Succession

You are currently studying the change in ecosystems, succession. Examples of succession are all around us; fields turning to wood areas, ponds filling in, forest fires and even volcanic eruptions. A global issue is desertification. Check the resources and let me know what you think, is desertification a natural part of succession or is it simply a result of depleting resources and misuse of our lands?

http://pubs.usgs.gov/gip/deserts/desertification/
http://www.greenfacts.org/en/desertification/
http://www.unccd.int/