DENDROLOGY

Detailed explanation-1: -The first species to colonize bare rock are usually lichens. In primary succession, they are thus the pioneer organisms . Before they can colonize an environment, many organisms need soil. Acids that break down the rock and start the process of soil formation are secreted by lichens that colonize bare rock.

Detailed explanation-2: -Primary Succession When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil.

Detailed explanation-3: -Lichens contribute to the Earth’s biological diversity. There are more than 5, 500 species of lichens and lichen-dependent fungi in North America. Lichen diversity is promoted by good air quality, habitat continuity, availability of preferred substrates, and favorable climate.