Project Details
Projekt
On the influence of stand spatial structure and species diversity on growth and recruitment of structurally complex forests: evaluating the role of distance-dependent and species-sensitive competition indices within the Acadian region of northeastern North America
Applicant
Dr. Christian Kühne
Subject Area
Forestry
Term
from 2014 to 2016
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 264014365
Forest management in many parts of the Northern hemisphere is moving away from the conventional single-species, even-aged management toward selection harvesting systems. The widespread adoption of such practices has outpaced fundamental research addressing the ability of selection systems to meet the intended objectives for more complex and diverse forest structures ensuring a more continuous provision of ecosystem goods and services. By simulating and predicting long-term future developments forest growth and yield models are a potential means to overcome these deficiencies. Forest growth simulators often rely on competition indices that express and quantify local neighborhood effects to analyze tree-to-tree interactions and the resulting stand dynamics. Multiple studies have attempted to find the best index of competition for predicting tree growth, and stand yield. No clear trends, however, have emerged from these analyses, even when just a certain class of indices, e.g. distance-independent indices, was compared. In addition, most analyses focusing on distance-dependent competition indices were conducted in even-aged, single species stands with limited remeasurements. In the Acadian Forest of northeastern North America the shift toward novel management procedures has created unprecedented stand structures with unknown consequences for the future forest development and timber supply. However, several study sites with a permanent plot system have been installed in forest stands that have been alternatively managed for research since the 1960s. Remeasurements of tree growth and recruitment as well as the collection of stem-mapped data now allow for the comprehensive evaluation of growth and regeneration dynamics in these structurally complex forest sites. Moreover, given the wider availability of stem-mapped permanent measurement plots and the necessary computing technology to make spatially explicit estimates of competition, a comprehensive assessment of competition measures is now warranted for these mixed-species and structurally complex forests. The proposed project will analyze how the variation of structural forest characteristics such as species diversity and tree spatial distribution influence the performance of different competition indices. Based on these findings, new individual tree growth and ingrowth (occurrence, frequency, composition of regeneration) equations will be developed and inserted into the distance dependent Acadian Variant of the Forest Vegetation Simulator (FVS-ACD) currently being developed. The proposed project therefore offers the opportunity to answer fundamental research questions regarding tree-to-tree competition, while also addressing an important applied research need for improved regional growth and yield models.
DFG Programme
Research Fellowships
International Connection
USA
