Amazing Facts About Garden Trees

Human beings often do feel a strong affinity for trees. We feel at peace when we are surrounded by them and we have a long, long history of using them to provide us with many of the basic things we need to live. Most of us know how important trees are, but few of us actually stop to think about how amazing the trees in our gardens really are. To help gardeners to stop and take some time to appreciate our arboreal friends, here are five amazing facts about trees:

Trees help us breathe – and not only by releasing oxygen and absorbing CO2.

Most of us are well aware that trees and other plants are a source of around half of the oxygen we breathe. (The other half is provided by phytoplankton in the world's seas and oceans.) Most people are also well aware that trees absorb carbon dioxide and so can help reduce the concentration of this harmful greenhouse gas in the atmosphere. Trees, of course, play a vital role in fighting global warming. But they can also help us breathe by removing all sorts of air pollution, including nitrogen oxides, ammonia and sulphur dioxide, from the air in our gardens. They 'clean' the air making it safer for us to breathe.

Trees are essential to the world's water cycle.

As children, we all learn that water from the oceans evaporates in sunlight, condenses as clouds and falls as rain, then the cycle repeats itself. What few people truly understand is the important role that trees have to play in the water cycle. Forests are crucial to maintaining the water cycle and ensuring natural precipitation, as well as for storage of water after it falls as rain.

Over the ocean, the simple cycle described above largely holds true. 100% of the rain that falls is water of oceanic origin. In coastal areas, however, only around 60% of the water that falls as rain has come from the sea – the other 40% is of forest origin. Further inland, 50% of the rainfall is of forest origin. Transpiration, the release of water through the pores of trees and other plants, accounts for up to half- or even more – of all moisture returned to the air.

Trees use an underground 'internet' of mycorrhizal fungi to communicate.

Like most plants, trees have symbiotic relationships with soil biota – including bacteria, and fungi that live on their roots. Forests (or gardens) are not made up of individual trees and plants – the whole ecosystem is one big joined-up network. Trees use an underground 'internet' or postal network to share resources. Mother trees, for example, will send nutrients and water to saplings around her to help them grow. They can recognise their own 'children' and help them thrive. They will even send 'wisdom' when in threat, defence signals that increase the resistance of the saplings to future stresses.

Trees can send chemical signals to warn their neighbours about insect attack.

Some trees also send chemical signals through the air to warn their neighbours of an insect attack. Amazingly, the neighbouring plants will become more resistant to insects after receiving these signals. Trees are deeply social. They not only send warnings, they also nurse sick trees nearby, keep felled stumps alive, and co-operate to make sure neighbouring trees get enough light.

Trees can even 'talk' through chemicals to other species.

Astonishingly, trees don't only communicate with other trees. Embattled trees call for backup- releasing chemicals that attract arthropods that will eat the invading insects. One study even showed that apple trees under attack by caterpillars release chemicals that attract caterpillar-eating birds.

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