what is the effect of forest vegetation on soil properties?

Question

how the trees influenced on the physical ,chemical,biological properties of soil which is persent in the forest

Answer 1

That's a topic to write on forever.
First of all it depends on the kind of trees, how deep they root. Anyways - their leaves or needles and the trees when they die create a layer of organic material which stores humidity. So the capability of dealing with water is greatly improved, water stays longer in the ground. But also some trees go deep and get water from deep under the earth. Then in other areas trees filter water from the fog (Redwoods) and therefore keep the area moist.
they change the pH value in the soil, evergreen forests I believe create a slightly more acidic ground than leafy trees.
And then there is the alder - which also has nitrogen bacteria at their roots. Which is really good for other plants to grow in the same spot.
A nice thick forest keeps the land together so it will not slide away just after a few rainfalls. Erosion is greatly reduced. You can actually see in areas where they did clear cut if this is close to a river which had salmon before that the salmon will be gone. Because those salmon need gravel for their spawning, but with trees gone the land slides away and soil is flushed into the river and the salmon can't spawn.

Answer 2

Will just add two things The death and decay of trees adds chemicals to the soil. Carbon Nitrogen and oxygen come to mind but sure there are more. Before this area got so technical, remember being told how forest provide shelter for animals birds and insects that help plants polleniate.

Answer 3

The forest vegetation helps to retain the water table at shallow levels therby keeps the soil moist. The roots of the trees also helps is bonding the soil and thereby prevents its erosion.