"'Forest transition" means hope for a future Earth

Nov 14, 2006 15:43 GMT  ·  By

While forests disappear at a fast rhythm in some countries, in others forested surface is increasing, raising hopes for a turning point for the world.

New approach search beyond simply tree covered area of a country assesses the volume of timber, biomass, and captured carbon within the area.

A new study considers both area and the density of trees per hectare, but also their size (large enough to produce timber) to determine the volume of "growing stock".

The researchers discovered that growing stock has in fact increased in the last 15 years in 22 of the world's 50 most forested countries.

Increase in forested areas was linked to countries' per capita Gross Domestic Product, of more than $4,600 (roughly Chile's GDP).

The only exception is Canada, which improbably reported identical area and growing stock in 1990 and 2005.

The results in India and China, which do not accomplish this income level, prove the importance and impact of government policies.

But forests are still being lost in such important countries as Brazil and Indonesia, and this deforestation has far more severe effects, as these forests harbor the highest biodiversities in the world.

An important issue is that the forests of Earth's two most populated nations have passed out from a negative trend: China's forests are expanding; India's have reached equilibrium, changes due in large part to urban migration, agricultural yield increases and reforestation policies.

Among the 50 studied countries, relative forested area decreased fastest from 1990 to 2005 in Nigeria, Indonesia and the Philippines, and increased fastest in Vietnam, Spain, Ukraine and China.

Countries with increases in forest stock were: Austria, Belarus, Chile, China, Czech Republic, Finland, France, India, Italy, Ivory Coast, Japan, Malaysia, Nepal, Norway, Poland, Russia, Spain, Sweden, Turkey, Ukraine, the United States and Vietnam.

In absolute terms, Indonesia and Brazil suffered the greatest losses of both forested square kilometers and cubic meters of growing stock; China and the USA got the greatest gains.

Japan's forest area is virtually unchanged since World War II (22.2 million hectares in 1947 vs. 23.7 million hectares today), but the density of its forests, thus its growing stock, has increased at a rate of 1.6% per year.

"China has experienced falling forest density in many parts of the country since 1949, but its area of forested land has steadily risen," said ecologist Dr. Fang of Beijing.

Indonesia lost about 2% per year in forested area and 4% in density.

Instead, Spain increased its forested area by 2% annually and its density by almost 1%.

Forestry data 200 years old reveal that several places worldwide have passed from net deforestation to net reforestation - the "forest transition."

In France, forest surface increased by one-third between 1830 and 1960 and by a further 25% from 1960 to 2005. In northeastern USA, the forests of Massachusetts, Pennsylvania, Ohio, and Illinois have increased by more than half since the 1800s.

In Connecticut, the forested area increased from 30 % to 60 % between 1860 and 2002.

In China, forested areas have increased from 96 million in the late 70's to 143 million hectares currently. South Korea and Vietnam also experienced "forest transition".

Asia lost 792,000 hectares of forest in the 90's but has gained more than 1 million hectares between 2000 and 2005. And probably more nations will reach the stage of "forest transition" in the next 30 years.

Despite the ecological disasters in Brasilia and Indonesia, many tropical countries pass trough a reverse situation. Forests in El Salvador grew by about 20 % from 1992 to 2001.

Forested areas are recovering fast in the Dominican Republic (Eastern half of the Haiti Island), contrasting to deforested Haiti Republic on the Western side of the island.

"The main obstacles to forest transition are fast-growing poor populations who burn wood to cook, sell it for quick cash, and clear forest for crops. Harvesting biomass for fuel also forestalls the restoration of land to nature. Through paper recycling and a growing reliance on electronic communication, people help the transition by lessening demand for wood products." said Dr. Pekka E. Kauppi of the University of Helsinki, Finland.

The researchers signal that it's possible to combine a large commercial harvest and "growing stock".

"The USA gained growing stock during 1990 to 2005 while harvesting much round wood and some fuel. China did likewise. On the other hand, Indonesia and Brazil lost much growing stock without harvesting as much timber as either the USA or China." said Dr. Roger A. Sedjo, an economist at Washington DC, USA.

Industrial wood production in forest plantations will increase from about one-third today to half by 2025 and three-quarters by 2050.

"Plantations and the trade to make them effective reduce the impact of industrial pressures on the expanse of natural forests, which may be rich in soil carbon and biodiversity," adds Sedjo.

"A rapid forest transition at a global scale would mean that atmospheric CO2 might not rise as fast as many fear." said Paul E. Waggoner (New Haven, CT, USA).

Forest transitions also stop the habitat loss for many endangered species, like tigers or many monkeys and parrots.

As intensive agriculture takes place of an extensive one, lands' need for agriculture is shrinking, even if people's number increases and they eat better.

Foresters shifting from extensive to intensive strategies also spared large forest territories.

"This great reversal began a great restoration of the landscape by 2050, expanding the global forest by 10 % - about 300 million hectares, the area of India." said Jesse H. Ausubel (New York, USA).

"Without depopulation or impoverishment, increasing numbers of countries are experiencing transitions in forest area and density," adds Dr. Kauppi.

"While complacency would be misplaced, our insights provide grounds for optimism about the prospects for returning forests."