Most of North America’s largest timber companies are wedded to a model of intensive, industrial forestry that is far from climate friendly. Industrial forestry is a set of techniques aimed at producing as much commercially valuable timber per acre as quickly as possible, such as large-scale clearcutting, replanting trees in monocultures, and heavy applications of herbicides and fertilizers.
The amount of time between timber harvests is known in forestry terms as a rotation, and rotation length can vary significantly depending on tree species, geography and the approach to forest management. Generally speaking, industrial forestry favors shorter rotations – say 30 to 50 years in temperate regions – over longer ones.
From a purely financial perspective, short-rotation industrial forestry is understandable. Forest managers have powerful incentives to harvest timber as soon as it is merchantable, even though waiting longer can mean more timber production. This is because of the time value of money: a dollar in hand today is worth more than one earned in the future. When companies sink capital into timber, they can’t invest it elsewhere. Money invested in stocks and bonds will generate income on a regular basis; investment in trees will have to wait decades to generate a return. Capital is tied up for so long that it becomes a deterrent to allowing trees to grow older: optimal capital management and optimal carbon management are conflicting goals for so long as carbon emissions are untaxed and carbon sequestration and storage is not valued.
This is why we need to change the structure of incentives that drive industrial forestry through:
- Public policy tools such as carbon taxes and cap-and-trade programs
- Market-based tools such as socially responsible investing and high-bar forest certification
We need to reward long-rotation, lower-impact logging if we are serious about tackling global warming: the preponderance of evidence indicates that forests managed on longer rotations sequester significantly more carbon than do those managed on shorter ones.
Conventional industrial forestry doesn’t just store less carbon; it can be a huge source of GHG emissions. This point was driven home by a 2015 study that found that the aggressive logging of Oregon’s forests since the turn of the century represented between 16% and 32% of overall emissions in the state – an amount equivalent to two to four million new cars on the road. The main reasons cited for this enormous carbon release were reduction of forest cover resulting from rapid and extensive clearcutting of carbon-dense older forests.
Much is made of the fact that wood stores carbon for the length of its life in a building, ignoring the fact the carbon embodied in wood products accounts for only a fraction of the overall carbon stored in the forest they come from – as little as third by some estimates. Of the remainder, large amounts may be released to the atmosphere when logging slash rots and soils are exposed by logging. For decades after they occur, clearcuts emit more carbon than regeneration absorbs in spite of the rapid growth rate of young trees. This is because decomposer microbes in the soil work more quickly after a stand is logged, releasing CO2 as they decompose branches, roots and other organic matter. And, the larger the openings, the faster and greater the release. When it comes to pumping large amounts of carbon into the atmosphere, large-scale clearcutting of older forests may be second only to total deforestation (e.g. clearing forests for agriculture) – more even than catastrophic wildfire.