Climate effects of timber use

Calculator for estimating the climate effects of timber use

Use this calculator to illustrate the development of carbon stock in forests over time and the related climate effects.

Carbon sinks and carbon stock in forests

The carbon sinks of forest reduce atmospheric concentrations of CO2. Forests act as carbon sinks if they sequester more carbon or other greenhouse gases than they release. This increases the carbon stock of the forests. The growth of the tree stand and the forest litter feeding the soil are some of the factors increasing the carbon stock of forests. On the other hand, the carbon stock is reduced by felling, timber harvesting, decay of the tree stand and soil respiration. GHGs are constantly being removed and released in forests, making forests either net sinks or net sources.

Changes in carbon stock measured by carbon balance

If the carbon stock is reduced as a result of deforestation, for example, the land area acts as a source of emissions. If the carbon stock increases, such as in Finnish commercial forests, the land area acts as a carbon sink. The sum of emissions by sources and removals by sinks can be described with net emissions. Part of the carbon included in the carbon balance of forests is stored for decades in long-lasting harvested wood products, meaning that the products also act as a carbon stock. The increase of carbon stock in harvested wood products is reported as GHG removals comparable to sinks, as stock changes in terms of CO2 balances of biomass are accounted in the reporting instead of biomass carbon flows.

Viewpoints into the climate effects of forest and timber use

The emissions and removals related to forests and the use of timber and the resulting climate effects can be examined from various viewpoints, offering answers to different types of questions. The viewpoint affects which factors are taken into account and how they are consistently defined.

For example, examining the absolute state of the environment differs from observing the attempts to mitigate climate change. Absolute GHG emissions and removals are used to describe the state of the environment, whereas GHG emissions and removals calculated in proportion to a reference situation are used to assess the climate effects of various actions.

A reference situation refers to a scenario where the examined action, such as timber harvesting, does not take place. In this case, the examined action, such as wood products or energy, would be replaced by an alternative product or service. This is relevant when taking about substitution and emissions avoided as a result.

GHG emissions and removals adjust the radiation balance (radiative forcing) of the planet and, thus, have either a warming or a cooling effect on the climate. The dynamics related to the emissions and removals of forests and timber use impact their climate effects.

Created: Head of Unit Sampo Soimakallio and Researcher Anna Lipsanen, Finnish Environment Institute (Syke).

In addition to the Canemure project, the content of the site was produced with the support of the Maj and Tor Nessling Foundation.

Published 2021-10-29 at 9:46, updated 2023-04-11 at 12:19

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