plot in Davis, California, U.S., after which the block of trees was divided into three subplots. In one subplot, 30 cm (12 in.) of compacted fill soil was installed over the root zone, while in a second subplot, aeration piping was installed prior to fill installation. A third subplot was left without fill (control). Oxygen diffusion rate (ODR) and moisture levels were measured in the base soil before and after addition of fill. Trunk diameter was measured at fill installation and 1 year later, while stem water potential was measured after 1 year. Fill soil neither reduced soil aeration levels nor had a negative impact on tree growth. Tree growth in fill subplots was equivalent to or greater than controls. Aeration piping did not enhance oxygen diffusion rates in the underlying field soil. Roots developed in the fill but did not grow preferentially around aeration pipes. Although aeration deficit may play a role in fill-induced plant injury, other factors may play an equal or greater role. These factors include soil compaction and root injury during fill installation, and water deficit following fill installation. All factors should be considered in pre- and post-fill tree management plans.
How Do We Know That Trees Improve Soils? Underlying all aspects of the role of agroforestry in maintenance of soil fertility is the fundamental proposition that trees improve soils. How we know that this is true? 1. The soil that develops under natural forest and woodland is fertile. It is well structured, has a good water-holding capacity and has a store of nutrients bound up in the organic matter. Farmers know they will get a good crop by planting on cleared natural forest. 2. The cycles of carbon and nutrients under natural forest ecosystems are relatively closed, with much recycling and low inputs and outputs. 3. The practice of shifting cultivation demonstrated the power of trees to restore fertility lost during cropping. 4. Experience of reclamation forestry has demonstrated the power of trees to build up fertility on degraded land.
Acta Phytoecologica Sinica Modeling canopy rainfall interception in the upper watershed of the Minjiang River. Li ChongWei , Liu ShiRong , Sun PengSen , Zhang YuanDong , Ge JianPing College of Life Sciences, Beijing Normal University, Beijing 100875, China. The headwaters of the Minjiang River are on the eastern edge of the Tibetan plateau. Canopy rainfall interception plays an important role in the water balance at the regional-scale. Many studies on canopy rainfall interception have been carried out at the stand level but less effort has been devoted towards understanding canopy interception at large scale, neither in the Minjiang River basin nor other areas. In this study, modeling canopy rainfall interception in subalpine forests and meadows in the upper reaches of the Minjiang River was carried out by using field surveys, MODIS data, and RS, GPS and GIS technologies. LAI (leaf area index), vegetation cover and canopy capacity per unit leaf area were the main parameters used in the model. LAI was derived from the vegetation index and measured using a LAI-2000 in the forests and LAI-3000 in the sub-alpine meadows. The LAI of coniferous stands were multiplied by a correction factor because of the clumped arrangement of needles in the crown. Normalized difference vegetation index ( NDVI ) and enhanced vegetation index ( EVI ) were composed by red, near-infrared and blue reflectances from the 500 m 32-day composites available from the MODIS level 3 surface reflectance (MOD09A1). The results indicated that LAI was non-linearly correlated to NDVI and EVI . EVI was preferable to NDVI as NDVI saturates in well-vegetated areas and the degree of correlation between LAI and EVI is higher than that between LAI and NDVI . The results showed that the LAI of vegetation in the upper reaches of the Minjiang River were in the following categories: 28.57% between 0 and 2, 63.06% between 2 and 4.5, and 8.37% above 4.5. LAI was estimated using EVI , and the results showed that LAI could better reflect the spatial distribution of the vegetation. LAI in the upper watershed was lower than down river due to a large number of trees in the down river. Vegetation cover was derived from NDVI . The spatial distribution of canopy capacity per unit leaf area was modeled on the basis of a vegetation-classification map (1:1000000). Canopy rainfall interception in the well-vegetated areas was higher than that in other areas. The model was validated using field measurements made in Wolong and Miyaluo and some additional sites in the upper watershed of the Minjiang River. Empirical expressions to describe evaporation from the wet canopy were derived from additional sites and evaporation from the wet canopy was closely correlated to rainfall. Based on the empirical expressions, simulation results showed that there was a 15.4 percent error in Wolong and a 19.4 percent error in Miyaluo
Semakin banyak pohon, semakin sedikit limpasan permukaan air hujan
Fayetteville, Arkansas: increasing tree canopy from 27-40% reduced their storm water runoff by 31%
South Miami residential study found that a 21% existing tree canopy reduces the storm water runoff by 15%
For every 5% of tree cover added to a community, storm water is reduced by approximately 2%
Communal Benefits of tree Even though trees may be private property, their size often makes them part of the community as well. Because trees occupy considerable space, planning is required if both you and your neighbors are to benefit. With proper selection and maintenance, trees can enhance and function on one property without infringing on the rights and privileges of neighbors. City trees often serve several architectural and engineering functions. They provide privacy, emphasize views, or screen out objectionable views. They reduce glare and reflection. They direct pedestrian traffic. They provide background to and soften, complement, or enhance architecture.
Pergerakan air hujan di dalam profil tanah 2. Trees Clean the Soil The term phytoremediation is a fancy word for the absorption of dangerous chemicals and other pollutants that have entered the soil. Trees can either store harmful pollutants or actually change the pollutant into less harmful forms. Trees filter sewage and farm chemicals, reduce the effects of animal wastes, clean roadside spills and clean water runoff into streams.
Interception, evaporation and absorption of precipitation
Ground surface effects:
Below ground effects:
Infiltration, permeation and filtration
Journal of the Indian Society of Soil Science Impact of growing trees/grasses on physical properties of a saline soil. Nandagoudar, S. A. , Patil, S. G. , Manjunatha, M. V. , Hebbara, M. , Gupta, R. K. , Minhas, P. S. AICRP on Management of Salt-affected Soils and Use of Saline Water in Agriculture, Agricultural Research Station, Gangawati, Karnataka 583 227, India. A field experiment was conducted at Agricultural Research Station, Gangawati, Karnataka, India, to study the effect of tree species alone or in combination with grasses on physical properties of a saline soil. Six tree species viz. Casuarina equisetifolia, Acacia nilotica, Dalbergia sissoo, Azadirachta indica, Sesbania grandiflora and Hardwickia binata and napier grass ( Pennisetum purpureum ) were planted in 1991 and physical properties were determined during 1995-96. Due to the improvement in soil organic carbon, physical characteristics such as porosity, infiltration rate, hydraulic conductivity and aggregate stability improved under different tree covers, while, bulk density and erodibility of soil decreased. Acacia nilotica and Casuarina equisetifolia had higher influence on these bio-physical properties than the other species. Grasses when planted with trees had complementary effect
Hydrological Sciences Journal Measurement of rainfall interception by xerophytic shrubs in re-vegetated sand dunes. Wang XinPing , Li XinRong , Zhang JingGuang , Zhang ZhiShan , Berndtsson, R. Shapotou Desert Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 260 Donggang West Road, Lanzhou 730000, China . More than 40 years of re-vegetation using mainly xerophytic shrubs Artemisia ordosica Krasch. and Caragana korshinskii Kom. at Shapotou Desert Experimental Research Station near Lanzhou, China has resulted in established dwarf-shrub and herbaceous cover on sand dunes. Precipitation, as the sole source of water replenishment in the semiarid area, plays a pertinent role in sustaining the desert ecosystem. A field study was conducted to (a) measure interception loss on shrub canopies during individual rainfall events, (b) determine the canopy storage capacity of individual plants, and (c) explore the relationship between interception and rainfall parameters. The total rainfall and its respective partitions as throughfall were determined and the interception losses in the studied ecosystem were quantified. Interception loss was shown to differ among the xerophyte taxa studied. During the growing seasons, the average shrub community interception loss is 6.9% and 11.7% of the simultaneous overall precipitation, for A. ordosica and C. korshinskii , respectively. Taking into account the observed rainfall conditions and vegetation cover characteristics, it was concluded that the interception loss was 2.7% of the total annual precipitation verified in the period for the A. ordosica community with an average cover of 30%, canopy projection area of 0.8 m2 and canopy storage capacity of 0.75 mm. In contrast, interception loss for the C. korshinskii community was 3.8% with an average cover of 46%, canopy projection area of 3.8 m2 and canopy storage capacity of 0.71 mm. For individual plants of both shrubs, the proportion of interception loss to gross rainfall decreased notably as the rainfall intensity increased between 0 and 2 mm h-1, while it tended to remain constant at about 0.1-0.2 for A. ordosica and 0.1-0.3 for C. korshinskii when the rainfall intensity was >2 mm h-1.
Food production, poverty alleviation and environmental challenges as influenced by limited water resources and population growth. Volume 1A. 18th International Congress on Irrigation and Drainage, Montréal, Canada, 2002 Towards improving of water management in fruit-tree plantations under micro-irrigation. Koumanov, K. S. Nat.Cent. Agric.Sci., Inst.Fruit Growing, 12 Ostromila, Plovdiv 4004, Bulgaria. Precise water balance under micro-sprinkling and drip irrigation of fruit trees showed that the application efficiency was strongly dependent on both the climatic conditions and the soil hydraulic properties. Root activity affected irrigation water redistribution, creating zones with low soil moisture values (down to wilting point) along the skeletal roots very soon (20 hours) after the irrigation. Under drip irrigation, soil moisture in the remaining part of the bulb was still close to field capacity but roots were not able to access it. When the wetted soil volume was larger, as under micro-sprinkler irrigation, root water uptake was found to be, spatially and temporarily, very dynamic. Hence, crop water use efficiency would be increased if irrigation strategy was based on physical models of evaporation from partially wetted soil surface, irrigation water redistribution in the soil, and root water uptake. Microsprinkling was found to affect positively microclimate in fruit-tree plantations, decreasing air temperatures and increasing significantly air humidity. This effect was more pronounced in dry and hot conditions. The experiments were carried out in peach and almond plantations on various soil types carried out in Bulgaria and California, USA
3. Trees Control Noise Pollution Trees muffle urban noise almost as effectively as stone walls. Trees, planted at strategic points in a neighborhood or around your house, can abate major noises from freeways and airports.
4. Trees Slow Storm Water Runoff Flash flooding can be dramatically reduced by a forest or by planting trees. One Colorado blue spruce, either planted or growing wild, can intercept more than 1000 gallons of water annually when fully grown. Underground water-holding aquifers are recharged with this slowing down of water runoff
Intercept rainwater on leaves, branches and trunks – slowing its movement
Evaporation of some of this intercepted precipitation of the tree surfaces
Absorption of a small portion into leaves or stems
Physical Geography Vegetation effects on soil and water losses on weathered granitic hillslopes, South China. Woo, M. K. , Luk, S. H. Dep. Geography, McMaster Univ., Hamilton, Ont. L8S 4K1, Canada. Deforestation of weathered granitic hillslopes of South China (Guangdong Province) has led to widespread erosion. Using small experimental plots under different vegetation cover, the effects of land use on soil and water losses were examined. Overland flow increased as the cover conditions changed from forest to fern, to tilled soil and, eventually, to bare ground. This is related to the amount of interception and infiltration, both of which decreased as the vegetation cover decreased. Most slopes consist of a combination of loose materials and weathered granite and the resistance to sediment entrainment could not be easily determined. The potential sediment yield increased as vegetation cover decreased. Based on empirical relationships between rainfall, overland flow and potential sediment yield, it is demonstrated that soil and water losses can be greatly reduced as vegetation is re-established on these denuded subtropical slopes.
Organic material from leaf litter and other tree detritus tends to increase infiltration rates by increasing pore spaces in soil
Organic material also increases the moisture-holding capacity of these sites
Root mats of trees also tend to break up most soils further improving infiltration and moisture-holding capacity
Indian Journal of Agroforestry Effect of soil depth on early performance and characteristics of roots of some tree species on a hill slope. Singh, K. A. ICAR Research Complex for Eastern Region, Barapani (Meghalaya) - 793 103, India. A field experiment was conducted in Meghalaya, India, to determine the effects of soil depths on root characteristics and biomass productivity of four tree species ( Pinus kesiya, Michelia champaca, Grevillea robusta and Cupressus torulosa ) planted on a hill slope. Changes in root characteristics revealed that vertical penetration of main root, number of roots and root weight per plant increased in proportion to soil depth occupied by the tree species. The main root changed its course of orientation sensing impediments and moved down the hill slope. Mean root spread decreased significantly in the deep soil in case of M. champaca and P. kesiya but it increased marginally in case of G. robusta and C. torulosa as compared to shallow soils. Broadleaved M. champaca and G. robusta had reduced root length, thicker proximal diameter of main and lateral roots in shallow soils while in pine group of plants, either length of main root was shorter in deep soil than the shallow soil as in case of P. kesiya or there was no significant difference in root length as in case of C. torulosa , both the tree species also grew thicker roots in the deep soils. Effect of soil depth on plant growth became evident 18 months after planting. The differential behaviour of tree species in response to soil depths indicated their adaptation and success on the hill slopes through changes in root characteristics particularly root spread and modification in different parts of shoot i.e., basal and breast height diameters, number of branches per plant, canopy length in case of broadleaved tree species and canopy length and canopy diameter both in case of pine group of tree species. Thus, the little difference in root number under different soil depths and tendency to spread extensively under shallow soil depth leading to minimal variation in total biomass productivity helped P. kesiya to be most adaptive on the shallow soils of the hill slopes followed by M. champaca , a broadleaved tree species
Nutrient Cycling in Agroecosystems Shade tree effects in an 8-year-old cocoa agroforestry system: biomass and nutrient diagnosis of Theobroma cacao by vector analysis. Isaac, M. E. , Timmer, V. R. , Quashie-Sam, S. J. Faculty of Forestry, University of Toronto, 33 Willcocks St., Earth Science Centre, Toronto, M5S 3B3, Canada. Farm product diversification, shade provision and low access to fertilizers often result in the purposeful integration of upper canopy trees in cocoa ( Theobroma cacao ) plantations. Subsequent modification to light and soil conditions presumably affects nutrient availability and cocoa tree nutrition. However, the level of complementarity between species requires investigation to minimize interspecific competition and improve resource availability. We hypothesized beneficial effects of upper canopy trees on cocoa biomass, light regulation, soil fertility and nutrient uptake. We measured cocoa standing biomass and soil nutrient stocks under no shade (monoculture) and under three structurally and functionally distinct shade trees: Albizia zygia (D.C.) Macbr, a nitrogen fixer; Milicia excelsa (Welw.), a native timber species; and Newbouldia laevis (Seem.), a native small stature species. Vector analysis was employed to diagnosis tree nutrition. Cocoa biomass was higher under shade (22.8 for sole cocoa versus 41.1 Mg ha-1 for cocoa under Milicia ), and declined along a spatial gradient from the shade tree ( P <0.05). Percent canopy openness differed between the three shade species ( P =0.0136), although light infiltration was within the optimal range for cocoa production under all three species. Soil exchangeable K was increased under Newbouldia , while available P decreased and total N status was unaffected under all shade treatments. Nutrient uptake by cocoa increased under shade (43-80% and 22-45% for N and P, respectively), with K (96-140%) as the most responsive nutrient in these multistrata systems. Addition of low-density shade trees positively affected cocoa biomass close to the shade tree, however proper management of upper stratum trees is required for optimum cocoa productivity and sustainability
Deep roots tend to improve the rates of percolation of water from upper soil horizons into lower substrates
Trees take up water through their roots that is eventually transpired onto leaf surfaces and evaporated
Tree roots act as natural pollution filters (biofilters) using nitrogen, phosphorus and potassium.
Indian Forester Pattern of root distribution in 30-month old five tree and two shrub species of an arid region of north-western India. Virendra Singh , Rajbahadur , Hooda, M. S. , Balkrishan Department of Agroforestry, Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana, India. Structure and distribution of root systems were studied in 30-month old trees of 5 species ( Acacia nilotica, Leucaena leucocephala, Dalbergia sissoo, Azadirachta indica and Prosopis cineraria ) and 2 shrub species ( Prosopis juliflora and Cajanus cajan ) raised at a spacing of 4×0.5 m at Hisar, Haryana. Maximum penetration of root systems was observed in P. cineraria (138 cm depth), followed by Acacia nilotica, D. sissoo, L. leucocephala and P. juliflora , while Azadirachta indica and C. cajan showed comparatively shallow root systems (85 and 65 cm depth, respectively). P. juliflora showed the maximum root spread (347 cm), followed by L. leucocephala (228 cm), Acacia nilotica (216 cm), D. sissoo (187 cm), Azadirachta indica (95 cm), C. cajan (80 cm) and P. cineraria (31 cm). The top 30 cm of soil had the maximum distribution of root biomass in C. cajan, Azadirachta indica and L. leucocephala (45-62% of the total), whereas the maximum distribution of root biomass in P. juliflora, Acacia nilotica and D. sissoo (34-40% of the total) was in the top 30-60 cm of soil. Root distribution in P. cineraria was almost uniform throughout the soil column. The superficial location of a high proportion of roots in stands of C. cajan, Azadirachta indica and L. leucocephala indicates that these species will show strong root competition if intercropped with crops, in comparison with Acacia nilotica, D. sissoo and P. juliflora in which most of the roots had a subsurface location. A vertical root system and narrow crown in P. cineraria make this species the most suitable for agroforestry systems
5. Trees Are Carbon Sinks To produce its food, a tree absorbs and locks away carbon dioxide in the wood, roots and leaves. Carbon dioxide is a global warming suspect. A forest is a carbon storage area or a "sink" that can lock up as much carbon as it produces. This locking-up process "stores" carbon as wood and not as an available "greenhouse" gas.
Set to protect a community’s green infrastructure and maximize the environmental benefits
For metropolitan areas east of the Mississippi
Average tree cover for all land use 40%
Suburban residential 50%
Urban residential 25%
Central business districts 15%
What Makes a Good Soil Improving Tree? It would be useful to have guidelines on which properties of a tree or shrub species make it desirable for the point of view of soil fertility. This would help in identifying naturally occurring species and selecting trees for systems which have soil improvement as a specific objective. Nitrogen fixation and a high biomass production have been widely recognized as desirable. However, many properties are specific to particular objectives of systems in which the trees are used. Even species that are shunned for their competitive effects may have a role in certain designs. An example is the way in which Eucalyptus species with a high water uptake, which adversely affects yields in adjacent crops, have been employed to lower the water table and so reduce salinization.
SIKLUS ENERGI Peranan Matahari 6. Trees Clean the Air Trees help cleanse the air by intercepting airborne particles, reducing heat, and absorbing such pollutants as carbon monoxide, sulfur dioxide, and nitrogen dioxide. Trees remove this air pollution by lowering air temperature, through respiration, and by retaining particulates.
Field Capacity is the amount of water held in the soil after gravitational water had drained away
Movement of water is the soil is controlled :
Gravitational forces if saturated
Matric forces if unsaturated
Pergerakan air dalam tanah 7. Trees Shade and Cool Shade resulting in cooling is what a tree is best known for. Shade from trees reduces the need for air conditioning in summer. In winter, trees break the force of winter winds, lowering heating costs. Studies have shown that parts of cities without cooling shade from trees can literally be "heat islands" with temperatures as much as 12 degrees Fahrenheit higher than surrounding areas.
Infiltration is the mode of entry of all water into the soil
Rate of infiltration determined:
Initial water content
Internal characteristics of the soil
Intensity and duration of rainfall
Temperature of soil and water
Soil Factors Influencing Infiltration 8. Trees Act as Windbreaks During windy and cold seasons, trees located on the windward side act as windbreaks. A windbreak can lower home heating bills up to 30% and have a significant effect on reducing snow drifts. A reduction in wind can also reduce the drying effect on soil and vegetation behind the windbreak and help keep precious topsoil in place.
Microrelief under trees provides catchment basins during heavy rains
Removal of litter layer reduces the infiltration rate
Soil Factors Influencing Infiltration 9. Trees Fight Soil Erosion Erosion control has always started with tree and grass planting projects. Tree roots bind the soil and their leaves break the force of wind and rain on soil. Trees fight soil erosion, conserve rainwater and reduce water runoff and sediment deposit after storms.
Forest Ecology and Management Spatial distribution of root length density and soil water of linear agroforestry systems in sub-humid Kenya: implications for agroforestry models. Radersma, S. , Ong, C. K. Department of Soil Quality, Agricultural University, P.O. Box 8005, 6700 EC Wageningen, Netherlands. IN SIMULTANEOUS AGROFORESTRY SYSTEMS TREES CAN COMPETE WITH CROPS FOR WATER, ESPECIALLY IN SEMI-ARID AREAS. HOWEVER, IN THE (SUB)HUMID TROPICS, ON P-FIXING OXISOLS/FERRALSOLS SMALL DECREASES IN SOIL WATER CONTENT CAUSED A DECREASE IN P-TRANSPORT TO ROOTS AND THEREWITH A SOIL-DRYING INDUCED P-DEFICIENCY. THE AIM OF THIS STUDY WAS TO ASSESS THE SPATIAL DISTRIBUTION OF SOIL WATER CONTENT IN CROP FIELDS BORDERING TREE LINES AND ITS RELATION WITH ROOT LENGTH DENSITY DISTRIBUTION OF THE TREES THROUGHOUT THE SOIL PROFILE. TO ACHIEVE THIS, SOIL WATER CONTENT AND TREE ROOT LENGTH DENSITIES THROUGHOUT THE SOIL PROFILE WERE MEASURED OVER A PERIOD OF 2 YEARS IN AN EXPERIMENT WITH LINES OF FOUR TREE SPECIES IN THE MIDDLE OF MAIZE FIELDS IN SUB-HUMID WESTERN KENYA. SOIL WATER CONTENT WAS SIGNIFICANTLY REDUCED (2-7 VOL.%) NEAR TWO OF THE THREE FAST-GROWING TREE SPECIES, EUCALYPTUS GRANDIS AND GREVILLEA ROBUSTA , BUT NOT NEAR CEDRELLA SERRATA AND THE SLOWER GROWING MARKHAMIA LUTEA . THESE DIFFERENCES WERE RELATED TO DIFFERENCES IN WATER USE. EUCALYPTUS AND GREVILLEA SHOWED HIGH WATER USE AND CEDRELLA AND MARKHAMIA LOW WATER USE. HOWEVER, SOIL WATER CONTENT DISTRIBUTION WAS NOT RELATED TO ROOT LENGTH DENSITY DISTRIBUTION. ROOT LENGTH DENSITIES HARDLY DECREASED WITH DISTANCE TO GREVILLEA AND CLEARLY DECREASED WITH DISTANCE TO CEDRELLA . MOST WATER-UPTAKE MODELS, INCLUDING THOSE OF AGROFORESTRY MODELS, ASSUME THAT ROOT LENGTH DENSITY DISTRIBUTION THROUGHOUT THE PROFILE IS PROPORTIONAL TO WATER EXTRACTION THROUGHOUT THE PROFILE. THE ABSENCE OF A CLEAR RELATION BETWEEN ROOT LENGTH DENSITY AND WATER EXTRACTION NEAR GREVILLEA TREE LINES OPPOSED THIS VIEW. IT CAN BE EXPLAINED BY A DECREASE IN WATER-POTENTIAL GRADIENT BETWEEN ROOT AND SOIL AT INCREASING DISTANCE FROM THE TREE BASE. IF THE CHANGE IN ROOT LENGTH DENSITY IS SIMILAR OR SMALLER THAN THE CHANGE IN WATER-POTENTIAL GRADIENT BETWEEN ROOT AND SOIL, THE DECREASE IN WATER-POTENTIAL GRADIENT BETWEEN ROOT AND SOIL IS OF SIMILAR OR LARGER IMPORTANCE FOR DETERMINING TREE-WATER EXTRACTION DISTRIBUTION THROUGHOUT THE PROFILE THAN ROOT LENGTH DENSITY. THUS, MODELING OF SPATIAL AGROFORESTRY SYSTEMS CANNOT ASSUME A DIRECT RELATION BETWEEN TREE-WATER EXTRACTION AND ROOT LENGTH DENSITY, BUT NEEDS TO INCLUDE DECREASING WATER-POTENTIAL GRADIENT BETWEEN ROOT AND SOIL ALONG ROOTS WITH INCREASING DISTANCE TO THE STEM BASE, ESPECIALLY OVER THE HORIZONTAL DIMENSION.
Indian Forester Impact of soil water availability on carbon sequestration in tree biomass and soil in arid region of India. Singh, G. , Bilas Singh , Rathod, T. R. Division of Forest Ecology and Desert Development, Arid Forest Research Institute, Jodhpur (Rajasthan), India. ARID REGIONS HAVE LOW CAPACITY TO SEQUESTER CARBON DUE TO LOW SOIL WATER AVAILABILITY AND PLANT GROWTH. HOWEVER, CONSIDERING THE LARGE EXTENT OF SUCH AREAS TOTAL CAPACITY OF CARBON SEQUESTRATION MAY BE IMPORTANT. ONE-YEAR-OLD PLANTED SEEDLINGS OF E. CAMALDULENSIS , A. NILOTICA AND D. SISSOO WERE MAINTAINED AT DIFFERENT WATER REGIMES BY RE-IRRIGATING THE SEEDLINGS AT 36.2 MM (T1), 26.5 MM (T2), 20.2 MM (T3), 18.1 MM (T4) AND LIVE SAVING IRRIGATION (T5) WHEN THE SOIL WATER CONTENT DECREASED TO 7.56, 5.79, 4.44, 3.23% AND DRYING OF LEAVES (T5) IN THE RESPECTIVE TREATMENTS CONDUCTED AT THE EXPERIMENTAL FIELD OF ARID FOREST RESEARCH INSTITUTE, JODHPUR, RAJASTHAN, INDIA. CARBON CONTENT BOTH IN DRY BIOMASS AND SOIL INCREASED WITH AGE OF THE SEEDLINGS, BUT IT DECREASED WITH DECREASING IRRIGATION QUANTITY. A NEGATIVE CARBON BALANCE WAS OBSERVED IN T5 AT 12 MONTHS AGE. AT THE AGE OF 48 MONTHS, CARBON CONTENT VARIED FROM 14.91 TO 0.72 KG SEEDLING-1 IN E. CAMALDULENSIS , 8.67 TO 1.74 KG SEEDLING-1 IN A. NILOTICA AND 12.42 TO 0.36 KG SEEDLING-1 IN D. SISSOO . CARBON DENSITY WAS HIGH UNDER A. NILOTICA AND LOW UNDER E. CAMALDULENSIS . THE STUDY SUGGESTS THAT SEVERITY OF SOIL WATER STRESS AFFECTED CARBON SEQUESTRATION, WHEREAS ENHANCED AVAILABILITY OF SOIL WATER THROUGH IRRIGATION INCREASED CARBON STORAGE IN BIOMASS AND SOIL. THEREFORE, THERE IS SCOPE TO INCREASE CARBON SEQUESTRATION IN DRY AREAS THROUGH RAINWATER MANAGEMENT AND SUPPLYING ADDITIONAL IRRIGATION DURING AVAILABILITY OF WATER.
Australian Journal of Botany Impacts of tree plantations on groundwater in south-eastern Australia. Benyon, R. G. , Theiveyanathan, S. , Doody, T. M. Ensis, PO Box 946, Mount Gambier, SA 5290, Australia. In some regions dependent on groundwater, such as the lower southeast of South Australia in the Green Triangle, deep-rooted, woody vegetation might have undesirable hydrological impacts by competing for finite, good-quality groundwater resources. In other regions, such as the Riverina in south-central New South Wales, where rising water tables and associated salinization is threatening the viability of agriculture, woody vegetation might have beneficial hydrological impacts. In response to a growing need to better understand the impacts of tree plantations on groundwater, annual evapotranspiration and transpiration were measured at 21 plantation sites in the Green Triangle and the Riverina. Sources of tree water uptake from rainfall and groundwater were determined by measurements of evapotranspiration and soil water over periods of 2-5 years. In the Green Triangle, under a combination of permeable soil over groundwater of low salinity (<2000 mg L-1) at 6-m depth or less, in a highly transmissive aquifer, annual evapotranspiration at eight research sites in Pinus radiata and Eucalyptus globulus plantations averaged 1090 mm year-1 (range 847-1343 mm year-1), compared with mean annual precipitation of 630 mm year-1. These plantation sites used groundwater at a mean annual rate of 435 mm year-1 (range 108-670 mm year-1). At eight other plantation sites that had greater depth to the water table or a root-impeding layer, annual evapotranspiration was equal to, or slightly less than, annual rainfall (mean 623 mm year-1, range 540-795 mm year-1). In the Riverina, where groundwater was always present within 3 m of the surface, Eucalyptus grandis trees at three sites with medium or heavy clay, alkaline, sodic, saline subsoils used little or no groundwater, whereas E. grandis and Corymbia maculata trees at a site with a neutral sandy soil and groundwater of low salinity used 380 and 730 mm year-1 of groundwater (respectively 41 and 53% of total annual evapotranspiration). We conclude that commonly grown Eucalyptus species and P. radiata are able to use groundwater under a combination of light- or medium-textured soil and shallow depth to a low-salinity water table
Water Resources Research Ecohydrological controls on soil moisture and hydraulic conductivity within a pinyon-juniper woodland. Lebron, I. , Madsen, M. D. , Chandler, D. G., Robinson, D. A. , Wendroth, O. , Belnap, J. Department of Soils and Biometeorology, Utah State University, Logan, Utah, USA. THE IMPACT OF PINYON-JUNIPER WOODLAND ENCROACHMENT ON RANGELAND ECOSYSTEMS IS OFTEN ASSOCIATED WITH A REDUCTION OF STREAMFLOW AND RECHARGE AND AN INCREASE IN SOIL EROSION. THE OBJECTIVE OF THIS STUDY IS TO INVESTIGATE VEGETATIONAL CONTROL ON SEASONAL SOIL HYDROLOGIC PROPERTIES ALONG A 15-M TRANSECT IN PINYON-JUNIPER WOODLAND WITH BIOCRUST. WE DEMONSTRATE THAT THE JUNIPER TREE CONTROLS SOIL WATER CONTENT (SWC) PATTERNS DIRECTLY UNDER THE CANOPY VIA INTERCEPTION, AND BEYOND THE CANOPY VIA SHADING IN A PREFERRED ORIENTATION, OPPOSITE TO THE PREVAILING WIND DIRECTION. THE JUNIPER ALSO CONTROLS THE SWC AND UNSATURATED HYDRAULIC CONDUCTIVITY MEASURED CLOSE TO WATER SATURATION ( K ( H )) UNDER THE CANOPY BY THE CREATION OF SOIL WATER REPELLENCY DUE TO NEEDLE DROP. WE USE THIS INFORMATION TO REFINE THE HYDROLOGIC FUNCTIONAL UNIT (HFU) CONCEPT INTO THREE INTERACTING HYDROLOGIC UNITS: CANOPY PATCHES, INTERCANOPY PATCHES, AND A TRANSITIONAL UNIT FORMED BY INTERCANOPY PATCHES IN THE RAIN SHADOW OF THE JUNIPER TREE. SPATIAL AUTOREGRESSIVE STATE-SPACE MODELS SHOW THE CLOSE RELATIONSHIP BETWEEN K ( H ) CLOSE TO SOIL WATER SATURATION AND SWC AT MEDIUM AND LOW LEVELS, INTEGRATING A NUMBER OF INFLUENCES ON HYDRAULIC CONDUCTIVITY.
Small frost crystals intermingled with soil particles
Found in woodland soils with litter
May be more permeable than unfrozen soil
Has loose porous structure
Found in highly aggregated soils and also formed in organic layers and litter layers
Effects Of Trees On Soils The capacity of trees to maintain or improve soils is shown by the high fertility status and closed nutrient cycling under natural forest, the restoration of fertility under forest fallow in shifting cultivation, and the experience of reclamation forestry and agroforestry. Soil transects frequently show higher organic matter and better soil physical properties under trees. Some species, most notably Faidherbia albida, regularly give higher crop yields beneath the tree canopy. Trees improve soil fertility by processes which: * increase additions to the soil; * reduce losses from the soil; * improve soil physical, chemical and biological conditions. The most important sets of processes are those by which trees: * check runoff and soil erosion; * maintain soil organic matter and physical properties; * increase nutrient inputs, through nitrogen fixation and uptake from deep soil horizons; * promote more closed nutrient cycling.
American Society of Agricultural Engineers Vol. 34(1): January-February 1991 Citrus Tree Spacing Effects on Soil Water Use, Root Density, and Fruit Yield J. D. Whitney, A. Elezaby, W. S. Castle, T. A. Wheaton, R. C. Littell Soil water content, root density, and fruit yield measurements were made on 'Hamlin' orange trees on Milam rootstock at two tree spacings-6 x 4.5 m (370 trees/ ha) and 4.5 x 2.5 m (889 trees/ ha). Soil water use per unit land area for the seven- and eight-year-old trees was not significantly affected by tree spacing. Water use was greatest underneath the canopy dripline and generally decreased with increasing soil depth to 1.65 m. Root densities of the seven-year-old trees were greater at the 4.5 X 2.5 m spacing and generally decreased with depth. Fruit yields per ha were greater for the 4.5 x 2.5 m spacing in the early years, were comparable for both spacings during the seventh and eighth years, and favored the 6 x 4.5 spacing in the 9th year.
Common in soils going through freeze-thaw sequences
Common in exposed soil areas (agriculture)
Much less permeable that other frost types
Tree effects on soil Trees may also adversely affect associated crops. The effects of allelopathy (inhibition effects) have probably been exaggerated by mistaking them for, or confounding them with, other processes. Competition for water is a serious but not insuperable problem in all dry environments, whereas competition for nutrients has rarely been demonstrated. Where the net effect of tree—crop interactions is positive, the length of the tree—crop interface, or extent of the ecological fields, should be maximized. If the net effect is negative, the aim of agroforestry system design should be to reduce the length of the interface. A range of properties have been identified which make tree species suited to soil improvement. For many purposes, high biomass production, nitrogen fixation, a combination of fine feeder roots with tap roots and litter with high nutrient content are suitable. Tolerance to initially poor soil conditions is clearly needed for reclamation. About 100 species have been identified which are known to fulfil soil-improving functions, but there is much scope to increase this range.
Forests and prairies rarely yield runoff regardless of steepness, even when frozen
Forested areas provide storm water protection and protect the quantity and quality of groundwater
Hydrological Processes Rainfall interception by an isolated evergreen oak tree in a Mediterranean savannah. David, T. S. , Gash, J. H. C. , Valente, F. , Pereira, J. S. , Ferreira, M. I. , David, J. S. Estação Florestal Nacional, INIAP, Av. da República, Quinta do Marquês, 2780-159 Oeiras, Portugal. Redistribution of ground-level rainfall and interception loss by an isolated Quercus ilex tree were measured over 2 years in a Mediterranean oak savannah. Stemflow, meteorological variables and sap flow were also monitored. Rainfall at ground level was measured by a set of rain-gauges located in a radial layout centred on the tree trunk and extending beyond the crown limits. Interception loss was computed as the difference between the volume of rainwater that would reach the ground in the absence of the tree and the volume of water that actually fell on the ground sampling area (stemflow included). This procedure provided correct interception loss estimates, irrespective of rainfall inclination. Results have shown a clear non-random spatial distribution of ground-level rainfall, with rainwater concentrations upwind beneath the crown and rain-shadows downwind. Interception loss amounted to 22% of gross rainfall, per unit of crown-projected area. Stand interception loss, per unit of ground area, was only 8% of gross rainfall and 28% of tree evapotranspiration. These values reflect the low crown cover fraction of the stand (0.39) and the specific features of the Mediterranean rainfall regime (predominantly with few large storms). Nevertheless, it still is an important component of the water balance of these Mediterranean ecosystems .
Tree root damage to buildings. Volume 1: causes, diagnosis and remedy. Volume 2: patterns of soil drying in proximity to trees on clay soils. Tree root damage to buildings. Volume 1: causes, diagnosis and remedy. Volume 2: patterns of soil drying in proximity to trees on clay soils. Biddle, P. G. Willowmead, Ickleton Road, Wantage, Oxon. OX12 9JA, UK. This 2-volume set of books provides a comprehensive analysis of, and practical guide to, how the interaction of trees, soils and water can cause foundation movement and damage to buildings. The problems addressed are multidisciplinary, involving structural engineers, engineers, arboriculturalists, soil scientists, insurers and their loss adjusters, architects, and builders and planners, as well as providing work to the legal profession. All aspects of the problems involved are addressed. Volume 1 has 20 chapters, each with a brief summary and a case study at the end; essential points are highlighted. The first 10 chapters describe the interactions of trees, soils, water and buildings: (1) Introduction; (2) The tree - an account of tree physiology and growth; (3) The root system; (4) The soil - types and behaviour in relation to water content; (5) Seasonal changes in soil moisture content; (6) Persistent moisture deficits - when the winter process of rewetting of the soil after summer drying is not complete; (7) Interaction between trees and buildings - soil and foundation movements, buildings and persistent water deficit, and the influences of buildings on the soil and tree roots; (8) Influence of the weather; (9) Comparative effects of different species, and of individual trees and groups; and (10) Other forms of damage by tree roots - direct physical damage and damage to drains and underground services. Chapters 11-16 describe the investigation of damage: (11) Strategy for investigating damage; (12-14) Site investigations: I. The building; II, The soil; and III. The tree; (15) Monitoring building movement; and (16) Heave and recovery: diagnosis and prediction. Chapters 17-20 address remedy and prevention: (17) Remedial action after damage; (18) Prediction and prevention of damage; (19) The legal framework; and (20) A revised role for the professions. Volume 1 ends with a list of references, cross references between botanical and common names, and a subject index. Volume 2 presents the accumulated results from 3 research projects which started in 1978 (with the Milton Keynes (UK) Development Corporation), and were extended in 1981 (under instruction from the UK National House-Building Council) and 1983 (under instruction from the UK Department of the Environment). These investigated the pattern of soil drying, both spatially and with time, that occurs in the proximity of trees on clay soils. A total of 60 trees on open-field sites were studied. These included a range of tree species and clay soil types. The relevance and application of these results to urban situations are addressed in Volume 1. The methods used in the research are described in the introduction to Volume 2 - they involved the use of 5 neutron probe access tubes per tree, by means of which the soil water profiles of each were monitored over long periods. The rest of the volume presents detailed research data for each tree, including photographs and coloured diagrams. These cover the overall time period 1978-94, although different periods apply to different trees.
Black Earth Creek receives 80% of its water from groundwater
Main recharge occurs in spring and fall
Recharge from the agricultural uplands is highly variable
Wooded hill slopes generate no significant runoff
Forested slopes are significant recharge areas
Lesovedenie Effect of soil density on the growth of the root systems of tree seedlings. Korotaev, A. A. Lesotekhnicheskaya Akademiya, Sankt-Peterburg, Russia. Seedlings of Picea abies , Larix sibirica , Pinus sylvestris , Betula pendula , Quercus robur and Tilia cordata were grown in soils of density 1.2, 1.3...1.9 g/cm³. Data are presented on depth of root penetration and total root biomass. In terms of root growth rate and the ability to penetrate dense soil layers, oak and larch were the best and spruce and lime were the poorest species. The critical density of clay loam illuvial soil is 1.89 g/m³ for oak, 1.84 for birch, 1.80 for birch, 1.72 for pine, 1.61 for spruce, and 1.55 g/cm³ for lime. In experiments where the soil density in the lower horizon was greater, the total root biomass produced was virtually the same, as reduced root growth in the dense soil was compensated by more active root growth in the topsoil .
Urban trees enhance water infiltration Traditional stormwater management focuses on regulating the flow of runoff to waterways, but generally does little to restore the hydrologic cycle disrupted by extensive pavement and compacted urban soils with low permeability. The lack of infiltration opportunities affects groundwater recharge and has negative repercussions on water quality downstream. Researchers know that urban forests, like rural forest land, can play a pivotal role in stormwater mitigation, but developing approaches that exploit the ability of trees to handle stormwater is difficult in highly built city cores or in urban sprawl where asphalt can be the dominant cover feature. keepitcleandenver.org/how.html
Environmental Management Volume 44, Number 4 / October, 2009 Transpiration and Root Development of Urban Trees in Structural Soil Stormwater Reservoirs Julia Bartens , Susan D. Day , J. Roger Harris, Theresa M. Wynn and Joseph E. Dove Stormwater management that relies on ecosystem processes, such as tree canopy interception and rhizosphere biology, can be difficult to achieve in built environments because urban land is costly and urban soil inhospitable to vegetation. Yet such systems offer a potentially valuable tool for achieving both sustainable urban forests and stormwater management. We evaluated tree water uptake and root distribution in a novel stormwater mitigation facility that integrates trees directly into detention reservoirs under pavement. The system relies on structural soils: highly porous engineered mixes designed to support tree root growth and pavement. To evaluate tree performance under the peculiar conditions of such a stormwater detention reservoir (i.e., periodically inundated), we grew green ash ( Fraxinus pennsylvanica Marsh.) and swamp white oak ( Quercus bicolor Willd.) in either CUSoil or a Carolina Stalite-based mix subjected to three simulated below-system infiltration rates for two growing seasons. Infiltration rate affected both transpiration and rooting depth. In a factorial experiment with ash, rooting depth always increased with infiltration rate for Stalite, but this relation was less consistent for CUSoil. Slow-drainage rates reduced transpiration and restricted rooting depth for both species and soils, and trunk growth was restricted for oak, which grew the most in moderate infiltration. Transpiration rates under slow infiltration were 55% (oak) and 70% (ash) of the most rapidly transpiring treatment (moderate for oak and rapid for ash). We conclude this system is feasible and provides another tool to address runoff that integrates the function of urban green spaces with other urban needs.
Trees enhance water infiltration Virginia Tech scientists used two container experiments to establish that urban tree roots have the potential to penetrate compacted subsoils and increase infiltration rates in reservoirs being used to store stormwater. In one study, roots of both black oak and red maple trees penetrated clay loam soil compacted to 1.6 g cm-3, increasing infiltration rates by an average of 153%. In another experiment, researchers created a small-scale version of the stormwater best management practice (BMP) under study by the three universities. This BMP includes a below-pavement stormwater detention reservoir constructed of structural soil. Structural soils are engineered mixes designed to both support pavement loads and simultaneously provide rooting space for trees. In this study, green ash trees increased the average infiltration rate by 27 fold compared with unplanted controls. In the experiment, a structural soil reservoir (CUSoil, Amereq Corp., New York) was separated from compacted clay loam subsoil (1.6 g cm‑3) by a woven geotextile in 102-liter containers. The roots of ash trees planted in the structural soil penetrated both the geotextile and the subsoil within two years.
The impact of urban trees on hydrology is extremely variable and complex, in general increases in tree cover and tree size over a site will result in reduced total runoff amounts and peak runoff rates.
Effects are greatest during the growing season
Effects are greatest on sites whose soils are relatively impermeable
TREES Help Cities Meet Clean Water Regulations Tree cover in urban areas can provide cities with reduced costs for stormwater management and improvement in water quality. American Forests has developed a computer software package to measure the effects of urban tree cover and impervious surfaces on stormwater that will help city managers meet ever tightening water quality regula- tions. Scientific research and time-tested engineering practices pro- vide the basis for the software calculations.
Trees have a relatively greater effect on smaller storm runoff amounts than on large storm events
Surface and below-ground effects on runoff are much more significant than the above-ground effects
All of the effects on runoff are greatest when urban trees are large and well-established on undisturbed sites
Vegetasi pohon sangat berpengaruh positif terhadap lingkungan termalnya dalam hal laju penurunan temperatur udara dan temperatur udara rata-rata.
Dengan demikian maka mekanisme pohon dalam pengendalian lingkungan termal dapat diintepretasikan sebagai berikut :
- Pohon berpengaruh positif terhadap temperatur udara berdasarkan mekanisme pembayangan ( canopy effect ), di mana pohon memayungi daerah di bawahnya dari sinar matahari langsung sehingga tidak menjadi panas dan berpengaruh pada udara.
- Pohon berpengaruh positif terhadap proses pendinginan (penurunan temperatur udara sore hari) berdasarkan mekanisme evapotranspiration , di mana pelepasan air dari permukaan daun pada sore hari mendinginkan permukaan daun dan mempengaruhi temperatur udara di sekitarnya.
Pohon berpengaruh negatif terhadap proses pemanasan (naiknya temperatur udara pagi hari) berdasarkan mekanisme ‘selimut’ di mana canopy menghalangi pertukaran panas dengan daerah sekitarnya sehingga lingkungan di bawahnya cepat menjadi panas. Efek dari laju naik temperatur udara tidak terlalu berpengaruh pada temperatur udara rata-rata.
Can urban tree roots improve infiltration through compacted subsoils for stormwater management? Global land use patterns and increasing pressures on water resources demand creative urban stormwater management. Strategies encouraging infiltration can enhance groundwater recharge and water quality. We examined whether tree roots can penetrate compacted subsoils and increase infiltration rates in the context of a novel infiltration BMP (I-BMP). Urban subsoils are often relatively impermeable, and the construction of many stormwater detention best management practices (D-BMPs) exacerbates this condition. Root paths can act as conduits for water, but this function has not been demonstrated for stormwater BMPs where standing water and dense subsoils create a unique environment. We examined whether tree roots can penetrate compacted subsoils and increase infiltration rates in the context of a novel infiltration BMP (I-BMP). Black oak ( Quercus velutina Lam.) and red maple ( Acer rubrum L.) trees, and an unplanted control, were installed in cylindrical planting sleeves surrounded by clay loam soil at two compaction levels (bulk density = 1.3 or 1.6 g cm−3) in irrigated containers. Roots of both species penetrated the more compacted soil, increasing infiltration rates by an average of 153%. Similarly, green ash ( Fraxinus pennsylvanica Marsh.) trees were grown in CUSoil (Amereq Corp., New York) separated from compacted clay loam subsoil (1.6 g cm−3) by a geotextile. A drain hole at mid depth in the CUSoil layer mimicked the overflow drain in a stormwater I-BMP thus allowing water to pool above the subsoil. Roots penetrated the geotextile and subsoil and increased average infiltration rate 27-fold compared to unplanted controls. Although high water tables may limit tree rooting depth, some species may be effective tools for increasing water infiltration and enhancing groundwater recharge in this and other I-BMPs (e.g., raingardens and bioswales).
Urban tree roots have the potential to penetrate compacted subsoils and increase infiltration rates in reservoirs being used to store stormwater. Bartens et al. Can Urban Tree Roots Improve Infiltration through Compacted Subsoils for Stormwater Management? Journal of Environmental Quality , 2008; 37 (6): 2048
Landscape ecology of trees and forests. Proceedings of the twelfth annual IALE (UK) conference, Cirencester, UK, 21-24 June 2004 Investigating the impact of tree shelter belts on agricultural soils. Carroll, Z. L. , Bird, S. B. , Emmett, B. A. , Reynolds, B. , Sinclair, F. L. Centre for Ecology and Hydrology, Orton Building, Deiniol Road, Bangor, Gwynedd, Wales, LL57 2UP, UK. There is growing concern that modern agricultural practices have reduced the infiltration capacity of the soil, thereby reducing the soil's ability to absorb rainwater. There are few quantitative data available, however, on the impact of land use on runoff and flood risk. A preliminary study was undertaken in the Nant Pontbren catchment, mid-Wales, UK. This land is used extensively for grazing and experimental tree shelterbelts were established in selected pastures. Infiltration rates were up to 60 times higher in areas planted with trees than in adjacent grazed pastures and significant differences were also observed for soil moisture and pH. Surprisingly, soil bulk density varied little between the two areas. The results indicate that more research is needed to gain a better understanding of the processes in operation. This study demonstrates that farm trees could represent a key landscape feature, reducing runoff even when only a small proportion of the land cover.
ISHS Acta Horticulturae 620: XXVI International Horticultural Congress: Asian Plants with Unique Horticultural Potential: Genetic Resources, Cultural Practices, and Utilization EFFECT OF RAINFALL INTERCEPTION ON SOIL MOISTURE, TREE SAP FLOW, AND FRUIT QUALITY IN PEACH ( PRUNUS PERSICA ) D.G. Choi, D.C. Choi, D.H. You, H.G. Kim, J. Ryu, S.D. Effect of soil covering with black polyethylene film for rainfall interception (RI) on soil moisture, tree sap flow, and fruit quality in ‘Okubo’ peach were investigated to find out the factor decreasing fruit quality, when it rained at fruit mature season. Cell size of fruit was rapidly increased until the late of May, nearly stopped at the early of June, and regrew from the late of June in the natural condition. Change of soil water was less and slower in the treatment of RI than that in the control. The RI retarded the soil water increasing, whereas soil water in the control plot fluctuated with rainfall amount change. Soil water content in RI plot showed 80% lower at small raining and 40% lower at heavy raining than that in the control plot. Amount of tree sap flow during raining was high in all treatments. Tree sap flow kept high during the stable soil water period without rain, whereas it did lower during the unstable soil water period after rain. Pit splitting rate was 20% in control tree and 10% in the RI. Fruit hardness and sugar content were higher in RI treatment than that in the control. Therefore, taste of fruits in the RI treatment was better than that of the control.
Agroforestry Systems (Netherlands) Effects of mulching with multipurpose-tree prunings on soil and water run-off under semi-arid conditions in Kenya. Omoro, L. M. A. , Nair, P. K. R. Agroforestry Program, University of Florida, Gainesville, Florida, USA. The effect of adding leaf mulches of Grevillea robusta, Cassia siamea and Gliricidia sepium on the rate of soil and water runoff from a crop field were studied during 2 cropping seasons in an Alfisol under semi-arid conditions in Kenya. Two rates of mulch of each species (2.24 t and 4.48 t, on dry matter basis, per ha) and a no-mulch control constituted the 7 treatments. Soil and water runoff losses after each major rainfall event and the changes in ground and crop cover were measured. Rainfall erosivity and changes in soil bulk density and infiltration rate were also determined. Soil losses from the plots with mulches of C. siamea, G. sepium and G. robusta were lower than those from the control. Over the 2 seasons, the cumulative soil losses from plots mulched with cassia, gliricidia and grevillea were 11%, 57% and 81% of that of the control plot. Similarly, water runoff losses from cassia, gliricidia and grevillea mulch plots were 28%, 48% and 58% of that of the control plot, respectively. Thus, cassia was found to be better than gliricidia and grevillea in reducing both soil and water runoff losses. Soil bulk density did not change while the infiltration rate at the end of the experiment was higher than in the beginning. However, there were no significant differences in these soil physical properties among the treatments
So How Do We Protect Water Quality and Our Streams as Watersheds Change? Trees and forests play an incredible role in reducing stormwater in several ways and removing or filtering pollutanting that would otherwise wind up in our waterways. Interception Tree canopies intercept and capture rainfall, reducing the amount that reaches the ground. In urban and suburban settings, a single deciduous tree can intercept between 500 and 760 gallons per year, while a mature evergreen can intercept over 4,000 per year. Soil Infiltration Tree roots and forest soils allow for better infiltration of rainfall with rates of up to 15 inches per hour. The leaf littered forest floor acts like a gaint sponge, allowing for slow infiltration into soils befre releasing it to natural channels and recharging ground water. Evapotranspiration Tree consumer stormwater through a process called evapotranspiration. Water is taken up by roots and move up through the tree until it is transpired back into the atmosphere as water vapor. A single mature oak tree can consume (transpire) over 40,000 gallons of water each year. Phytoremediation Trees are very good at removing pollutants such as nitrates & phosphates; and other contaminates such as heavy metals, pesticides, solvents, oils, and hydrocarbons that are found in stormwater. Riparian Buffers Trees and Riparian Forests protect and buffer streams and are critical to maintaining healthy, clean streams. Tree roots provide streambank stability, reducing erosion, filter out sediments, remove nutrients, shade and cool the water, provide habitat for many different species, and provide the primary food source for aquatic insects that are a critical part of the aquatic food chain. Until recently, stormwater management strategies focused on detaining large volumes of water in basins that had little to no effect on removing the pollutants in the stormwater. In December 2006, PA DEP unveiled new stormwater best management practices (BMPs) that work to protect water quality and put stormwater back into the ground where it fell. One of the 10 principles in the BMP manual is to preserve and utilize natural systems such as forests, trees, and native soils.
Trees and Forests Reduce the Impacts of Stormwater As we begin to remove forest canopy and replace it with roads, parking lots, driveways, homes, patios, pools (impervious surfaces) and even grass, we immediately have impact on watersheds and receiving streams (or lakes). With the increased amount of impervious surfaces, water runs off the land, traveling on the surface towards the streams. As this ‘storm water runoff’ travels to the streams it collects pollutants and increases speed. The changes to the landscape, not only increase the volume of water that goes to the stream, it also shortens the amount of time it takes the water to get to the stream. These increased or peak flows cause water to move quickly to the streams. This leads to flooding, streambank erosion, widening of streams, sediment deposited in streams, a loss of fish habitat, and decline in water quality. In Pennsylvania there are over 12,200 miles of polluted streams and over 3,000 miles of streams that are impaired by storm water runoff.
Geoderma Analysing the space-time distribution of soil water storage of a forest ecosystem using spatio-temporal kriging. Jost, G. , Heuvelink, G. B. M. , Papritz, A. Institute of Forest Ecology, BOKU-University of Natural Resources and Applied Life Sciences, Vienna, Peter Jordan Str. 82, A-1190 Vienna, Austria. Editors: Oliver, M. A., Lark, R. M. In forest the soil water balance is strongly influenced by tree species composition. For example, differences in transpiration rate lead to differences in soil water storage (SWS) and differences in canopy interception cause differences in infiltration. To analyse the influence of tree species composition on SWS at the scale of a forest stand, we compare spatio-temporal patterns in vegetation and SWS. Geostatistical space-time models provide a probabilistic framework for mapping SWS from point observations. The accuracy of these models may be improved by incorporating knowledge about the process of evapotranspiration. In this paper we combine a physical-deterministic evapotranspiration model with space-time geostatistical interpolation to predict soil water storage in the upper 30 cm of soil (SWS30) for a 0.5 ha plot in a mixed stand of Norway spruce ( Picea abies (L.) Karst.) and European beech ( Fagus sylvatica L.) in Kreisbach, Lower Austria. Soil water storage was measured at 198 locations by permanently installed wave guides. This was repeated 28 times, about every two weeks during the growing seasons of 2000 and 2001. Incorporation of a process-based model in space-time prediction of SWS30 reduced the effect of precipitation on SWS30 predictions prior to precipitation. Spatial patterns of SWS30 between the permanent wilting point and field capacity depend on the precipitation and drying history, which is affected by vegetation. Early in the growing season spruce starts to transpire markedly, which is common for coniferous trees. During dry periods, spruce reduces transpiration earlier than beech. Overall beech transpires more than spruce during the growing season. The greater transpiration rates of beech are compensated for by greater soil water recharge after precipitation because less rainfall is intercepted. At low water contents near the permanent wilting point SWS30 was spatially quite uniform. This was also the case at water contents nearfield capacity, probably because the soil physical parameters varied little. Space-time interpolation of SWS30 and the prediction of soil water discharge and soil water recharge during periods of drying and rewetting demonstrate the important role of vegetation on the spatial patterns of SWS30.
Benefits of Trees Most trees and shrubs in cities or communities are planted to provide beauty or shade. These are two excellent reasons for their use. Woody plants also serve many other purposes, and it often is helpful to consider these other functions when selecting a tree or shrub for the landscape. The benefits of trees can be grouped into social, communal, environmental, and economic categories.
Logging effects on soil moisture losses Ziemer, Robert R. Date: 1978 Ph.D. dissertation, Colorado State University, Ft. Collins, Colorado. 132 p. The depletion of soil moisture within the surface 15 feet by an isolated mature sugar pine and an adjacent uncut forest in the California Sierra Nevada was measured by the neutron method every 2 weeks for 5 consecutive summers. Soil moisture recharge was measured periodically during the intervening winters. Groundwater fluctuations within the surface 50 feet were continuously recorded during the same period. Each fall, a wetting front progressed from the soil surface, eventually recharging the entire soil profile to ""field capacity"". During the recharge period, although the top portion of the soil was at ""field capacity"", the trees continued to deplete moisture from the drier soil below the wetting front into early winter. Groundwater levels began to rise within days after rainfall, whereas weeks or months were required for the wetting front to progress through the unsaturated zone above the water table. Soil moisture depletion by the isolated tree was maximum at a depth of 8 to 13 feet and extended about 15 feet away from the tree. The influence of the tree on soil moisture depletion extended to a depth of about 18 feet and to a distance of about 40 feet. An excellent linear relationship was found between the quantity of soil moisture depleted by the tree at the end of the summer and distance from the tree. The isolated tree used between 2200 and 2600 cubic feet more soil moisture than a bare portion of the plot outside of the influence of the tree.“
SIKLUS HIDROLOGI Peranan vegetasi pohon References Burgess, S. and 5 others. 1998. Trees as water pumps: restoring water balances in Australian and Kenyan soils. Agroforestry Today 10(3): 18-20). MacDicken, K.G. 1991. Selection and Management of Nitrogen Fixing Trees. Winrock International, Morriltion, Arkansas, USA. Nair, P.K.R., and Latt, C.R. (eds.) 1997. Directions in tropical agroforestry research. Agroforestry Systems, Special Issue, 38: 1-249. Niang, A. and 5 others. 1999. Soil fertility replenishment in western Kenya. Agroforestry Today 11(1-2): 19-21. von Carlowitz, P.G. 1986. Multipurpose Tree and Shrub Seed Directory. ICRAF, Nairobi. von Carlowitz, P.G., Wolf, G.V., and Kemperman, R.E.M. 1991. Multipurpose Tree and Shrub Database. An Information and Decision-support System. GTZ, Eschborn, Germany. Webb, D.B., Wood, P. J., Smith, J.P., and Henman, G.S. 1984. A Guide to Species Selection in Tropical and Sub-tropical Plantations. Commonwealth Forestry Institute, Oxford, UK. Young, A. 1989. Agroforestry for Soil Conservation. CAB International, Wallingford, UK.
SIKLUS HIDROLOGI Peranan bentang lahan Social Benefits OF TREE We like trees around us because they make life more pleasant. Most of us respond to the presence of trees beyond simply observing their beauty. We feel serene, peaceful, restful, and tranquil in a grove of trees. We are at home there. Hospital patients have been shown to recover from surgery more quickly when their hospital room offered a view of trees. The strong ties between people and trees are most evident in the resistance of community residents to removing trees to widen streets. Or we note the heroic efforts of individuals and organizations to save particularly large or historic trees in a community. The stature, strength, and endurance of trees give them a cathedral-like quality. Because of their potential for long life, trees frequently are planted as living memorials. We often become personally attached to trees that we or those we love have planted.
Austral ecology ISSN 1442-9985 2005, vol. 30, no3, pp. 336-347 Woodland trees enhance water infiltration in a fragmented agricultural landscape in eastern Australia ELDRIDGE David J. ; FREUDENBERGER David Since European settlement, Eucalyptus box woodlands have been substantially modified by agricultural practices, and in many areas in southern Australia are now restricted to scattered or clumped trees. We report here on a study to examine the impact of trees on water flow (infiltration) in an agricultural landscape with substantial areas of extant native vegetation. We examined infiltration through coarse- and fine-textured soils within four landscape strata, the zones below Eucalyptus melliodora and Callitris glaucophylla canopies, the intertree zone dominated by perennial grasses and a landscape homogenized by cultivation and dominated by annual crops. We measured sorptivity, the early phase of water flow, and steady-state infiltration with disc permeameters at two supply potentials. These different potentials enabled us to separate infiltration into (i) flow through large (biopores) and small pores and (ii) flow through small pores only where biopores are prevented from conducting water. On the fine-textured soils, both sorptivity and steady-state infiltration were significantly greater (approximately fivefold) under the timbered strata compared with the grassy slopes or cultivation. Differences were attributable to the greater proportion of macropores below the tree canopies compared with the nontimbered strata. The lack of a significant difference on the coarse-textured soils, despite their macropore status, was attributed to differences in surface litter and plant cover, which would maintain continuous macropores at the surface and thus conduct large amounts of water. The tendency of slopes covered by cryptogamic crusts and grasses to shed run-off and for the trees to absorb substantial quantities of water reinforced the important ecological service provided by trees, which moderates large run-off events and captures small amounts of water leaking from the grassy patches. In the absence of these 'ecosystem wicks', run-off would find its way into regional groundwater and contribute to rising salinity.
Journal of Hydrology (Amsterdam) Soil water depletion and recharge patterns in mixed and pure forest stands of European beech and Norway spruce. Schume, H. , GeorgJost , Hager, H. Institute of Forest Ecology, BOKU, University of Natural Resources and Applied Life Sciences, Peter Jordan Strasse 82, Vienna A-1190, Austria. Automated time domain reflectometry (TDR) measurements in high resolution over soil depth and over time were performed in a mixed beech-spruce and a spruce stand during two hydrologically contrasting seasons. Soil drying was more intensive and reached deeper soil layers in the mixed stand, which on the other hand allowed more stand precipitation, compensating for the higher evapotranspiration rates. These results were confirmed by a large number of spatially distributed TDR measurements along grids of different spacing, which additionally covered a beech stand. Spatial water depletion patterns of the topsoil in spring appeared to be largely congruent with tree species distribution and reflected the higher water consumption of fully foliated beech. Variability was highest in the mixed stand, where a spatial correlation within a range of about 7 m was observed. The pure stands lacked spatial correlation. The effect of the mixed stand on soil water depletion and recharge turned out to be non-additive as compared to the pure stands of beech and spruce: changes of soil water storage under the mixed stand almost equalled the values measured in the beech stand. During selected drying periods in 2000 average daily water extraction rates from the uppermost 60 cm of soil amounted to 1.65 mm in the beech as well as in the mixed stand, which is about 45% more than under pure spruce. Maximum differences of up to 84% occurred in periods with high evaporative demand. The over-proportionate evapotranspiration of the mixed stand was exclusively attributable to beech, which deepened and intensified its fine-root system in mixture, while spruce rooted more shallowly. The mixed stand extracted a higher percentage of water from deeper soil layers than the pure stands.
Peran Vegetasi Salah satu peran vegetasi untuk mengendalikan lingkungan termal adalah melalui mekanisme evapotranspiation (proses penguapan air dari daun ke udara) yang dapat mempercepat pendinginan permukaan daun yang juga berakibat pada penurunan temperatur udara. Pengukuran terhadap proses evapotranspiration pernah dilakukan oleh DOE Lawrence Berkeley National Laboratory dan dilaporkan bahwa pohon berdiameter 30 feet dapat melepas air sebanyak 40 galon / hari. Pohon dan tanaman mendinginkan udara dengan cara membayangi dan mungurangi jumlah sinar matahari yang mencapai tanah. Jumlah sinar matahari yang menembus canopy dinyatakan dalam nilai transmitansi1 yang bervariasi dari 0 – 100%. Nilai 0 berarti sinar matahari sama sekali tidak dapat menembus canopy , nilai 100 berarti tidak ada sinar matahari yang ditahan oleh canopy .
Journal of Arid Environments Rain-water management for tree planting in the Indian desert. Gupta, G. N. Arid Forest Research Inst., Division of Forest & Desert Development, New Pali Road, Jodhpur 342005, Rajasthan, India. The influence of different systems of water harvesting and moisture conservation on soil moisture storage, growth, biomass accumulation and nutrient uptake by Azadirachta indica (neem), Tecomella undulata (rohida) and Prosopis cineraria (khejri) was studied in Rajasthan, India, during 1990-1992. The ridge and furrow method of water harvesting was found to be the best treatment and significantly improved the growth of all 3 species (height by 58%, 35% and 40%, collar circumference by 73%, 56% and 63%, and crown diameter by 111%, 51% and 131%, respectively). Biomass accumulation by A. indica and T. undulata increased 3.8-fold and 4.6-fold and root mass 4.5-fold and 3.8-fold, respectively. The mulching treatment was beneficial to A. indica and weeding treatment to all the 3 species. Tree roots in water harvesting plots were deeper and had a spread several times larger than the control. Nutrient uptake by these tree species increased several-fold as a result of the different water harvesting and moisture conservation treatments.
SIKLUS HIDROLOGI Peranan vegetasi pohon Economic Benefits of Tree Individual trees and shrubs have value, but the variability of species, size, condition, and function makes determining their economic value difficult. The economic benefits of trees can be both direct and indirect. Direct economic benefits are usually associated with energy costs. Air-conditioning costs are lower in a tree-shaded home. Heating costs are reduced when a home has a windbreak. Trees increase in value from the time they are planted until they mature. Trees are a wise investment of funds because landscaped homes are more valuable than nonlandscaped homes. The savings in energy costs and the increase in property value directly benefit each home owner. The indirect economic benefits of trees are even greater. These benefits are available to the community or region. Lowered electricity bills are paid by customers when power companies are able to use less water in their cooling towers, build fewer new facilities to meet peak demands, use reduced amounts of fossil fuel in their furnaces, and use fewer measures to control air pollution. Communities also can save money if fewer facilities must be built to control storm water in the region. To the individual, these savings are small, but to the community, reductions in these expenses are often in the thousands of dollars.
Plant and Soil Effects of changes in tree species composition on water flow dynamics - model applications and their limitations. Armbruster, M. , Seegert, J. , Feger, K. H. Institute of Soil Science and Site Ecology, Dresden University of Technology, 01735 Tharandt, Germany. Editors: Hüttl, R. F., Bens, O. Water-plant relations play a key role in the water cycling in terrestrial ecosystems. Consequently, changes in tree species composition may have distinct effects on the water retention capacity as well as on the pattern of streamflow generation. Such changes may result from modified interception properties and transpiration related to differences in canopy properties and root distribution. In order to evaluate the potential hydrological effects of the current silvicultural conversion from monocultural conifer stands into mixed or pure deciduous stands the hydrological model BROOK90 was applied to two forested upland catchments in Germany. The Rotherdbach catchment (9.4 ha, 93 yr-old Norway spruce) is situated in the Eastern Ore Mountains. The Schluchsee catchment (11 ha, 55-yr-old Norway spruce) is located in the higher altitudes of the Black Forest. The calibrated model is capable to describe rather well the temporal variation of streamflow but also the portions of the individual flow components. Data for a beech scenario were adapted for each site using a standard parameter set for deciduous trees provided by BROOK90 . The annual discharge in the fictional beech stand at Rotherdbach is 30 to 50% higher compared to spruce with an increase of soil moisture and especially the slow streamflow components. This mainly results from low interception rates during winter time. In contrast, the spruce stand has a permanently higher interception rate. Effects of tree species conversion are moderate at Schluchsee. The annual discharge of a fictional beech stand at Schluchsee is 7 to 14% higher compared to spruce. There in contrast to Rotherdbach, effects of tree species conversion on soil moisture dynamics are small since vertical percolation in the highly permeable soil dominates and precipitation is abundant. Practical forestry will favorably establish mixed beech-spruce rather than pure beech stands. However, it is critical to simulate mixed stands with BROOK90 . Therefore, a simple summation of model results from spruce and beech according to their respective area in a fictional mixed stand can only be a first approximation. Advanced hydrological simulation of mixed stand conditions should regard interactions of tree species and spatial parameter distribution. However, this is not yet feasible due to a distinct lack of information. As a consequence, there is a strong need to collect relevant hydrological and ecophysiological data in mixed stands in the future .
Infiltration is governed by two forces: gravity and capillary action. While smaller pores offer greater resistance to gravity, very small pores pull water through capillary action in addition to and even against the force of gravity. The rate of infiltration is affected by soil characteristics including ease of entry, storage capacity, and transmission rate through the soil. The soil texture and structure, vegetation types and cover, water content of the soil, soil temperature , and rainfall intensity all play a role in controlling infiltration rate and capacity. For example, coarse-grained sandy soils have large spaces between each grain and allow water to infiltrate quickly. Vegetation creates more porous soils by both protecting the soil from pounding rainfall, which can close natural gaps between soil particles, and loosening soil through root action. This is why forested areas have the highest infiltration rates of any vegetative types.
Infiltration is the process by which water on the ground surface enters the soil . Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes saturated. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. It is related to the saturated hydraulic conductivity of the near-surface soil. The rate of infiltration can be measured using an infiltrometer.
Tree Physiology Converging patterns of uptake and hydraulic redistribution of soil water in contrasting woody vegetation types. Meinzer, F. C., Brooks, J. R., Bucci, S., Goldstein, G., Scholz, F. G., Warren, J. M. Forestry Sciences Laboratory, USDA Forest Service, 3200 SW Jefferson Way, Corvallis, OR 97331-4401, USA. Editors: Meinzer, F. C., Goldstein, G., Phillips, N. G. We used concurrent measurements of soil water content and soil water potential (Ψsoil) to assess the effects of Ψsoil on uptake and hydraulic redistribution (HR) of soil water by roots during seasonal drought cycles at six sites characterized by differences in the types and amounts of woody vegetation and in climate. The six sites included a semi-arid old-growth ponderosa pine ( Pinus ponderosa ) forest, a moist old-growth Douglas-fir ( Pseudotsuga menziesii ) forest, a 24-year-old Douglas-fir forest, in Washington, USA, and three Brazilian savanna sites, in Distrito Federal, differing in tree density. At all of the sites, HR was confined largely to the upper 60 cm of soil. There was a common threshold relationship between the relative magnitude of HR and Ψsoil among the six study sites. Below a threshold Ψsoil of approximately -0.4 MPa, overnight recharge of soil water storage increased sharply, and reached a maximum value of 80-90% over a range of Ψsoil from ~-1.2 to -1.5 MPa. Although amounts of water hydraulically redistributed to the upper 60 cm of soil were relatively small (0 to 0.4 mm day-1), they greatly reduced the rates of seasonal decline in Ψsoil. The effectiveness of HR in delaying soil drying diminished with increasing sapwood area per ground area. The relationship between soil water utilization and Ψsoil in the 20-60-cm layer was nearly identical for all six sites. Soil water utilization varied with a surrogate measure of rhizosphere conductance in a similar manner at all six sites. The similarities in relationships between Ψsoil and HR, soil water utilization and relative rhizosphere conductance among the six sites, suggests that, despite probable differences in maximum rooting depth and density, there was a convergence in biophysical controls on soil water utilization and redistribution in the upper soil layers where the density of finer roots is greatest.
TREE FOR SOIL IMPROVEMENT The following are the principal trees and shrubs that have been employed for soil improvement (from Webb et al., 1984; von Carlowitz, 1986; von Carlowitz et al., 1991; MacDicken, 1994; Young, 1989a, p. 159). Acacia auriculiformis Acacia cyanophylla Acacia mangium Acacia mearnsii Acacia nilotica Acacia senegal Acacia seyal Acacia tortilis Albizia lebbeck Albizia saman (Samanea saman) Anacardium occidentale Alnus acuminata Alnus nepalensis Alnus spp. Atriplex spp. Azadirachta indica Bactris gasipaes Bamboo genera Cajanus cajan Calliandra calothyrsus Casuarina cunninghamiana Casuarina equisetifolia Casuarina glauca Centrosema pubescens Cordia alliodora Crotalaria spp. Dalbergia sissoo Dactyladenia barteri (Acioa barteri) Dendrocalamus spp. Erythrina caffra Erythrina orientalis Erythrina poeppigiana Faidherbia albida (Acacia albida) Flemingia congesta (Flemingia macrophylla) Gliricidia sepium Grevillea robusta Inga edulis Inga jinicuil Leucaena diversifolia Leucaena leucocephala Melaleuca leucadendron Melia azedarach Musanga cecropioides Paraserianthes falcataria (Albizia falcataria) Parkia biglobosa (Parkia africana) Paulownia elongata Peltophorum dasyrrachis Populus deltoides Prosopis chilensis Prosopis cineraria Prosopis glandulosa Prosopis juliflora Prosopis tamarugo Schinus molle Senna reticulata Senna siamea (Cassia siamea) Senna spectabilis (Cassia spectabilis) Sesbania bispinosa Sesbania grandiflora Sesbania rostrata Sesbania sesban Tamarix aphylla Tephrosia candida *Tephrosia vogelii *Tithonia diversifolia Ziziphus mauritiana Ziziphus nummularia Zizyphus spina-christi
RAIN GARDENS Tree box filters are mini bioretention areas installed beneath trees that can be very effective at controlling runoff, especially when distributed throughout the site.1 Runoff is directed to the tree box, where it is cleaned by vegetation and soil before entering a catch basin. The runoff collected in the tree-boxes helps irrigate the trees. Tree box filters are based on an effective and widely used “bioretention or rain garden” technology with improvements to enhance pollutant removal, increase performance reliability, increase ease of construction, reduce maintenance costs and improve aesthetics. Typical landscape plants (shrubs, ornamental grasses, trees and flowers) are used as an integral part of the bioretention / filtration system. They can fit into any landscape scheme increasing the quality of life in urban areas by adding beauty, habitat value, and reducing urban heat island effects. Manufactured Tree Box Filters For Stormwater Management (Source: Virginia DCR Stormwater Management Program )
RAIN GARDENS TREE BOX FILTER The system consists of a container filled with a soil mixture, a mulch layer, under-drain system and a shrub or tree. Stormwater runoff drains directly from impervious surfaces through a filter media. Treated water flows out of the system through an under drain connected to a storm drainpipe / inlet or into the surrounding soil. Tree box filters can also be used to control runoff volumes / flows by adding storage volume beneath the filter box with an outlet control device. Tree Box Filters For Stormwater Management (Source: Prince George's County, MD Bioretention Manual)