东北红豆杉幼苗幼树更新特征及地形因子对其的影响OA

To clarify the basic law of natural regeneration of the Taxus cuspidata population and reveal the influence of topograph-ic factors on the regeneration process of understory seedlings and saplings,this study took seedlings and saplings of wild T.cuspidata populations as research objects.Based on the dynamic monitoring plot of T.cuspidata in Muling,the main limit-ing factors for the natural regeneration of seedlings and saplings were analyzed.The results showed that the most suitable habitat for T.cuspidata seedlings and saplings was at an altitude of 672-740 m.Both basal diameter and plant height of seedlings and saplings on shady slopes were higher than those on sunny slopes.Seedlings on upper and middle slope posi-tions accounted for 90.18％of the total surveyed individuals,and saplings on upper and middle slope positions accounted for 70.00％of the total.The quantity of seedlings and saplings on upper and middle slope positions was greater than that on lower slope positions.Seedlings and saplings of T.cuspidata exhibited a significant spatially aggregated distribution pat-tern,and the aggregation intensity increased with the rise of kernel density grade,with the highest aggregation density oc-curring in the northwest and north areas.Correlation analysis indicated that topographic factors significantly affected the re-generation of seedlings and saplings.For seedlings,basal diameter had a significant negative correlation with slope aspect(P<0.05),plant height showed an extremely significant negative correlation with slope gradient(P<0.01)and a signifi-cant positive correlation with slope aspect(P<0.05),individual number had an extremely significant positive correlation with elevation(P<0.01).Slope gradient and elevation were the dominant factors affecting seedling regeneration.For sap-lings,basal diameter presented an extremely significant negative correlation with slope gradient(P<0.01)and a signifi-cant negative correlation with altitude(P<0.05),plant height had an extremely significant negative correlation with alti-tude(P<0.01).Slope gradient and altitude were the key topographic factors affecting sapling regeneration.Therefore,the in situ conservation and ex situ restoration of natural T.cuspidata populations should comprehensively consider the com-bined effects of various topographic factors.Combined with the regeneration rules and spatial distribution characteristics of seedlings and saplings under different topographic conditions,conservation areas should be scientifically delineated and restoration schemes optimized.