Diagnosis, monitoring and evaluation of forest health and protection
- Forest health.
- Importance of de?nitions and concepts.
- Factors affecting forest health.
- Forest declines.
- Methods used in forest health diagnosis, monitoring, and evaluation.
- Status and trend.
- Terrestrial investigations.
Over the last 30 years forest health became a popular issue together with the concern about acid rain, air pollution, and climate change. Terms like forest decline, and the German ?Waldsterben' (forest death) and ?Neuartigen Waldscha ¨den' (new type of forest damage) became frequent in scienti?c literature as well as in popular media. This concern resulted in an unprecedent effort to study and monitor forest health. Since then the situation has evolved and now forest health diagnosis and monitoring is relevant to a much broader area of interest, including recent (e.g., climate ?uctuation and change, biodiversity, sustainable resource management) and ?traditional' issues (e.g., pests, diseases, forest ?re). Broadly, forest health diagnosis, monitoring, and evaluation aims to identify forest health problems, track forest health status through time and identify its relationship with environmental (biotic and abiotic) factors. It embraces a variety of activities and involves several topics and scienti?c disciplines. Forest health diagnosis, monitoring and evaluation is addressed here in terms of (1) de?nitions, factors affecting forest health and most known forest health declines in the world, (2) methods of diagnosis, monitoring, and evaluation, and (3) relevance and applications.
[...] Recent de?nitions of forest health as well as the criteria and indicators for sustainable forest management (SFM) consider key words such as ?long-term sustainability,' ?resilience,' ?maintenance' of ?ecosystems structure and functions,' ?multiple bene?ts and products.' Overall, this suggests that the health of individual trees is somewhat different from the health of the forest: although the detection of individual unhealthy trees is important as they may be signaling the occurrence of problems that may become serious in the future, it is important to consider that death of trees is as important as birth and growth to the vitality of forests. [...]
[...] In general terms, health assessment at the ecosystem level needs to consider resilience, vigor, and organization of the ecosystem as well as the presence of stressors that may exceed the tolerance limit of the system. Resilience, vigor, and organization can be interpreted in operational terms as diversity, integrity of the physical, biotic, and trophic networks, productivity, equilibrium between demand and supply of essential resources, resistance to catastrophic change, and ability to recover. Also, the occurrence of endangered species has to be considered. [...]
[...] A number of indicators can be used in forest health monitoring and the choice of the most suited ones depends on the problem being examined, the available resources, the available expertise, and the ecological, spatial, and temporal coverage of the investigation. Indicators can be considered according to their nature (e.g., stress, response), ecosystem compartment (e.g., atmosphere, vegetation, soil), platform used (terrestrial, aerial, satellite), and method of detection (from visual assessment in the ?eld to biochemical analysis in the laboratory). Terrestrial investigations 1. [...]