Spatiotemporal growth dynamics and disturbances in a subalpine spruce forest in the Alps: A dendroecological reconstruction

The recent history was reconstructed and the large-scale disturbance regime evaluated of a subalpine spruce (Picea abies (L.) Karst.) stand in the eastern Italian Alps. A 0.4-ha plot was cut for experimental purposes. Living trees, dead stems, and decaying stumps were identified, labeled, and mapped. Cross sections were taken from 117 trees. Ring-width measurements and skeleton plot analyses were performed. Past cutting in the stand was reconstructed from growth releases after suppression and the presence of synchronous scars. The site was heavily impacted by human activities. Timber cutting done on small patchy areas in the past did not negatively affect the stability of the stand. The presence of a waiting period in many trees shows that they grew slowly under a loose canopy. After a waiting period, a gap formed allowing their growth. The seedlings and saplings waiting under the canopy are very important to assure spatiotemporal stability. Skeleton plots are essential for a high resolution record of growth dynamics and disturbances. Basal cross sections contain more qualitative information than cross sections taken at higher stem levels. The method may be applied to reconstruct stand dynamics in other regions, where historical information is scarce or completely missing.