Güteansprache am stehenden Baum

Alfeld

2005

S. 416-420

4 Abb., 11 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200126911

Additional information on the quality of growing stock in forests has been obtained for the first time in Baden-Württemberg and Rheinland-Pfalz during the course of Germany's second Federal Forest Inventory (2001-2002). The additional investigation aims to collect data on the quality of growing stock, which can be used to support decision making in the field of forestry and timber processing. The practice of so-called "Trunk Quality Rating" has been conceived at the Forest Research Institute Baden-Württemberg (FVA), and is the combination of elements of the Swiss National Forest Inventory and a practice described in literature as the "butt trunk method". The method assesses timber quality by assigning one of six grades to the tree's trunk; with a value of 1 corresponding to excellent quality and 6 to very poor quality. Quality classes are determined according to a sorting rule, which is supported by a series of pictures. Relevant features such as branchiness, bark appearance, stem form and defects are all taken into consideration. This paper focuses on the relationship between trunk quality and diameter at breast-height (DBH), and presents the results of a study into the quality of large diameter spruce and beech trunks in selected growth zones in Baden-Württemberg. The relationship between trunk quality and DBH ist also investigated and presented individually for spruce, beech and Douglas fir. Quality grades are similarly distributed for all species, with the predominant proportion of growing stock being assigned to grades 3 and 4, as can be expected. Grade 1 (excellent quality) and grade 6 (only partially suitable for harvesting) account for less than 1% of the total. A significant difference in trunk quality is observed for both spruce and beech within the selected growth zones, as well as between both species. Analysis of the dimension trends for individual species reveals that all species display a wider differentiation of grades that tends to result in higher quality with increasing diameter. The Douglas fir exhibits the strongest quality dynamics of all tree species studied across the diameter distribution. The prevalence of grade 1 and 2 trunks, in particular, increase more than a several hundred times with regard to the initial value. This is possible due to pruning a/or silvicultural treatments that favour trees promising good quality in the future. Spruce trees display a stronger quality dynamic than beech, however unlike the douglas fir, each of these species exhibit a proportionally strong increase in both good and bad grades with increasing diameter.