Analysis of the pattern change process of Changbai Mountain wind-damaged landscape in the past thirty years

The wind-damaged landscape formed by the 1986 typhoon in Changbai Mountain Nature Reserve was studied in this paper. High-definition remote sensing images in 1987, 1993, 1999, 2004, 2010 and 2016 were selected to decode to analyze the change of each patch type in the study area. Fragstats 4.2 was used to quantitatively analyze the landscape pattern indices, and a combination of principal component analysis and comprehensive landscape evaluation index was used to make a comprehensive evaluation to reveal the process of landscape pattern changes 30 years after the wind damage. The results were as follows:（1） the dominance of herbaceous-shrub kept decreasing, but the distribution was homogenous, the patch shape was regular, and the degree of aggregation was high; broad-leaved forest and coniferous forest firstly increased in large patches during the recovery process, and later on the area increase was mainly in small patches, the patch shape of broad-leaved forest tended to be regular, and coniferous forest was complex; Betula ermanii forest firstly increased in small patches, and later on the large patches grew in succession, the shape became more complicated, and there was a trend of contiguous growth.（2） At the landscape level, small and scattered patches were converted into large and concentrated patches in the restoration process, the irregularity of shape increased and the connectivity of the landscape decreased. As the restoration continues, the landscape tended to be homogenized.（3） According to the landscape transfer matrix, herbaceous-shrub patches in the study area would be continuously transformed into arboreal patches, the proportion of herbaceous-shrub gradually decreased, while arboreal increased. Among them, herbaceous-shrub mainly transformed into broad-leaved forest, broad-leaved forest mainly transformed into coniferous forest, and coniferous forest mainly transformed into Betula ermanii forest. The four patch types of herbaceous-shrub, broad-leaved forest, coniferous forest, and Betula ermanii forest showed a succession relationship during the restoration process.（4） Through the principal component analysis method, two principal components related to landscape scale and shape and landscape dispersion, respectively, were identified as key indices to characterize landscape restoration.（5） Using the combination of principal component analysis and the comprehensive landscape evaluation index to evaluate the wind-damaged landscape in Changbai M