摘要
以长白山西南部地区(地理中心坐标:125°58′54″E、41°44′31″N)为研究区域,以蒙古栎(Quercus mongolica)天然次生林为研究对象,分别在代表研究区域主要植被特征的同一座山、同一海拔高度的阳坡和阴坡,各设置固定样地3块(20 m×30 m)。在两坡向样地内分别设置3个样方(10 m×10 m),阳坡3个样方蒙古栎样木分别为17、13、17株,阴坡3个样方蒙古栎样木分别为13、19、10株,在生长季晚期测量样方内蒙古栎样木胸径、树高;利用生长锥(内径5 mm)钻取样方内所有树木的微生长芯,利用Lintab6年轮分析仪还原树木历年胸径。利用异速生长方程,结合树木年代学方法,测算两坡向蒙古栎林生物量、净初级生产力(NPP);在生长季初,利用挖壕法在各样地中随机设置3个异养呼吸样方(1 m×1 m),样方内随机放置土壤环1个(环高5.0 cm,内径19.5 cm),利用LGR便携式温室气体分析仪配备土壤呼吸气室,观测土壤异养呼吸速率;结合微气象法,整合森林净初级生产力及土壤异养呼吸速率数据,综合估算净生态系统生产力(NEP)。依据试验测试数据,分析坡向环境对蒙古栎林净初级生产力和净生态系统生产力的影响。结果表明:(1)两个坡向蒙古栎林净初级生产力呈现逐年增加的趋势。径向生长在生长初期较快,随着树龄增长生长速度趋于平缓,生长旺盛期在2~10 a。(2)目前,蒙古栎林两坡向生物量,由大到小依次为树干、粗根、树枝、树叶、细根;蒙古栎林两坡向净初级生产力,由大到小依次为树叶、树干、细根、树枝、粗根,阳坡蒙古栎林净初级生产力为840.21 g·m^(-2)·a^(-1)、阴坡蒙古栎林净初级生产力801.22 g·m^(-2)·a^(-1),两坡向蒙古栎林净初级生产力没有显著差异。(3)阳坡土壤异养呼吸通量分别为172.30 g·m^(-2)、阴坡土壤异养呼吸通量212.95 g·m^(-2),阳坡显著低于阴坡(P<0.05)。(4)当前,阳坡净生态系统生产力为667.91 g·m^(-2)·a^(-1)、阴坡净生态系统生产力588.27 g·m^(-2)·a^(-1),阳坡比阴坡高13.54%。(5)近20 a,蒙古栎径向生长速率先快后慢,净初级生产力呈现逐年增长趋势,1998—2017年阳坡净初级生产力显著高于阴坡。土壤异养呼吸通量显著低于阴坡;但阳坡和阴坡的净生态系统生产力,差异不显著。(6)坡向通过影响水热因子的再分配,导致蒙古栎林净初级生产力、土壤异养呼吸通量、净生态系统生产力的高空间异质性,致使其碳封存能力评估和比较还存在很大的不确定性。
The southwestern region of Changbai Mountain(geographic center coordinates:125°58′54″E,41°44′31″N)as the research area,and the natural secondary forest of Quercus mongolica as the research object,three fixed plots(20 m×30 m)were set up the sunny slope and shady slope at the same altitude on the same mountain representing the main vegetation characteristics of the study area.Three quadrat(10 m×10 m)were set up within two slope direction plots,there were 17,13 and 17 trees of Q.mongolica in the three quadrats on the sunny slope,and 13,19 and 10 trees of Q.mongolica in the three plots on the shady slope.The diameter at breast height and tree height of the Q.mongolica in the quadrat were measured in the late growth season;the growth cone(inner diameter of 5 mm)was used to drill and sample the micro growth cores of all trees in the quadrat,and use the Lintab6 annual ring analyzer to restore the tree’s diameter at breast height over the years.The allometry growth equation and the method of tree chronology was used to calculate the biomass and net primary productivity(NPP)of Q.mongolica forest in two slope directions.At the beginning of the growing season,three heterotrophic respiration square(1 m×1 m)were randomly set up in various fields and the excavation method was used,randomly place one soil ring(height of 5.0 cm and inner diameter of 19.5 cm),LGR portable greenhouse gas analyzer to equip soil respiration chamber was used to observe the rate of soil heterotrophic respiration.By combining the micro meteorological method and integrating data on forest net primary productivity and soil heterotrophic respiration rate,the net ecosystem productivity(NEP)can be comprehensively estimated.Based on experimental test data,analyzed the effect of slope environment on the net primary productivity and net ecosystem productivity of Q.mongolica forest.The results showed that:(1)The net primary productivity of Q.mongolica on both slopes showed an increasing trend year by year.The radial growth was fast in the initial stage,and then tended to be gentle with the tree age growth,and the vigorous growth period was the first 2^(-1)0 a.(2)The descending order of biomass in two slope directions of Q.mongolica forest was trunk,coarse root,branch,leaf and fine root,the descending order of NPP was leaf,trunk,fine root,branch and coarse root,and the NPP of sunny slope and shady slope were 840.21 and 801.22 g·m^(-2)·a^(-1),respectively,and there was no significant difference in net primary productivity between Q.mongolica forests on both slopes(P>0.05).(3)The soil heterotrophic respiration fluxes of the sunny slope and shady slope were 172.30 and 212.95 g·m^(-2)respectively,and the sunny slope was significantly lower than the shady slope(P<0.05).(4)The net ecosystem productivity of sunny slope and shady slope were 667.91 and 588.27 g·m^(-2)·a^(-1)respectively,and sunny slope was 13.54%higher than shady slope.(5)In recent 20 a,the radial growth rate of Q.mongolica was first fast and then slow,and the net primary productivity showed an increasing trend year by year,the net primary productivity of 1998^(-2)017 on sunny slope was significantly higher than that on shady slope.The soil heterotrophic respiration fluxes were significantly lower than that on shady slopes;however,there was no significant difference in net ecosystem productivity between sunny and shady slopes.(6)The slope directions leads to high spatial heterogeneity of net primary productivity,soil heterotrophic respiration fluxes and net ecosystem productivity of Q.mongolica forests by affecting the redistribution of hydrothermal factors,resulting in great uncertainty in the assessment and comparison of its carbon storage capacity.
作者
华明阳
孙忠林
尹智博
冯颖
赵卓
Hua Mingyang;Sun Zhonglin;Yin Zhibo;Feng Ying;Zhao Zhuo(Inner Mongolia Minzu University,Tongliao 028043,P.R.China;Tonghua Normal University;Jilin Normal University)
出处
《东北林业大学学报》
CAS
CSCD
北大核心
2023年第6期13-19,共7页
Journal of Northeast Forestry University
基金
内蒙古民族大学博士科研启动基金项目(BS519)
吉林省教育厅“十三五”科学技术研究规划项目(JJKH20180865KJ)。
关键词
蒙古栎林
净初级生产力
净生态系统生产力
坡向
长白山区
Quercus mongolica forest
Net primary productivity
Net ecosystem productivity
Slope direction
Changbai Mountain area
