亚热带杉木、马尾松人工林的林内降雨、林冠截留和树干茎流

本文用统计分析方法对江西分宜县山下林场杉木、马尾松人工林的林内降雨、林冠截留和树干茎流进行了研究。结果表明:在该林分中林内降雨量和树干茎流量随降雨量的增加而以直线形式增加;林冠截留量随降雨量的增加呈幂函数关系上升。在杉木林内,随郁闭度的增大,林内降雨率和树干茎流率减少,而林冠截留率增大,马尾松林和杉木林相比,林内降雨率和树干茎流率较大,而林冠截留率较小。     

格氏栲和杉木人工林枯枝落叶层溶解有机碳浓度及季节动态

于2002 年的1 月、4 月、7 月和10 月对中亚热带格氏栲和杉木人工林(monoculture plantations of Castanopsis kawakamii and Cunninghamia lanceolata,33 年生) 枯枝落叶层(包括Oi、Oe 和Oa 层)进行了取样,并采用TOC 分析仪测定枯枝落叶层样品的溶解有机碳(DOC)浓度。结果表明,杉木人工林枯枝落叶层DOC 平均浓度(1341.7 mg·kg-1)高于格氏栲人工林(1178.9 mg·kg-1)。两种林分枯枝落叶层中,Oe 层的DOC 浓度均高于Oi 和Oa 层。格氏栲和杉木人工林枯枝落叶层不同分解层次DOC 浓度的季节变化模式基本相似,均在秋季或冬季出现最大值。枯枝落叶层DOC 浓度及季节变化与温度、湿度、生物活性及枯枝落叶层中有机质数量等有关。表2 图2 参31。     

三峡库区马尾松林穿透雨和树干茎流空间变异特征

【目的】探讨马尾松林下穿透雨和树干茎流空间分布特征及其影响因素,为准确量化马尾松林下降水分配过程以及水源涵养功能评价提供科学依据。【方法】2017年5—9月,在1个马尾松林下布设16个截面面积为3 000 cm~2的雨量收集器来观测穿透雨,选择27株马尾松标准木研究树干茎流的空间变异特征,应用Pearson相关分析研究冠层结构参数与穿透雨、树干茎流之间的关系,并用Monte Carlo抽样方法确定在一定误差范围内估测穿透雨所需雨量收集器的数量。【结果】研究期间林外总降雨量1 008. 4 mm,林下总穿透雨量和树干茎流量分别为829. 8和14. 4 mm,各占总降雨量的82. 3%和1. 4%;树干茎流量和茎流率均随降雨量的增加而增加,但茎流量变异系数随着降雨量增加而减小,且茎流量变异系数达到60%后趋于稳定,树干茎流量与树木的冠幅面积和胸径呈显著正相关(P0. 01);穿透雨率随降雨量增加而增加,穿透雨率达到87%后趋于稳定,用"S"曲线函数可较好地拟合穿透雨率与降雨量的关系(P0. 01);在测定样地中,穿透雨量存在较大的空间异质性,其变异系数随降雨量增加先显著降低而后稳定,两者用倒数函数拟合效果较好(P0. 01);冠层结构是影响穿透雨量空间变异的主要影响因子,但其作用因降雨量的大小而不同;叶面积指数、冠层厚度、测点距树干的距离以及冠层覆盖度均能影响穿透雨的空间分布,其中以叶面积指数对穿透雨量的影响最大;不同雨量级在相同置信区间达到相同的误差水平,所用穿透雨收集器数量不同,随着雨量级增大,用较少雨量收集器就可以达到相同的误差水平,当雨量级在0～10mm时,所用穿透雨收集器数量最多,即95%置信区间下,5%误差范围内,所需最少的穿透雨收集器数量为13个;雨量级在大于40 mm时,达到相同误差水平所用集水槽数量最少,即95%置信区间下,测的穿透雨值在5%误差范围内,所需最少的穿透雨收集器数量为6个。【结论】马尾松林下穿透雨量和树干茎流量空间变异特征同时受降雨特征和冠层结构特征的影响,且穿透雨量和树干茎流量的空间异质性均随着降雨量增大而减小,而后趋于稳定,但树干茎流量的空间变异系数稳定值大于穿透雨,冠层结构决定了林内穿透雨量空间分布的总格局,其中以叶面积指数与穿透雨率相关性最强,而胸径对树干茎流量的影响最为显著;本研究在参考降雨量级0～10 mm时,在95%或90%的置信区间下,若将穿透雨数值控制在5%误差范围内,在50 m×50 m样地内至少需布设13或11个3 000 cm~2收集器。     

亚热带杉木、马尾松人工林的林内降雨、林冠截留和树干茎流*

本文用统计分析方法对江西分宜县山下林场杉木、马尾松人工林的林内降雨、林冠截留和树干茎流进行了研究。结果表明:在该林分中林内降雨量和树干茎流量随降雨量的增加而以直线形式增加;林冠截留量随降雨量的增加呈幂函数关系上升。在杉木林内,随郁闭度的增大,林内降雨率和树干茎流率减少,而林冠截留率增大,马尾松林和杉木林相比,林内降雨率和树干茎流率较大,而林冠截留率较小。     

不同树种树干茎流氮和可溶性有机碳动态变化及其影响因子

[目的]为揭示树干茎流养分动态变化特征及其与降水量、种间差异之间的关系,以期为解析不同树种树干茎流养分通量和输入提供技术支撑.[方法]以安徽仙寓山常绿阔叶树(青冈Cyclobalanopsis glauca、薄叶山矾Symplocos anomala、甜槠Castanopsis eyrei)和针叶树(杉木Cunning...     

长沙市郊枫香人工林降水再分配及养分动态

采用定位试验研究方法对长沙市郊枫香人工林生态系统水文过程及养分动态进行了研究.结果表明：该森林生态系统春季平均降雨量为18.73 mm,其中以林冠穿透雨形式输入林地水量占降雨量的81.63%,以树干流形式输入林地水量占1.54%;树冠截留率随降雨量的增大而减小,平均树冠截留率为16.83%;在枫香人工林中,降水pH值的变化不大,且基本呈中性;养分元素质量浓度在各过程中变化不尽相同,Ca^2＋、K^＋质量浓度在穿透水和树干茎流中呈上升趋势,NH4^＋质量浓度在树干茎流中呈上升趋势,Zn^2＋、PO4^3-质量浓度呈下降趋势,Mg^2＋、Cu^2＋质量浓度变化不大.     

日本北海道东部高位泥沼远东红皮云杉、库页冷杉和日本桤木树干茎流化学及其对沼泽孔隙水化学的影响(英文)

在日本北海道高位泥沼池,调查了远东红皮云杉(Piceaglehnii)、库页冷杉(Abies sachalinensis)和日本桤木(Alnusjaponica)树干茎流液的化学性质和泥炭孔隙水的化学性质,包括了横切和纵切面孔隙水化学性质。沼泽森林树干基部茎流对泥炭孔隙水化学性质有明显的作用,而且树基部的泥炭孔隙水化学性质具有物种特异性。远东红皮云杉茎流液和泥炭孔隙水中盐分含量最高,日本桤木则最低;盐分从茎基部向树冠形成浓度梯度。树冠下泥炭孔隙水化学受化学过程控制,孔隙水充沛条件下,控制作用减弱,因地势平缓(1°)茎流移动缓慢。事实上,泥炭孔隙水充足会使茎流化学物质浓度降低。微生物活动、优势树冠的营养再生介导的表面水和茎流对森林沼泽地微生境化学环境的空间异质性有贡献。图2表2参44。     

Dissolved organic carbon and nitrogen in precipitation, throughfall and stemflow fromSchima superba andCunninghamia lanceolata plantations in subtropical China

Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two plantations ofSchima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO₃ ⁻−N, NH₄ ⁺−N and total dissolved N (TDN). DON was calculated by subtracting NO₃ ⁻−N and NH₄ ⁺−N from TDN. The results showed that the precipitation had a mean DOC concentration of 1.7 mg·L⁻¹ and DON concentration of 0.13 mg·L⁻¹. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L⁻¹ in the SS and 10.3 and 0.19 mg·L⁻¹ in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L⁻¹ respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L⁻¹ respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipitation tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September–November period. Foundation item: This study was supported by the Teaching and Research Award program for MOE P.R.C. (TRAPOYT). Biography: Guo Jian-fen (1977-), female, Ph. Doctor in College of Life Science, Xiamen University, Xiamen 361005, P.R. China. Responsible editor: Zhu Hong     

不同坡位6年生杉木木荷混交林生物量分布格局分析

对不同坡位6年生杉木木荷混交林林分生长及生物量进行分析研究。研究结果表明,杉木木荷混交林平均胸径、平均树高生长量以及地上部分和地下部分各个器官生物量均体现为下坡位>中坡位>上坡位;杉木各器官生物量表现为树干>树叶>树枝,木荷各器官生物量表现为树干>树枝>树叶;就杉木及木荷不同径级根生物量差异而言,杉木各径级根表现为骨骼根>中根>大根>粗根>小根>细根,木荷则表现为骨骼根>中根>大根>小根>细根。     

杉木,马尾松,木荷纯林及其不同混交林生长状况的分析

对杉木、马尾松、木荷纯林及其习种不同的混交林分生物量和空间分布状况的调查分析,揭示混交林与生物量间的相互关系,以及生物量的空间分布规律,以便合理利用土壤、防止地力衰退,保持林业永续利用。     

Concentrations and seasonal dynamics of dissolved organic carbon in forest floors of two plantations （Castanopsis kawakamii and Cunninghamia lanceolata） in subtropical China

The concentrations and seasonal dynamics of DOC in forest floors of monoculture plantations ofCastanopsis kawakamii and Chinese fir (Cunninghamia lanceolata) were assessed in Sanming, Fujian, China (26°11′30″N, 117°26′00″E). Forest floor samples were taken in January, April, July and October in 2002 and divided into undecomposed material (horizon Oi), partially decomposed organic material (horizon Oe), and fully decomposed organic material (horizon Oa). Upon collection, DOC concentrations of samples were analyzed by a High Temperature TOC. The results showed that the annual average DOC concentration of Chinese fir (1341.7 mg·kg⁻¹) in the forest floor was higher than that ofCastanopsis kawakamii (1178.9 mg·kg⁻¹). Difference in DOC concentrations was observed among three horizons of the forest floor. DOC concentration of forest floor in the two forests was the highest in horizon Oe. Seasonal trends of DOC concentrations in different horizons of forest floors were similar and the maximal value occurred in autumn (or winter). The concentration and temporal change of DOC in studied forests were probably related to the variation in moisture, temperature, biological activity and quantity of organic matter in the forest floor. Foundation item: This study was supported by the Teaching and Research Award program for MOE P.R.C. (TRAPOYT) Biography: ZHANG Jiang-shan (1946-), male, Researcher in Fujian Normal University, Fuzhou 350007, P.R. China. Responsible editor: Zhu Hong     

氮添加对马尾松和木荷幼苗根系土壤挥发性有机化合物的影响

为了解土壤挥发性有机化合物(VOCs)对氮沉降的响应,本研究以马尾松和木荷幼苗为研究对象,设置3个氮水平(5.6、15.6和20.6 g·m^-2·a^-1)和两种氮添加方式(土壤施氮和叶面施氮),通过质子转移反应飞行时间质谱仪分析植物土壤VOCs对不同氮水平和氮添加方式的响应。结果表明,马尾松和木荷幼苗根系土壤释放的总VOCs通量为19.50~70.94 pmol·g^-1·h^-1,以含氧VOCs(乙醛、甲醇和乙烯酮)和含氮VOCs(甲酰胺和丙胺)为主,分别占总VOCs的22.04%~47.71%和3.31%~38.68%。两种氮添加方式均显著地促进马尾松和木荷幼苗根系土壤含氮VOCs释放,这与土壤铵态氮和硝态氮含量显著相关。叶面施氮处理下马尾松根系土壤总VOCs释放显著增加,不同幼苗根系土壤释放的不同种类VOCs对氮水平和氮添加方式的响应不一致。研究结果可为评估土壤VOCs对大气氮沉降增加的响应提供基础数据。     

Dissolved organic carbon and nitrogen leaching from Scots pine, Norway spruce and silver birch stands in southern Sweden

The effects of three common tree species - Scots pine, Norway spruce and silver birch - on leaching of dissolved organic carbon and dissolved nitrogen were studied in an experimental forest with podzolised soils in southern Sweden. We analyzed soil water collected with lysimeters and modeled water fluxes to estimate dissolved C and N fluxes. Specific UV absorbance (SUVA) was analyzed to get information about the quality of dissolved organic matter leached from the different stands. Under the O horizon, DOC concentrations and fluxes in the birch stands were lower than in the spruce and pine stands; annual fluxes were 21 g m⁻² y⁻¹ for birch and 38 g m⁻² y⁻¹ and 37 g C m⁻² y⁻¹ for spruce and pine, respectively. Under the B horizon, annual fluxes for all tree species ranged between 3 and 5 g C m⁻² y⁻¹, implying greater loss of DOC in the mineral soil in the coniferous stands than in the birch stands. We did not find any effect of tree species on the quality of the dissolved organic matter, as measured by SUVA, indicating that the chemical composition of the organic matter was similar in leachates from all three tree species. Substantial amounts of nitrogen was leached out of the soil profile at the bottom of the B horizon from the pine and birch stands, whereas the spruce stands seemed to retain most of the nitrogen in the soil. These differences in N leaching have implications for soil N budgets.     

Changes in dissolved organic matter with depth suggest the potential for postharvest organic matter retention to increase subsurface soil carbon pools

Research into postharvest management of forests often focuses on balancing the need for increased biomass yield against factors that may directly impact the productivity of the subsequent stand (e.g. nutrient and water availability, soil microclimate, etc.). Postharvest organic matter management, however, also exerts a strong influence over the translocation of carbon (C) into and through the soil profile and may provide a mechanism to increase soil C content. The effects of contrasting postharvest organic matter retention treatments (bole-only removal, BO; whole-tree removal, WT) on soil solution C concentration and quality were quantified at the Fall River and Matlock Long-term Soil Productivity (LTSP) studies in Washington state. Solutions were collected monthly at depths of 20 and 100 cm and analyzed for dissolved organic C (DOC), dissolved organic nitrogen (DON) and DOC:DON ratio. Comparisons of DOC concentrations with depth illustrate divergent trends between the two treatments, with an overall decrease in DOC with depth in the BO treatment and either an increase or no change with depth in the WT treatment. Trends in DON concentrations with depth were less clear, partly due to the very low concentrations observed, although the relationship of DOC:DON with depth shows a decrease in the BO treatment and little to no change in DOC quality in the WT treatment. This illustrates that more recalcitrant organic matter (higher DOC:DON) is being removed from solution as it moves through the soil profile. Only 35–40% of the DOC moving past 20 cm in the BO treatment is present at 100 cm. Conversely, 98–117% of the DOC at 20 cm in the WT treatment is present at 100 cm. Thus, 11 and 30 kg C ha⁻¹ yr⁻¹ are removed from solution between 20 and 100 cm in the BO treatment at the Matlock and Fall River LTSP studies, respectively. Although much of this C is often assumed to be utilized for microbial respiration, DOC:DON ratios of the potential organic substrates and the unique mineralogy of the soils of this region suggest that a significant portion may in fact be incorporated into a more recalcitrant soil C pool. Thus, postharvest organic matter retention may provide a mechanism to increase soil C sequestration on these soils.     

Overstory vegetation influence nitrogen and dissolved organic carbon flux from the atmosphere to the forest floor: Boreal Plain,Canada

Nitrate, ammonium, total dissolved nitrogen (TDN), dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) concentrations and flux were measured for one year in bulk deposition and throughfall from three stand types (upland deciduous, upland conifer and wetland conifer) on the Boreal Plain, Canada. Annual (November 2006 to October 2007 water year) flux rates in bulk deposition were 80, 216, 114 and 410 mg N m⁻² for nitrate, ammonium, DON and TDN, respectively, and 3.5 g C m⁻² for DOC. The nitrate and ammonium flux in throughfall were approximately 50% of the flux in bulk deposition, while TDN flux in throughfall was 60–74% of the flux in bulk deposition. The DOC flux in throughfall was approximately 2 times greater than DOC flux in bulk deposition, while there was no detectable difference in DON flux. The forest canopy generally had the most impact on throughfall chemistry during the active growing season as compared with the dormant season, although DOC concentrations in throughfall of deciduous stands was highest during autumn. For the upland stands, TDN flow-weighted mean concentrations in the snowpack were not detectably different from the concentrations in throughfall and bulk deposition throughout the rest of the year. However, ammonium concentrations were lower and DON concentrations were higher in the snowpack than in either throughfall or bulk deposition for the other seasons, suggesting some transformation of ammonium to DON within the snowpack.