Abstract

Keywords

stand history, stand dynamics, Methods: dendroecology, Plants: Pinus mugo, dendroecology

Abstract

The purpose of this paper is to determine if tree rings can be used to reconstruct the disturbance history in a pure mountain pine (Pinus mugo Turra) stand. Particulary, can tree rings be used as indicators of tree-decline history prior to tree death? Dendroecological and phytopathological analyses were undertaken in the Swiss National Park on trees recently dead and infected by Armillaria spp. and by Heterobasidion annosum. Age structure and ring-width chronologies were used to determine the way the stand established, and to follow the development of the stand. Trees seemingly have established after a fire at the beginning of 1800. After 1858 the ring-width chronologies show a distinct growth release, which may be explained by logging, as also confirmed by historical sources. Starting in the first decades of 1900, all trees showed a more pronounced decreasing trend in ring-width patterns until death, probably caused by root infections. However, tree rings do not enable the onset of infection to be dated. The calendar year of death of the standing dead trees was determined by cross-dating ring-width patterns of dead trees to reference chronologies from living trees. This procedure is not, however, exact as there may be multiple intermittent missing rings. All trees infected by Armillaria showed a slow growth decrease indicating suppression for several decades, and suggesting that Armillaria attacked trees that were already weakened by competition. In contrast, trees infected by H. annosum died over a very short period of time, although they may have been infected a long time previously. Tree rings enabled the history (e.g. fire, frost, logging, fungal diseases) of the stand to be reconstruted.

LWF Classification

Network: LWF, Category: non-ISI(rev/non-rev?),