ISSUE:

Flooding has increased in the valley where I live since timber companies began to harvest the trees. Is this a cause and effect relationship?

FACTS:

U.S. Government and University research personnel have repeatedly shown that the practice of cutting trees, no matter how many, in managing forest lands, does not cause flooding.

A flood occurs anytime that surface water flow is greater than stream capacity. This will occur when an excessive amount of rain falls in a short period of time (e.g., several inches in 3-4 hours).

Forest land has an exceptional ability to absorb rainfall. As rain falls to the ground, the water flows underground, through soil pores and channels that are created by dying and decaying roots, to the stream.

Studies conducted on West Virginia forest lands have shown that water can infiltrate forest soils at a rate of 19 inches per hour to as much as 260 inches per hour.

Rainfall does not infiltrate road surfaces as readily as it does the undisturbed forest floor. Foresters construct forest roads to ensure that water is quickly directed off of the road surface and back into the undisturbed forest soil.

On a steep slope, with roads at various levels on the hillside, the same water may be infiltrated four to five times as it descends the slope.

Trees use water from the soil and pass it into the air as vapor through a process called evapotranspiration. This occurs only during spring and summer when green plants, including trees, are growing.

For a short time after trees are harvested, moisture that would have entered the atmosphere as water vapor ends up in the stream system. The increase is both small and brief, lasting only a few years, until the natural re-growth of trees, shrubs and grasses begins, once again, to take up the additional moisture.