27 Facts About Trees + Forests
Meaghan Weeden | December 7, 2021 | 7 min read
27 facts fresh from the forest
Forests are complex living worlds composed of intertwined layers of life and stretching across massive, diverse landscapes, blanketing our planet with swaths of green. They’re also nature’s great providers, pulling carbon from the atmosphere and sequestering it via photosynthesis, filtering and absorbing air pollutants, releasing clean oxygen for us to breathe, providing habitat and food for wildlife, stabilizing soils, growing food and medicine, protecting us from harmful UV rays, acting as natural air conditioners, securing our freshwater supplies, and amongst many other benefits!
As such, the importance of trees and forests in our lives cannot be overstated — from cooling our climate to delivering water deep inland, their roots touch everything. From ancient times to today, humans have depended on trees and forests for food, shade, and shelter. As a result, we all share a deep, natural connection to trees.
Ready to learn some specific reasons why trees are awesome? Here are 27 interesting facts about forests and the impacts of deforestation around the world:
That’s right: rainforest plants are used in some of the world’s most important, life-saving medicines. More discoveries are made every year, but many rely on access to healthy forests.
2. 1/4 of all modern medicines come from tropical forest plants, including 2/3 of all cancer-fighting drugs
As well as saving people’s lives, these medicinal plants are worth a staggering US$108 billion a year.
When it rains, they absorb stormwater into their roots and leaves, reducing erosion and flooding. Later, their leaves release it back into the air through transpiration, producing a powerful cooling effect that affects local microclimates.
Trees reduce the need for carbon emissions from heating and cooling by helping to regulate air temperature. Well placed trees can reduce air conditioning costs by 30% and heating costs by as much as 50%.
The total forest area is 4.06 billion hectares, and approximately 1/2 of that forest area is relatively intact. Around 1/3 of that is primary forest, or forests with no visible indications of human activities and ecological processes that are not significantly disturbed.
6. Tropical rainforests cover less than 3% of Earth's area, yet they are home to more 1/2 of our planet's terrestrial animal species
And it’s estimated that one hectare (2.47 acres) can contain over 750 types of trees and 1500 species of higher plants.
Trees can absorb an average of 22 pounds of CO2 per year for the first 20 years of life. A typical passenger vehicle emits about 4.6 metric tons of carbon dioxide per year — so it stands to reason that we would need to plant 460 trees to offset average transportation impact.
Trees release oxygen when they use solar energy to create glucose from carbon dioxide and water. They use some of that oxygen when they break some of the glucose back down to power their metabolisms. But on average, they produce more oxygen than they use up — which is great for us!
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10. Adding a single tree to an open pasture can increase bird biodiversity from almost zero species to as high as 80
As one tree is joined by others to form a stand, biodiversity will gradually grow. Once the stand approaches 100% forest cover, endangered and at-risk species like large predators and deep forest birds begin to appear, building species richness.
11. Although the planet lost more than 1.33 million square kilometers between 1982 and 2016 mostly in the tropics, we gained about 3.5 million square kilometers of tree cover elsewhere (mostly in the northern hemisphere)
But it comes with a catch. These new trees, many growing in tree plantations, are not a perfect replacement for rich and diverse primary forests.
12. The total forest area globally is 4.06 billion hectares, or approximately 5,000m2 (or 50 x 100m) per person
But forests are not equally distributed around the globe. More than 1/2 of the world’s forests are found in only 5 countries (the Russian Federation, Brazil, Canada, the United States of America and China) and 2/3 (66 percent) of forests are found in 10 countries.
Primary forests, especially in the tropics and savannahs where deforestation is particularly intense, are old growth forests teeming with biodiversity, which is lost when these areas are cleared.
14. Agricultural expansion continues to be the main driver of deforestation and forest degradation and the associated loss of forest biodiversity
Large-scale commercial agriculture (primarily cattle ranching and cultivation of soybean and oil palm) accounted for 40% of tropical deforestation between 2000 and 2010, and local subsistence agriculture for another 33%.
This is down from 16 million hectares per year in the 1990s. And while this is good news, we’re still losing forests at a blistering rate — and with evidence that climate change is gathering momentum across the globe, we can’t afford to keep losing them.
The majority of tree species are angiosperms with enclosed seeds and broad leaves that usually change color and die every fall. They include oaks, maples and dogwoods and are deciduous. Gymnosperm trees, or those with unenclosed seeds, include species like pine, cedar, spruce and fir and are usually evergreen.
These families are, in order of magnitude, Leguminosae, Rubiaceae, Myrtaceae, Lauraceae, Euphorbiaceae, Malvaceae, Melasomataceae, Annonaceae, Arecaceae and Sapotaceae.
This means that they are specific to only one area. Endemic tree species are particularly threatened by deforestation, because if they are completely wiped out from an area and do not exist anywhere else, they’re likely to become extinct.
19. The colonization of land by plants between 425 and 600 million years ago — and the eventual spread of forests — helped create a breathable atmosphere...
with enough oxygen to support humans and the other oxygen-dependent life forms we share the planet with.
20. 1.6 billion people depend on forest resources for their livelihoods and most of them (1.2 billion) use trees on farms to generate food and cash
For those living in poverty, trees provide an important safety net if crops fail or diseases sweep the land, preventing heads of households from working.
21. An estimated 880 million people spend part of their time collecting fuelwood or producing charcoal
And in many countries in the developing world, people draw on fuelwood to meet as much as 90% of their energy requirements. As you might imagine, this contributes to deforestation, and is part of why it’s so important to include local communities in reforestation projects.
22. Areas managed by indigenous peoples (approximately 28% of the world’s land surface) include some of the most ecologically intact forests and many hotspots of biodiversity
That’s because indigenous peoples hold to their traditional ways of life and draw on ancestral knowledge to tread softly in the natural world.
23. Globally, 18% of the world’s forest area, or more than 700 million hectares, fall within legally established protected areas such as national parks, conservation areas and game reserves
In a recent study, it was found that people are paying an estimated 8 billion visits a year to these areas — greater than the total global population.
24. The largest share of forest in protected areas is found in South America (31%) and the lowest in Europe (5%)
This is in part due to historically heavy settlement in Europe, logging, and agriculture, as well as less total land area.
25. Tropical tree cover loss is now causing more emissions every year than 85 million cars would over their entire lifetime
If tropical deforestation were a country, it would rank third in carbon dioxide-equivalent emissions, only behind China and the United States of America. In fact, tropical forests are net carbon emitters due to deforestation.
26. The Amazon contributes 20% of the oxygen produced on land via photosynthesis. In contrast, phytoplankton produce a staggering 70% of Earth’s oxygen
For this reason, it may make more sense to call the Amazon Earth’s air conditioner, rather than its lungs.
Crucially, a majority of this carbon resides in forest soils, anchored by networks of symbiotic roots, fungi and microbes. Because of this, forests are typically considered carbon sinks, or places that absorb more carbon than the release.