The Importance of Trees
“Trees are poems that the earth writes upon the sky.” ― Kahlil Gibran
“The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth.” — Charles Darwin
The Ecology of Trees
Trees are the longest living organisms on Earth. Today there are approximately 3 trillion trees standing with around 15 billion lost yearly due to deforestation. Humans have destroyed around 46% of forest cover on the planet. It can take hundreds to thousands of years for a healthy forest to evolve. But it can only take a short period of time, sometimes just days, to cut one down.
Trees are integral to the health of our planet. They provide nourishment and shelter to many creatures, including humans. Through photosynthesis, trees take in carbon dioxide and produce the oxygen and biomass we need to survive. Trees shade us from the heat, protect us from the rain and wind, conserve water, preserve soil, clean the air of pollutants and absorb carbon, helping to keep the world cooler.
Each tree is its own majestic ecosystem, a vast web of pollinators, seed dispersers, predators and prey. Large stands of trees are healthier together, attracting more species. When a forest or tree becomes isolated, the movement of plants and animals is compromised, often leading to a long-term decline in population.
The Sentience of Trees
Trees have evolved to protect other fellow trees, which in turn protects the whole forest.
How do they do this? Scientists now know what many indigenous groups have known for ages: trees are sophisticated, communal organisms that live in families connected by fungal networks that share water and nutrients. The oldest “grandmother” trees are critical for the health of forests. Their deep roots share nutrients and water with nearby struggling trees or shallow rooted seedlings. Amazingly, cutting down mother trees can greatly affect and compromise weaker neighboring trees.
Trees also communicate with each other through the underground web and the air via scented pheromone signals. Distress signals related to drought, disease, or insect attacks are sent by trees to their neighbors to warn them of an imminent intrusion. An imperiled tree can alter its behavior and, in some cases, release toxic chemicals to stop or deter the attack, as is the case with the Sub-Saharan African Acacia Tree. When giraffes eat their leaves, they will warn one another and collectively release tannings into their leaves, which can sicken and even kill animals.
The Culture of Trees
No story is as ancient and universal as the tree of life. Since time immemorial, trees have shaped the way people see their society and the physical world.
In Nordic myth, a great tree called Yggdrasil connects the nine worlds of the universe. In Iroquois legend, a pregnant woman creates the world on a turtle’s back by planting a heavenly tree. In Abrahamic religions, a tree of eternal life grows in the Garden of Eden. In his theory of evolution, Darwin conveys the interconnection of all organisms by drawing a tree of life.
Trees in the Amazon
The largest rainforest on earth, the Amazon contains around 390 billion trees, three times more than stars in the Milky Way.
Incredibly, these trees produce about half of the Amazon’s rainfall. Trees in the Amazon and elsewhere act as giant pumps, sucking water up through their roots and releasing it through leaves, a process known as transpiration. One tree can lift approximately 100 gallons of water out of the ground and release it into the air each day! Every day, trees in the Amazon release 22 billion tons of moisture, seeding the clouds with rain.
Forest giants like the Brazil nut tree or the shihuahuaco also play a crucial role in carbon dioxide absorption. By itself, a mature shihuahuaco sequesters almost one third of an average hectare of rainforest. As a whole, the Amazon rainforest absorbs about 2 billion tons of CO2 per year, about 5% of global annual emissions.
From the Blog: Trees
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