不同类型侧柏人工林下草本层植物多样性及其生物量研究

以兰州市仁寿山5种不同类型的侧柏人工林为研究对象，通过样地调查法，探究林分类型与林下草本层植物的多样性及其生物量的相关性。结果表明，1）5种侧柏人工林及天然草地中草本层以禾本科和菊科植物为主，群落之间相似性不高，优势种、伴生种明显，且物种数侧柏纯林>侧柏混交林>天然草地；2）林分类型与林下草本层植物的多样性之间存在不显著的相关关系。侧柏-榆树、侧柏-山杏混交林下草本层植物的α多样性最高，其次为天然草地、侧柏纯林，侧柏-山桃、侧柏-刺槐混交林下草本层植物的α多样性最低；3）林分类型与林下草本层植物的生物量之间存在不显著的相关关系。侧柏-榆树混交林下草本层植物的地上生物量最小，地下生物量最大，侧柏纯林下草本层植物的地上生物量最大，地下生物量最小。综上所述，在兰州地区相对于天然草地与侧柏纯林，侧柏混交林具有更强的林地生产力和水土保持能力，其中以侧柏-榆树、侧柏-山杏混交林的生态效益最高。

Diversity and Biomass of Herbaceous Layer Plants Under Different Types of Platycladus orientalis Plantations

This study investigated the correlation between stand types and the diversity and biomass of understory herbaceous layer plants through sample plot survey method by selecting five different types of Platycladus orientalis plantations in the Renshou Mountain,Lanzhou City as the sample plot.The results showed that 1) the herbaceous layer plants of P.orientalis plantation and natural grassland were dominated by family Gramineae and Compositae.The community was low in similarity,and the dominant species and associated species were obvious.The quantities of species of pure P.orientalis forest was larger than mixed forest.The quantities of species of mixed forest was larger than natural grassland.2) There was low significant correlation between stand types and diversity of herbaceous layer plants.The α diversity of herbaceous layer plants under the mixed P.orientalis-Ulmus pumila forest and the mixed P.orientalis Prunus sibirica forest was the highest,followed by natural grassland and pure P.orientalis forest.The α diversity was the lowest of herbaceous layer plants under the mixed forests of P.orientalis-Amygdalus davidiana and P.orientalis-Robinia pseudoacacia.3) There was low significant correlation between stand types and biomass of herbaceous layer plants.The aboveground biomass of herbaceous layer plants in the mixed P.orientalis-U.pumila forest were the smallest and the underground biomass were the largest.In the pure P.orientalis forest,the aboveground biomass of herbaceous plants were the largest,while the underground biomass were the smallest.In conclusion,compared with natural grassland and pure P.orientalis forest in Lanzhou,P.orientalis mixed forests has stronger forest productivity and soil and water conservation capacity.Among them,the mixed forests of P.orientalis-U.pumila and P.orientalis-Prunus sibirica have the highest ecological benefits.