Managing Trees During Drought Conditions
â˘Transferir como PPTX, PDFâ˘
1 gostouâ˘1,191 visualizaçþes
Managing Trees During Drought Conditions Webinar by Heidi Kratsch
Recomendados
Mais conteĂşdo relacionado
Semelhante a Managing Trees During Drought Conditions
Semelhante a Managing Trees During Drought Conditions (20)
Mais de University of Nevada Cooperative Extension
Mais de University of Nevada Cooperative Extension (20)
Ăltimo
Ăltimo (20)
Managing Trees During Drought Conditions
- 1. ManagingTrees During Drought Conditions Dr. Heidi Kratsch University of Nevada Cooperative Extension
- 2. What we will cover⌠â˘Impact of drought on trees â˘Most effective irrigation strategies for trees â˘Other management issues for trees during drought â˘Selecting trees for drought-resilience
- 4. Weâre killing our urban trees!
- 5. Transpiration ⢠Transpiration starts at the leaves. ⢠Capillary action pulls water from below. ⢠Soil moisture is depleted. ⢠Hot, dry air increases transpiration. ⢠Wind blowing across leaves increases transpiration.
- 6. Treeâs response to drought: ⢠Stomata close and photosynthesis slows. ⢠Death of root hairs and feeder roots ⢠Wilting, scorch, and defoliation ⢠New leaves may be smaller than normal. ⢠Premature fall color ⢠Dieback of shoots ⢠Growth in height and girth declines. ⢠Heavier than normal seed production ⢠Increased susceptibility to insect pests (spider mites, wood-boring insects)
- 8. 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, Journal of the AmericanWater Resources Association
- 9. 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 Trees are the most valuable asset in our urban areas.
- 10. Goal of irrigation Replace the water lost from the root zone due to: â˘Transpiration â˘Evaporation â˘Percolation below the rooting zone.
- 11. ⢠Up to 90 percent of the total root system length is accounted for by fine, absorbing roots. Fine, absorbing roots Sinker root
- 12. Need to wet 60% to 75% of the tree root zone.
- 13. Hydrozoning â˘Group plants with similar water needs and... â˘Irrigate zones on separate valves.
- 14. Two aspects to irrigation scheduling â˘Duration: How much water to apply⌠â˘Frequency: How often to apply it.
- 15. Water trees deeply Watering depth for different plants: Tree roots 18 to 24 inches Shrub roots 12 to 18 inches Herbaceous plant roots 6 to 12 inches Turfgrass roots 6 to 8 inches
- 16. Calculate estimated daily water use Gallons per plant = 0.623 x plant area x plant factor x reference evapotranspiration (ETo) per day á irrigation system efficiency Based on ASCE guidelines and modified for practical use.
- 17. Plant Area = Crown diameter2 x 0.7854 Example: Crown diameter = 10 ft., so 102 (10 x 10) x 0.7854 = 78.54 sq. ft.
- 18. Plant factor for trees ranges from 0.5 to 0.8 Actualwaterloss,in/day Reference water loss (ETo) ETo: 4 -6â fescue turf, 100% Home turf: 80% Trees: 50% to 80% http://www.washoeet.dri.edu/washoeEt.html
- 19. Water trees less frequently GALLONS OF WATER PER WEEK Plant water use Plant canopy diameter in feet 1 2 3 4 5 6 8 10 12 14 Tree medium low 29 21 52 42 81 64 116 92 158 126 Shrub medium low 9 3 7 5.5 12.5 10 20 17 29 21 43 35 Perennial medium low 1.5 1 4 3 10 5 Information valid for western Nevada and other similar climates during summer.
- 20. Micro-irrigation (Drip) â˘Slow application â˘Measured in GPH rather than GPM â˘Less loss to evaporation â˘Reduces runoff and leaching â˘System efficiency of 80% to 90% (sprinklers < 75%)
- 21. Micro-irrigation emission devices (low pressure 10-30 psi) ⢠Drip emitters â for shrubs and small trees (0.5â6 gph) ⢠Bubblers â best for new trees with a berm or trees in wells (2â20 gph) ⢠Micro-spray emitters â for medium to large trees (3â30 gph) The main difference is the mode of water dispersal.
- 22. Micro-spray emitters ⢠External emitters connected to the lateral distribution line using spaghetti tubing ⢠Fewer heads needed to cover large areas. ⢠Visible to easily check for damage.
- 23. Example: How long should I water? Size Drip Emitters Microspray Emitters Large trees (canopy 14+ feet) 20 2-gph emitters for 4 hours once a week Eight 20-gph emitters for 1 hour once a week Medium trees (canopy 10-12 feet) 14 2-gph emitters for 3 to 4 hours once a week Six 14-gph emitters for 1 to 1.5 hours once a week Small trees/large shrubs (canopy 6-8 feet) 10 2-gph emitters for 1.5 to 2.5 hours once a week Five 11-gph emitters for 0.5 to 1 hour once a week Based on gallons of water needed per tree.
- 24. ď ď ď CLAYSILTSAND The spread of the wetting front depends on soil texture.
- 25. Emitter arrangement for young trees ⢠Wet as much of the root ball as possible. ⢠Irrigation line should not be up against the trunk. ⢠Emitters should be placed within and beyond the spread of the root ball to encourage root growth into native soil. Roots donât seek water â they follow water.
- 26. Result of inadequate early water distribution Roots wonât spread into dry soil.
- 27. Emitter arrangement for mature trees Southern Nevada Water Authority New Mexico State University The depth and distribution of water application will determine the architecture of the root system.
- 28. How will the architecture of this treeâs root system look?
- 29. Remember where the roots are.
- 32. Irrigation of trees surrounded by turfgrass
- 33. Whatâs going on with this tree?
- 34. Other strategies for managing trees during drought ⢠Mulch at least out to the drip line, further if possible. ⢠Do not fertilize trees during drought conditions. ⢠Limit pruning to removal of dead wood or crossing branches.
- 35. Urban tree selection for drought resilience
- 36. Water is lost through leaf stomata (pores). What our eyes see What our eyes canât see
- 37. Plant adaptations to arid conditions ⢠Leaf size ⢠Leaf color ⢠Leaf orientation ⢠Extensive root system Rocky Mountain Juniper Common Hackberry Gambel OakFremont barberry
- 38. Some species susceptible to secondary infestation by bark beetles and borers â˘Ash â˘Some birches â˘Elm â˘Fir â˘Locust â˘Pine â˘Spruce
- 39. Many native trees are not drought-tolerant: â˘Aspen, Quaking â˘Birch, River â˘Cottonwood, Fremont â˘Douglas-fir â˘Fir: Subalpine,White â˘Pine, Ponderosa â˘Pine,White â˘Willow Ponderosa pine in an urban area
- 40. Trees that do surprisingly well with less water (in zones 4 â 7) ⢠Baldcypress ⢠Coffeetree, Kentucky ⢠Corktree, Amur ⢠Cyprus, Leyland ⢠Ginkgo ⢠Goldenraintree ⢠Hackberry: Common, Douglas, Netleaf ⢠Hawthorn: Cockspur, Green, Lavalle, Washington ⢠Honeylocust ⢠Juniper, Rocky Mountain ⢠Maple: Amur, Sycamore,Tatarian, Trident ⢠Mulberry: Red, White ⢠Oak: Bur, Chinkapin, Gambel, Shumard,Turkey ⢠Osage-orange ⢠Pine: Bristlecone, Jeffrey, Limber, Mugo ⢠Sycamore, American ⢠Zelkova, Japanese
- 41. Contact: Heidi Kratsch University of Nevada Cooperative Extension Phone: 775-784-4848 Email: KratschH@unce.unr.edu Questions? This presentation was brought to you by the Nevada Extension IPM Program and funded by USDA-NIFA.