tailieunhanh - Báo cáo lâm nghiệp: " Influence of stand density, thinning and elevated CO2 on stem wood density of spruce"

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: Influence of stand density, thinning and elevated CO2 on stem wood density of spruce. | JOURNAL OF FOREST SCIENCE 53 2007 9 400-405 Influence of stand density thinning and elevated CO2 on stem wood density of spruce I. Tomásková1 R. Pokorny1 M. V. Marek1 2 -Laboratory of Plants Ecological Physiology Institute of Systems Biology and Ecology Academy of Sciences of the Czech Republic Brno Czech Republic Faculty of Forestry and Wood Technology Mendel University of Agriculture and Forestry Brno Brno Czech Republic ABSTRACT Stem wood density SWD of young Norway spruce trees Picea abies L. Karst. growing at ambient A variant 350 pmol CO2 mol and elevated E variant A 350 pmol CO2 mol atmospheric CO2 concentration inside of the glass domes with adjustable windows was estimated after six and eight years of the cultivation. Stand density of two subvariants s - sparse with ca 5 000 trees ha and d - dense with ca 10 000 trees ha and thinning impact intensity of 27 on SWD and its variation along the stem vertical profile were investigated. After six years of CO2 fumigation stems of sparse subvariant had about 10 lower values of SWD comparing to dense ones although the difference was not statistically significant. In 2004 two years after thinning the SWD values were higher in all subvariants along the whole stem vertical profile. This increase was more obvious in E variant about 6 in d subvariant and only 3 in s subvariant . The highest increase of SWD values was found in Ed subvariant particularly in the middle stem part about 8 statistically significant increase . Keywords elevated CO2 Picea abies stand density stem wood density thinning Stem wood density SWD is the most important determinant of the wood quality. It allows estimation of biomass and carbon mass contained in terrestrial vegetation Fearnside 1997 . The SWD is defined as the dry mass to fresh volume ratio and ranges typically within the interval from to 1 g cm3 Roderick 2001 . SWD depends mainly on the cell size and the cell wall thickness. Specifically SWD of forest trees is influenced by many .