Forests are moderators, they absorb water excess in rainy days, reducing floods. Also, trees reales the water slowly to rivers, so that in drought seasons they provide water. Forest maintain the soil humid, so organic material is always there because of that, and this organic material feeds trees and decomposing organisms.
So all this will be affected with the forest cut down.
Plants, however, are rooted in place and must respond to the surrounding environmental factors. Plants have sophisticated systems to detect and respond to light, gravity, temperature, and physical touch.