Abstract: To examine the effects of slope form on natural renewal of Calamus rhabdocladus in the lowland secondary rainforest, we investigated population size, growth characteristics (plant height, ground diameter, and leaf area), and mortality rate of Calamus rhabdocladus in Ganzaling, Hainan Province. The relationship between different slope forms (convex slope, gentle slope, and concave slope) and population renewal at different growth stages was analyzed by means of variance analysis, multiple comparison, and correlation analysis. The results showed that slope forms had significant effects on population size, plant height, basal diameter, leafarea, relative growth rate, and mortality of C. rhabdocladus (all P<0.05), but with no effect on the ratio of height to diameter (P>0.05). The population size, plant height, and leaf area of C. rhabdocladus were the highest on concave. The slope form was an important environmental factor affecting population size and growth of C. rhabdocladus by changing soil water, nutrient and light in Ganzaling of Hainan. The concave slope was relatively favorable to regeneration and growth of C. rhabdocladus. In the course of resource renewal and conservation of artificial cultivation of C. rhabdocladus, the concave slope should be given priority.

Key words: soil moisture, scale-like pit, mulching, dryland jujube orchard.