All forests started at some point as barren rock before a series of lifeforms changed the landscape. The first organisms to inhabit the rocks are lichens, a symbiotic relationship between algae and bacteria that perform photosynthesis together while anchoring themselves to rocks.
Once enough lichens die, they will leave behind a thin amount of soil which small plants, like mosses, can root themselves into, pull nutrients from and begin their photosynthesis.
Eventually, lichens and mosses will cause cracks in rocks where enough soil will build up for ferns to take hold. These primordial plants grow much taller than mosses and can grow back each year.
After lichens, mosses, and ferns have populated an area for long enough, and depending on the amount of local rainfall and minerals in the rocks, a forest can begin to grow first with small bushes and then small trees which can eventually reach their true potential heights.
The bottom of the forest is called the “forest floor” and is typically covered with decaying leaves and sometimes grasses. It is home to most insects and is the starting point for all vegetation.
The short vegetation that is comfortable living under the shade of the trees is known as the understory. Here is where you will find most of the things that make navigation through the biome difficult.
Trees offer a pathway for many small animals to reach the upper layers of the forest.
The photosynthesis capital of the forest, out of reach to most humans, is the canopy. It is home to most birds and some tree climbing rodents.
Although humans usually explore the woods in the day, it can be quite active at night as well.