Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Trees, Soils and Mulch

703 views

Published on

Trees, Soils and Mulch

Published in: Education
  • Be the first to comment

  • Be the first to like this

Trees, Soils and Mulch

  1. 1. HEIDI KRATSCH TREES, SOILS & MULCH
  2. 2. OUTLINE • Tree root requirements • Soil and water • Urban soils • Soil improvement • Irrigation
  3. 3. • Stomates close • Decreased photosynthesis • Death of root hairs and feeder roots • Wilting, defoliation, scorch of leaves • New leaves may be smaller than normal. • Dieback of shoots • Growth in height and girth declines. • Heavier than normal seed production • Increased susceptibility to insect (spider mites, wood-boring insects) TREE RESPONSE TO DROUGHT
  4. 4. THE MYTH THAT WON’T DIE!
  5. 5. • Oxygen - burns sugars provided by the canopy (leaves) for energy • Release carbon dioxide in the process • If the two gases cannot freely exchange with the atmosphere • roots die • Tree can’t get water or nutrients. TREE ROOTS NEED OXYGEN Depth of rooting is limited by the availability of oxygen
  6. 6. WHERE ARE THE TREE’S ROOTS?
  7. 7. COMPOSITION OF AN IDEAL SOIL Water Air Mineral fraction Organic matter (5%) Pore SpaceSolids
  8. 8. SOIL TEXTURE The mineral particles: sand, silt, and clay
  9. 9. SOIL TEXTURE INFLUENCES PORE SPACE Sand particles Clay particles Water flow Air flow High water-holding capacity
  10. 10. SOIL TEXTURE AND PHYSICAL PROPERTIES Texture Available water Aeration Drainage Compaction Sand Loam Silt loam Clay loam Clay
  11. 11. GOOD SOIL HAS STRUCTURE • The combination of sand, silt and clay (with organic matter) into secondary particles called aggregates. Soil aggregate micropores macropores
  12. 12. • Seals off soil surface. • Deprives roots of pore space. • Clay soils compact COMPACTION DESTROYS STRUCTURE
  13. 13. IMPROVE WATER RELATIONS BY PROMOTING SOIL STRUCTURE
  14. 14. • Improves drainage and aeration of clay soils • Improves water-holding capacity of sandy soils • Reduces compaction • Provides/retains nutrients • Locally lowers soil pH • Add no more than 15 to 20% by volume to tree planting holes • Higher levels can cause significant soil settling as organic matter breaks down AMENDING SOILS WITH ORGANIC MATTER
  15. 15. ORGANIC MATTER IS ESSENTIAL TO THE LIFE OF THE SOIL
  16. 16. STRUCTURE DEVELOPS OVER TIME • In an undisturbed setting, soils are allowed to form naturally. • Over time, provides ideal conditions for plant roots.
  17. 17. THE REALITY IN URBAN AREAS…
  18. 18. PROMOTE SOIL STRUCTURE BY ADDING ORGANIC MATTER • Organic amendments – incorporated into the soil • Mulch - placed on top of the soil Increasing organic matter by 2% decreases water use by 50%
  19. 19. SOIL AMENDMENTS DEFINED Compost: • The rich, black, soil-like end-product of decomposed leaves and other plant materials (leaves, twigs, bark, etc.). • Can be used as a soil conditioner, as plant food or as mulch. • Look for ‘finished compost’ – should not be able to recognize the original ingredients. • Unfinished compost should be piled and left to finish before use.
  20. 20. COMPOST QUALITY MATTERS If you purchase compost: • ‘Compost’ is not a regulated term. A range of products are marketed as ‘compost.’ • Quality depends on: • Maturity • pH • Presence of weed seeds • Toxic substances • Population of soil microbes • Do not use compost that is still hot, smells like ammonia or you can recognize uncomposted ingredients.
  21. 21. SOIL AMENDMENTS DEFINED Composted manure • The rich, black, soil-like end-product of decomposed animal waste and the bedding used to make the stalls or coops easier to clean. • Also called ‘aged’ or ‘well-rotted.’ • Very high in nitrogen • Never use raw manure on established plants. • Do not use dog or cat waste (meat-eaters)
  22. 22. SOIL AMENDMENTS DEFINED Composted soil • No such thing! • Soil is already ‘done’ and cannot be composted. • Usually means compost or topsoil. Humus • Refers to components of soil that are rich in organic matter. • Slippery term – could mean anything or nothing (not regulated) • Completely finished compost is virtually 100% humus.
  23. 23. SOIL AMENDMENTS DEFINED Soil • What is in the ground • Unamended soils contain sand, silt and/or clay, plus ½ percent organic matter (in Nevada). • Organic content is very low compared to compost. Topsoil • Soil from the uppermost 6 to 12 inches of the ground. • Quality depends on source and how long it has been stored.
  24. 24. COMMON MULCH OPTIONS Organic • Compost • Composted wood chips • Pine bark nuggets • Pine needles • Shredded western red cedar (Gorilla Hair) • Chopped leaves • Chopped landscape waste (twigs, leaves, etc.) Inorganic • Decomposed granite • Pea gravel or crushed stone • Cobblestones • River rock • Lava rock • Shredded rubber Organic mulches do a better job of retaining soil moisture in the heat of summer
  25. 25. COMBUSTIBILITY OF LANDSCAPE MULCHES 0 50 100 150 200 250 Shredded Rubber Pine Needles Shredded Western Red Cedar Medium Pine Bark Nuggets Composted Wood Chips Flame Height Rate of Spread Temperature
  26. 26. ORGANIC MULCH COMPARISONS MULCH ADVANTAGES DISADVANTAGES Compost Beneficial microbes May compact Composted wood chips Looks attractive and holds moisture May blow with strong wind Medium pine bark nuggets Looks attractive and holds moisture May blow with strong wind Pine needles Holds moisture Extreme fire hazard; may mat Gorilla hair Holds moisture; stays put Extreme fire hazard Chopped leaves Holds moisture Poor weed control Peat moss None When dry, wicks water from the soil Pine needles and gorilla hair used no less than 30 feet from the home
  27. 27. • More fine roots available to absorb water. • Tree with more fine roots is more resilient to drought. TREES ROOT DENSELY UNDER MULCH
  28. 28. APPLYING COMPOST • Do not apply amendments to tree planting holes (or up to 20% in very poor soils) • If planting trees in an ‘island’, amend soil to 25% to 30% by volume. • Incorporate 4 inches of compost into the top 12 inches of the planting bed (32 cubic feet of compost per 100 square feet of planting bed). • As a mulch – apply 2 inches deep over the soil surface within the tree canopy. Can be also used under other landscape mulches.
  29. 29. TREES PLANTED IN AN ISLAND
  30. 30. • Provide tree rings HOW CAN WE HELP TREES SURVIVE?
  31. 31. HOW LARGE SHOULD THE TREE RING BE?
  32. 32. BIRCH IN PLANTED ISLAND
  33. 33. HYDROZONES ARE AN IMPORTANT ELEMENT OF WATER EFFICIENT LANDSCAPING
  34. 34. IS THIS DROUGHT STRESS?
  35. 35. WATER USE OF LANDSCAPE PLANTS • 3,000 square feet of lawn • Apply 2” water per week • 0.623 gal./ square foot x 3,000 square feet x 2 inches = 3,738 gal. water per week • 2 medium to large trees • Require ~120 gal./tree per week • Total = 240 gal. water per week
  36. 36. HOW DO YOU GET RID OF GRASS UNDER TREES? • Apply a thick layer of mulch (4 to 5 inches) around the tree. • Apply 3 inches if using compost as mulch.
  37. 37. TO IMPROVE DROUGHT RESILIENCE Need to provide water to 60 percent of the root system to avoid stress Water to a depth of 18 to 20 inches
  38. 38. SOIL TEXTURE AND DRAINAGE PROPERTIES Sand Silt Loam Clay Loam Coarse Texture Medium Texture Fine Texture Can’t I just add Sand or Clay to adjust the texture of the soil?
  39. 39. DRIP IRRIGATION Advantages: • More water absorbed by plant roots in sandy soils • Less loss to evaporation Disadvantages: • Emitters need to be moved each year • Emitters can become clogged • Longer run times
  40. 40. DRIP IRRIGATION ON NEWLY PLANTED BRISTLECONE PINE
  41. 41. DRIP IRRIGATION ON SMALL TREES
  42. 42. TURF-BASED LANDSCAPE • 4,850 square feet • 15% hardscape • 45% turf • 15% shrubs • 21% perennial beds • 5% ground cover plants • 12 trees • Irrigated by pop-up sprinklers Average annual water use = 72,875 gallons Rosenberg et al., 2010, Value Landscape Engineering: Identifying costs, water use, labor, and impacts to support landscape choice
  43. 43. PERENNIAL-BASED LANDSCAPE • 4,655 square feet • 20% hardscape • 5% turfgrass • 0% shrubs • 72% perennial beds • 3% ground cover plants • 8 trees • Turf irrigated by pop-up; drip in remaining areas Average annual water use = 49,523 gallons
  44. 44. WOODLAND STYLE LANDSCAPE • 4,870 square feet • 20% hardscape • 0% turf • 60% shrub beds • 20% perennial beds • 0% ground cover plants • 18 trees • Irrigated entirely by drip Average annual water use = 22,610 gallons
  45. 45. FOR MORE INFORMATION The Combustibility of Landscape Mulches • http://www.unce.unr.edu/publications/files/nr/2011 /sp1104.pdf or... • http://goo.gl/pL1EBN Calculate water use of your landscape: • http://vle.cuwcd.com/ DIY book: Water-Efficient Landscaping in the Intermountain West by Kratsch (and many others)

×