Why does deforestation increase the decomposition rate?

It is because deforestation will lead to numerous removal of vegetation. Then the soil erosion problem will be intensified. So, the soil fertility will decrease. Also, there are less vegetation for intercept of water.

So, more and more organisms suffer from drought. Some of them may even die due to lack of water.

Therefore, there are more dead bodies, so that the decomposers are activated and the decomposition rate will increase~~~