Characteristics of Seedling/Sapling Regenerations and Their Response to Topographic Factors in a Large Dynamic Monitoring Sample Plot of Picea Crassifolia Forest in the Qilian Mountains,China
Forest natural regeneration is a pivotal course for ecological restoration and reconstruction,playing a crucial role in maintaining dynamic stability and sustainable development of forests.The seedling/sapling stage is a critical period that determines the quality and quantity of forest natural regeneration.Topography,as one of the main environmental driving factors for forest natural regeneration,significantly influences the growth of saplings and seedlings.Previous studies,relying on sampling methods at elevation gradient plots or transects,had relatively low sampling intensities,making it difficult to comprehensively reveal the regeneration patterns and distribution characteristics of regenerating seedlings.In this study,seedlings/saplings of Picea crassifolia(Qinghai spruce)in a large dynamic monitoring sample plot(340 m × 300 m)in the Dayekou watershed in the middle part of the Qilian Mountains were measured for evaluation of topography effects on natural regeneration.It collected data on the density,ground diameter,height,crown width of seedlings/saplings,and DEM(with a resolution of 12.5 m).A database was constructed using ArcGIS to analyze the impact of slope aspect,slope gradient,slope position,and elevation on the characteristics of seedling/sapling regenerations.The regeneration characteristics under different topographic position indices were also explored.Additionally,K-means clustering analysis was used to divide six topographic habitats with regeneration characteristics.(1)The density of seedlings/saplings was higher on north-facing slopes than on west-facing slopes,while their ground diameter,height,and crown width were greater on west-facing slopes than on north-facing slopes.In areas with higher slopes,the density of seedlings/saplings was higher,but their ground diameter,height,and crown width were lower;the density of seedlings/saplings peaked at mid-slope positions,and their ground diameter,height,and crown width peaked at upper slope positions;the lower the elevation,the greater the density of seedlings/saplings were,and the smaller their ground diameter,height,and crown width were.(2)The density of seedlings/saplings was greater on shaded slopes and semi-shaded slopes of high topographic position,and semi-shaded slopes of low topographic position;the ground diameter,plant height,and crown spread of seedlings/saplings were greater on semi-positive slopes of high topographic position.(3)The density of seedlings/saplings is the highest in the southeast corner of the plot,with higher density of seedlings than that of saplings.(4)The ground diameter,plant height and crown width were extremely significantly positively correlated with each other and they were significantly negatively correlated with density,while they were significantly or extremely significantly correlated with some topographic factors.This study can provide a theoretical basis for evaluation of natural regeneration of Picea crassifolia forest in the Qilian Mountains,as well as a reference for the scientific management of seedlings/saplings of Picea crassifolia forest,or related studies in similar areas.
万方数据
维普
