Proportion and distribution of structural frameworks in natural forests

Abstract

Distribution patterns play an important role in forest community development and dynamics, as well as in forest management and biodiversity maintenance. Distribution patterns may be understood to be a combination of five structural frameworks based on the relationships between nearest neighbors. The forest “random structural framework-stability” hypothesis asserts that a random framework accounts for the stability in the basal area and number of individuals in forest stands. However, the relative importance and stability of each framework is unclear at the regional scale. We analyzed a dataset collected from 34 fixed plots in eight national nature reserves near the Tropic of Cancer in Guangxi, China, to explore the proportions and probability density distributions of the five frameworks. The results showed that regular frameworks were uncommon, accounting for only 0.0–1.38% of frameworks, whereas random frameworks were left skewed and ranged from 45.83% to 61.01%. The abundance of slightly regular frameworks was 11.81–27.84%, and 3.25–7.16% higher than the slightly clumped framework, and both frameworks shared a similar distribution. The abundance of clumped framework was 4.15–28.65%, with a coefficient of variation of 0.53–0.66. These results suggest that natural forests are characterized by clumped distributions, that frameworks account for various proportion and play different roles in different ecosystems and tree groups. Furthermore, our results validate and refine the forest “random structural framework-stability” hypothesis, and contribute to the understanding of forest structure, the assessment of forest resources, and sustainable forest management.