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Forest management plans in Bavaria are generally updated only once every 10 years. However, the increasingly dynamic forest structure due to climatic changes requires more frequent data collection in order to maintain up-to-date information. This study explored the use of RapidEye satellite data to provide more frequent updates to the information database. Forest structural information such as quadratic mean diameter (dq), basal area (BA), stem number (SN) and volume (V) were estimated using multi-seasonal analysis of three RapidEye datasets from 2009. Spectral indices and textural metrics provided additional image feature layers. Forest inventory plots were stratified based on the forest type. A correlation analysis was conducted between terrestrial inventory data and that derived from RapidEye data. A cross-validated stepwise forward regression analysis was performed for each forest type. The coefficient of determination and relative root mean square error (rRMSE) showed that stratification improved the regression models, which obtained determination measures ranging from 0.37 to 0.63 and rRMSE ranging from 25 to 131 per cent. Biases of the regression estimates were small, hence the results obtained from applying the models were of an acceptable level of accuracy. The analysis confirmed the potential of RapidEye data to support forest management.

The objective of this study was to determine whether a suite of wood quantity and quality attributes of balsam fir and black spruce forests could be predicted using airborne laser scanner data.In situ estimates of stand structure and wood fibre attributes were derived from measurements at sample plots covering a wide range of forest conditions of insular Newfoundland. Models developed to predict field estimates explained 52 –90 per cent of the variation in structure attributes, including mean and quadratic mean diameter at breast height, average and dominant height, stem density, basal area, total and merchantable volume and above-ground total biomass. Crossvalidated root mean square errors were ,24 per cent of mean values, with the exception of stem density, for which errors were 27– 32 per cent. Models of fibre attributes explained 18 –53 per cent of the variation in fibre length, wood density, radial diameter, coarseness, microfibril angle, modulus of elasticity, wall thickness and specific surface with cross-validated root mean square errors of ,14 per cent of mean values. Similar results were achieved for fibre attribute models derived using geographic, climate and vegetation variables. The results demonstrate potential for inventory of quantity and quality attributes over a large region of boreal forests in Newfoundland, Canada.

A new stand-level dynamics model based on observed stand growth trajectories is presented. This stand-level dynamics model uses the trajectories of observed plots through Reineke’s quadratic mean diameter-density space to predict the change in quadratic mean diameter, ingrowth and mortality over time. The model uses the collection of observed trajectories as a probability distribution that is used to guide an informed random walk. An imputation model is used to select k nearest neighbors (bandwidth) which are then used to build joint kernel distributions. From these kernel distributions, m random samples (sample intensity) are averaged to predict the change in quadratic mean diameter, ingrowth and mortality. All levels of k tested (10, 20, 30) performed well as long as sampling intensity was above 1. Variability in predictions was reduced at sampling intensities above 1, but no significant differences were visible among sampling intensities 5 and above.

Summary In this study, we examined density–size relationships for Sitka spruce (Picea sitchensis (Bong.) Carr.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) using data collected in stands in Great Britain (GB) and Western Canada. These two conifers are native to Western North America and have been widely planted in GB. Results indicate differences between stands in Canada and GB in both the intercept and slope of the log maximum density–log size boundary lines. In GB, the slope (b) of the relationship between log of stand density (number of trees per hectare) and log of quadratic mean diameter (Dq) is steeper than the theoretical value of −1.605 (−2.063 for Sitka spruce and −1.864 for Douglas-fir). Values of b are lower in Canada (−1.437 for Sitka spruce and −1.241 for Douglas-fir) than in GB . Within each region, b is similar for the two species. However, the intercept term differs for Sitka spruce and Douglas-fir in GB. These differences provide additional evidence that density–size boundary line relationships are influenced by environmental and other factors and indicate the need for development of density–size relationships for each species and for each region where the species is grown. Maximum stand density index (SDI) values calculated using these relationships are 1868 and 2073 for Sitka spruce and 1491 and 1815 for Douglas-fir in GB and Canada, respectively. Differences in maximum SDI between these two regions may be related to differences in climate, provenance, stand history and other factors. Maximum density–size relationships presented in this paper can be used as a starting point for managing stand density for both even-aged and continuous cover stands and for identifying potential maximum stocking in stands of these species in GB and Canada.

Summary A generalized height – diameter ( h - d ) model was developed in order to predict the total height of individual trees in uneven-aged stands in the region of El Salto, Durango (Mexico). Seven generalized h-d equations were evaluated and the equation proposed by Sharma and Parton, which includes the diameter at breast height of the tree and the quadratic mean diameter and the dominant height of the stand as independent variables, was selected as the best model. In order to address the among-plot variability, a non-linear mixed-effects modelling approach was used to fi t the selected model for all the species or groups of species. The mixed model included a random parameter that affected the model asymptote. Calibration of the obtained h-d model for a particular species or group of species in a plot of interest was carried out with only a single randomly selected tree from the species or group of species within the plot. The stochastic component added to the mixed-effects model enabled the observed natural variability in heights within diameter classes for the same stand to be mimicked, thereby providing more realistic predictions. The equation developed represents a new tool for evaluation and management of uneven-aged stands in the region.

A stand density management diagram (SDMD) was constructed for Pinus radiata D. Don plantations in Galicia (north-western Spain) on the basis of four equations that were fitted simultaneously to data collected from 223 permanent plots. The relative spacing index was used to characterize the growing stock. The diagram provides information about quadratic mean diameter, stand merchantable volume, stand above-ground biomass, stand stem biomass and stand carbon pools. In addition, an estimation of the average slenderness coefficient for the whole stand and for each quarter of the stand diameter distribution was included. This information can be used to assess the stability of the whole stand and different crown classes, respectively. The SDMD outlined here allows foresters to make quick and easy comparisons among different thinning schedules in which both timber production and the risk of damage from wind or snow are considered. Two alternative density management systems, one that includes thinning operations and another that only includes the density-related mortality provided by a mortality function, are outlined in the diagram. © Institute of Chartered Foresters, 2009. All rights reserved.

Summary Forest site productivity is the production that can be realized at a certain site with a given genotype and a specifi ed management regime. Site productivity depends both on natural factors inherent to the site and on management-related factors. This review of the evolution of site assessment highlights three tenets of forest site productivity: the height – age site index, Eichhorn’s rule and the thinning response hypothesis. These tenets rely on the hypotheses that height growth correlates well with stand volume growth, that total volume production of a given tree species at a given stand height should be identical for all site classes and that stand volume growth is independent of thinning practice for a wide range of thinning grades. The maturation of long-term fi eld experiments has provided for the revision of these hypotheses, and contributed to an understanding of situations where they do not hold. This led to the introduction of the concept of yield level, the stand volume growth per unit of height growth. The use of the yield level theory for estimating site productivity has facilitated the development of a three-dimensional model of the relationship between stem number, quadratic mean diameter and stand basal area. Given this model, a stand density index based on the combination of stem number and quadratic mean diameter provides an indication of the yield level, which may be used to adjust height-age – based estimates of site productivity.