Journal of Forest Science, 2006 (vol. 52), issue 4

Development of young substitute larch (Larix decidua Mill.) stands after first thinning

J. Novák, M. Slodičák

J. For. Sci., 2006, 52(4):147-157 | DOI: 10.17221/4497-JFS  

European larch (Larix decidua Mill.) is one of the most important tree species in substitute stands of the Krušné hory Mts. (northern part of the Czech Republic). At present, young larch stands have dynamic height growth and their canopy is closing. Therefore, the proper forest treatment with respect to all functions of these stands is an urgent issue. The aim of the study is to recognise when it is possible to start with thinning and what types of thinning regimes are more suitable in larch stands with respect to their functions as substitute tree species stands. Research was conducted on experimental series Kalek established in a larch monoculture...

Transformation of even-aged spruce stands at the School Forest Enterprise Kostelec nad Černými lesy: Structure and final cutting of mature stand

J. Remeš

J. For. Sci., 2006, 52(4):158-171 | DOI: 10.17221/4498-JFS  

This paper deals with the transformation of pure even-aged forest stands to mixed and more uneven-aged stands on an example of selected even-aged Norway spruce stands in the School Forest Enterprise (SFE) in Kostelec nad Černými lesy. A forest stand where individual tree felling was used as the main method of forest stand regeneration was chosen as a conversion example. The main criterion of tree maturity is the culmination of mean volume increment of a single tree. The analyses confirmed a very high variability in the growth potential of individual trees. The potential and actual increment was strongly influenced by the stand position of tree and...

Development of the primary values of yield tables of spruce in comparison with their development on permanent research plots

R. Petráš, L. Brezina, J. Mecko

J. For. Sci., 2006, 52(4):172-180 | DOI: 10.17221/4499-JFS  

Development of yield curves of mean and top height and development of mean diameter of the yield tables of spruce is compared with their development on 28 permanent research plots with 156 repeated measurements. The time gap of repeated measurements on research plots is in the range of 10-38 years. The agreement and differences in the development of model and empirical curves were examined by means of mathematical and statistical characteristics. The development of mean and top heights in the yield tables of spruce is consistent with their development on permanent research plots. Mean diameters of yield tables are systematically smaller by about 4%....

Object-oriented classification of Ikonos satellite data for the identification of tree species composition

F. Hájek

J. For. Sci., 2006, 52(4):181-187 | DOI: 10.17221/4500-JFS  

This paper describes the automated classification of tree species composition from Ikonos 4-meter imagery using an object-oriented approach. The image was acquired over a man-planted forest area with the proportion of various forest types (conifers, broadleaved, mixed) in the Krušné hory Mts., Czech Republic. In order to enlarge the class signature space, additional channels were calculated by low-pass filtering, IHS transformation and Haralick texture measures. Employing these layers, image segmentation and classification were conducted on several levels to create a hierarchical image object network. The higher level separated the image into smaller...

Comparison and selection of growth models using the Schnute model

Y. Lei, S. Y. Zhang

J. For. Sci., 2006, 52(4):188-196 | DOI: 10.17221/4501-JFS  

Forestmodellers have long faced the problem of selecting an appropriate mathematical model to describe tree ontogenetic or size-shape empirical relationships for tree species. A common practice is to develop many models (or a model pool) that include different functional forms, and then to select the most appropriate one for a given data set. However, this process may impose subjective restrictions on the functional form. In this process, little attention is paid to the features (e.g. asymptote and inflection point rather than asymptote and nonasymptote) of different functional forms, and to the intrinsic curve of a given data set. In order to find...