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Woodlots and Water Quality

Posted: June 11, 2012

Did you know that approximately 66% of Pennsylvania is still covered by forests? So much forested cover means that many land owners and farmers have small or even sizable woodlots on their property.
Forested streams provide healthy stream habitat for wildlife. Photo: Gary Wilson, NRCS

Forested streams provide healthy stream habitat for wildlife. Photo: Gary Wilson, NRCS

Terms such as forest or woodlot have very broad definitions. They can include anything from a small stand of mature oaks to sprawling acres of conifers to a few acres of abandoned pasture that is converting into an early succession forest filled with saplings and underbrush. These woodlots are valuable uses of land just as pastures or crop fields are, and a combination of the three is even better! If managed properly, woodlots can improve the quality of water in nearby streams and decrease impacts on the land. They can also provide a valuable source of income from your property and even increase the wildlife you see!

One ecologically valuable type of wooded area borders a stream or standing body of water. These areas act as a streamside buffer by limiting the amount of polluted runoff that reaches a stream by slowing the runoff down, allowing the soil to absorb water and naturally filter out pollutants. Wooded areas located between streams and pastures or fields can limit the amount of nutrients from manure and fertilizers that make it into the waterway. This alone is a huge benefit and has a direct, positive impact on the water quality. Stricter regulations for protecting water quality have recently been established that require buffers such as these with widths of at least 100 feet to border streams throughout properties, although even a narrower buffer will have benefits. Some cost-share programs are available to assist in implementing these Best Management Practices to establish forested riparian buffers through the Conservation Reserve Enhancement Program (CREP).

Woodlots can also capture and hold excess water from rainstorms. The soils in forests are very porous because of a high organic content from decomposing leaf litter. Since most trees have deep root systems, much more water can be collected by the trees as it percolates into the ground in a forest than the amount of water collected by crops with shorter root systems in a field. Another benefit of these long root systems is that they hold the soil in place and stabilize the stream banks which prevent erosion and sedimentation from occurring. The leaves on the trees slow hard driving rains down, preventing the rain drops from eroding the soil. The shade created by the leaves of mature trees also helps to cool the water in the streams which increases the dissolved oxygen levels making a healthier environment for fish and other aquatic organisms. Dead limbs and other debris also create fish habitat and nourish insects in the streams. Some of the highest quality trout streams in Pennsylvania are found running through forests. This can make casting a fly line a challenge, but it allows for healthier fish populations.

A final benefit of the forests and woodlots on your property is that they offer a unique habitat for animals. All animals- birds, mammals and even reptiles and amphibians- benefit from the diverse species of trees and other types of vegetation that are common to Pennsylvania’s forests. Smaller woodlots may serve a major purpose of connecting larger patches of forests together and creating forested corridors. This prevents habitat fragmentation by allowing safe areas through which wildlife travels. By managing your woodlots properly, you can help to ensure that quality habitat remains for the wildlife, as well as preventing or limiting unwanted or unexpected interactions between wildlife and humans.

The best way to manage a woodlot on your property is to create a Forest Stewardship Management Plan. In these plans, the number and types of trees are accounted for and evaluated for health and monetary value if harvested. The management plan offers suggestions to improve your woodlot all the while taking into consideration actions that can prevent erosion and sedimentation as well as other ways to improve water quality. By following these plans, you can ensure that you have a sustainable, healthy, potentially profitable woodlot while limiting your impact on other natural resources.

Here are some resources for information on environmental tree benefits, Forest Stewardship or identifying the trees you have.