This study compares the tree and ground cover of 2 localities having different grazing histories in the tree-line ecotone of Western Norway. Data from the sampling of trees, saplings, seedlings and ground cover, tree age determinations, aerial
photographs, interviews and literature research are used. The results show differences in the structure of the tree-line ecotone with regard to tree-age, height, circumference and the structure of the understory. Ground cover differs in species composition
, mainly with regard to light preferences. Together, the differences stress the importance of site history consideration in order to understand changes in the tree-line ecotone, because dissimilar site histories may create differing local responses
A decade of tree-line monitoring in the southern Swedish Scandes in Climatological extremes in the mountains, Physical background, geomorphological and ecological consequences.
Results from long-term tree-line monitoring, based on repeat photography from fixed photopoints, are presented. The tree-line studied is a broad ecotone with sparse and mixed populations of Betula pubescens ssp. tortuosa, Picea abies and Pinus
Holocene climate reconstructions from the Fennoscandian tree-line area based on pollen data from Toskaljavri
C 14 dating ; Cold area ; Finland ; Holocene ; Palaeoclimatology ; Palynology ; Pollen diagram ; Precipitation ; Quaternary ; Temperature ; Treeline
Due to its location on the eastern North Atlantic seabord, the Fennoscandian tree-line area is an ideal area to use biological proxies to assess the relative roles of the Scandinavian ice sheet and of oceanic, atmospheric, and astronomic forcings
on regional climate history. Here the AA. report pollen-based July mean temperature and annual precipitation reconstructions from a sediment core from Toskaljavri, a high-altitude tree-line lake in northwestern Finland.
Tree-tundra competitive hierarchies, soil fertility gradients, and treeline elevation in Glacier National Park, Montana
Biomass ; Ecosystem ; Ecotone ; Forest ; Geochemistry ; Montana ; Soil properties ; Treeline ; Tundra ; United States of America
. The tundra-line may be lower where more nutrients are available because tundra species may more readily alter their competitive ability than do the tree species in this area.
China ; Dendrology ; Ecology ; Forest ; Tibet ; Treeline
pure stands. In eastern Tibet they also form the upper treeline at more than 4.700 m. - (IfL)
Junipers mark the northwestern distribution limit of forests on the Tibetan plateau towards the central Asian steppes. They are a light-demanding, but drought-tolerant and cold-resistant tree species. In the more humid regions of eastern Tibet where
other conifer species from the genera Pica, Abies or Larix occur junipers are confined to south slopes. However, when other tree species are removed or absent due to other reasons, junipers occur on all exposures. In the forest-steppe ecotones they form
This study improves the understanding of the tree-limit phenomenon in general by identifying and analysing regional spatial patterns of the present-day tree-limit position (m a.s.l.) and structure of mountain birch along relevant topographical
Biogeography ; Conceptual model ; Geomorphology ; Impact ; Montana ; Mountain ; Spatial distribution ; Treeline ; United States of America
The aim of this study is to propose a conceptual model that describes the multi-spatial-scale relationship between treeline advance and geomorphology. The approach examines the spatial patterns of tree occurrence in Glacier National Park, Montana
, at 3 spatial scales to establish the relative roles of macro- (landscape scale), meso- (aspect and elevation), and microscale (level of individual tree growth, establishment, and death) controls on tree establishment at the highest locations of alpine
The impact of elevation, topography and snow load damage of trees on the position of the actual timberline on the fells in central Finnish Lapland
Altitude ; Biogeography ; Cold area ; Finland ; Forest ; Lapland ; Snow ; Topography ; Treeline
affecting these positions and snow load damage to trees on the fells Aakenustunturi, Yllästunturi and Pyhätunturi. The potential for ascending timberlines in the region is also discussed.
Early Holocene tree growth at a high elevation site in the northernmost Scandes of Sweden (Lapland) : a palaeobiogeographical case stduy based on megafossil evidence
C 14 dating ; Holocene ; Lapland ; Methodology ; Palaeobiogeography ; Palaeoclimate ; Palynology ; Sweden ; Treeline
This paper focuses on early Holocene tree growth and alpine tree-limits in the northernmost Swedish Scandes. Megafossil wood remnants in peats and lakes were searched for over a large area at elevations high above the modern tree-limits. The results
Tree-limit landscape evolution at the southern fringe of the Swedish Scandes (Dalarna province) - Holocene and 20th century perspectives
Birch ; C 14 dating ; Climatic change ; Climatic warming ; Environment ; Forest ; Holocene ; Palaeo-ecology ; Phytogeography ; Pine ; Spruce ; Sweden ; Treeline ; Twentieth Century
The long-term history relies mainly on radiocarbon-dated megafossil tree remains preserved in peat and mineral soil. The more recent perspective was analysed from age distributions in the most marginal, extant tree populations. Results about
Holocene and Modern tree-limit evolution are presented : species-limit positions (Pinus sylvestris, Picea abies, Betula pubescens) at 4 study sites in 1915, 1975, 2003. Thus, 20th century warming and associated biological consequences in the study area fit
The Fall Line : a physiographic-forest vegetation boundary
Appalachian Mountains ; Boundary ; Coastal plain ; Eastern United States ; Forest ; Plant species ; Southern United States ; Tree ; United States of America ; Vegetation
Les AA. émettent l'hypothèse que la présence ou l'absence d'habitats adaptés à la régénération des espèces d'arbres de chaque côté de la Fall Line basée sur des caractéristiques géomorphologiques et de sol sont les facteurs primaires déterminant la
C14 dating ; Canada ; Coastal environment ; Conifer ; Holocene ; Model ; Palaeo-environment ; Quaternary ; Quebec ; Sea level ; Treeline ; Vertical displacement;Vertical movement
The AA. postulated that the ages of trees lying on recently freed surfaces can yield minimum dates for the emergence of the coastline and then serve to substantiate recent uplift trends projected by the 14C method. Thus, this study aims to quantify
this recent downward displacement of tree margins and to discuss its postulated relationship with coastal emergence.
Canada ; Cold area ; Dendroclimatology ; Dendrology ; Palaeoclimatology ; Quebec ; Temperature ; Treeline
During the past 8 centuries, light rings (LRs) have occasionally formed in black spruce at treeline near Bush Lake, northern Quebec. New analyses of climate data compiled during the period of overlapping tree-ring and instrumental records show
that years of LR formation at Bush Lake have unusually cool May, June, August, and September temperatures. Visual assessments of LR occurrence provide a new approach for extracting quantitative paleoclimatic information from tree rings.