Forests and forest soils play a broad, complex and interactive role within the environment

Soils have provided the foundation for trees and entire forests over millions of years. Soil is an important component of forest and woodland ecosystems as it helps regulate important ecosystem processes, such as nutrient uptake, decomposition, and water availability. Soils provide trees with anchorage, water and nutrients. In turn, trees as well as other plants and vegetation, are an important factor in the creation of new soil as leaves and other vegetation rot and decompose.

However, the relationship between soils and forests is much more complex and far-ranging. Soils and forests are intrinsically linked, with huge impacts on each other and on the wider environment.  The interactions between forests and forest soils help to maintain the environmental conditions needed for agricultural production. These positive effects are far reaching and ultimately help to ensure a productive food system, improved rural livelihoods and a healthy environment in the face of change.

Forests, forest soils and their interactions carry out key functions that contribute to food security and a healthy environment

1. Climate change: what forests and forest soils do

Carbon emissions are a major contributor to climate change. The world´s forests, in one of their 
many roles, act as a significant carbon store. 650 billion tonnes of carbon, or nearly one third of the 
total in terrestrial ecosystems, are captured in forests. Forest soils also store a quantity of carbon 
equalling that of the global forest biomass, about 45 percent each. An additional ten percent of 
carbon is found in forest dead wood and litter. In total, forests store as much carbon as the 
atmosphere.

2. Sustainable soil management needs sustainable forest management, including 
restoration

The planet needs sustainably managed forests to control soil erosion and to conserve soil. Tree roots 
stabilize ridge, hill and mountain slopes and provide the soil with the necessary mechanical structural 
support to prevent shallow movements of land mass: landslides rarely occur in areas with high forest 
cover.

Sound forest management practices, including measures to introduce or maintain forest cover on 
erosion-prone soils and run-off pathways, will help control or reduce the risk of soil erosion and 
shallow landslides. Forest restoration in dryland areas is vital for soil protection.

3. Major ecosystem benefits of forests and soils: clean water and watershed 
management


By reducing soil erosion and the risk of landslides and avalanches, sustainably managed forests
contribute significantly to the systems providing and maintaining the planet’s supplies of clean water, 
while also ensuring a balanced water cycle.


Forests are also a key component of watershed management – an integrated approach of using 
natural resources in a geographical area drained by a water course. Watershed management is a very 
sound way to protect and rehabilitate areas prone to soil degradation and erosion in upland areas. 
Forest and soil characteristics are among the key parameters assessed in watershed management 
planning. Moreover, measures to restore and enhance soil fertility, e.g. through reforestation, have 
many benefits and are therefore an integral part of any watershed management plan.


4. Soil conservation in semi-arid and arid areas starts with forests and trees

By helping to prevent soil erosion, forests act as a crucial protector of soil resources, for example in 
preventing or reducing salinization. The challenge in arid-zone forests is therefore to optimize the 
trade-offs, between water yield and soil protection.


5. Forests can reduce mountain soils’ sensitivity to degradation


Steep slopes and thin soil make mountain ecosystems extremely vulnerable to erosion. Mountain 
soils are often degraded and invariably do not provide enough nutrients for plants to grow well. FAO 
estimates that around 45 percent of the world’s mountain area is not or only marginally suitable for 
agriculture. The degradation of mountain soil and vegetation cover may happen gradually or rapidly 
but often takes many years to repair; in some cases it is irreversible.


The challenges that mountain farmers must overcome are many: short vegetation periods, steep 
slopes, shallow soils and the occurrence of landslides. To survive, they have had to develop different 
ways of averting or spreading risks, employing complex and diversified farming systems on croplands, 
pastures and forests. They know that they must make use of different soil types at different altitudes and at different times of the year.

In order to protect our soils, we need to protect our trees and forests

The importance of these effects has often been ignored in the past, with the clearance of tree vegetation and the subsequent loss of millions of hectares of productive land. Furthermore, as forests continue to be cleared-exposing the land to direct attack from wind and rain-soil erosion and land degradation are still undermining agriculture's resource base. In order to protect our soils, we need to protect our trees and forests. Both of these vital resources play pivotal roles in food security and a healthy environment.