However, it is not limited to construction site activities. Native and introduced trees are easily disturbed by a number of changes in their surroundings. Anything that alters a tree's natural site can be considered site disturbance. Compaction and grade changes beneath or within close proximity to trees are major types of site disturbance. Minor disturbances, such as suddenly exposing trees to direct sunlight by removing neighboring trees, mowing, fertilizing, mulching, and shallow cultivation, also have been observed to cause trees to decline and die.
Oaks are often the most commonly affected deciduous native species for Oklahoma.
Pine trees and other conifers, native or introduced, also are highly susceptible to the activities described above. This fact sheet will focus on site disturbances that involve soil. Early symptoms of decline include leaves becoming smaller in size, early fall coloration, premature defoliation, and dieback of twigs and progressively larger branches beginning in the upper crown and moving downward. Sucker growth may become more prolific on the trunk and larger branches. Decline usually progresses from the top to the bottom of the tree.