An Update on Deforestation

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Tropical rainforests are destroyed at an alarming rate and replaced with palm oil plantations. Gavin Pearsons/Oxford Scientific/Getty

Interest in specific environmental issues ebbs and flows, and while problems like desertification, acid rain, and deforestation were once at the forefront of the public consciousness, they have been mostly supplanted by other pressing challenges (what do you think today’s top environmental issues are?).

Does this shift in focus really mean we solved earlier problems, or is it just that the level of urgency about other issues has ratcheted up since then?

Let’s take a contemporary look at deforestation, which can be defined as the loss or destruction of naturally occurring forests.

Global Trends

Between 2000 and 2012, deforestation occurred on 888,000 square miles globally. This was partially offset by 309,000 square miles where forests grew back. The net result is an average forest loss of 31 million acres per year during that period – that’s about the size of the state of Mississippi, each year.

This forest loss trend is not distributed evenly over the planet. Several areas are experiencing important reforestation (the regrowth of recently cut forest) and afforestation (the planting of new forests were none were in recent history, i.e., less than 50 years).

Hotspots of Forest Loss

The highest rates of deforestation are found in Indonesia, Malaysia, Paraguay, Bolivia, Zambia, and Angola. Large acreage of forest loss (and some gain too, as the forest regrows) can be found in the vast boreal forests of Canada and Russia.

We often associate deforestation with the Amazon basin, but the problem is widespread in that region beyond the Amazon forest. Since 2001 in all of Latin America, a large amount of forest is growing back, but not nearly enough to stall deforestation. During the period 2001-2010, there has been a net loss of over 44 million acres.

That’s almost the size of Oklahoma.

Drivers of Deforestation

Intensive forestry in subtropical areas and in boreal forests is a major agent of forest loss. The vast majority of forest loss in tropical areas occurs when forests are converted to agriculture production and pastures for cattle. Forests are not logged for the commercial value of the wood itself, but instead they are burned as the fastest way to clear land. Cattle are then brought in to graze on grasses that now replace the trees. In some areas plantations are put in, notably large palm oil operations. In other places, like Argentina, forests are cut to grow soybeans, a major ingredient in pig and poultry feed.

What About Climate Change?

The loss of forests means disappearing habitats for wildlife and degraded watersheds, but it also impacts our climate in a multitude of ways. Trees absorb atmospheric carbon dioxide, the number one greenhouse gas and contributor to climate change. By cutting down forests we reduce the planet’s capacity to pull carbon out of the atmosphere and achieve a balanced carbon dioxide budget. Slash from forestry operations is often burned, releasing in the air the carbon stored in the wood. In addition, the soil left exposed after the machinery is gone continues to release stored carbon into the atmosphere.

Forest loss affects the water cycle, too. The dense tropical forests found along the equator release phenomenal amounts of water in the air through a process called transpiration. This water condenses into clouds, which then release the water further away in the form of torrential tropical rains. It is too soon to really understand how deforestation’s interference with this process affects climate change, but we can be assured that it has consequences within and outside tropical regions.

Mapping of Forest Cover Change

Scientists, managers, and any concerned citizens can access a free online forest monitoring system, Global Forest Watch, to track changes in our forests. Global Forest Watch is an international cooperative project using an open data philosophy to allow better forest management.

Sources

Aide et al. 2013. Deforestation and Reforestation of Latin America and the Caribbean (2001-2010). Biotropica 45:262-271.

Hansen et al. 2013. High-Resolution Global Maps of 21st-Century Forest Cover Change. Science 342: 850-853.