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The most rapid climate warming is occurring in northern, permafrost environments. Peatlands of these regions are particularly sensitive to climate warming, with the high ground ice content of peat plateaux resulting in the formation of collapse scars as ground temperatures warm.To quantify the rates of permafrost thaw and associated vegetation changes, we sampled the plant and lichen communities in transects spanning actively thawing collapse scar margins at sites from mid‐Boreal to Low Subarctic conditions, within Canada's Northwest Territories. Seventeen transects were sampled in 2007/08 and 14 of these were resampled 10 years later.The rate of lateral permafrost thaw of collapse scar margins ranged from −6 to 63 cm year−1 (mean: 22.0 cm ± 4.7 cm year−1 (SE)); variability was high and no trends with respect to latitude or temperature gradients were detected.Plant communities displayed a clear gradient from lichen‐ and ericaceous shrub‐dominated peat plateaux, to collapse scars primarily characterized by Sphagnum mosses and graminoids. Both space‐for‐time (distance from collapsing margin) and direct measurement of 10‐year changes showed a successional sequence following permafrost thaw; floating mat communities characterized by Sphagnum riparium or S. balticum proceeded to lawn communities of S. angustifolium and, finally, to hummock communities with Mylia anomala or S. fuscum. This successional sequence was associated with increased water table depth and lower soil water content in plant communities farther from the actively collapsing front, illustrating that peat growth above the water table was driving plant community successional changes.The most rapid plant community succession occurred in recently thawed environments as peat growth propelled the ground surface above the water table while the slowest succession occurred in the collapse scar hummock communities located farthest from the actively collapsing peat plateau margin.Synthesis. In just 10 years, significant vegetation change was detected, in association with both permafrost thaw and subsequent plant community succession. These changes occurred across a broad climatic and latitudinal gradient, from mid‐Boreal to Low Subarctic and have implications for wildlife, global C cycle and indigenous communities who depend on this landscape for harvesting, spiritual and cultural practices. [ABSTRACT FROM AUTHOR]

The accurate identification of forest degradation and its driving factors is a prerequisite for implementing high-quality forest management. However, distinguishing degradation patterns is often neglected in large-scale forest quality assessments. The indicators were constructed to identify typical forest degradation patterns using remote sensing indexes, followed by an analysis of the spatiotemporal dynamics of forest degradation and quantification of the contributions from various driving factors. The results indicated that the constructed indicators could effectively distinguish typical forest degradation patterns, with a fire degradation identification accuracy of 90.0% and a fitting accuracy of drought and pest degradation higher than 0.7. The cold temperate conifer forest zone had the largest proportion of fire degradation, accounting for 67.7% of the area, and totals of 99.0% of the subtropical evergreen broadleaf forest zone and 92.8% of the temperate conifer and broadleaf mixed forest zone were moderately to severely affected by drought, with long-term stability. Additionally, 0.1% of the temperate grassland region and 0.1% of the cold temperate conifer forest zone underwent severe pest infestations, with a long-term stable trend. Meteorological factors were the primary contributors to all typical degradation patterns, accounting for 81.35%, 58.70%, and 82.29%, respectively. The research developed an index for assessing forest degradation and explained the importance of natural and anthropogenic factors in forest degradation. The results are beneficial for the scientific management of forest degradation and for improving forest management efficiency. [ABSTRACT FROM AUTHOR]