Trees and Home Construction

Minimizing the impact of construction activity on trees

Bulletin 870-99

Tree Environment and Construction Activities

A tree's environment is the complex of soil, climate (microclimate), and topography (physiography). Other plants and animals living in the immediate area or acting upon the tree are part of the tree's environment as well (Table 2).

The set of environmental characteristics describing the location where a tree grows is called its "site." All trees, for example, grow well on sites that are relatively flat to gently sloping and that contain deep, moist, well-drained, nutrient-rich soils in a climate suitable for that species. However, tree species differ in their ability to grow in (tolerate) specific site situations that differ from the ideal. Red maple and Scotch pine are tolerant of wide variations in soil drainage and are found growing well on sites with soils ranging from quite dry to fairly wet. By contrast, yellow poplar and black walnut are far less tolerant of variations in soil drainage and are commonly found growing to mature trees only on deep, well-drained soils.

Some tree species such as American beech and white ash are quite intolerant of changes in their environment once they become established. Removing the surrounding trees from an American beech or a white ash tree that grew as part of a natural stand often leads to their eventual death. By contrast, American elm and most of the oaks will tolerate such changes in their environment, although they will go through an adjustment period. The Appendix lists many common Ohio trees, ranks their tolerance to construction activities, and provides additional comments on their adaptive abilities.

When evaluating site conditions where a tree is growing or is to be planted, it is important to look at the specific site. In some locations, site characteristics are quite uniform over relatively large areas. In other locations, site conditions vary dramatically within a few feet.

When evaluating the potential impact of construction activities on a tree, it is important to understand that trees, like humans, are not just dead or alive, but have varying degrees of health. One can envision a continuum from optimum health to death. Over time, depending on the tree's condition, it moves back and fourth along the continuum. How a plant responds to an unfavorable change in its environment often depends on its health at the time. A healthy tree may tolerate changes that would kill a less healthy tree.

Construction activities that commonly damage or kill desirable trees directly, or secondarily by affecting their environment, include using equipment that can damage trees or compact the soil, regrading the land surface, excavating and trenching, paving and other surfacing, storing and disposing of waste materials, and the removal of existing vegetation (Table 3). Column 2 of Table 3 outlines the more common direct impacts of these construction activities on trees or their environment. Column 3 presents the possible final effects of the assault on the trees.

Notice that the possible outcomes of construction damages to trees and their environment are the same for all of the construction activities - death of all or part of the tree, a reduction in attractiveness, a decrease in the tree's health and vigor, and an increase in the tree's susceptibility to insect, disease, and environmental stresses. However, each construction activity results in specific damages to the trees or their environment to produce these outcomes. These damages are different and must be understood if they are to be prevented or minimized.