Frost hardiness vs. growth performance in trembling aspen: an experimental test of assisted migration

Schreiber, S. G., et al., 2013. Journal of Applied Ecology

Original research (primary data)
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Abstract

Summary: According to the range limit hypothesis, the distribution of many temperate species is restricted by a trade-off between their capacity to survive winter extremes in the north (or high elevation) and their ability to compete with better-adapted species in the south (or low elevation range limits). This trade-off has important implications in forestry, particularly in the context of managed seed movement under climate change. In this study, we aim to quantify trade-offs among growth, frost hardiness and timing of leaf senescence and bud break in populations of trembling aspen, Populus tremuloides Michx., which were observed in a large reciprocal transplant experiment across five planting sites in western Canada, including additional provenances from Minnesota. After 10 years, we found pronounced increases in productivity as a result of long-distance transfers in a north-west direction. For example, provenances moved 1600 km north-west from Minnesota to central Alberta (a shift of 7° latitude to the north) produced almost twice the biomass of local sources. Similarly, provenances moved 800 km from central Alberta to north-east British Columbia (4° latitude north) also produced twice the biomass of local sources. We further found that increased growth was not associated with lower survival rates. Bud break in provenances transferred north-west generally occurred slightly later than in local sources, suggesting decreased risk of spring frost injury. Leaf abscission was later in provenances transferred in a north-west direction, but they appeared to be very frost hardy, well ahead of very rare early fall frost events. Synthesis and applications. This study demonstrated that assisted migration prescriptions have considerable potential to enhance forest productivity. In the case of aspen, even long-distance seed transfers in a north-west direction were successful. We conclude that benefits in productivity outweigh potential risks associated with northward transfer of aspen planting stock under both current and projected future climate conditions. This study demonstrated that assisted migration prescriptions have considerable potential to enhance forest productivity. In the case of aspen, even long-distance seed transfers in a north-west direction were successful. We conclude that benefits in productivity outweigh potential risks associated with northward transfer of aspen planting stock under both current and projected future climate conditions.

Case studies

Basic information

  • Case ID: INT-060-1
  • Intervention type: Restoration
  • Intervention description:

    Field experiment. Assisted migration: human-aided movement of reforestation stock to appropriate climate environments … afforest affected areas with differently adapted planting stock of the same species to better match current and anticipated climate conditions

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Loss of timber production  Positive Tree productivity measures: height, biomass, and % survival Frost hardiness
  • Approach implemented in the field: Yes
  • Specific location:

    south-eastern boreal plains of Saskatchewan, the Alberta foothills ecoregion, the central boreal plains of Alberta, the northern boreal plains of Alberta, the taiga plains of British Columbia

  • Country: Canada
  • Habitat/Biome type: Boreal forests and taiga |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: Effectiveness of intervention compared to the local provenance (this assesses the performace of the trees currently growing in the area, that are making up the forest without intervention) Measures of effectiveness for the climate impact are also relevant for the natural ecosystem b/c these forests are critical for providing wildlife habitat and therefore effectiveness of the reforestation efforts are framed as important for natural environment as well
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: Yes
  • Impacts for the ecosystem: Positive
  • Ecosystem measures: Tree productivity measures: height, biomass, and % survival Frost hardiness
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: