Explain howa small lake can become a forest?

Answer 1

Ponds and lakes typically become forests by silting up. The sediments of a river can become trapped in a shallow lake and eventually becomes higher than the water level or water table. This forst forms a meadow, and later the larger trees grow in. This is now occurring at Mirror Lake in Yosemite National Forest.

Lakes that dry up will usually not become forests because they lack groundwater, and there may be a concentration of alkali salts in the lake bed.

Answer 2

while the dead organisms dies, the body flows to the bottom of the lake. The lake decompose the body and leaves a segment. this process contains oxygen. so when the oxygen is take, the other living organisms in the lake dies without oxygen and sinks down to the bottom and performs the process again. new soil comes so plants grows. the lake slowly turns into a wetland, then marsh, then swamp, at last, a forest.