Individual-tree growth dynamics of mature Abies alba during repeated irregular group shelterwood (Femelschlag) cuttings

Abstract

This study investigated the individual-tree diameter response of mature silver fir ( Abies alba Mill.) to reproduction harvests (Femelschlag: an irregular group shelterwood method) on six sites in the Black Forest, Germany. On each site, four different treatments were applied, including a control treatment and short-, medium, and long-term regeneration periods aimed at the complete removal of overstory trees within 20, 35, and 50 years, respectively. These treatments created a wide variety of growing conditions for individual trees. Relationships between relative diameter growth and stand-level and neighborhood interaction indices were evaluated. Growing conditions for individual trees in control conditions were best characterized using Lorimer’s index for a 16 m radius neighborhood. Equations predicting tree growth in control stands underpredicted initial growth of trees after harvesting operations, suggesting a release effect that is not captured by postharvest density. This effect was larger for smaller trees and influenced by removal intensity. Growth response to density reductions was also influenced by previous harvests. Our results suggest that the growth response of mature trees to reproduction harvests may become an important consideration when increased emphasis is placed on managing for long-term regeneration periods.

Extracting environmentally driven growth trends from diameter increment series based on a multiplicative decomposition model

“…It is quite plausible that within sequences of consecutive thinnings, the effect of a single thinning intervention reached its maximum later in time. Such a consideration of previous thinnings appears necessary and appropriate, as Puettmann et al (2009) recently demonstrated for silver fir (Abies alba Mill.) that growth response to release cannot simply be captured from knowledge of post-harvest density but is clearly also influenced by previous harvests.…”

“…In this context, it is important to recognize that a sequence of consecutive thinnings may result in accumulative thinning effects on tree increment that are not completely assessable from current tree and stand parameters (Puettmann et al 2009). Therefore, it was necessary to introduce an accumulative thinning index that expressed not only the increment effect of the actual thinning but also the history of the preceding thinnings (e.g., intervals, intensities).…”

Early responses to thinning treatments designed to accelerate late successional forest structure in young coniferous stands of western Oregon, USA

“…A positive relationship often exists between the size of an individual relative to the population and growth rate (Schmitt et al 1987;D'Amato and Puettmann 2004), a pattern also found in this study. Individual tree growth is strongly limited by the number of larger trees near the subject tree (D' Amato and Puettmann 2004;Puettmann et al 2009b). If competition is asymmetric with larger individuals suppressing the growth of smaller individuals, then as population density increases, so should the steepness of the curve between initial size and growth rate (Schmitt et al 1987).…”

Effects of thinning-induced changes in structural heterogeneity on growth, ingrowth, and mortality in secondary coastal Douglas-fir forests

“…We assume that the spatially explicit measures TDM, MDI, and M that characterize forest structure for tree neighborhoods would outperform spatially nonexplicit metrics if growth or mortality were modelled and predicted at the individual-tree level (D'Amato and Puettmann 2004;Puettmann et al 2009;Fraver et al 2014). Thus, although spatial information was not especially beneficial in predicting growth or mortality at the sample-plot level, as demonstrated in this study, it may be quite beneficial for predictions at the individual-tree level, suggesting that tree-level (neighborhood) information may not scale up to sample plot level predictions.…”