Building Resistance and Resilience: Regeneration Should Not be Left to Chance

Abstract

Contemporary forest planning has tasked managers with developing goals associated with resistance and resilience. In practice, silviculturists use forest structure and tree species composition to characterize goals and desired future conditions, write prescriptions, and monitor outcomes associated with resistance and resilience. Although rarely discussed in the exploding literature relating to forest resistance and resilience, silvicultural regeneration methods are important and underutilized tools to meet these goals. We propose alternative silvicultural systems for building resistance and resilience to two common large-scale bark beetle disturbance agents in the Intermountain West, United States: mountain pine beetle (Dendroctonus ponderosae Hopkins) and spruce beetle (Dendroctonus rufipennis Kirby). Shelterwood, and shelterwood-with-reserves, silvicultural systems provide the desirable facilitative characteristics of a mature overstory on maintaining advance reproduction and the establishment of new cohorts of desirable tree species. These also allow the timely regeneration of large treatment areas necessary to rapidly promote desired future conditions in the face of inevitable disturbance. When implemented proactively, regeneration treatments allow silviculturists to take advantage of currently existing vegetation for the creation of age class and tree species diversity. In general, these examples illustrate the need for proactive planning for regeneration in response to any disturbance where desired future conditions include particular species. Furthermore, we argue that timely silvicultural interventions that focus on regenerating trees may be a key factor in achieving goals relating to resilience to specific disturbance types. Waiting until after the disturbance has occurred could result in the lost opportunity to establish desired species composition or stand structure-and may well result in a considerable restoration challenge.

Overlapping outbreaks of multiple bark beetle species are rarely more severe than single‐species outbreaks

“…This is consistent with previous research that suggests that greater tree diversity contributes to lower-severity outbreaks by diluting the abundance of any given host (Connor et al, 2014;Guo et al, 2019;Jactel & Brockerhoff, 2007). Our results thus lend broad support to management strategies that promote resilience through increased tree diversity, which may help reduce stand-scale severity and increase the chances for recovery (Long et al, 2018).…”

Does Gap Opening and Planting to Rehabilitate the Degraded Tropical Natural Forests Affect the Forest Composition and Structure?

“…This method is based on the succession theory of tropical natural forests. In line with this theory, the research results of Long et al (2018) showed that the management of Engelmann spruce in Intermountain West used a small group selection cutting system, which is preferred because it mimics the dynamics of the gap phase. Furthermore, some research on gap opening and planting for rehabilitation of degraded natural forests in Indonesia dan Brazil showed that the cultivation of local superior intolerant tree species using gap opening and planting is more costeffective and needs shorter-term investment (Grogan et al, 2013;Schwartz et al, 2017;Elias & Suwarna, 2019).…”

The Hungry Bob Fire & Fire Surrogate Study: A 20-Year Evaluation of the Treatment Effects

“…Two remaining questions for these dry second-growth ponderosa pine forests are: what is the long-term effect of the different treatments on future regeneration [35,36], and what is the optimal minimum spacing between overstory trees, between pole-sized trees, and between sawlog-sized trees for improving restoration prescriptions [37,38]? An assessment of fuel loading, snag life cycles, and soils will be assessed in a future manuscript.…”