What Erosion Is Caused by Forest Harvesting?

Vegetation

• It's not just the dead vegetation that falls to the forest floor that secures the top layer of soil; living plants secure the soil, too. Small plants' root systems weave the forest floor together like a fabric with overlapping strands of fiber. Larger plants' roots penetrate even deeper into the soil, securing it from mudslides. Trees and large plants are wind blocks to soil surfaces within the perimeter of forested areas. If logging removes the wind screen function, then it will cause an increase in erosion.

Soil Types

• Not all terrain and soil types are equally vulnerable to erosion from forest harvesting. Consider the soil you might build a house on. If it's pure, loamy soil with lots of clay, then it will be easy to excavate -- for you, or for wind and rain. If it's full of rocks and gritty sand, which tend to interlock and make excavation very difficult, then the soil and rain will have a harder time eroding it.

Harvest Practices

• Clear-cutting has been the most criticized logging practice. Clear-cutting is the process of removing every single tree on a track of land, and often most of the surrounding foliage. Proponents have argued that well-managed clear-cutting has economic benefits because it reduces the cost of harvesting. Regardless of the economic benefits, clear-cutting or anything resembling clear-cutting causes a significant and sometimes massive increase in erosion. Selective logging can reduce the potential for erosion by managing the likelihood of wildfires, which can, themselves, result in erosion.

Erosion Sediment

• Erosion is problematic in itself. However, the sediment erosion creates can do more harm than the erosion itself. Sediment is essentially soil and sand that gets redistributed by water. It can wreak havoc on fish populations. When the soil emulsifies in water, it becomes murky. Fish cannot see, and some fish may not be able to survive in murky water. A contiguous band of untouched forest must be left on either side of all waterways to act as a sediment filter, protecting the water quality.