Using a spatiotemporal climate model to assess population-level Douglas-fir growth sensitivity to climate change across large climatic gradients in British Columbia, Canada

Abstract:Increasing the resilience of ecological and sociological systems has been proposed as an option to adapt to changing future climatic conditions. However, few studies test the applicability of those strategies to forest management. This paper uses a real forest health incident to assess the ability of forest management strategies to affect ecological and economic resilience of the forest. Two landscape scale strategies are compared to business as usual management for their ability to increase resilience to a climate-change induced mountain pine beetle outbreak in the Kamloops Timber Supply Area, British Columbia, Canada for the period 1980 to 2060. Proactive management to reduce high risk species while maintaining or increasing diversity through reforestation was found to be more resilient in terms of the metrics: post-disturbance growing stock, improved volume and stability of timber flow, and net revenue. However, landscape-scale indicators of diversity were little affected by management. Our results were robust to uncertainty in tree growth rates and timber value and show that adapting to climate change through improving the resilience of forested landscapes is an economically viable option.

Section: Study Areamentioning

confidence: 99%

Section: Uncertainty Assessmentmentioning

confidence: 99%

Applying Resilience Concepts in Forest Management: A Retrospective Simulation Approach

Dymond

Spittlehouse

Tedder

et al. 2015

“…Common garden experiments comparing provenances of forest trees indicate that phenological, growth, stress resistance, and reproductive traits vary such that realized population niches are well matched with their current geographic occurrences (e.g., [17][18][19][20]). Similarly, growth sensitivity to interannual climate variation depends on population position in climate space for both Pinus contorta (lodgepole pine) and Pseudotsuga menziesii (Douglas fir) [21,22]. While a species', or even a population's, fundamental niche can be broad for a particular trait (e.g., relative growth rate, cold hardiness), interactions among genotypes and tradeoffs between stress tolerance and growth create narrow "seed zones" for populations of even broadly distributed species [18].…”

Section: Introductionmentioning

confidence: 99%

Lab and Field Warming Similarly Advance Germination Date and Limit Germination Rate for High and Low Elevation Provenances of Two Widespread Subalpine Conifers

Kueppers

Faist

Ferrenberg

et al. 2017

Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. We tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 • C warmer, and two soil moisture levels. We tracked germination rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by~300 m elevation. Warming advanced germination timing and initial seedling development by a total of~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Together these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.

“…Even though it is common for treeline to be dominated by more than one species, studies often focus on how climate sensitivity of an individual species varies across vast regions with different macroclimates [11,[16][17][18][19][20][21]. Studies like these have shown synchrony within a climatic zone and significant differences in influential climate variables and climate sensitivity across climatic zones [11,[16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Site- and Species-Specific Influences on Sub-Alpine Conifer Growth in Mt. Rainier National Park, USA

Legendre-Fixx

Anderegg

Ettinger

et al. 2017

Abstract:Identifying the factors that influence the climate sensitivity of treeline species is critical to understanding carbon sequestration, forest dynamics, and conservation in high elevation forest/meadow ecotones. Using tree cores from four sub-alpine conifer species collected from three sides of Mt. Rainier, WA, USA, we investigated the influences of species identity and sites with different local climates on radial growth-climate relationships. We created chronologies for each species at each site, determined influential plant-relevant annual and seasonal climatic variables influencing growth, and investigated how the strength of climate sensitivity varied across species and location. Overall, similar climate variables constrained growth on all three sides of the mountain for each of the four study species. Summer warmth positively influenced radial growth, whereas snow, spring warmth, previous summer warmth, and spring humidity negatively influenced growth. We discovered only a few subtle differences in the climate sensitivity of co-occurring species at the same site and between the same species at different sites in pairwise comparisons. A model including species by climate interactions provided the best balance between parsimony and fit, but did not lead to substantially greater predictive power relative to a model without site or species interactions. Our results imply that at treeline in moist temperate regions like Mt. Rainier, the same climatic variables drive annual variation in growth across species and locations, despite species differences in physiology and site differences in mean climates.