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Sustainable Forestry

Bryan Jones
25 November 2019

Sustainable forestry

"In Finland’s vast forest lives a monster with a voracious appetite."

Once it would have been called a pulp mill. But after a recent makeover costing £1.2bn it is now known as a bioproduct mill. The plant consumes 6.5million cubic metres of wood a year.

The forest is home to wolves, bears, deer and plenty of other wildlife, and its trees lock away carbon that would otherwise be in the air, warming the atmosphere.

On the face of things, such rapacious industrialisation of the Finnish forest, which covers three-quarters of the country's landscape looks the antithesis of 'tree-hugging' environmentalism. However, for every tree harvested, four saplings are planted. These are allowed to grow for a few years and then thinned to encourage the best specimens to develop fully. The thinnings are not wasted as 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 is that the annual growth of trees in Finland exceeds the volume of felling and natural loss by over 20million cubic metres.

The mill's stated aim is to make the best use of every part of a tree, both to maximise the value of its wood and, where possible to lock up its carbon.

During one of its key function of manufacturing plywood, peeling of the timber permits the grains of sheets to be arranged in ways that create composite materials far stronger than the original timber. These materials are increasingly being used as substitutes for steel and concrete, even in some high-rise buildings. Not only does this keep the wood’s carbon locked-up, but it also reduces the need for steel and concrete, which require fossil fuels in their manufacture, a process which also generates very large volumes of carbon dioxide.

In addition to its primary business of turning out planks and plywood, the firm has come up with several new ideas which are of particular interest from an environmental perspective. 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. The company is working on a lignin-based material which acts as a 'plasticiser' permitting concrete to flow more easily when being pumped onto building sites.

This article is based on one published in the Economist - How to make use of all of a tree.