Do you remember the hydrological cycle that you learned about in school? Rain and snow fall from the sky. Tree leaves and branches slow the fall of rain. In the spring, snow slowly melts, the melt slowed because trees shade the snow and cool the air. Some of the rain and melted snow infiltrate deep into the ground, aided by the presence of tree roots, to become part of the ground water that flows downhill, slowed by tree roots. …Transpiration from tree leaves, and evaporation from the land, lakes and ocean return the water to the sky and the cycle starts over again. But wait. Remove a major part of the trees from the cycle and what happens? Rain and snow land directly on the ground. Less rain infiltrates the soil and, with no tree roots, what ground water there is flows downhill more quickly.