Afew years after a devastating forest fire, pioneer trees become established. after another 50 years, those trees are replaced by trees of different species. this change in the composition of the plant community is the result of abiotic changes brought about by:

Abiotic factors composed of water, light, temperature and air etc. due to fire's this primary succession was completely destroyed. Their remaining organic bodies were decomposed in soil texture.

In order to establish secondary succession there is need of water and light, because water help in translocation of food and nutrients in plants while light is important for photosynthesis.

Photosynthesis need three major components. these are H₂O, CO₂ and light, all these components are abiotic part of ecosystem. However, when secondary succession occurs, then light play a key role in changing the composition of plant community. The best example is the difference in height of plants of different community.

The answer is reflection.