![]() concluded that topography had a greater effect on climate sensitivity than species identity. Peterson and Peterson also reported consistency between the identities of the influential climate variables across locations with different aspect, and that species identity has a greater influence on climate sensitivity than site. found that co-occuring conifers across two regions responded to the same most influential variable. For two climatically different sub-alpine regions, Nakawatase and Peterson reported that tree growth in the wetter region was limited by growing degree days, whereas in the drier region soil moisture limited growth. Those studies that do consider species differences at multiple sites have found conflicting results. Most studies that explicitly compare species responses tend to focus on a single site or species that don’t directly co-occur. įewer studies examine the radial growth climate sensitivity of multiple species at different locations. In short, understanding the factors that impact climate sensitivity of trees is critical in order to be prepared for future changes at the community or ecosystem level. Finally, high mountain meadows in parks receive high recreational visitation, thus, changes to the extent of and diversity in mountain meadows could have impacts on the experience of visitors to protected natural areas. Additionally, larger scale ecosystem functions may be strongly influenced by the position of treeline, especially in the Pacific Northwest, where forests hold large amounts of carbon. This may have negative consequences for the plants and animals associated with high mountain meadows. For example, high mountain meadows are species rich (e.g., ), and-due to their isolation from each other, and the shape of mountains-are likely to decrease in area if sub-alpine tree growth increases greatly with climate warming. Since sub-alpine trees set the important forest/meadow ecotone at high elevations, the drivers of variability in climate–growth responses of sub-alpine tree species may therefore have particular significance for ecosystem function, resource management and conservation (e.g., the amount of carbon stored in trees, the upslope movement of treeline, conversion of alpine habitat to forests). On a warming planet where multiple aspects of climate are changing, climate sensitivities that differ among sub-alpine tree species could result in differing growth responses. 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.Ĭlimate change is expected to affect alpine and sub-alpine areas and forecasting changes to these areas is critical for natural resource management and conservation. Our results imply that at treeline in moist temperate regions like Mt. 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. 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. Summer warmth positively influenced radial growth, whereas snow, spring warmth, previous summer warmth, and spring humidity negatively influenced growth. ![]() Overall, similar climate variables constrained growth on all three sides of the mountain for each of the four study species. 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. Rainier, WA, USA, we investigated the influences of species identity and sites with different local climates on radial growth–climate relationships. Using tree cores from four sub-alpine conifer species collected from three sides of Mt. ![]() 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.
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