Presentation on theme: "Trees and Forests Affect/Effect Science 6. How Do Trees Affect a Forest? They break the wind and with less air movement, there is less drying. They shade."— Presentation transcript:
How Do Trees Affect a Forest? They break the wind and with less air movement, there is less drying. They shade the ground from the sun thereby lowering air temperature; forests tend to be cool, humid places and the soil is moist there. Forest soil is also very rich in nutrient because of all the leaves, branches, and stems which decompose into humus.
How Do Other Living Organisms Affect the Trees in a Forest? Herbivores such as deer and caterpillars eat leaves; large populations of tent caterpillars can have a devastating effect on popular trees in Alberta, wiping out all the leaves in stands of such trees in a short time; these trees grow secondary leaves which are fewer in number and smaller in size; the trees will not survive to successive summers of tent caterpillars.
How Do Other Living Organisms Affect the Trees in a Forest? Coniferous trees are also affected by certain insects; the spruce bud worm kills the growing shoots on spruce trees. Birds can hurt trees; yellow-bellied sapsuckers peck rows of shallow holes around the trunk of trees to draw out the sap; often the birds will make a series of holes in one tree and drain enough sap to kill sections of the tree. Blight, which is a kind of fungus, can get on leaves and into the wood of tree stems, gradually destroying leaves or wood and eventually killing the tree.