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Class 7 science project

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project of science on class 6,7,8

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Class 7 science project

  1. 1. TH 7 CLASS BOYS WELCOME YOU TO THIS PROJECT
  2. 2. CONTENTS;1. Types of forest 2. Information 3. Temperate needle leaf 4. Temperate broad leaf and mixed 5. Tropical moist 6. Tropical dry 7. Sparse trees and parkland 8. Tropical forest types
  3. 3. TYPES OF FOREST 1 Temperate needleleaf 2 Temperate broadleaf and mixed 3 Tropical moist 4 Tropical dry 5 Sparse trees and parkland 6 Tropical forest types .
  4. 4. TEMPERATE NEEDLE LEAF Temperate needleleaf forests mostly occupy the higher latitude regions of the northern hemisphere, as well as high altitude zones and some warm temperate areas, especially on nutrient-poor or otherwise unfavourable soils. These forests are composed entirely, or nearly so, of coniferous species (Coniferophyta). In the Northern Hemisphere pines Pinus, spruces Picea, larches Larix, firs Abies, Douglas firs Pseudotsuga and hemlocks Tsuga, make up the canopy, but other taxa are also important. In the Southern Hemisphere, most coniferous trees (members of the Araucariaceae and Podocarpaceae) occur in mixtures with broadleaf species, and are classed as broadleaf and mixed forests.
  5. 5. Temperate broadleaf and mixed Temperate broadleaf and mixed forests include a substantial component of trees in the Anthophyta. They are generally characteristic of the warmer temperate latitudes, but extend to cool temperate ones, particularly in the southern hemisphere. They include such forest types as the mixed deciduous forests of the United States and their counterparts in China and Japan, the broadleaf evergreen rainforests of Japan, Chile and Tasmania, the sclerophyllous forests of Australia, central Chile, the Mediterranean and California, and the southern beech Nothofagus forests of Chile and New Zealand
  6. 6. Tropical moist There are many different types of tropical moist forests,although most extensive are the lowland evergreen broad leaf rainforests, for example várzea and igapó forests and the terra firma forests of the Amazon Basin; the peat swamp forests, dipterocarp forests of Southeast Asia; and the high forests of the Congo Basin. Forests located on mountains are also included in this category, divided largely into upper and lower montane formations on the basis of the variation of physiognomy corresponding to
  7. 7. Tropical dry Tropical dry forests are characteristic of areas in the tropics affected by seasonal drought. The seasonality of rainfall is usually reflected in the deciduousness of the forest canopy, with most trees being leafless for several months of the year. However, under some conditions, e.g. less fertile soils or less predictable drought regimes, the proportion of evergreen species increases and the forests are characterised as "sclerophyllous". Thorn forest, a dense forest of low stature with a high frequency of thorny or spiny species, is found where drought is prolonged, and especially where grazing animals are plentiful. On very poor soils, and especially where fire is a recurrent phenomenon, woody savannas develop (see
  8. 8. Sparse trees and parkland sparse trees and parkland are forests with open canopies of 10–30% crown cover. They occur principally in areas of transition from forested to non-forested landscapes. The two major zones in which these ecosystems occur are in the boreal region and in the seasonally dry tropics. At high latitudes, north of the main zone of boreal forest or taiga, growing conditions are not adequate to maintain a continuous closed forest cover, so tree cover is both sparse and discontinuous. This vegetation is variously called open taiga, open lichen woodland, and forest tundra. It is species-poor, has high bryophyte cover, and is frequently affected by fire.
  9. 9. Tropical forest types Lowland evergreen broadleaf rain forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude that display little or no seasonality, the canopy being >75% evergreen broadleaf. Lower montane forest – Natural forests with > 30% canopy cover, between 1200–1800 m altitude, with any seasonality regime and leaf type mixture. Upper montane forest – Natural forests with > 30% canopy cover, above 1,800 m (5,906 ft) altitude, with any seasonality regime and leaf type mixture. Freshwater swamp forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil. Semi-evergreen moist broadleaf forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude in which between 50– 75% of the canopy is evergreen, > 75% are broadleaves, and the trees display seasonality of flowering and fruiting.
  10. 10. •Mixed broadleaf/needleleaf forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%). •Needleleaf forest – Natural forest with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is predominantly (> 75%) needleleaf. •Mangroves – Natural forests with > 30% canopy cover, composed of species of mangrove tree, generally along coasts in or near brackish or seawater. •Deciduous/semi-deciduous broadleaf forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude in which between 50–100% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover). •Sclerophyllous dry forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.
  11. 11. •Thorn forest – Natural forests with > 30% canopy cover, below 1,200 m (3,937 ft) altitude, in which the canopy is mainly composed of deciduous trees with thorns and succulent phanerophytes with thorns may be frequent. •Sparse trees and parkland – Natural forests in which the tree canopy cover is between 10–30%, such as in the savannah regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms). •Disturbed natural forest – Any forest type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc. •Exotic species plantation – Intensively managed forests with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country. •Native species plantation – Intensively managed forests with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.
  12. 12. Reforestation Reforestation is the natural or intentional restocking of existing forests and woodlands that have been depleted, usually through deforestation.[1] Reforestation can be used to improve the quality of human life by soaking up pollution and dust from the air, rebuild natural habitats and ecosystems, mitigate global warming since forests facilitate biosequestration of atmospheric carbon dioxide, and harvest for resources, particularly timber.
  13. 13. Contents •1 Management •2 For harvesting •3 For climate change mitigation •4 Incentives •5 Examples
  14. 14. Management Reforestation of large areas can be done through the use of measuring rope (for accurate plant spacing) and dibbers, (or wheeled augers for planting the larger trees) for making the hole in which a seedling or plant can be inserted. Indigenous soil inoculants (e.g., Laccaria bicolor) can optionally be used to increase survival rates in hardy environments. A debatable issue in managed reforestation is whether or not the succeeding forest will have the same biodiversity as the original forest. If the forest is replaced with only one species of tree and all other vegetation is prevented from growing back, a monoculture forest similar to agricultural crops would be the result. However, most reforestation involves the planting of different feedlots of seedlings taken from the area often of multiple species. Another important factor is the natural regeneration of a wide variety of plant and animal species that can occur on a clear cut. In some areas the suppression of forest fires for hundreds of years has resulted in large single aged and single species forest stands. The logging of small clear cuts and or prescribed burning, actually increases the biodiversity in these areas by creating a greater variety of tree stand ages and species.
  15. 15. For harvesting Reforestation need not be only used for recovery of accidentally destroyed forests. In some countries, such as Finland, the forests are managed by the wood products and pulp and paper industry. In such an arrangement, like other crops, trees are replanted wherever they are cut. In such circumstances, the industry can cut the trees in a way to allow easier reforestation. The wood products industry systematically replaces many of the trees it cuts, employing large numbers of summer workers for tree planting work. For example, in 2010, Weyerhaeuser reported planting 50 million seedlings.[3] In just 20 years, a teak plantation in Costa Rica can produce up to about 400 m of wood per hectare. As the natural teak forests of Asia become more scarce or difficult to obtain, the prices commanded by plantationgrown teak grow higher every year. Other species such as mahogany grow slower than teak in Tropical America but are also extremely valuable. Faster growers include pine, eucalyptus, and Gmelina.[4]
  16. 16. . Other species such as mahogany grow slower than teak in Tropical America but are also extremely valuable. Faster growers include pine, eucalyptus, and Gmelina.[4] Reforestation, if several native species are used, can provide other benefits in addition to financial returns, including restoration of the soil, rejuvenation of local flora and fauna, and the capturing and sequestering of 38 tons of carbon dioxide per hectare per year.[5] The reestablishment of forests is not just simple tree planting. Forests are made up of a diversity of species and they build dead organic matter into soils over time. A major tree-planting program in a place like this would enhance the local climate and reduce the demands of burning large amounts of fossil fuels for cooling in the summer.
  17. 17. For climate change mitigation Forests are an important part of the global carbon cycle because trees and plants absorb carbon dioxide through photosynthesis. By removing this greenhouse gas from the air, forests function as terrestrial carbon sinks, meaning they store large amounts of carbon. At any time, forests account for as much as double the amount of carbon in the atmosphere.[7]:1456 Even as more anthropogenic carbon is produced, forests remove around three billion tons of anthropogenic carbon every year. This amounts to about 30% of all carbon dioxide emissions from fossil fuels. Therefore, an increase in the overall forest cover around the world would tend to mitigate global warming. There are four major strategies available to mitigate carbon emissions through forestry activities: increase the amount of forested land through a reforestation process; increase the carbon density of existing forests at a stand and landscape scale; expand the use of forest products that will sustainably replace fossil-fuel emissions; and reduce carbon emissions that are caused from deforestation and degradation.[7]:1456
  18. 18. Achieving the first strategy would require enormous and wide-ranging efforts. However, there are many organizations around the world that encourage treeplanting as a way to offset carbon emissions for the express purpose of fighting climate change. For example, in China, the Jane Goodall Institute, through their Shanghai Roots & Shoots division, launched the Million Tree Project in Kulun Qi, Inner Mongolia to plant one million trees to stop desertification and help curb climate change.[8][9] China has used 24 billion metres squared of new forest plantation and natural forest regrowth to offset 21% of Chinese fossil fuel emissions in 2000[7]:1456. In Java, Indonesia each newlywed couple is to give whoever is sermonizing their wedding 5 seedlings to combat global warming. Each couple that wishes to have a divorce has to give 25 seedlings to whoever divorces them.[10]
  19. 19. The second stategy has to do with selecting species for treeplanting. In theory, planting any kind of tree to produce more forest cover would absorb more carbon dioxide from the atmosphere. On the other hand, a genetically modified tree specimen might grow much faster than any other regular tree.[11]:93 Some of these trees are already being developed in the lumber and biofuel industries. These fast-growing trees would not only be planted for those industries but they can also be planted to help absorb carbon dioxide faster than slowgrowing trees.[11]:93 Extensive forest resources placed anywhere in the world will not always have the same impact. For example, large reforestation programs in boreal or subarctic regions have a limited impact on climate mitigation. This is because it substitutes a bright snow-dominated region that reflects the sunlight with dark forest canopies. A study from the National Center for Atmospheric Research in Boulder, Colorado, USA, found that trees in temperate latitudes have a net warming effect on the atmosphere. The heat that dark leaves release without absorbing outweighs the carbon they sequester.[12] On the other hand, a positive example would be reforestation projects in tropical regions, which would lead to a positive biophysical change such as the formation of clouds. These clouds would then reflect the sunlight, creating a positive impact on climate mitigation.[7]:1457
  20. 20. There is an advantage to planting trees in tropical climates with wet seasons. In such a setting, trees have a quicker growth rate because they can grow year-round. Trees in tropical climates have, on average, larger, brighter, and more abundant leaves than non-tropical climates. A study of the girth of 70,000 trees across Africa has shown that tropical forests are soaking up more carbon dioxide pollution than previously realized. The research suggests almost one fifth of fossil fuel emissions are absorbed by forests across Africa, Amazonia and Asia. Simon Lewis, a climate expert at the University of Leeds, who led the study, said: "Tropical forest trees are absorbing about 18% of the carbon dioxide added to the atmosphere each year from burning fossil fuels, substantially buffering the rate of change."[13] It is also important to deal with the rate of deforestation. At this point, there are 13 billion metres squared of tropical regions that are deforested every year. There is potential for these regions to reduce rates of deforestation by 50% by 2050, which would be a huge contribution to stabilize the global climate.
  21. 21. Incentives Some incentives for reforestation can be as simple as a financial compensation. Streck and Scholz (2006) explain how a group of scientists from various institutions have developed a compensated reduction of deforestation approach which would reward developing countries that disrupt any further act of deforestation. Countries that participate and take the option to reduce their emissions from deforestation during a committed period of time would receive financial compensation for the carbon dioxide emissions that they avoided.[14]:875 To raise the payments, the host country would issue government bonds or negotiate some kind of loan with a financial institution that would want to take part in the compensation promised to the other country. The funds received by the country could be invested to help find alternatives to the extensive cutdown of forests. This whole process of cutting emissions would be voluntary, but once the country has agreed to lower their emissions they would be obligated to reduce their emissions. However, if a country was not able to meet their obligation, their target would get added to their next commitment period. The authors of these proposals see this as a solely government-to-government agreement; private entities would not participate in the compensation trades.[14]:876
  22. 22. Examples Forest regrowth in Mount Baker-Snoqualmie National Forest, Washington state, USA It is the stated goal of the US Forest Service to manage forest resources sustainably. This includes reforestation after timber harvest, among other programs.[15] In Germany, reforestation is required as part of the federal forest law. 31% of Germany is forested, according to the second forest inventory of 2001–2003. The size of the forest area in Germany increased between the first and the second forest inventory due to forestation of degenerated bogs and agricultural areas. In China, extensive replanting programs have existed since the 1970s. Programs have had overall success. The forest cover has increased from 12% of China's land area to 16%. However, specific programs have had limited success. The "Green Wall of China", an attempt to limit the expansion of the Gobi Desert is planned to be 2,800 miles (4,500 km) long and to be completed in 2050. In Canada, overall forest cover is increasing over the last decades. In Borneo Dr Willie Smits, bought up nearly 2000 ha of deforested degraded land in East Kalimantan that had suffered from mechanical logging, drought and severe fires and was covered in alang-alang grass. In a project called Samboja Lestari an area was reforested. The Groasis Waterbox was designed specifically to establish trees in areas undergoing desertification. It collects dew and infrequent rain, and slowly releases it to the plants roots, promoting deeper root growth.[17]
  23. 23. Deforestation From Wikipedia, the free encyclopedia For other uses, see Deforestation (disambiguation). Satellite photograph of deforestation in progress in the Tierras Bajas project in eastern Bolivia. Deforestation, clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use.[1] Examples of deforestation include conversion of forestland to farms, ranches, or urban use.

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