& Key message Volume predictions of sample trees are basic inputs for essential National Forest Inventory (NFI) estimates. The predicted volumes are rarely comparable among European NFIs because of country-specific dbh-thresholds and differences regarding the inclusion of the tree parts stump, stem top, and branches. Twenty-one European NFIs implemented harmonisation measures to provide consistent stem volume predictions for comparable forest resource estimates. & Context The harmonisation of forest information has become increasingly important. International programs and interest groups from the wood industry, energy, and environmental sectors require comparable information. European NFIs as primary source of forest information are well-placed to support policies and decision-making processes with harmonised estimates. & Aims The main objectives were to present the implementation of stem volume harmonisation by European NFIs, to obtain comparable growing stocks according to five reference definitions, and to compare the different results. & Methods The applied harmonisation approach identifies the deviations between country-level and common reference definitions. The deviations are minimised through country-specific bridging functions. Growing stocks were calculated from the unharmonised, and harmonised stem volume estimates and comparisons were made. This article is part of the topical collection on Forest information for bioeconomy outlooks at European level
Fire is a significant agent for the development of boreal and hemiboreal forests, altering soil and light conditions, affecting seedbanks, and removing seed trees. Burned areas should be managed with care, as inappropriate techniques prolong the regeneration period and reduce the diversity and resilience of stands to disturbances. To study the effects of fire and postfire management on the successional changes in regeneration abundance, species composition and tree height sample plots were established in sandy pine forests in northwestern Estonia on areas burned 2 or 22 years ago. Five types of sample plots were established: (i) areas without fire damage, (ii) burned uncleared areas, (iii) burned forest areas cleared after forest fire, (iv) burned uncleared areas with live trees, and (v) burned uncleared areas with dead trees. Three main tree species common to hemiboreal forests were analyzed: Betula spp., Pinus sylvestris L., and Populus tremula L. Results showed that clearing burned areas after wildfire significantly reduced the abundance of regeneration compared with burned uncleared areas but favored height growth of P. sylvestris in later development. To regenerate and maintain mixed stands after wildfire, retaining some residual trees can facilitate regeneration compared with complete clearing, although a dense stand with live trees or a large amount of deadwood can hinder regeneration.Résumé : Le feu est un agent important de développement des forêts boréales et hémiboréales; il modifie le sol et la luminosité, affecte les banques de graines et élimine les arbres semenciers. Les aires brûlées doivent être aménagées avec soin puisque des techniques inappropriées prolongent la période de régénération et réduisent la diversité et la résilience des peuplements aux perturbations. Pour étudier les effets du feu et de l'aménagement après feu sur les changements successionnels dans l'abondance de régénération, la composition en espèces et la hauteur des arbres, des placettes échantillons ont été établies dans des pinèdes sur sols sablonneux ayant brûlées 2 ou 22 ans auparavant dans le nord-ouest de l'Estonie. Cinq types de placettes échantillons ont été établies : (i) aires exemptes de dommage causé par le feu, (ii) aires brûlées avec des arbres vivants ou morts non récupérés après le feu, (iii) aires brûlées où tous les arbres vivants et morts ont été récoltés après le feu, (iv) aires brûlées avec des arbres vivants non récupérés et (v) aires brûlées avec des arbres morts non récupérés. Trois espèces d'arbre communes aux forêts hémiboréales ont été analysées : Betula spp., Pinus sylvestris L. et Populus tremula L. Les résultats montrent que les aires brûlées et récupérées après le feu étaient associées à une abondance de régénération significativement plus faible que les aires brûlées non récupérées, mais à une plus forte croissance en hauteur de P. sylvestris au cours des stades plus avancés de développement. Pour régénérer et maintenir des peuplements mixtes après un feu, la rétention de quelques arbres résidue...
This paper describes a new SAS/STAT ® procedure for fitting models to non-normal or normal data with correlations or nonconstant variability. The GLIMMIX procedure is an add-on for the SAS/STAT product in SAS ® 9.1 on the Windows platform. PROC GLIMMIX extends the SAS mixed model tools in a number of ways. For example, it• models data from non-Gaussian distributions• implements low-rank smoothing based on mixed models • provides new features for LS-means comparisons and display• enables you to use SAS programming statements to compute model effects, or to define link and variance functions• fits models to multivariate data in which observations do not all have the same distribution or linkApplications of the GLIMMIX procedure include estimating trends in disease rates, modeling counts or proportions over time in a clinical trial, predicting probability of occurrence in time series and spatial data, and joint modeling of correlated binary and continuous data.This paper describes generalized linear mixed models and how to use the GLIMMIX procedure for estimation, inference, and prediction.
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