Sebastian Hein

Valuable Broadleaved Forests in Europe

1. Introduction 1.1 Increasing Interest in Valuable Broadleaved Tree Species 1.2 Aim of the Book 2. State of the Art 2.1 Future Prospects for the Production of Timber from Valuable Broadleaves 2.2 Results of a Questionnaire on Management of Valuable Broadleaved Forests in Europe 3. Prerequisites for Growing Valuable Broadleaves 3.1 Genetics and Tree Breeding 3.2 Diseases, Disorders and Pests of Selected Valuable Broadleaved Tree Species 4. Management of Valuable Broadleaves 4.1 Crown Architecture of Valuable Broadleaved Species 4.2 Modeling Natural Pruning of Common Ash, Sycamore and Wild Cherry 4.3 Controlling Diameter Growth of Common Ash, Sycamore and Wild Cherry 4.4 Final Cutting Systems of Valuable Broadleaves 4.5.Wood Properties and Wood Processing of Valuable Broadleaved Trees Demonstrated with Common Ash and Maple in Southwest Germany 5. Environment and Society 5.1 Valuable Broadleaved Trees in the Landscape 5.2 Effects of Management of Valuable Broadleaved Trees on Nature Conservation 5.3 Do Species Matter? Valuable Broadleaves as an Object of Public Perception and Policy 6. Conclusions 6.1 Basic Features for Growing Valuable Broadleaved Trees in Europe 6.2 Future Strategies for Growing Valuable Broadleaved Trees in Europe 6.3 Future Research Needs and Challenges for Growing Valuable Broadleaved Trees in Europe Appendices

Cutpoint analysis for models with binary outcomes: a case study on branch mortality

Models of binary outcomes are commonly used in forestry, but the predictions errors of these types of models are difficult to present effectively. In addition, most studies generally use a fixed value of 0.5 as the separation between events and non-events. The use of cutpoint analysis has been widely utilized in the health sciences and other fields, while it is relatively uncommon in the forestry literature. Cutpoint analysis involves locating the optimal value that minimizes prediction errors associated with binary outcomes. This case study illustrates the use of cutpoint analysis to improve a dynamic model of individual branch mortality. In this study, the use of cutpoint analysis increased the model specificity (prediction of events) from 77.8% (standard cutpoint of 0.5) to 90.3% (optimal cutpoint of 0.672). At the same time, the sensitivity of the model decreased only slightly and the false positive rate (non-event predicted as an event) was greatly decreased from 22.2 to 9.7%. In addition, the use of receiver operating characteristics (ROC) curves was an effective approach for evaluating prediction errors of models of binary outcomes. Cutpoint analysis is a simple yet effective method for improving predictions of binary outcomes and should be used more regularly, particularly when modelling the binary outcome of rare events such as mortality.

Comparative analysis of occluded branch characteristics for Fraxinus excelsior and Acer pseudoplatanus with natural and artificial pruning

The aim of this study was to develop models on branch characteristics for Fraxinus excelsior L. (common ash) and Acer pseudoplatanus L. (sycamore maple) based on 44 and 25 sample trees, respectively. A total of 635 ash and 334 maple branches were sampled. The data set on artificial pruning was pooled among the two species with a total of 71 branches from 16 trees. The material was used to predict (i) the time for a complete occlusion, (ii) the total radius of the occluded branch inside the trunk, (iii) the branch insertion angle, and (iv) the dead branch portion of the occluded branch. In addition, the effects of species and natural versus artificial pruning were assessed. Generalized hierarchical mixed models with univariate or multivariate approaches were used in this analysis. The diameter of the occluded branch and the stem radial increment played a dominant role as predictors. Artificial pruning led to a significant reduction in occlusion time and a shorter occluded branch radius. Only few species-sp...

Algorithm for Matching Sets of Time Series

Time series are time-stamped sequences of values which represent a parameter of the observed processes in subsequent time points. Given a set of time series describing a set of similar processes, the model of the behavior of processes is constructed as a range of classification trees which describe the characteristics of each particular time point in series. An algorithm for matching a sequence of values with the model is used for searching common patterns in the sets of time series, and for predicting the starting time points of undated time series. The algorithm was developed and analyzed in the frame of the study of tree-ring time series. The implementation and the empirical analysis of the algorithm on the tree-ring time series are presented.

Crown and tree allometry of open-grown ash ( Fraxinus excelsior L.) and sycamore ( Acer pseudoplatanus L.)

The aim of this study was to set up allometric models on the development of open-grown trees (OGT) of ash (Fraxinus excelsior L.) and sycamore (Acer pseudoplatanus L.). Sampling was carried out during a study on valuable broadleaves in Europe and covers a geographical location from 0° to 9° eastern longitude and 47° to 51° northern latitude in Western Europe. We set up models describing (I) crown allometry, taking into account possible effects of (II) site-specific differences and (III) species effects. In addition, simulations were used calculating the potential width of the knotty core inside the stem for self-pruned OGTs. The models also procured insight into space occupation of OGTs. This investigation on crown and tree allometry for a broad range of tree size complements dynamic models on growth of broadleaved trees only monitored at young ages and for a small number of years. It quantifies the relationship between tree height, stem diameter, height-stem diameter ratio, height to crown base, and descriptors of crown form. Only for the models on the crown width/length ratio (WL ratio) and on the crown ratio were there no significant allometric differences between the two species. For none of the models were site effects found to be significant. Self-pruning of ash and sycamore OGTs was slow and the simulated knottiness of the trunk was considerable. Therefore artificial pruning is necessary for a long clear bole, although both species are known for fast self-pruning. In addition, comparison of crown allometric models for forest trees and open-grown ash and sycamore trees underlined the need for specific models in agroforestry based on OGT. Specifically, when tree diameter being equal, OGTs have larger crowns compared to trees from closed forests. During tree development crown form changes uniformly with no significant species-related difference: The vertical crown expansion of young ash and sycamore overweighs the lateral expansion. As trees mature, the crown WL ratio increases leading to crown width values almost equal to crown length. Thus in their early stages of development ash and sycamore OGTs invest more in the vertical space occupation and only at later stages in horizontal expansion.

Crown and branch attributes of mid-aged Betula alnoides plantations in response to planting density

ABSTRACT Both crown and branch characteristics greatly affect tree growth and timber quality, and their development is closely related to planting density (PD). Here crown and branch attributes of Betula alnoides were investigated in a 14-year-old experimental plantation in southern China with five planting densities ranging from 500 to 3333 stems per hectare (sph). The results showed that high PD significantly reduced crown and branch sizes. The ratios of crown diameter to stem diameter at breast height at the stand level and for dominant and co-dominant trees were almost constant regardless of PD. PD also had no significant influence on the number and angle of branches, and only planting with the highest density significantly increased branch density and mortality. Insertion angle (IA) of dead branches was greater than that of live branches and these differences were significant at the two low planting densities (833 and 500 sph). Linear mixed models revealed that branch diameter (BD) was negatively correlated with its relative height in the crown and IA. The binary-logistic regression model indicated that branch status (live or dead) was codetermined by BD and PD. These findings can help farmers cultivate high-quality wood of B. alnoides and obtain a higher economic return.

Croissance, qualité et mortalité du Noyer hybride sur différentes stations dans le Bade-Wurtemberg (Allemagne)

Hybrid walnut is more and more common in Germany, due to its superior growth in particular. However, only very basic knowledge about growth, quality, mortality and site requirements is available to German tree growers for the three most popular French hybrids (MJ209xRA, NG23xRA and NG38xRA). More accurate information is now being provided by the findings of a large-scale experimental scheme set up in the Baden-Wurttemberg (Germany) between 2001 and 2005. Concerning height and girth growth, the hybrid NG23xRA yields the best results. Site conditions that rule out hybrid walnut plantation or adversely affect the tree’s shape are soils where heavy clay dominates and hence susceptible to hydromorphism, as well as an inadequate saturation rate for exchangeable bases. Hybrid NG23xRA can be expected to give the best results in terms of quality. This hybrid has fewer strong branches and their development is relatively homogenous. It is clear from these findings that in order to produce high quality wood from hybrid walnut in Germany it is essential to carefully choose the cultivar and the matching site as well as provide intensive care in the first years of growth.