Can't see the trees for the forest: complex factors influence tree survival in a temperate second growth forest

Abstract

Citation: Eitzel, M. V., J. Battles, R. York, and P. de Valpine. 2015. Can't see the trees for the forest: complex factors influence tree survival in a temperate second growth forest. Ecosphere 6(11):247. http://dx.doi.org/10.1890/ES15-00105.1Abstract. Forest decline is a widespread, well-recognized problem, but studies reporting decreases in tree survival have been largely limited to relatively rare old-growth forests or low-diversity systems, and to models which are species-aggregated or cannot easily accommodate yearly climate variables. We created survival models for a multispecies second-growth forest in the Sierra Nevada of California using a hierarchical state-space framework. We accounted for a mosaic of measurement intervals and random plot variation, and we directly included yearly stand development variables alongside climate variables and topographic proxies for nutrient, water, and light availability. Our model captured the expected dependence of survival on tree size, but revealed different relationships between size and survival for each species. At the community level, including stand development variables accounted for decreasing survival time trends, but species-specific models demonstrated a diversity of factors influencing survival, including time trends, fundamental niche limitations, and the impact of competition. Our results on time trends and competitive performance showed local exceptions to existing theories of Sierran forest dynamics, with some shade-tolerant species increasing in survival over time and others performing better than expected under more crowded conditions. Within species, low survival was concentrated in susceptible subsets of our population and single estimates of annual survival rates did not reflect this heterogeneity in survival.

Compounding effects of white pine blister rust, mountain pine beetle, and fire threaten four white pine species

“…Uncertainty was estimated using maximum likelihood. Specifically, we obtained confidence intervals of mortality using profile likelihood as outlined by Eitzel et al (2015). We estimated per‐capita recruitment based on the final density (Table 1).…”

Demographic costs and benefits of natural regeneration during tropical forest restoration

“…Observation errors result because measurements of both tree basal diameter and tree presence/absence are imperfect (Eitzel et al . ; Metcalf et al . ).…”

Erratum

“…In the paper by Eitzel et al. (“Can't see the trees for the forest: Complex factors influence tree survival in a temperate second growth forest”; Ecosphere 6 :247), methods for estimating models of tree survival and results for seven species at a site in the Sierra Nevada mountains, California, USA, were presented. One important explanatory variable was basal area of each plot, which was smoothed over time to provide annual values.…”