Supportive
Biotic factors in the forest literally are supportive of one particular abiotic factor, the soil and rock bed. The soil in a forest, made up of dead and decaying animal and plant matter including the living organisms that break down and excrete this matter, protects the rocks from the weathering of elements and holds onto moisture. The root systems of plants and especially trees help hold the soil together.
Reciprocal
The heat and light of the sun is absorbed by the trees and plants in the forest biome, converting the light energy and combining with rainwater to convert into complex and specialized cells that provide nutrition for herbivores, including bacteria, insects and animals. The main byproduct of plant respiration is oxygen, which is a prerequisite for most terrestrial life to exist.
Regenerative
The production -> consumption -> decomposition cycle is supported by abiotic factors to perpetuate the biotic factors. Sunlight is the source of the photosynthetic effect, which is the genesis of the production cycle. Rain and other water flows sustain plants and trees with vital nutrients that aid in growth. Minerals in the soil, leeched from bedrock and distributed throughout the food chain are necessary for many animals to survive.
Symbiotic
Forests, sometimes called the planet's lungs, are thought to have been a key factor in generating the oxygen-rich environment that supports the many lifeforms on Earth. This development occurred due to volcanic activity spewing huge amounts of carbon dioxide into the atmosphere billions of years ago, causing the flourishing of photosynthetic, CO2 breathing, O2 exhaling plants that helped regulate the temperature and atmosphere of the planet Earth.