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  • 1. Urban Forestry Plant: Elm Tree Urban Forestry
  • 2. Urban forestry
    • The care and management of urban forests, (tree populations in urban settings) for the purpose of improving the urban environment
    • Most urban trees are non-native and selected for particular aesthetic qualities
  • 3. Elm Tree
    • The American or White elm is the largest species of elm.  Usually over 100ft high.
    • Due to its graceful form and size, it was an extremely popular urban tree before the spread of Dutch elm disease. 
    • Once found mostly in eastern North America, remaining populations of mature American elms are concentrated in the American Midwest and Canadian Prairies.   
  • 4. Dutch Elm Disease
    • Dutch elm disease (or DED) is caused by a fungus. After the disease is contracted, spores rapidly reproduce and spread toxins throughout the tree.
    • Fungus is spread by the elm beetle
    • The fungus blocks the vascular system of the tree preventing water and minerals from reaching the branches and leaves.
    • The leaves wilt and eventually the tree dies.
    • In Washington, DC, the disease has killed over 25,000 elms since 1950 with only 8,200 elms presently remaining on city streets.
  • 5. Combating Elm Disease
    • Because Elms are such an important urban species, much $ and effort goes into keeping them alive
    • Fungicides are injected into the root flare
    • Disease resistant elms are often planted as replacement trees. Washington DC tries to maintain the annual DED loss at below 2% of the remaining elm population.
  • 6. Anthracnose
    • Fungus that attacks hardwood shade trees
    • Kills the buds, damages the leaves and causes premature leaf drop
    • Over time weakens the tree and makes it susceptible to borers and other pest damage
    • Fungus overwinters in leaves on the ground.
    • Remove all fallen leaves and dispose of them
    • Treat by using fungicides
    • Tree on right was treated
  • 7. Emerald Ash Borer
    • Asian Beetle that bores under the bark of ash trees & lays eggs.
    • The larva hatch and eat the cambium layer of the tree
    • Has killed millions of trees around the great lakes and is moving south into WV, PA, & VA.
    • Treatment is expensive and requires trained applicators.
  • 8. Cankers
    • Caused by fungus penetration of the bark
    • Treatment – pruning below affected area
    • Sterilize tools afterwards so as not to spread the disease.
  • 9. Rust Diseases
    • Cedar Apple Rust is biggest problem
    • Affects crab apple trees and junipers
    • Lives part of life cycle on each tree
    • Destroy galls before April when they spread by spores
    • Don’t grow cedars and apples close together
    • Select resistant plants
  • 10. Galls
    • Growths that form on the leaves or stems of plants
    • Can be caused by insects or viruses
    • Rarely affect the overall health of a tree
    • No treatment is required