Forests are precious resources that we will increasingly rely on for our water, food and energy as the world’s population grows.

But while the news coverage of forests – from illegal wood harvesting to massive forest fires – tends to be negative, researchers from the University of Helsinki now say that woodland areas are increasing in size in our happier and more prosperous societies.

To support their argument, they point to UN data that shows forests have expanded in Europe, North America, the Caribbean, East Asia, and Western Central Asia. However, woodlands have decreased in Central America, South America, South and Southeast Asia, and three regions of Africa.

“From 2010 to 2015, net tropical forest loss was dominated in South America by Brazil, in Asia by Indonesia, and in Africa by Nigeria,” they write.

But in high-income nations between 1990 to 2015 forest stock increased annually by 1.31%, while it notched up a 0.5% rise in middle-income states. However, the amount of forest spaces fell by 0.72% in 22 low-income countries, the authors say.

Several global climate models have attributed this change to so-called carbon dioxide (CO2) fertilization – in which atmospheric CO2 boosts tree growth. The authors said this “greening process” has been going on since the 1800s in Western Europe, when amounts of CO2 in the atmosphere began to rise. This process has tended to mirror the rise of modern industrial and economic growth.

‘A sort of balance’

“When people are feeling good, it benefits forests,” Pekka Kauppi from the University of Helsinki, one of the researchers, told BBC News. “It is not just income. When a society works properly then deforestation automatically seems to disappear, and society reaches a sort of a balance with the forests.

"Once a country has a decent life they do not deplete forests, they want to protect them," he continued. "When livelihoods come from other sources, not subsistence farming, then marginal lands are abandoned and people just leave the forests to grow back.”

Forests increase in relation to development and not just carbon emissions, study says.
Image: REUTERS/Yves Herman

The professor said other parts of the world have also started to see increases in forest cover relative to their economic development, rather than just increases relative to levels of CO2. Europe, the US, Japan and New Zealand have all added to the sizes of their forests in the past 100 years, while in the past 50 years China and Chile’s tree cover has increased, too.

This reversal of the deforestation process is known as “forest transition” or “landscape turnaround.”

Despite the overall increase, large regional differences between forests remain. The authors say: “Unfortunately, deforestation continues at biologically rich forests. The new expanding forests are biologically less diverse, especially where they consist of planted monocultures [i.e. as crops for harvesting].”

Forests in more developed economies have benefited from their countries’ investments in sustainable forest management and nature protection programmes. The writers add that, as subsistence farming comes to an end and “marginal lands” are abandoned, agricultural production tends to focus on more fertile areas. This, in turn, frees up peripheral spaces for forest expansion.

A greener future?
This process, if replicated across the developing world, could herald good news for our green spaces, the report suggests: “Given the recent advances of forest transitions, the world [could] approach a peak of agricultural land, implying prospects for the end of global deforestation.”

But they conclude that it's not all good news: “Despite the positive trends in domestic forests, developed nations increasingly outsource their biomass needs [such as for energy production] abroad through international trade, and all nations rely on unsustainable energy use and wasteful patterns of material consumption.”

So, whether humans will be able to live sustainably depends on whether we can curb our desire to buy and consume products of all kinds, both at home and from around the world.