Tree Canopies: Are These the Most Overlooked Ecosystems on Earth?

Intro

Imagine yourself coming across a tall and majestic tree on a walk — either in a forest, park or garden. What is the first thing you do? You look up the tree right? And you’ll most probably be greeted by quite a lovely sight — the straight and brown tree trunk giving way to twisting branches and dancing leaves. What you’ll be looking at is a tree canopy —  the uppermost parts of a tree that contain its branches, leaves and twigs.

When many trees grow together, like in a forest, their branches come close to each other, forming a giant leafy umbrella over our heads. For many years we didn’t pay much attention to this far-away umbrella. Especially because it’s no easy task climbing up trees. But when scientists finally decided to give tree canopies a harder look they discovered that there is a whole new world up there! A world teeming with birds, plants, insects and a lot of life!

Many wonderful discoveries have been made but there is still much left to know about life in the treetops. Scientists from around the world are coming together to carry out more ‘canopy research’ and devise new ways of climbing trees. Read on to find out more about this exciting field!

When (and how) did we start exploring tree canopies?

Our first explorations of the tree canopy were actually conducted from the ground. In the 1970s Terry Erwin, an American entomologist, wanted to study the insects that lived up in the tree canopies. But he couldn’t climb up the gigantic trees in his place of work— the tropical forests of Panama in South America. So he decided to bring the insects to him. Erwin ‘fogged’ trees in Panama with an insecticide — a chemical used to kill insects. The insecticide killed thousands of insects in the trees, which came falling down to the forest floor. Erwin discovered that most of these insects belonged to new species, ones that we had never seen before nor described by science! This discovery shocked the world. It showed us that Earth was home to much more biodiversity than we had guessed and that there were many more creatures and critters waiting to be discovered. And tree canopies were the first place to start looking!

Fogging’ treetops
‘Fogging’ treetops to study canopy insects, Credit: Nigel Stork

After Erwin’s discovery, scientists came up with many creative ways to explore tree canopies. And most of these involved actually climbing up trees. Mountain-climbing equipment —like strong ropes, and harnesses came in very handy for this. A popular method to access canopies is known as the ‘Single-Rope-Technique’. It involves getting a rope over a tree branch high up in the canopy and securing a harness to it. The rope forms a ‘loop’ between the branch and forest floor. An ‘ascender’ (to climb up) and ‘descender’ (to come down) — devices that are again borrowed from mountain-climbing, are attached to the rope. Climbers can get into the harness and use these devices to get up into the canopy, swinging on the rope — like Tarzan!

researcher climbing trees
A researcher climbing trees using ropes and a harness, Credit: WIkimedia/TreeMinion15

But if this sounds scary to you don’t worry! There are other ways to get up into tree tops. A ‘canopy platform’ is a large wooden plank that is again pulled up trees using ropes. You can safely sit on it and explore the leafy canopy at leisure. Scientists have also built ‘canopy walkways’ which are interconnected bridges between trees. So you can now actually walk among the treetops! Canopy ‘cranes’ and ‘rafts’ are also some other interesting ways of accessing tree canopies from above. More recently, researchers have built a robot with a camera that can go up a tree and allow us to view the canopy without actually climbing. Could tree climbing be a thing of the past? Unlikely. Because it turns out that nothing beats exploring and experiencing the canopy from the treetops themselves!

A canopy walkway
A canopy walkway , Credit: Wikimedia/Vyacheslav Argenberg

A world of hidden treasures

Dr Vivek Ramachandran, a canopy researcher from India, describes his first experience climbing a tree in a rainforest — “As I emerged out of the mid-canopy into the lower branches of the tree, I was greeted by a panoramic view of the landscape. Looking down, I saw the tops of the surrounding trees and felt the fine mist from the clouds. A curious Malabar giant squirrel was alarmed at seeing my head poke out of the foliage and darted to an adjacent tree, disturbing a flock of Mountain Imperial pigeons that had been feeding on it. Never having been so far off the ground depending solely on a rope was a little scary but also exhilarating.” Dr Vivek studies ‘arboreal’ mammals which are animals that live on trees. There is now even a special word for researchers who work in the treetops— ‘arobornauts’. Just like astronauts explore space, arbornauts explore the unknown world of the canopies.

A Nilgiri Marten
A Nilgiri Marten: an arboreal mammal found in the forests of South India, Credit: Wikimedia/CLPramod

Arbornauts have found that tree canopies provide homes to many unique plants and animals, many of which are not found off treetops. Epiphytes — which are plants that grow on trees, are abundant in the canopies of many forests. They grow on the branches of tall trees, where they get plenty of access to sunlight.  Epiphytes also support multiple canopy animals —frogs and lizards were found to lay their eggs between the leaves of these plants while many insects, spiders and worms also make their homes in these plants. Birds are also very dependent on tree canopies for food and shelter. They eat the fruits and leaves of trees and epiphytes and make their nests within the canopies. Treetops are also home to many small, furry mammals that swing and jump between branches. Think squirrels, monkeys and even Koala bears! A really cool example of an arboreal mammal is the Kinkajou, a sort of racoon, that lives up in the tree canopies of forests in Central and South America.  

Epiphytes
Epiphytes growing in the tree canopy, Credit: Wikimedia/Ligar

The animals that live in tree canopies are also equally important for the trees —they eat and disperse the fruits and seeds of these trees, allowing them to reproduce.

A Panther Chameleon
A Panther Chameleon, found in the treetops of Madagascar, Credit: Wikimedia/Christian Grenier

Conserving Canopies

We have just about started discovering the many ways in which tree canopies are important —for many plants and animals as well as for the health of whole ecosystems like forests. But canopies and all the life they house, face many threats in the form of climate change and deforestation. When we talk about nature conservation and restoration we should keep in mind that tree canopies are also vital habitats that deserve our attention. Preserving these natural wonders is crucial, so future generations can continue to explore and enjoy the incredible life of the treetops.

References

  1. Lowman, M. (2021). Life in the treetops—an overview of forest canopy science and its future directions. Plants, People, Planet3(1), 16-21.
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  10. https://www.britannica.com/animal/kinkajou
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Contributors

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