tailieunhanh - Báo cáo lâm nghiệp: "Horizontal structure of forest stands on permanent research plots in the Krkonoše Mts. and its development"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Horizontal structure of forest stands on permanent research plots in the Krkonoše Mts. and its development. | JOURNAL OF FOREST SCIENCE 56 2010 11 531-540 Horizontal structure of forest stands on permanent research plots in the Krkonose Mts. and its development D. Zahradnik S. Vacek L. Bílek I. Noskova Z. Vacek Faculty of Forestry and Wood Sciences Czech University of Life Sciences Prague Prague Czech Republic ABSTRACT Horizontal structure on 38 permanent research plots is described for juvenile growth and developmental phases natural seeding advance growth plantations and tree layer of a parent stand. Hopkins-Skellam index Pielou-Mountford index Clark-Evans index and Ripley s A-function were computed. The results are presented separately for beech stands mixed stands spruce stands stands in the timberline ecotone and relict pinewood. The numbers and distribution of natural and combined regeneration recruits are mostly sufficient from the aspect of ecological environmental and production functions of forest. The horizontal structure of juvenile growth and developmental phases of natural and combined regeneration shows mostly clustering it is random or moderately regular at places with a single dominant proportion of artificial regeneration. In the tree layer the horizontal structure of forest stands is mostly random to moderately regular. In the future silvicultural measures should be aimed to support the structure of homogeneous stands of younger growth phases that have originated on a large scale after the air-pollution disaster. Keywords Clark-Evans index forest stands Hopkins-Skellam index horizontal structure K-function Krkonose Mts. Pielou-Mountford index The spatial structure of forest stand is a stand framework assessed in a horizontal and vertical direction. Stand density stocking and canopy closure are usually investigated in forest stands from the aspect of horizontal structure while from the aspect of vertical structure it is the formation of one or several stand storeys and of stand layers within them Vacek 1982 . In addition Schutz 2002 differentiated between