Topic 1: Soil Development

Introduction

In this topic you will examine how soils develop, and how they can be damaged by inappropriate management actions. Soils are critical to forests. They provide the rooting medium for trees, and to a certain extent determine the productivity of the forest. The development of soils is dependent on a range of factors, including the parent materials, the climate and time. In turn, the vegetation of forests is dependent on the soil, the climate, past disturbances and other factors. Understanding these critical relationships is an important aspect of sustainable forest management.

Under natural conditions, soils develop over time unless that development is disturbed by some external factor, such as a period of erosion following a natural disturbance. Forest operations that fail to respect the soil can also trigger soil degradation, as can land-use practices such as grazing livestock within forests. A more recent concern is that intensive plantation forestry, particularly fast-growing plantations, might exhaust the nutritional capacity of a soil, and this is also examined in this module.

Video Lectures

3.1.1 Soil formation: The parent materials

3.1.2 Soil formation

Resources

Textbook Reading:

• Chapter 6 of the course text:
  Innes, J., & Tikina, A. (Eds.). (2014). Sustainable forest management: From principles to practice. London: Earthscan Publications. ISBN: 1844077241

Further Reading and Viewing:

• Virtual Soil Science Learning Resources. (2011, September 1). The five factors of soil formation [Video file]. Retrieved from https://www.youtube.com/watch?v=bTzslvAD1Es The factors controlling the development of soil formation are provided in this video, filmed in a mountain environment in western North America.
• Virtual Soil Science Learning Resources. (2012, March 28). Virtual soil science learning resources – Introduction [Video file]. Retrieved from https://www.youtube.com/channel/UCS07a1P4LLh4oep941lxTKQ This video is part of a series developed for the Virtual Soil Science Learning Resources, which originated at the University of British Columbia (https://www.youtube.com/channel/UCS07a1P4LLh4oep941lxTKQ). You are encouraged to look at these videos as they provide an excellent introduction to soils, although the series is focused exclusively on Canada.
• Scharf, SCDNR Land, Water, and Conservation Division. (n.d.). Soil Composition and Formation. Retrieved from http://nerrs.noaa.gov/doc/siteprofile/acebasin/html/envicond/soil/slform.htm
  Understanding soils is best when placed in the context of a particular area. The Ashepoo-Combahee-Edisto (ACE) Basin of South Carolina has been described in detail, and this case study is recommended to establish both an understanding of soil processes (this topic) and biogeochemistry (next topic). The description of the soils of this area can be found at above web link.

Other sources:

• Binkley, D., & Fisher, R.F. (2013). Ecology and management of forest soils (4^th ed.). Chichester: Wiley-Blackwell. ISBN-10: 0470979461; ISBN-13: 978-0470979464
• Coleman, D.C., & Crossley, D.A. (1996). Fundamentals of soil ecology. San Diego, CA: Academic Press. ISBN 0-12-179725-2
• Lukac, M., & Godbold, D.L. (2011). Soil ecology in northern forests: A belowground view of a changing world. Cambridge: Cambridge University Press. ISBN: 9780521714211
• Pankhurst, C.E., Doube, B.M., & Gupta, V.V.S.R. (Eds.). (1997). Biological indicators of soil health. Wallingford: CAB International. ISBN 0851991580. Retrieved from http://www.isprambiente.gov.it/files/biodiversita/Pankhurst_1997_Biological_indicators.pdf

Self-test