Look Down to See What’s Up: A Systematic Overview of Treefall Dynamics in Forests

Abstract

Abstract:The study of treefall and its after-effects is a common theme in studies of forest structure and local dynamics, yet its value as descriptor of broader-scale ecological dynamics is rarely explored. Here we synthesize the most highly cited literature on treefalls, from 1985 to 2016 (in three-year blocks), highlighting the importance of the causes, characteristics and consequences of such events. We then ask how this knowledge might contribute to the broader conceptual model of forest dynamics, and develop two conceptual models, which we use to illustrate both the classic and alternative views of how forests 'work'. Treefalls are one of the few 'integrating' attributes of forests, because of their ubiquity and longevity, and therefore can inform a variety of processes (e.g., tree mortality, turnover rates, structural impacts, recruitment, and fire frequency) due to their impacts occurring simultaneously over space (patterns), and time (legacy effects). The substantial knowledge that already exists on localized treefall dynamics should be combined with more integrative approaches to studying forest ecosystems, to investigate landscape-scale patterns of treefall and reconstruct past disturbance events.

Analyzing linear spatial features in ecology

“…Worldwide, the positions and sizes of trees are commonly recorded in ecological-plot networks, but the equivalent measurements are almost never collected for the fallen trees (Falinski 1978, Lieberman et al 1985. This is despite the important role of treefall in disturbance (including opening of canopy gaps and physical displacement of, or damage to, living trees), nutrient cycling, carbon storage, soil stability, and fire mediation (Keller and Swanson 1979, Grove and Meggs 2003, Buettel et al 2017. Second, we have demonstrated a method of mathematical analysis of these data (vector sums and dot products) that is relatively simple and intuitive; borrowed from methods of physics used on vector fields.…”

“…Ecological plot networks, such as the globally distributed Center for Tropical Forest Science (ctfs.si.edu) sites, routinely record data such as the species identity, size and spatial position of trees (Anderson-Teixeira et al 2015). However, the dead trees, enduring as fallen logs on the forest floor, are rarely measured in this way (Buettel et al 2017) other than occasional sampling of the dead wood biomass (Kirby et al 1998) or quantification using remote sensing (Pasher andKing 2009, M€ ucke et al 2013). Yet, coarse-woody debris CWD) and logs are crucial to the dynamics of forest ecosystems, due to their roles in canopy gap creation, displacement of living trees, cycling of nutrients and organic matter, carbon storage, and provision of habitat for seedlings and animals (Harmon et al 1986).…”

Snagfall the first decade after severe bark beetle infestation of high‐elevation forests in Colorado, USA

“…, Hutto , Lindenmayer and Noss , Buettel et al. ), and one that will become more complex if projected climatic changes alter wood decay and snagfall (Oberle et al. ).…”

“…, Buettel et al. ). Canopy openings created by snagfall gaps influence seedling regeneration and the growth of residual trees (Stuart et al.…”

How Forest Gap and Elevation Shaped Abies faxoniana Rehd. et Wils. Regeneration in a Subalpine Coniferous Forest, Southwestern China

“…In recent decades, to meet sustainable forest ecosystem functions (e.g., diversity and resilience) and silvan economic benefits (e.g., timber production) [4,5], forest ecologists and managers have increasingly emphasized new silvicultural concepts that imitate natural disturbances for forest management [6,7]. Gap-based silviculture is an intuitive and effective approach for promoting plant regeneration in the majority of mature forests and has been extensively documented in proposals for forest management [8,9].…”