Most of the plants in the grasslands are grasses and that doesn’t require much water but trees in forests need the right amount of water to nourish and grow. Rainfall in grasslands is more but has lesser precipitation as compared to the forests. The vegetation in grasslands is mainly grass with a small amount of trees of the heights of medium or small and non woody plants but forests have all kinds of plants and trees. Grasslands happen in areas which are too dry for forests. Look for the study material of vedantu.