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，研究布设了40块面积为400平方米的永久样地，并在两次调查中均对所有胸径（CBH，Diameter at Breast Height）≥2厘米的木本个体开展了测量。2015至2019年间，该区域植物区系丰富度从23种增至34种，其中尤以Cenostigma pyramidale与Handroanthus impetiginosus为代表，二者因较高的植物社会学价值表现突出。尽管在两次调查的对应年份间，胸径级中心值为4.4 cm的个体数量减少了8.7%，但林分蓄积量却提升了4.85立方米·公顷⁻¹，即年均增加1.21立方米·公顷⁻¹·年⁻¹。植物区系组成、径级分布及蓄积量的变化，反映了植被的发育过程与部分动态特征，可用于指示该保护单元的保护现状，进而验证其预设保护目标的达成情况。