Forestry trees play a significant role in the Earth’s biosphere, accounting for a remarkable 75% of the gross primary productivity. Furthermore, they constitute approximately 80% of the planet’s plant biomass, showcasing their substantial contribution to global vegetation. In terms of sheer biomass, the world’s forests hold approximately 606 gigatonnes of living biomass, encompassing both above-ground and below-ground components, while an additional 59 gigatonnes exist in the form of dead wood. However, it is important to note that the total biomass of the Earth has been gradually declining since 1990 due to human activities and their impact on natural ecosystems.

Forest ecosystems can be found in diverse regions capable of sustaining tree growth, ranging from lowland areas to altitudes reaching up to the tree line. Nevertheless, certain factors such as frequent natural fires or other disturbances, as well as human-induced alterations, can limit the presence of forests in specific regions. Forests exhibit a wide range of species diversity, varying from instances where numerous tree species coexist within a relatively small area, such as in tropical rainforests and temperate deciduous forests, to scenarios where fewer species dominate vast expanses, as seen in taiga and arid montane coniferous forests. These ecosystems harbor a multitude of animal and plant species, with high biomass per unit area compared to other types of vegetation communities.

When examining the structure of a forest, it becomes apparent that it consists of several distinct layers. Common to all forest types are the forest floor, understory, and canopy layers. In tropical rainforests, an additional layer known as the emergent layer exists, characterized by towering trees that surpass the general canopy. Each layer of the forest supports a unique assemblage of plants and animals, their distribution and abundance influenced by factors such as sunlight availability, moisture levels, and food resources.

Understanding the intricate layers and complexity of forest ecosystems underscores their importance and highlights the diverse array of life they sustain. Forests serve as vital habitats for countless organisms, contribute significantly to the planet’s biomass and primary productivity, and play a crucial role in maintaining the overall health and balance of the Earth’s biosphere.