Answer:
Accumulation of waste products.
Step-by-step explanation:
The accumulation of the waste products under the tree is the limit factors that affects the growth of the grass. The accumulation of the waste products proposes that the molecules are damaged by the oxidation process and they are accumulated on the soil.
The leaves of the beech tree shades and falls on the ground and it decays there forming a rich soil. It covers the grassland nearby. Also the beech tree branches out making a small canopy over the grassland. So sunlight is prevent to reach the ground. This limits the growth of the meadows and thus the population of the meadow grass is seen to decline under the tree.