Rising global temperatures are predicted to improve conditions for tree growth above the current treeline, leading to an upslope advance of trees. competition, herbivory, availability of safe sites, frost, disturbance) also influence the position of the treeline at local-scales. Limits to tree growth across the globe are widely reported to occur as a consequence of low mean growing-season soil temperature, but other less well-studied factors (e.g. Long lag periods in treeline change may be expected where recurrent disturbance is a feature of the landscape.Īlpine treelines are conspicuous and sharp transition zones, defining the upper elevational limit of tree growth. These results indicate fire is a strong demographic filter on treeline dynamics there is a clear need to frame alpine treeline establishment processes beyond just being a response to climate warming. Establishment of saplings above treeline was largely restricted to unburned areas. disturbance) are crucial to understand recruitment trends. Population dynamics at the alpine treeline were responsive to recent climate change, but other factors (e.g. However, small trees were reduced in number in woodlands when burned twice within a decade. Below treeline, subalpine woodland stands were largely resilient to fire trees resprouted from lignotubers. No saplings were seen above treeline after two fires, despite evidence that saplings were common pre-fire. Short-distance advance of the treeline occurred between 20, but was largely restricted to areas that were unburned during this period. ![]() We quantify changes in treeline position (sapling recruitment above treeline) over time in relation to warming and disturbance by fire, and examine changes in stand structure below treeline (stand density, size class analyses). The location and basal girth of all trees and saplings were recorded across treelines at four mountains in 20. niphophila (Snow Gum, Myrtaceae) species. ![]() Alpine treelines are composed of Eucalyptus pauciflora subsp. ![]() We examine multi-decadal shifts in the distribution of trees at the alpine treeline in response to regional warming and repeated disturbance by fire in the Victorian Alps, south-east Australia. How species respond to climate change will depend on biological characteristics, species physiological limits, traits (such as dispersal), and interactions with disturbance.
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