All wild forests are teeming with life and contain a magic balance between innumerable species and processes. They are biological treasure houses, beyond any human-created museum. An individual can easily walk through a forest without noticing the masses
of elements that work in concert to generate and sustain a dynamic environment, from the tiniest insect to the amount of sunlight that penetrates a canopy.
About 10,000 years ago, 50 per cent of the Earth’sland surface was forested. Today, a little over 30 per centis covered with forests and a lot of that decline is due to humans. Trees and forests are the lifeblood of the planet and they are in trouble, globally, and therefore so are we.
The value of forests
Trees with woody trunks and a vascular system, towering over the land, have existed on Earth for more than350 million years. Not only did trees provide indispensable shade for dinosaurs, they also helped modify the water and energy flow between the land and atmosphere.
Every tree in the world participates in many biological processes, but one of the most notable is photosynthesis.In this process, leaves absorb carbon dioxide (CO2) from the atmosphere, mix it with water, convert it into sugar using the sun’s energy, and give off oxygen as a byproduct. Infact, trees are the greatest CO2 warehouses to have ever evolved. For every tonne of wood created, 1.5 tonnes of CO2 is absorbed and 1 tonne of oxygen is released. Old forests are superlative at capturing and storing vast amounts of CO2.
Wild forests occupy amazing swathes of land.The northern forests or boreal make up the largest uninterrupted, or contiguous, forested area on the surface of the planet – the Earth’s emerald crown. Stretching across Canada, through central Alaska, northern Asia, Russia, Europe, Scandinavia and northern Scotland, the taiga contains one-third of all trees in the world, and is characterised by very long and very cold winters.
In sections, these forests are populated by the most widespread tree on the globe, the European aspen, as well as especially resilient species such as the deciduous Siberian larch, which can withstand temperatures of -55°C. These biological communities thrive in the northern environments.
The temperate forests, meanwhile, are located about half way between the tropics and the poles in both hemispheres and have moderate climates with four distinct seasons. In the southern hemisphere there are relatively small areas of temperate forests, in South America, Africa, New Zealand and Australia. In the northern hemisphere they are primarily found in Europe, the eastern half of the United States and parts of China and Japan.
Temperate forests contain the biggest trees in the world, including coastal redwoods of northern California which have been known to reach in excess of 115m and are the tallest of all 80,000 known tree species. The second tallest are our own mountain ash, or swamp gums, which have been recorded in excess of 99m in Tasmania and Victoria.
Tropical forests hug the equator within 10 degrees or so, occupying an area of about 6 per cent of the Earth’s surface. Yetthese exquisite forests contain at least half the known species of plants and animals in the world. The three largest tropical forests in ascending order are South America’s Amazon, Africa’s Congo and South-East Asia’s Indonesian jungles.
Amazon wealth
The Amazon is crucial habitat to one in 10 of the 1.6 million known species on the planet. More than 2000 tree species live in a hectare of Amazonia. It is typically warm, wet and windless throughout the year.
Tropical rainforests such as the Amazon are splendid rainmakers. The bright morning sunshine heats up the vegetation and evaporates water from it, resulting in the upward convection of wet air. As the air rises, it forms clouds and produces rain in the afternoon and evening. More than half of the rain that falls on the great jungles of the Amazon River Basin returns to the atmosphere through the leaves of trees, to fall again as rain on the Amazon forests. That daily cloud formation reflects a massive amount of incoming solar radiation back into space; these clouds are of paramount importance for keeping the world cool.
Frighteningly though, this most majestic of jungles is breaking down with alarming regularity and the effectsare amplifying around the globe. Human activity, including accelerated deforestation, is wreaking havoc with wildfires, droughts, heat waves and insect epidemics.
Global alarm bells
Below I list some of the most dire forest situations around the world, starting with the Amazon. Not to depress you, but to show the bigger picture and the need for an immediate and concerted international global effort to save them. As well as fighting to slow climate change and save the oceans, we must protect the forests. Take a deep breath while you can!
The Amazon has not evolved to contend with severe winds. In 2005 a lethal combination was unleashed: first, a powerful thunderstorm 100km long by 200km wide ripped through the Amazon Basin from the south-east to north- west. It levelled half a billion mature trees or 23 per cent of the estimated mean annual carbon accumulation capacity of the Amazon forest (trees emit CO2 when they decompose).
Then a one-in-one-hundred-year drought occurred. The Amazon failed to absorb an estimated 1.5 billion tonnes of CO2 that year, and over the following decade it released approximately 5 billion tonnes of CO2 from the decomposing 500 million blown-down trees. Two years later, extreme droughts in the south-east Amazon rainforest created conditions for epic wildfires, 10 times more fires than inan average year. The area that burned in 2007 was the equivalent to one million soccer fields. Then in 2010, the second one-in-a-hundred-year drought gripped.
That enormous area of dead jungle is releasing 8 billion tonnes of CO2 over the ensuing decade. All those billions of dead trees means that Earth is losing its tremendous rain- making machines, and instead it is absorbing mega amounts of incoming solar radiation rather than reflecting it.
What this means is that the Earth’s largest tropical forest, the Amazon Basin, has begun a transition from pristinewilderness to drought and fire-dominated regimes on a scale never witnessed since our progenitors first walked the planet seven million years ago. The Amazon jungle has reachedits tipping point; it’s on the verge en masse of contributing to rising greenhouse gases rather than removing them.
As if all these deadly events were not frightening enough, 158 scientists recently issued a warning that at the current rate of Amazonian deforestation, 57 per cent of the 15,000 tree species are heading toward extinction, including mahogany and food-bearing Brazil nuts, cacao and acai palms.
Extreme conditions
The Amazon, of course, is not alone in suffering the effects of deforestation and climate change. Extreme droughts in North Africa are killing Atlas cedar trees from Morocco
to Algeria. Heat and drought are battering high-elevation tropical forests in Uganda, mountain acacia in Zimbabwe and centuries-old aloe plants in Namibia. Tropical forests
of Malaysia and Borneo have suffered significant death. Drought has also lambasted the tropical forests of north- west and south-west India, fir in South Korea, the junipers of Saudi Arabia and pine and fir of central Turkey.
Heat waves, droughts and wildfires have ravaged Australian forests, too. The Black Saturday bush fires that scorched Victoria on Saturday, February 7, 2009, were Australia’s all-time worst bushfire disasters, resulting in the deaths of 173 people and the highest ever loss of wildlife.
Drought is killing the marri and jarrah forests, which are precious habitat for threatened Carnaby’s black-co*ckatoos of south-west Western Australia. Deadly heat-induced stress in northern Tasmanian forests caused blue and white gums to exude their sap, dubbed the “ginger syndrome” for the blood-like bark discolouration. More than 2000 square kilometres of the Cooma-Monaro region of NSW are nowa mass graveyard of ribbon gums because it is too dry for these forests to exist.
Rising temperatures, insect epidemics and wildfires have left an indelible stamp across the North American continent. Trillions of indigenous bark beetles killed 30 billion mature pines and spruce across the west, and those decaying trees are now leaking greenhouse gases into the atmosphere, instead of removing them. Last year, wildfires charred over four million hectares across America – it was the costliest fire season on record at $1.7 billion.
If this isn’t shocking enough, Chinese oil companies intend on buying one-third of Ecuador’s remaining Amazon jungle or 2.7 million hectares for oil and gas exploration. This would be a huge blow in conservation efforts to protect the remaining Amazon forests from further damage and exploitation. The insatiable Asian demand for prized timbers is also driving lucrative illegal logging from Madagascar to the Congo, and from Thailand and Cambodia across the Pacific into Russia.
