Neoglacial Climate Control of Subarctic Picea abies Stand Dynamics and Range Limit in Northern Sweden

摘要: The study focused on the performance of spruce (Picea abies [L.] Karst.) range limit in northern (subarctic) Sweden during Neoglacial period Holocene, mainly after climax Little Ice Age. Subfossil wood remains suggest that geographic tree has remained fairly stable for slightly more than past 2000 14C yr. Previous postulates about delayed immigration and continual spread are contradicted favor a dynamic climate/spruce equilibrium. mechanism restricting distribution was inferred to be severe annual ground frost characterizing this climatically continental snowpoor region, which is crossed by discontinuous permafrost. An extensive (landscape scale) age structure analysis showed near-exponential population build-up over 100 yr or so. This manifested as densification outlying stands sparse advance some tens kilometers. These responses clearly related increased snowfall early (December) late winter (March). In consequence, permafrost declined general, made least prone sites equable establishment persistent growth (less risk desiccation) spruce. inferences strengthened tendencies decreased regeneration vitality decades, coincident with exceptionally cold snow-poor winters. It speculated studied system, i.e. outliers checked frost, small-scale analogy situation preceding general Holocene expansion Fennoscandia.