Link, R. (2010): <b>The variation of wood specific gravity and aboveground biomass along gradients of topography and elevation in tropical montane forests of southern Ecuador</b> University of Göttingen, <i>bachelor thesis</i>
Resource Description
Title:
The variation of wood specific gravity and aboveground biomass along gradients of topography and elevation in tropical montane forests of southern Ecuador
FOR816dw ID:
1123
Publication Date:
2010-09-07
License and Usage Rights:
Resource Owner(s):
Individual:
Roman Link
Contact:
email:
romanlink <at> gmx.de
Abstract:
Wood specifc gravity (WSG) is a key plant functional trait and an important variable for aboveground tree biomass (AGB) and carbon stock estimation. Knowledge about spatial patterns of WSG and its environmental constraints in tropical mountain forests is comparatively scarce, especially when it comes to the effects of elevation and topography. Moreover, the answer to the question whether gradients in WSG in uence spatial patterns of AGB remains uncertain. In this study, altitudinal and topographical gradients in AGB and WSG were assessed in a tropical mountain forest ecosystem in southern Ecuador. For this purpose, a total of 1769 trees in 54 permanent sample plots along environmental gradients were censused and WSG was measured using a Pilodyn 6J wood tester. The obtained data were used to estimate AGB using allometric models from Chave et al. (2005) both with and without tree height as a predictive variable. WSG was found to increase signifcantly upslope by an average of 9,3 %, but did not show altitudinal gradients. If computed with tree height, AGB decreased signi cantly both upslope and with elevation. AGB on lower slopes in the average was 95,8 % bigger than on upper slopes and decreased more than 1.5-fold with increasing altitude from a mean of 288.9 t ha-1 at approx. 1000 m a.s.l. to 112.3 t ha-1 at approx. 3000 m a.s.l.. If computed without tree height, AGB was found to be lowest at intermediate elevations, and AGB results were systematically higher. A possible explanation for the upslope decrease in WSG are reduced growth rates induced by nutrient limitation. The reason for the gradients in AGB is most likely the altitudinal and upslope decrease in tree height in the study area which in former studies has been related to nutrient limitation as well. Given the enormous altitudinal decrease of tree height in tropical mountain forests, performance of allometric models which do not use tree height as a predictive variable was found to be poor. The observed gradients in WSG could not predict the patterns in AGB, in contrast, AGB was found to be highest in sites with low WSG.
Additional Infos:
within subproject A1
Literature type specific fields:
THESIS
Degree:
bachelor
Degree Institution:
University of Göttingen
Total Pages:
46
Metadata Provider:
Individual:
Jürgen Homeier
Contact:
email:
jhomeie <at> gwdg.de
Faculty of Resource Management
University of Applied Sciences and Arts (HAWK)
37077 Göttingen
Germany
