How does forest help the environment

The first inkling that plants suck CO 2 from the air dates back to the s, when Swiss pastor Jean Senebier grew plants under different experimental conditions. He suggested that plants decompose CO 2 from the air and incorporate the carbon, an idea corroborated by subsequent discoveries about the mechanisms of photosynthesis. The rationale is that trees can lock up carbon in their wood and roots for decades or even centuries.

The climate treaty known as the Kyoto Protocol allowed rich countries to count carbon storage in forests towards their targets for limiting greenhouse-gas emissions. Later negotiations laid out a framework for enabling wealthy countries to pay poorer tropical countries to reduce emissions from deforestation and to increase carbon in forests.

Source: X. Song et al. Nature , — Such schemes required firm data on how much carbon is locked up in forests. In the past few decades, scientists have worked to create national estimates of carbon loss and gain from vegetation by studying field plots and by combing through satellite data. Researchers have known for decades that tree leaves absorb more sunlight than do other types of land cover, such as fields or bare ground. This effect is especially pronounced at higher latitudes and in mountainous or dry regions, where slower-growing coniferous trees with dark leaves cover light-coloured ground or snow that would otherwise reflect sunlight.

Most scientists agree, however, that tropical forests are clear climate coolers: trees there grow relatively fast and transpire massive amounts of water that forms clouds, two effects that help to cool the climate. More-recent studies have branched out to include other ways in which forests can influence climate.

As trees live, grow and die, scientists have learnt, they are in constant conversation with the air, swapping carbon, water, light and a bewildering array of chemicals that can interact with the climate. Atmospheric chemist Nadine Unger, then at Yale University in New Haven, Connecticut, conducted one of the first global studies examining one part of this exchange: the influence of volatile organic compounds, or VOCs, emitted by trees.

These include isoprene, a small hydrocarbon that can warm the globe in several ways. It can react with nitrogen oxides in the air to form ozone — a potent climate-warming gas when it resides in the lower atmosphere. Isoprene can also lengthen the lifetime of atmospheric methane — another greenhouse gas. Yet isoprene can have a cooling influence, too, by helping to produce aerosol particles that block incoming sunlight. Unger ran an Earth-system model that estimated the effects of chemical emissions from forests.

Her results suggest that the conversion of forests to farmland throughout the industrial era might have had little overall impact on climate 3. As a corollary, Unger suggested that reforestation would also have uncertain climate effects. Trees in tropical and temperate zones emit huge quantities of isoprene that is not accounted for in most forestry schemes.

She acknowledged that her study was a first step, and called for increased monitoring of forest chemicals and their atmospheric interactions. The article, and especially the headline which Unger did not write , triggered a tsunami of complaints from researchers, who disputed the science and said the piece threatened to undermine years of research and advocacy. At metres high, the Zotino Tall Tower Observatory measures gases and aerosols above taiga forest in central Siberia.

A similar tall tower in the Amazon makes measurements above the tropical rainforest. Unger says she received death threats, and that some colleagues stopped speaking to her. Some scientists, however, agreed that it was important to look at the impacts of forest VOCs. A team led by Dominick Spracklen and Catherine Scott, atmospheric chemists at the University of Leeds, UK, ran a model that included how aerosols from forests can seed clouds, which reflect sunlight.

They concluded that the net effect of VOCs from forests is to cool the global climate 4. Unger, who is now at the University of Exeter, UK, and Spracklen are discussing using a common experimental design to try to resolve their differences.

They and other researchers say that such studies are hamstrung by sparse data sets on forest emissions. The latest findings are piling on even more complexity.

Ecologist Sunitha Pangala at Lancaster University, UK, spent much of and in the Amazon rainforest, where she placed gas-measuring chambers around the trunks of more than 2, trees. Researchers had previously assumed that methane leaked into the air directly from the soil, where it is produced by microbes. The new work suggests that trees could be another conduit for that microbial methane, potentially explaining why more methane has been detected above tropical wetlands than has been measured emanating from soil alone.

In a study first published last October, Gauci and other colleagues added another wrinkle when they found both methane and nitrous oxide, also a greenhouse gas, leaking from trees in upland forests 6. The global significance of these findings is still unclear. Pangala and Gauci both estimate that the cooling effect of trees taking up carbon greatly outstrips the warming from tree emissions of methane and nitrous oxide.

But Kristofer Covey, an environmental scientist at Skidmore College in Saratoga Springs, New York, has found methane leaking from non-wetland trees in temperate forests 7 , and argues that such emissions could, in some places, diminish the climate benefits of trees more than researchers and environmentalists realize.

The recent explosion of results underscores the need for a full account of the impacts of forests, says Unger. Scientists who champion forests say that although more research is always good, existing results are mature enough to support the use of forests to fight climate change, especially given the urgency of the problem. Read our F. Earth Rangers: Where kids go to save animals! Forests are a Breath of Fresh Air With a little help from the sun and a process called photosynthesis, trees are able to provide us and other animals with fresh air!

Forests Keep Things Cool It always feels so refreshing to cool off in the shade on a hot day—and the bigger the tree, the better the shade. Forests Help the Soil Stay Put Soil has a very important job when it comes to keeping an ecosystem healthy: it provides nutrients for plants and helps protect their roots.

Forests are Good for the Soul Do you ever feel refreshed and re-energized after playing among the trees? Forests Always Draw a Crowd There are over 40 national parks and provincial parks in Canada, each with their own unique qualities to discover.

Pixel Puzzler 6: Guess the Animal, Part 1. How do plants and animals handle the cold? So, did we break the world record? Caption This! Happy Halloween! Follow Us. French app is out now! Rizvi, A. Osipova, E. What is the issue? Why is it important? What can be done? Other benefits in support of both people and nature are considerable: Globally, 1. This helps conserve the benefits that people and societies get from forests, including forest carbon stocks and livelihoods.

Restoring forest landscapes helps enhance climate change mitigation and adaptation. As the co-founder and Secretariat of the Bonn Challenge — a global effort to bring million hectares of deforested and degraded land under restoration by — IUCN supports national and sub-national decision makers in reaching this important goal.

Reaching the million hectare target could sequester up to 1. Enabling rights-based land use ensures community involvement in land-use outcomes. IUCN produces results on the ground through partners and projects worldwide to help strengthen community control over forests, alleviate poverty, empower women and men, enhance biodiversity, and sustainably manage forests.

Unlocking forest benefits is critical to a sustainable and equitable supply of forest goods and services.