Forests are the largest terrestrial ecosystems on Earth, covering significant areas worldwide, with 45 percent located in tropical latitudes. They contribute to 75% of the Earth’s gross primary production and hold 80% of its plant biomass, with net production estimated at 21.9 gigatonnes for tropical forests, 8.1 gigatonnes for temperate forests, and 2.6 gigatonnes for boreal forests.
Forests create distinct biomes influenced by latitude and precipitation, including boreal, tropical moist, dry, and temperate forests. They typically thrive in high rainfall areas, while drier conditions lead to a transition to savanna. This transition can occur quickly when tree coverage falls below 40 to 45 percent.
Research in the Amazon shows that trees can affect local rainfall patterns, potentially starting the wet season earlier than normal. However, deforestation and climate change threaten this balance, risking a shift from forest to savanna.
