Floristic and Structure of Woody Vegetation in a Caatinga Area Between 2015 and 2019, in ASSÚ/RN

Abstract To characterize the floristic composition and horizontal structure of the National Forest of Açú from 2015 to 2019, 20 permanent plots of 400 m² were allocated, and all woody individuals with a diameter at breast height (CBH) ≥ 2 cm were measured on both occasions. Between 2015 and 2019, there was an increase in floristic richness from 23 to 34 species, especially Cenostigma pyramidale and Handroanthus impetiginosus due to their high phytosociological values. Although an 8.7% reduction in the number of individuals in the 4.4 cm class center was observed between the respective years, there was a volumetric increase of 4.85 m³ ha-1, that is 1.21 m³ ha-1 year-1. Changes in floristic composition, diameter distribution, and volumetry reflect the development of vegetation and part of its dynamics; indicating its state of conservation and, consequently, the achievement of the conservation objectives proposed by the Unit.

摘要 为表征2015至2019年阿苏国家森林公园（National Forest of Açú）的植物区系组成与水平结构，本研究布设20块面积为400平方米的永久样地，并对两次调查中所有胸高直径（CBH）≥2厘米的木本个体开展测定。2015至2019年间，该区域物种丰富度从23种增至34种，其中锥穗苏木（Cenostigma pyramidale）与掌叶黄钟木（Handroanthus impetiginosus）因具备较高的植物社会学价值而贡献突出。尽管两次调查间，以4.4厘米为中心的径级个体数量减少了8.7%，但单位面积蓄积量却提升了4.85 m³·ha⁻¹，即年均增长1.21 m³·ha⁻¹。植物区系组成、径级分布与蓄积量的变化，可反映该植被的发育进程及其动态特征，进而指示其保护现状，并佐证该园区所设定的保护目标已得以实现。