Objectives

The objective of this module is to deal with two important aspects of the natural environment of forests. By the time you have completed this module, you will have a good understanding of some of the physical and biological determinants of forests, particularly if you have also completed Module II.

Relevant Components

• The development of soils, including the weathering of rocks
• The description and classification of soils
• Biogeochemical cycles and soil fertility
• Soil as a resource
• Hydrological functions of trees and forests
• Hillslope hydrology in forested landscapes
• Watershed hydrology in forested landscapes
• Effects of forest management on water quantity and quality
• Geomorphological processes and forests

After taking this module, you should be able to:

1. Describe the development of soils, including the processes leading to the formation and loss of soils
   1. Explain how soils are formed
   2. Explain the processes leading to the degradation and loss of soils
   3. Explain how forest management can maintain soils

2. Explain how soils are classified and how soil fertility varies among soil types
   1. Describe the major soil types and their characteristics
   2. Explain what defines soil fertility
   3. Describe the processes by which soil fertility can be enhanced or degraded.

3. Describe the hydrological functions of forests
   1. Describe the hydrological cycle and how it can be affected by forest cover
   2. Explain the different ways that water can flow down a hillslope
   3. Explain the possible impacts of forest cover removal on hillslope hydrology

4. Explain how forest management can affect water supply
   1. Explain the concept of streamflow regimes
   2. Explain how changes in forest cover can affect the quantity and quality of water draining from an area
   3. Explain how forests affect geomorphological processes
5. Identify some potential geomorphic risks
   1. Identify where landslides might happen
   2. Identify some of the signs of past debris flow and debris torrent activity
   3. Identify where snow avalanches are likely