不同林龄人工沙棘林结构与林下物种多样性研究  

Seabuckthorn Plantation Structures at Different Ages and Its Understory Species Diversity

作　　者：李玉新[1] 赵忠[1] 陈金泉[1] 

机构地区：[1]西北农林科技大学西部环境与生态教育部重点实验室,陕西杨陵712100

出　　处：《西北植物学报》2010年第4期776-785,共10页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家十一五林业科技支撑计划项目(2006BAD03A1207)

摘　　要：采用样地调查的方法,研究了陕西省永寿县马莲滩流域不同林龄人工沙棘(Hippophae rhamnoides)林土壤理化性质、根系活力、林木径阶结构、林下物种多样性特征以及天然更新状况等,以探讨沙棘林衰败机理。结果显示:18年生沙棘人工林林分郁闭度为86.67%,根系活力和天然更新能力(241 trees.hm-2)衰退,林木径阶结构呈"衰退型";林下植物种较少(20种)且较分散,活根瘤虽然个体最大(横径>1.80 cm,纵径>1.15 cm),但比例最低(63%左右),固氮能力减弱。13年生沙棘人工林长势最好,林分郁闭度适中(76.67%),根系活力和天然更新能力(833 trees.hm-2)较强,林木径阶结构呈"稳定型";林下植物种较丰富且较集中(S=12,菊科、禾本科为主),活根瘤个体较大(横径>1.40 cm,纵径>0.85 cm)且比例最高(93%),固氮能力最强。8年生沙棘人工林为灌木状,覆盖度达86.67%,但透光性较好,林木长势好,根系活力较18年生沙棘强,天然更新最好(1 566 trees.hm-2),林木径阶结构呈"增长型",林下植物种最丰富且最为集中(S=18,菊科、禾本科为主),活根瘤虽然比例较高(85%),但根瘤个体最小(横径<0.95 cm,纵径>0.60 cm),固氮能力弱。研究表明,18年生沙棘人工林处于衰败状态,应对18年沙棘进行平茬更新,提高林分的稳定性和生态功能。The use of sample survey methodology to study the physical and chemical properties of soil,root vigor,tree diameter class structure,and its understory species diversity,and natural regeneration seabuckthorn plantations of different ages in Yongshou County Malian Beach Valley,in order to discuss the decline mechanism of seabuckthorn forest.The results shows that：18 a seabuckthorn plantation canopy is large（86.67% or so）.The root vigor and natural regeneration capacity（241 trees·hm^-2） are in recession,diameter class structure presents ＂recession-type＂.Its understory plants are less diversity（20 species） and more scatter.Although 18 a has the largest lived individual nodules（diameter〉1.80 cm,longitudinal diameter〉1.15 cm）,the proportion（63% or so） is the lowest,nitrogen fixation capacity is diminished.13 a seabuckthorn plantations grow in the best status,forest canopy density（76.67% or so） is moderate,root vigor and natural regeneration capacity（833 trees·hm^-2） are strong,diameter class structure presents ＂stabilization-type＂,its understory plant species are rich and more focused（S= 12,Compositae,Gramineae-based）.There are larger（diameter〉1.40 cm,longitudinal diameter〉0.85 cm） and the highest percentage of individual nodules（93%）,nitrogen-fixing capacity is the strongest.8 a seabuckthorn plantation is shrub-like.Although the coverage of 8 a is large（0.85）,transmission of light is still good,trees are growing well,root activity is stronger than that of 18 a seabuckthorn.There are the best natural regeneration（1 566 trees·hm^-2）,the most abundant understory plant species and the highest concentration（S=18,Compositae,Gramineae-based）.The diameter class structure presents ＂growth-type＂.Although 8 a has a higher proportion of lived root nodules（85% or so）,the individual nodules are minimum（diameter〈0.95 cm,longitudinal diameter〈0.60 cm） and nitrogen-fixing capacity is weak.Research indicates that 18 a seabuckthorn plantation is in

关 键 词：沙棘 林龄 生长状况 物种多样性 

分 类 号：Q948.157[生物学—植物学]