What we are doing to the forest of the world is but a mirror reflection of what we are doing to ourselves and to one another. ~ Chris Maser, the noted author.
Trees are a beautiful expression of Mother Earth’s creativity. They have been around for about 400 million years. In contrast, human beings have existed only for about 100 million years. In the words of Khalil Gibran, “Trees are poems that the earth writes upon the sky.”
Life cannot exist on Earth without trees become they produce most of the oxygen that humans and wild life breathe. Trees tower majestically into the atmosphere where they absorb carbon dioxide and release oxygen. A typical hardcore tree can absorb as much as 48 pounds of carbon dioxide per year and ,on an average, one tree produces nearly 260 pounds of oxygen per year. For survival, a human being needs 740 kg of oxygen every ~ worth at least seven or eight trees.
Trees occupy only about two-thirds of the territorial surface of the Earth, but they are responsible for approximately two-thirds of the planetary carbon capture through the process of photosynthesis. Apart from carbon storage, their services to the planet range from soil conservation to water-cycle regulation. They support natural and human food systems and maintain biodiversity by providing homes for countless species. Trees live in association with thousands of microorganisms in the soil.
This includes fungi that the trees need to survive. When trees inhale carbon dioxide from the atmosphere, much of the carbon of absorbed gas enters the soil to feed those micro-organisms, which are responsible for ensuring healthy soil that supports life and stores carbon for a long time. Trees have a localised cooling effect. They provide shade that maintains soil temperatures and, as the darkest object in the landscape, they absorb heat rather than reflect the same. In the process of “evapotranspiration”, they also channel energy from solar radiation into converting liquid water into vapour.
On the global scale, trees combat warming caused by climate change by storing carbon in their trunks and removing carbon dioxide from atmosphere. Studies reveal that one tree can have the cooling effect of 10 air-conditioning units. Trees influence the water cycle by acting as biological pumps: they suck water from the soil and deposit the same into the atmosphere by transforming it from liquid to vapour.
By doing this, forests contribute to cloud formation and precipitation. Trees also prevent flooding by trapping water rather than letting it rush into lakes and rivers. They keep soil in place that would otherwise be washed away in rain. There are thousands of gifts that trees provide us on Earth. Indeed, trees are miracles of science. Paul Ehrlich, the author of The Population Bomb, wrote: ‘There are examples of species all over the world that are essentially the walking dead, we are sawing off the limb that we are sitting on’.
He was referring to the Sixth Extinct ~ the Anthropocene (‘amthropo’ means human and ‘cene’ means new) extinction of plants and animals. Forest is one of the major parts of terrestrial ecosystems on the planet. Natural forest cover used to be a far higher proportion of the Earth’s land area before humanity got to it. Now we often treat trees as disposable; as something to be harvested for economic gain or as an inconvenience in the way of human development.
Since our species began practising agriculture around 12,000 years ago, we have cleared nearly half of the world’s estimated 5.8 trillion trees, according to a study published in the journal, Nature. Though forests still cover about 30 per cent of the world’s land areas, they are disappearing at an alarming rate. In the time it takes to utter the word ‘deforestation’, another chunk of the forest, the size of a football pitch, gets destroyed.
Today, deforestation is largely taking place in the fast growing tropical and subtropical regions, and in the rain forests, where population density is traditionally low but is now rising. While temperate zones were deforested long ago, it is now the tropical areas that are being deforested very quickly. The rainforests, the regions of astonishing biodiversity, are now facing major disturbances and human impacts. The wave of extinctions would extend beyond forests, depleting wildlife that depend on trees as well.
Between 1990 and 2016, the world lost 502,000 square miles of forest, according to the World Bank, altogether an area larger than South Africa. About 17 per cent of the Amazonian rainforest has been destroyed over the past 50 years, and recent losses have been on the rise. Although India has seen an increment in the total forest cover of 1 (one) per cent, still there are certain regions in the country that have reported a decrease in forest cover.
The causes of deforestation vary, but the land clearance for agriculture as in Brazil, is the leading factor behind deforestation. In densely populated countries, such as India and Ethiopia, firewood gathering is more often responsible. Other reasons are the shifting cultivation, rotational felling, other biotic pressures, diversion of forest lands for development activities, rapid urbanisation, large-scale development projects, mining etc.
The UN Food and Agricultural Organisation (FAO) has defined deforestation as the conversion of forest to some other land use or the longterm reduction of tree canopy cover below the 10 per cent threshold. Deforestation occurs when the land initially dominated by trees is converted to provide certain services in response to the human demand. In 2016, a study from the Maryland University reported that 73.4 million acres of the global tree cover were lost.
Regardless of the reason for the tree-cover losses, the consequences are usually the same. Soil organic matter declines, reducing the moisture storage capacity. Rainfall runoff increases. Percolation and aquifer recharge decreases. Soil erosion accelerates. Because of deforestation the localised cooling effect via evapotranspiration mentioned above is lost. Most places where trees formerly stood would immediately become warmer.
In one study it has been found that complete removal of a 25 sq km patch of forest caused the local annual temperature to increase by at least 20 C in tropical areas and 10C in temperate areas. According to an IPCC report deforestation accounts for 13 per cent of total carbon emissions and change in land use in general also causes 23 per cent of emissions. Hence, with all trees on the planet wiped out, previously forested ecosystem would become only a source of emission of carbon dioxide into the atmosphere, rather than a sink.
(The writer is a retired IAS officer)