ROOT CONDITION
Roots function both to absorb water and elements and to anchor trees in the
soil. If the physiological functioning of absorbing roots is impaired, such as
by flooding or root disease, tree vitality and health will be affected. If the
mechanical strength of woody roots is reduced by wood decay or serving,
wind-throw will be more likely. Windfirmness is influenced also by soil
moisture and depth, with trees on wet or shallow soils being more prone to
uprooting
Above-ground clues to poor root condition include thin crowns with dwarfted,
off-color or yellow foliage, reduced height or diameter growth, soil compaction
or erosion, construction activities resulting in severed or wounded roots and
soil fill around trees, discolored or resin-soaked wood at the root collar, and
fruiting bodies of root rot fungi growing at or near the base of the trees.
Most mushrooms growing under trees are not associated with root disease, but
generally are beneficial fungi or saprophytes growing on dead organic matter in
the litter or soil. Familiarity with the fruiting bodies of the common root
disease fungi in the northeastern U.S. is useful during tree hazard inspections
(Figure 8a-e). These fungi also often decay wood in the lower trunk of infected
trees. |
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Figure 8 - Fruiting bodies of common
root disease and butt rot fungi: a. Honey mushrooms (Armillaria spp.) occur on
hardwoods and conifers. |
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Figure 8 - Fruiting bodies of common
root disease and butt rot fungi: b. Annosus root rot conks (Heterobasidion
annosum) occur on conifers, especially pines. |
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Figure 8 - Fruiting bodies of common
root disease and butt rot fungi: e. c. Velvet top conks (Phaeolus schweinitzii)
occur on conifers, especially pines and spruces. |
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Figure 8 - Fruiting bodies of common
root disease and butt rot fungi: d. Ganoderma root rot conks (Ganoderma
lucidum) occur on hardwoods. |
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Figure 8 - Fruiting bodies of common
root disease and butt rot fungi: e. Sulphur fungus (Laetioporus sulphureus)
occurs on hardwoods (especially oak) and conifers. |
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