Abiotic disturbances and their influence on forest health: a review

Abstract

The United Nations declared 2011 to be the International Year of Forests which aims to increase public awareness of forests’ important ecological, economical and social functions. Forests provide shelter for people and habitat to biodiversity. They are a source of food, medicine and clean water and play a vital role in maintaining a stable global climate and environment. With such immeasurable values, protecting the world’s forests from devastating disturbances is crucial. Disturbances are a natural and integral part of forest ecosystems. When they exceed their normal range of variation, however, the impacts on forests can be extreme affecting entire landscapes, causing largeͲscale tree mortality and complete destruction of undergrowth and soils. Global climate change is exacerbating many of these impacts by making forests more prone to damage by altering the frequency, intensity and timing of some events such as cyclones, landslides, insect and disease outbreaks, and heat waves and droughts which increase the risk of largeͲscale fires. Much more information is available on the impacts of biotic disturbances, such as pest outbreaks, on forests than on the impacts of abiotic disturbances, those caused by nonͲliving factors such as storms, drought and tsunamis. FAO’s Global Forest Resources Assessment (FRA), carried out at fiveͲyear intervals, provides the data and information needed to support policies, decisions and negotiations in all matters where forests and forestry play a part. For the first time ever, countries were asked to report on the area of forest damaged by abiotic disturbances for FRA 2010. Information provided was sparse, mostly qualitative and did not allow for any trend analysis. To supplement the information in FRA 2010, and in acknowledgement of the increasing importance of abiotic influences on forest health, FAO prepared this more detailed study. Abiotic disturbances are expected to increase in intensity, quantity and frequency. Adaptive forest management is therefore essential to protect the world’s forests resources. Effective management practices and policies are built upon relevant and timely information and accurate data on disturbances and their impacts on forests. This paper is a first step in synthesizing such information to assist with the management and protection of forest health. Taking care of the world’s forests and effectively managing them not only ensures that they meet their objectives but also reduces the risk of damage from future abiotic disturbances and addresses global climate change concerns.