Tag Archives: forests of the future

Planting Trees Can be Bad for the Planet

Some scientists argue that deforestation is not always harmful for the planet. Christopher A. Williams, a professor at Clark University’s Graduate School of Geography (Worcester, Massachusetts), says that instead of warming up the Earth, deforestation can actually cool it down. (See Climate impacts of U.S. forest loss span net warming to net cooling, Feb. 2021) But some experts are concerned that Williams’ work is likely to be misconstrued as permission to continue deforesting, which is not his intention.

It’s widely accepted that our existing forests are vital carbon sinks, and the best course of action is to stop deforestation, while rewilding and reforesting areas already lost. Deforestation contributes to climate change, can cause wildfires, desertification, soil erosion and most of all – releases huge amounts of carbon dioxide which causes global warming.

While the above may be true, Williams’ new research argues that there are two factors we are not acknowledging: the significance of location and something known as ‘the albedo effect’. Put simply, ‘the albedo effect’ is the process in which forests retain heat. Forests tend to be darker than other surfaces, which means they absorb more sunlight and hold onto heat, explains Williams. As a result, some scientists believe that deforestation gets rid of unwanted heat which is contributing to global warming.

“We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both carbon and albedo effects,” says Professor Williams. He adds that it is important to consider the albedo effect of forests alongside their well-known carbon storage when aiming to cool the planet.

The team discovered that for approximately one quarter of the US, forest loss causes a persistent net cooling because the albedo effect outweighs the carbon effect.  “It is all about putting the right trees in the right place,” explains Williams, “and studies like ours can help identify where the potential for cooling is greatest.”

For instance, loss of forests east of the Mississippi River caused planetary warming, while forest loss in the Intermountain and Rocky Mountain West led to a net cooling. “If we fail to consider both the carbon and the albedo effects, large-scale tree-planting initiatives, such as Canada’s 2Billion Trees Initiative and The Nature Conservancy’s Plant a Billion Trees campaign, could end up placing trees in locations that are counterproductive for cooling the climate system,” he says.


When Logging Works: “Every Part of the Tree”

The rapacious industrialisation of the Finnish forest, which covers three-quarters of the country’s landscape, looks the antithesis of tree-hugging environmentalism. The forest is home to wolves, bears, deer and many other species of wildlife, and its trees lock away carbon that would otherwise be in the air, warming the atmosphere. Yet Metsä Group, which operates the Äänekoski pulp mill, claims the very opposite.  Metsä is ultimately controlled by a co-operative belonging to more than 100,000 families who have each owned large chunks of the forest for generations. For every tree harvested, four saplings are planted. These are allowed to grow for a few years and are then thinned to encourage the best specimens to develop vigorously. The thinnings, however, are not wasted. They are sent to the mill. The mature trees, meanwhile, are harvested when they are between six and ten decades old. The consequence of this husbandry, according to Finland’s Natural Resources Institute, is that the annual growth of trees in Finland exceeds the volume of felling and natural loss by over 20m cubic metres, despite the increasing demand for wood.

As for the mill itself, Metsä’s stated aim is to make best use of every part of a tree, both to maximise the value of its wood and, where possible, to continue to lock up its carbon. To this end, besides the bread-and-butter business of turning out planks and plywood, the firm has come up with several new ideas. Three are of particular interest. One is a better way of converting wood pulp into fibre that can be turned into textiles. A second is to produce plastic-free cardboard cartons which can be used as food containers and then recycled. The third is to find employment for lignin, a by-product of the pulping process which is, at the moment, usually burned…

Metsä has also teamed up with Itochu, a Japanese trading company with a large clothing business, to make fabric that will compete with oil-based synthetic fibres and provide an alternative to cotton, the growing of which requires a lot of land, irrigation and pesticides. Some fabrics—rayon, for example—can be made from wood….

The complex processes involved in processing wood result in several “sidestreams”. These are wastes that become raw materials for other processes. They include sulphuric acid, which is re-used by the mill, and biogas, tall oil (a byproduct of papermaking) and lignin—carbon-rich materials burnt to produce electricity. This powers the mill, and yields a surplus which is exported to the national grid. As a consequence, unlike some wood mills, the Äänekoski plant uses no fossil fuels.

Excerpts from Sustainable Forestry: If you go down to the woods today, Economist, Oct. 19, at 75

Survival of Tropical Forests: bird predators

[T]he Amazon rainforest contains more than 1,500 bird species. Around a quarter of them are found nowhere else on Earth. Many of these birds have evolved to fill a specific role – whether that means eating particular types of insects, or scattering a certain size of seed….A new paper published in Proceedings of the Royal Society explores  the link between deforestation in the Amazon and local bird diversity…[B]ird data was collected in 330 different sites in the Brazilian state of Pará, including arable and pastoral farmland and both primary and secondary forests. Primary forests are the original native vegetation, now increasingly degraded by logging and wild fires. Secondary forests are those which grow back in areas, often farmland, which have been abandoned by people…

The study focused on seed dispersal and insect predation, two ecosystem processes where birds play important roles. Fruit-eating (or frugivorous) birds spread the seeds of forest trees. Insect-eating (insectivorous) birds ensure that any germinating saplings have a fighting chance at survival. ..[S]witching from primary tropical forests to farmland dramatically reduced the “services” birds were able to provide.

This may seem fairly intuitive so far, given that there is a world of difference between a forest and cattle pasture. However, more significantly it was found that the traits were only partially restored in regenerating secondary forests. These areas have been branded as the “forests of the future” but we found them coming up short. These “forests of the future” cannot conserve all the biological interactions realised in primary forests, undisturbed or otherwise, which are essential for biodiversity conservation.  Once large seed-dispersing birds such as guans or cotingas are lost in an area, trees species with large seeds find it harder to recover. Regeneration becomes unlikely or impossible. Research from Brazil’s coastal Atlantic Forest has shown that the loss of such key species is driving the evolution of palm trees with smaller seeds. Some of these links may have been lost before we even knew them….The sorts of generalist insect-eaters that come to dominate farmland aren’t generally able to capture the well-disguised insects found in adjacent patches of forest.

Excerpt from Without birds, tropical forests won’t bounce back from deforestation, the conversation.com, Nov. 8, 2016