SDG 15 life on land

What's carbon forestry?

About the Forestry

Earth’s carbon balance is calculated as the carbon emissions from human activities minus the carbon uptake by oceans and land systems. Since the industrial use of fossil fuels began, the net carbon balance has resulted in increases in the atmospheric CO2 concentration from 280 parts per million to over 390 parts per million.

Forests Can Act as Either Carbon Sources or Carbon Sinks

A forest is considered to be a carbon source if it releases more carbon than it absorbs. Forest carbon is released when trees burn or when they decay after dying (as a result of old age or of fire, insect attack or other disturbance).

A forest is considered to be a carbon sink if it absorbs more carbon from the atmosphere than it releases. Carbon is absorbed from the atmosphere through photosynthesis. It then becomes deposited in forest biomass (that is, trunks, branches, roots and leaves), in dead organic matter (litter and dead wood) and in soils. This process of carbon absorption and deposition is known as carbon sequestration

The net balance of all of these carbon exchanges determines whether a forest is a carbon source or sink. 

Yet, the carbon source/sink balance is as dynamic as it is complex.

In trees, carbon comes from atmospheric carbon dioxide. Often this carbon is called Biogenic carbon, since living organisms cycle through it. Trees absorb carbon dioxide from the earth. Via a system called photosynthesis, atmosphere. Photosynthesis is used by plants to create different Carbon-based sugars that are needed for the functioning of the tree and for growing wood. Any part of a tree, from the trunks, limbs, leaves and roots, stores carbon. Dried tree wood, by weight, is around 50 percent coal. As a part of their physiology, trees often emit carbon dioxide into the environment. 

The carbon is added back to the atmosphere as any or more pieces of a tree decompose after death or burn during combustion. The

What's the Amount of Carbon in Trees?

The amount of carbon stored in trees depends on a number of things including tree species, growth conditions in the environment, age of tree and density of surrounding trees.

Calculating CO2 Stored In Trees Based on Mass of Tree

“Dry (moisture-free) wood is about 48-50% carbon, 38-42% oxygen, 6-7% hydrogen and a number of other elements, such as nitrogen and sulfur in very small percentages. These percentages are based on the weight of the elements as a percentage of dry wood mass.

Living trees, however, are very wet. In fact, although there can be great variation between tree species (and seasonally), a living tree may be made up of more than two thirds water by mass. Thus, a living tree is made up of 15-18% carbon, 9-10% hydrogen, and 65-75% oxygen by mass.”

Carbon is one of the most essential elements in trunks, branches, roots, and even leaves that shape the physical framework of the material of the tree. Although all vegetation stores carbon, since they live for a long time and because of their comparably dense nature and large scale, trees are especially valuable. Forests are close to a sea of carbon since forests are mainly made of trees with vast quantities of carbon. 

Why is Carbon Circulating in Forest Ecosystems?

The carbon found within forests is often changing because forests are inherently dynamic structures. Forests will simultaneously take up and store carbon by photosynthesis on the scale of minutes and release carbon as trees breathe and soils release carbon by decomposition by soil microbes.


There are natural boom and bust cycles in forests that are reflected in the forest’s carbon storage. For a number of causes, trees die and carbon is released back to the atmosphere as they do. Trees, occasionally in tiny stalls, isolated occurrences such as wind storms, avalanches, or small fires perish. Other times, trees die from natural disorders such as insects or diseases, floods, droughts, and vast numbers of trees and wildfires.

Learn Carbon and the Greenhouse Effect