Taper curves (i.e., functions describing the shape of a tree stem) can be used for conveniently computing the volume of a tree stem, using volume integrals, but they are not very commonly used in ecological research. The curves and their volume integrals are particularly convenient for computing the volume of snapped trees, where the shape of the stem (taper) is determined by the tree diameter and the height of the tree before snapping, and the volume is computed from the base of the tree to the snapping height (or any other point along the stem). Same functions can be used to compute the volume of a fallen part of a snapped tree just as easily.
We’ve written an easy-to-use R-script for several tree species in regions we are working in, based on previously published taper curves: Scots pine, Norway spruce, and birch in Finland, as well as black spruce and balsam fir in Quebec, Canada. Take a look at the script here.
Mountain forests of northern Fennoscandia are often referred to as “Europe’s last wilderness”. In a recent paper, written jointly with Bengt-Gunnar Jonsson (Mid-Sweden University) and Annika Hofgaard (Norwegian Institute for Nature Research) we reviewed the history, current state and discuss the unpredictable future of these forests.
See the full paper here, or access the pre-print version here.
A new paper on light availability effects on aquatic macrophyte community formation, utilizing variance partitioning approach, has been published online in Hydrobiologia. The paper was a joint effort with Hanna Luhtala, Harri Tolvanen and Risto Kalliola from the section of Geography, University of Turku.
Click here for the paper.
The TRADER-package for Tree Ring Analysis of Disturbance Events in R, co-authored with Jan Altman, Pavel Fibich and Jiri Dolezal is now available in CRAN.
Follow the link here.
Our new paper on modeling tree crown asymmetry in high-latitude boreal forests, using circular statistics has just been published in OIKOS. This paper was a collaborative effort with Kenichiro Shimatani (Institute of Statistics and Mathematics, Japan), Toshihiro Abe (Nanzan University, Japan), and Yasuhiro Kubota (University of the Ryukyus, Japan) and our research group.
For more details, click here or see the full paper here.
This paper is published in Science and it reviews the specific ecological nature of the boreal forests and the current status of forest health at the face of global change. The paper examines the trends of forest health across the circumboreal zone and suggests ways forward in sustaining more healthy forest ecosystems in the future.
Boreal forest health and global change, by S. Gauthier, P. Bernier, T. Kuuluvainen, A.Z.Shvidenko and D.G.Schepaschenko.
link to paper