Deforestation and Soil Erosion
Deforestation can not only wreak havoc for the environment in terms of contributing to global warming and its subsequent effect on the health of people (See Article: Deforestation and its Effects upon Health), but it can also lead to another problem, that of soil erosion.
Trees have extensive root systems which travel underground and seek out water and nutrients for the plant to use. These root systems also bind the soil by preventing it from moving easily and being washed away by rainwater or blown away in the wind. When deforestation cuts down and removes these trees, their root systems underground wither and decay and no longer bind the soil together. This makes it much more susceptible to erosion which can damage buildings on the land as their foundations shift, and create mudslides during heavy rain. Either of these scenarios can place the health and safety of those affected in jeopardy and result in injuries or loss of life.
Deforestation and soil erosion can also result in the loss of essential minerals needed by plants. So if the area was cleared of trees in order to provide land for crowing crops, over time this land may no longer prove suitable for growing crops of sufficient quality or quantities. Further wooded areas may then need to cleared to find fertile ground, which further exacerbates the problem.