Unit 2 - The Environmental Importance of  Forests


Lesson 7: Forests and the Soil

The forests are important to the quality of the soil:


As fallen leaves, woody debris, and dead organisms (both plants and animals) are slowly broken down by decomposers, the nutrients contained in this decaying organic matter are absorbed by the soil. Nutrients will then be used again.
Trees store harmful pollutants or convert the pollutant into less harmful forms.
The roots of trees, shrubs and plants hold the soil firmly in place, thus protecting against erosion. Also, trees provide shade and break the wind, which in turn reduces evaporation. Reduced levels of evaporation lead to moister soil, which is less subject to wind erosion.



The types and number of trees and other vegetation, in the forest, can also be an indicator of soil moisture.




Black Poplar trees grow in soft, wet soil.


To prevent soil damage, timber harvest is mostly conducted on frozen soils; if harvesting in summer and fall, it is conducted during dry weather only.
As you have read, the forests play an important part in helping the soil, but the reverse is also true.  The forest soils play an important role in tree growth; they provide:

  • for the storage and transportation of nutrients and water
  •  air space for the tree roots to breathe
  • the foundation to hold a tree in place

For the reasons mentioned in this lesson, protecting the soils during forest management activities is crucial to a soil's ability to provide the necessary components of tree growth.