While some pathogens are native to local ecosystems, many recent major disturbances occur from nonindigenous species that may pose dangerous and unpredictable threats to forest health (Boyd et al. However, climate change (i.e., changes in global temperatures and rainfall) and global trade have increased forest vulnerability to a number of natural disturbances, including diseases caused by pathogens such as fungi, bacteria, viruses and nematodes (Boyd et al. Achieving of these goals will enhance the capability of vegetation spectroscopy in early detection of forest stress and in managing forest diseases.įorests are essential ecosystems, providing numerous ecological, economic, social, and cultural services (Chen and Meentmeyer 2016) and a major portion of the global terrestrial carbon dioxide sink (Pan et al. This review also highlights some major issues to be addressed such as the need to explore other major forest diseases and geographic areas, to further develop hyperspectral sensors for early detection and discrimination of forest disturbances, to improve devices for remote sensing, to implement long-term monitoring, and to advance algorithms for exploitation of spectral data. Late disease conditions particularly affect the shortwave-infrared region, mostly related to water content. Overall, these reviewed studies have pointed out the green and red regions of the visible spectrum, the red-edge and the early near-infrared as the spectral regions most sensitive to the disease development as they are mostly related to chlorophyll changes and symptom development. Using several optical sensors from leaf to landscape-level, a number of forest diseases characterized by variable pathogenic processes have been detected, identified and quantified in many country sites worldwide.

The basic concepts of vegetation spectroscopy and its application in phytopathology are first outlined then the literature on the topic is discussed. This review highlights the potential of vegetation spectroscopy in improving the feasibility of assessing forest disturbances induced by diseases in a timely and cost-effective manner. Sustainable forest management is essential to confront the detrimental impacts of diseases on forest ecosystems.

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