Threats to trees ... deforestation

CONTENTS

What is deforestation?

Illegal deforestation in Madagascar © Diorit

Deforestation is the permanent destruction or loss of forests through deliberate, natural or accidental means. It is primarily due to human activities in order to make land available for other uses such as agriculture, ranching and development and unsustainable logging.

Deforestation is a very serious issue affecting the long-term health of our planet. Sadly, deforestation is taking place continually in forests all around the world.

While loss of any tree has negative implications on localized air quality and biodiversity, it is the current mass destruction of tropical rainforests that is of particular concern because forest ecosystems are home to much of the world’s biodiversity and are major contributors for good when it comes to restraining the negative effects of climate change on world populations.

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Why are forests important?

Gorilla © Michael Lambert

Forests are integrated ecosystems and home to some of the most diverse life on Earth. This is why humans have always been heavily dependent on forests and the products and facilities they provide.

Forests produce vital oxygen and provide homes for people and wildlife. Not only do many indigenous people rely on forests for food, fresh water, clothing, traditional medicine and shelter, but many of the world’s most endangered animals live in forests.

Forests play a critical role in absorbing the greenhouse gases that contribute to global warming as well as preventing soil erosion and helping maintain the water cycle.

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What happens when forests are lost?

When forests are lost or degraded, their destruction sets off a series of changes that affect life both locally and around the world. Some of these changes can have catastrophic implications for the future of life on Earth.

Deforestation can occur rapidly due to fire or when a forest is cleared to make way for agricultural use; however, it can also happen gradually as a result of forest degradation as temperatures rise due to climate change.

As the human population continues to grow there is a growing demand for food and housing. This has created incentives for the destruction of forests for farmland and development.

Fires are a natural and beneficial element of many forest landscapes but fire is often used as an excuse to clear forests for other uses.

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Deforestation increases loss of biodiversity

Lilac-breasted roller © Michael Lambert

Deforestation is a serious threat to Earth’s biodiversity. Around 80% of the world’s documented species can be found in tropical rainforests. Deforestation and forest degradation can cause species to decline and even become extinct as the removal of forest cover deprives them of habitat and makes them vulnerable to hunters and poachers

Loss of habitat has tremendous negative consequences for the future of medicinal research. To date, less than 1% of tropical plants have been analysed for their potential use to medical science. Deforestation has caused the loss to medical science of many species.

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Deforestation increases greenhouse gases

Land surface temperature, Dec 2016 © NASA

Deforestation is one of the major contributing factors to global climate change. Forests help to mitigate carbon dioxide and other greenhouse gas emissions; but when trees are cut down, burned or removed they release their stored carbon and this adds to rising temperatures, changes in weather and water patterns and an increase in extreme weather events.

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Deforestation disrupts water cycles

Trees also help maintain the water cycle by absorbing rainfall and returning water vapour back into the atmosphere, but when deforestation occurs the local climate can become drier and areas that were formerly forested can easily become barren deserts.

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Deforestation increases soil erosion

Consequences of soil erosion © Ita McCobb

Trees help to anchor fertile soil, but when they are removed erosion occurs, increasing runoff and reducing the protection the soil receives from tree litter. Many agricultural plants that replace the trees cannot stabilize soil. Plants such as coffee, cotton, palm oil, soybean and wheat can actually cause further soil erosion. Soil erosion can also lead to silt entering lakes, streams and other water sources, decreasing local water quality and contributing to poor health in local populations.

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Deforestation increases floods

Flooded trees © Ita McCobb

When it rains, trees manage excess water in the ground by absorbing and storing large amounts of water with the help of their roots. When they are cut down, this lack of management means that the flow of water is disrupted. This often results in floods in some areas and droughts in other places.

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Deforestation disrupts livelihoods

Millions of people around the world rely directly on forests for their livelihood, with their society’s social structure being built around their local woodland, but deforestation, tree clearing and land grabbing completely deprives them of the basis for their society and livelihood and so disrupts their lives, creating severe social problems that often leads to violent conflict.

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References: University of Michigan; UN-REDD programme; United Nations Environment Programme (UNEP); National Geographic; World Wildlife Fund; www.wwf.panda.org; Rainforest Connection (RFCx); The Forestry Commission UK; Forestry, An International Journal of Forest Research; US Department of Agriculture (USDA) Forest Service; The Woodland Trust; sciencedaily.com; US Environmental Protection Agency; Cornell University; The Forestry Commission UK; Cornell University; Food & Agriculture Organization of the UN; Institute of Chartered Foresters; Botanical Gardens Conservation International; International Plant Sentinel Network (IPSN); Zac Goldsmith in collaboration with The Countryside Restoration Trust, The Threat to England’s Trees; United States Department of Agriculture (USDA) Forest Service.