Aim of study: This paper reviews the global research during the last 6 years (2007)(2008)(2009)(2010)(2011)(2012) on the state, trends and potential of remote sensing for detecting, mapping and monitoring forest defoliation caused by insects.Area of study: The review covers research carried out within different countries in Europe and America.Main results: A nation or region wide monitoring system should be scaled in two levels, one using time-series with moderate to coarse resolutions, and the other with fine or high resolution. Thus, MODIS data is increasingly used for early warning detection, whereas Landsat data is predominant in defoliation damage research. Furthermore, ALS data currently stands as the more promising option for operative detection of defoliation.Vegetation indices based on infrared-medium/near-infrared ratios and on moisture content indicators are of great potential for mapping insect pest defoliation, although NDVI is the most widely used and tested.Research highlights: Among most promising methods for insect defoliation monitoring are Spectral Mixture Analysis, best suited for detection due to its sub-pixel recognition enhancing multispectral data, and use of logistic models as function of vegetation index change between two dates, recommended for predicting defoliation.

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The strategies for the conservation and sustainable use of forest genetic resources, which are essential for the future adaptation of forest species to changing environments, are also a source of valuable genetic resources for breeding and restoration activities. The first step to define and implement cost-effective strategies is to identify specific priority populations. Mexico, in spite of being characterized by high levels of tree species diversity, mostly lacks a combined strategy for the genetic conservation and use of forest genetic resources. The aims of this work are: (i) to identify areas for gene conservation, and (ii) to propose measures for the conservation and sustainable use of forest genetic resources of four pine species: Pinus greggii Engelm. ex Parl., Pinus oocarpa Schiede ex Schltdl., Pinus patula Schiede ex Schltdl. & Cham. and Pinus pseudostrobus Lindl. To do that, we use the existing information on the distribution, genetic variation and conservation and breeding efforts in Mexico. Overall, 51 areas for establishing genetic conservation units were prioritized and 6 genetic zones for the use of forest genetic resources in breeding and selection of forest reproductive material were identified. The current conservation efforts for the four priority Mexican pines should be improved to satisfy the needs of a national breeding and conservation network.

The identification of the factors controlling the understory species distribution and abundance is essential to understand the ecology and dynamics of natural forests and their management response. We assess the relationships between environmental gradients and shrub functional groups distribution patterns and niche characteristics in a transitional area between the Eurosiberian and Mediterranean biogeographic regions in Northern Spain. Here, 772 plots from the 3rd Spanish National Forest Inventory were used. Shrub functional groups respond to the same complex environmental gradients as trees, i.e., the north-south climatic gradient and a slope gradient. Unimodal response curves of shrub functional groups and families dominate along both gradients, providing evidence of successful functional turnover. Similar to tree species, the niche location of functionally related shrubs is close. Functional groups occupying environments with sharp contrast or transitional environments have the broadest niches, whereas those specialized functional groups occupying localized habitats showed the narrowest niches. The knowledge of shrub species distributions and niche characteristics along complex environmental gradients will improve our ability to discuss potential conservation management goals or threats due to land-use changes and future climate change.