Litterfall production modeling based on climatic variables and nutrient return from stands of Eucalyptus grandis Hill ex Maiden and Pinus taeda L.

Native grasslands in the Pampas of South America are increasingly being replaced by Eucalyptus and Pinus stands.The short rotation regimes used for the stands require high nutrient levels,with litterfall being a major source of nutrient return.To model the litterfall production using climatic variables and assess the nutrient return in 14-year-old Eucalyptus grandis and Pinus taeda stands,we measured litter production over 2 years,using conical litter traps,and monitored climatic variables.Mean temperature,accumulated precipitation,and mean maximum vapor pres-sure deficit at the seasonal level influenced litterfall produc-tion by E.grandis;seasonal accumulated precipitation and mean maximum temperature affected litterfall by P.taeda.The regression tree modeling based on these climatic vari-ables had great accuracy and predictive power for E.grandis(N=33;MAE(mean absolute error)=0.65;RMSE(root mean square error)=0.91;R^(2)=0.71)and P.taeda(N=108;MAE=1.50;RMSE=1.59;R^(2)=0.72).The nutrient return followed a similar pattern to litterfall deposition,as well as the order of importance of macronutrients(E.grandis:Ca>N>K>Mg>P;P.taeda:N>Ca>K>Mg>P)and micronutrients(E.grandis and P.taeda:Mn>Fe>Zn>Cu)in both species.This study constitutes a first approximation of factors that affect litterfall and nutrient return in these systems.

Nitrogen addition promotes foliar litterfall and element return in a subtropical forest,southwestern China

Nitrogen deposition has a considerable impact on biogeochemical cycling in terrestrial ecosystems.However,how litter production and element return respond to N addition remains poorly understood in nitrogen-rich subtropical regions.In this study,a 4-year nitrogen addition experiment explored its eff ects on foliar litter production and carbon,nitrogen and phosphorus in a subtropical Michelia wilsonii forest.A clear seasonal pattern in foliar litterfall was observed,regardless of nitrogen treatments,with a peak in spring and a smaller one in autumn.Foliar litter increased with increasing nitrogen but did not aff ect litter carbon concentrations and often decreased nitrogen and phosphorous concentrations.The eff ect of nitrogen addition was dependent on time(month/year).Carbon,nitrogen and phosphorous return showed similar bimodal seasonal patterns.Nitrogen addition increased carbon and nitrogen return but did not aff ect phosphorous.Our results suggest that the addition of nitrogen stimulates carbon and nutrient return via litterfall.

Seasonal Dynamics of Energy Return Through Litterfall of A Mixed Forest of Chinese Fir and T. odorum

Based on the measurement of monthly litterfall and their gross calor ic values, the seasonal dynamics of energy return through litterfall were determ ined in a pure and a mixed T. odorum (Tsoongiodendron odorum Chun) forests with Ch inese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian Provinc e. Annual ene rgy return through litterfall was estimated as 12.648×10 6J·m -2 for the mixed fo rest, being 4 2% higher than that of the pure forest, and a large proportion of the energy return comprised leaf litter. The conversion efficiency of solar rad i ation energy into litterfall was 0 56% for mixed forest and 0 54% for pure for es t, respectively. The monthly energy flux in litterfall of Chinese fir showed a t hree-apex curve, peaked in March, August and December, respectively, which was s imilar to that in various fractions of leaf, twig, flower and fruit litter. The consistency in monthly patterns among different litter fractions of Chinese fir was attributed to their solid connections all the while. The monthly energy flux in litterfall of T. odorum culminated in January, May and August, the same was true for its leaf and twig litter. However, energy flux in flower litter only oc curred during March to May and that in fruit litter appeared in January and Marc h. The monthly dynamics of energy flux through litterfall of the two forests wer e both determined by their respective litterfall pattern of Chinese fir. Seasona l energy flux in litterfall for both mixed and pure forests followed the sequenc e of spring>winter>summer>autumn, but fluctuations in the former were less disti nct than those in the latter.

Landscape patterns of overstory litterfall and related nutrient fluxes in a cool-temperate forest watershed in northern Hokkaido,Japan

Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.

庆安地区地表凋落物含水率预测研究

文章以黑龙江省庆安县曙光林场典型林分为研究对象,通过野外地表凋落物含水率的连续观测,分析了地表凋落物含水率动态变化。利用曙光林场春秋两季的气象数据计算出加拿大火险气候指数系统(FWI)的湿度码,用含水率数据与气象要素和FWI湿度码分别进行回归,得到两类含水率回归模型,旨在为庆安地区森林火险预测预报提供科学参考。

Monthly variation in litterfall and the amount of nutrients in an Aleurites montana plantation

In this study, the dynamics of monthly variation in litterfall and the amount of nutrients, i.e., organic C, N, P and K, in an Aleurites montana plantation were analyzed, based on a field study and experiments over one year. The results show that the litterfall mass of A. montana collected generally presents an ascending trend with maximum defoliation occurring in the autumn and winter （October-December）, accounting for 75.67% of the total amount of annual litterfalk The sequence in the amount of nutrients in A. montana litter was as follows： organic C 〉 N 〉 K 〉 P; their monthly amounts show various dynamic curves. Similar to the dynamics of the mass of monthly litterfall, the monthly returns of C, N, P and K generally show an ascending trend with their peak values all occurring in December. The mass of A. montana litterfall and the dynamics of its monthly nutrient return provide, to a certain degree, a scientific reference for planting and fertilizing A. montana.

Carbon Return and Dynamics of Litterfall in Natural Forest and Monoculture Plantation of Castanopsis kawakamii in Subtropical China

The amount of carbon returned through litterfall and its seasonal pattern were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata) (CF) in Sanming, Fujian Province, China. Mean annual carbon return through total litterfall over 3 years (from 1999 to 2001) was 5.097 t穐m2 in the NF, 4.337 t穐m2 in the CK and 2.502 t穐m2 in the CF respectively. Of the total carbon return in the three forests, leaf contribution accounted for 58.96%, 68.53% and 56.12% and twig 24.41%, 22.34% and 26.18%, respectively. The seasonal patterns of carbon return from total litterfall and leaf-litter were quite similar among the three forests. A peak of carbon input from litterfall in the NF and the CK occurred in spring except for the highest annual C return through branch litter of the NF in summer, while the CF showed the maximum C return in summer. The results of this study demonstrate that the natural forest has a greater C return through litterfall than monoculture plantations, which is beneficial to the increase of soil organic matter storage and the maintenance of soil fertility.

Litterfall production and nutrient return in different-aged Chinese fir(Cunninghamia lanceolata) plantations in South China

The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems.We monitored annual litterfall production, nutrient return,and monthly dynamics over a one-year period in Chinese fir plantations aged 10, 22, and 34 years. Our objective was to quantify litterfall and nutrient return over a complete harvest rotation of Chinese fir. Annual litterfall production increased with stand age and was recorded as（3,294.6 ± 360.4）,（3,733.9 ± 211.2）, and（4,876.1 ± 212.8） kg ha-1a-1in stands aged 10, 22 and 34 years, respectively. Total litter production was significantly greater in the stand aged34 years than in the stand aged 10 years（p ／ 0.05）. With the exception of miscellaneous components, needle litterfall constituted the highest proportion（27.5–43.6 %）, followed by branches/twigs（9.5–16.6 %）. In all three plantations,annual total nutrient return to soil was in the order of C（1,119.95–2,709.05 kg ha-1a-1） [ N（39.32–62.04 kg ha-1a-1） [ K（15.95–22.44 kg ha-1a-1） [ P（1.30–1.63 kg ha-1a-1）. C, N, K and P input to soil was significantly lower in the 10-year-old stand in comparison to the 22- and34-year-old stands（p ／ 0.05）. Litterfall production and nutrient return（C, N and K） followed similar patterns, and C and N input to soil was significantly related to litterfall production（needle, branch and total litterfall）. C, N, P and K input to soil and total litterfall production were mainly driven by needle litterfall.

Litterfall,decomposition and nutrient release of Shorea robusta and Tectona grandis in a sub-tropical forest of West Bengal,Eastern India

We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha-1 a-1 for S. robusta to 11.03 ± 3.72 t ha-1 a-1 for T. grandis and the decay constant （k） of decomposed leaf litter was distinctly higher for T. grandis （2.70 ± 0.50 a-1） compared to S. robusta （2.41 ±0.30 a-1）. Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis （P 〈 0.01）. Nutrient use efficiency （NUE） and nutrient accumulation index （NAI） of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P 〉 N 〉 K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order： N〉K^P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release （K 〉 P 〉 N） during decomposition of their leaf litter.Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity.

Nutrients in litterfall,forest floor and mineral soils in two adjacent forest ecosystems in Greece

The fluxes of masses and the nutrients Ca,Mg,K,N,P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak(Quercus frainetto L.)and European beech(Fagus sylvatica L.)in a mountainous area of northeastern Greece in 2010–2015.The foliar litterfall for both species reached about 70%of the total litterfall,and was significantly higher from the other two fractions(woody and rest litterfall).The fluxes of masses and nutrients were compared between ecosystems for each fraction separately.Only one significant statistical difference was found,that of K in the woody litterfall.In addition,the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems.Likewise,the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems.In the L horizon of the forest floors,statistical differences,as a result of species effect,were found for the stocks of Ca and N.In the FH horizons,the masses and all the nutrient stocks differed significantly,as the beech plot had much higher quantities of organic matter and nutrients.These higher quantities were probably due to low soil temperatures(microclimate)and high acidity in the beech plot(species effect)that slowed down decomposition.In the mineral soils,the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons.Because of the soil acidity in the beech plot,the stocks of exchangeable base cations were significantly higher in the oak plot,whereas the other nutrient stocks did not differ.

2008-2018年天童常绿阔叶林不同演替阶段凋落物月和年回收量数据集

凋落物生产是森林生态系统物质循环的重要组成部分,在维持森林土壤肥力、促进生态系统养分循环中起着重要作用。凋落物生产量也是衡量森林生产力等生态系统功能和碳平衡的重要指标。本数据集采自浙江天童森林生态系统国家野外科学观测研究站木荷林辅助观测场和栲树林综合观测场。上述两样地群落演替类型分属于常绿阔叶林演替中后期和顶级阶段。每个观测样地投影面积50 m×50 m,样地内各设27个0.5 m2凋落物框,分凋落物组分(枯枝、枯叶、花(果实)、树皮和杂物)进行收集和统计。数据集包含了两个样地2008–2018年凋落物各组分及总量的月和年回收量,已经过原始纸质记录比对、同期数据动态趋势比较等数据质量控制和评估。本数据集可以为理解常绿阔叶林演替进程中生态系统结构与功能的变化提供基础信息,也能为研究区域气候变化对森林生态系统的影响和常绿阔叶林分布区碳平衡评价提供数据支撑。

亚热带3种森林凋落物量及碳氮归还动态变化

[目的]探明亚热带不同森林类型的碳汇功能,为森林经营和针叶林改造中的树种选择提供指导。[方法]基于月动态监测,研究了罗卜岩自然保护区亚热带常绿阔叶林(米槠林)、常绿-落叶阔叶混交林(闽桦-闽楠林)和针叶林(马尾松林)3种森林类型的凋落物产量及碳氮归还动态变化。[结果](1)3种林分中马尾松林的年总凋落量最高〔9815 kg/(hm^(2)·a)〕,其次为闽桦-闽楠林〔9207 kg/(hm^(2)·a)〕,米槠林最低〔8083 kg/(hm^(2)·a)〕,叶是闽桦-闽楠林和马尾松林凋落物的主要组分,而米槠林凋落物以碎屑等其他组分为主;3种森林的总凋落量、叶、花果和其他组分凋落量月动态均呈双峰型曲线,峰值分别出现在11—12月和次年的4—5月。(2)3种林分总凋落物碳归还量为马尾松林〔4970 kg/(hm^(2)·a)〕>闽桦-闽楠林〔4458 kg/(hm^(2)·a)〕>米槠林〔3804 kg/(hm^(2)·a)〕,总凋落物氮归还量为闽桦-闽楠林〔160 kg/(hm^(2)·a)〕>马尾松林〔128 kg/(hm^(2)·a)〕>米槠林〔113 kg/(hm^(2)·a)〕,3种林分凋落物碳氮归还的月变化与其总凋落物量的月变化一致。(3)3种林分的凋落物质量差异显著,其中马尾松林的总凋落物碳氮比最高,闽桦-闽楠林最低;闽桦凋落物的木质素浓度最高,米槠最低;闽楠和马尾松凋落物的木质素/纤维素值最高,米槠最低。[结论]闽桦-闽楠林具有更高的年凋落物量和较快的潜在分解速率,可以更持续快速地为林地补充养分。

六种温带森林类型凋落物量长期动态及其环境驱动

阐明凋落物动态及其环境控制机制,可以为森林生态系统生产力及碳汇功能的维持提供重要的数据支持和理论依据。以长白山系余脉张广才岭西坡林龄相近但立地条件不同的4种天然次生林(即硬阔叶林、杨桦林、杂木林和蒙古栎林)和2种人工林(落叶松人工林和红松人工林)为研究对象,对其地上凋落物产量及其组分以及相关环境因子进行了14年(2008-2021年)的连续测定,旨在揭示森林凋落物量及其组分的时空变化(林型间和年际变异)及其环境驱动机制。结果表明:6种森林类型的凋落总量(TL)无显著差异,波动范围为500.5-556.1 g m^(-2)a^(-1);但其叶凋落量(LL)、繁殖组织凋落量(RT)和其他组织凋落量(OT)均存在显著差异,波动范围依次分别为333.9-391.8 g m^(-2)a^(-1)、8.43-69.93 g m^(-2)a^(-1)和93.4-185.9 g m^(-2)a^(-1)。6种森林类型的TL均存在显著的年际变化;其中LL和OT年际变化的显著性因森林类型而不同,而RT的年际变化不显著。除落叶松人工林外,其余5种森林类型的LL与生长季平均气温、日最低气温均值、土壤10 cm深度处的平均温度、最低温度(Tsmin)和土壤5 cm含水量(Ms)均呈显著正相关。杂木林、硬阔叶林和红松人工林的RT与Ms呈显著负相关;杂木林、杨桦林和硬阔叶林的OT与Tsmin呈显著负相关。样地水平的LL与土壤10 cm处含水量存在显著的正相关关系,而RT和OT则与其呈现显著负相关关系。这些结果表明林龄相似的温带森林地上凋落物总量有趋同趋势,但其通过改变组分分配格局来适应立地条件的变化;土壤湿度和温度变化会引起凋落物量的年际变化,但不同森林类型的凋落物量对环境波动的敏感性不同。

2005-2020年西双版纳热带季节雨林凋落物回收量和现存量动态数据集

凋落物是指植物地上部分产生并归还到地表的所有有机质的总称,是链接陆地生态系统地上和地下生态过程的关键媒介。凋落物回收量和现存量包括枯枝、枯叶、落果(花)、树皮、苔藓地衣及杂物的干重。枯落叶年总产量可评价森林生产力提供数据支撑,落果(花)对森林种子雨的研究具有重要价值,凋落物各组分的比例是影响生态系统碳循环过程和养分循环的重要因素。本数据集收集了2005–2020年西双版纳热带季节雨林凋落物各组分回收量和现存量动态数据。建立和共享本数据集可以为深入探讨全球水热格局变化情形下的植被结构和生态系统功能提供本底资料,为推动凋落物研究和热带季节雨林的研究提供依据。

缙云山常绿阔叶林凋落物量及动态特征

亚热带常绿阔叶林是中国森林的重要组成部分。从群落尺度探讨凋落物量、组成、动态及其气候影响因素,对了解森林生态系统的物质循环过程和群落构建机制等方面具有重要意义。基于缙云山常绿阔叶林永久样地2014—2021年的凋落物监测数据,分析该研究地凋落物量及其各组分之间的动态和组成特征,同时探讨温度和降水2类气候因子对凋落物量的影响。结果表明:1)缙云山亚热带常绿阔叶林年平均凋落物量为6.25 t/hm^(2),年际差异不显著(P>0.05);2)在凋落物组成上以叶片为主(占凋落物总量的72.50%);3)不同组分凋落物的凋落节律存在明显差异,其中叶片和繁殖体的凋落节律也与凋落物总量保持一致,均为双峰型,发生在4、5和11月,而枝条与其他残渣凋落物的凋落节律不明显;4)月平均气温、最湿月降水量和最干月降水量是影响凋落物量的主要气候因素,且月平均气温的影响更显著。其中月平均气温对凋落物总量、叶凋落物量、其他植物残渣影响显著,而繁殖体凋落物量主要受月平均气温、最湿月降水量和最干月降水量的影响。

滨海沙地3种林分类型的凋落物及其分解动态变化

【目的】探究滨海沙地天然林和人工林的凋落物量及其分解动态,为滨海防护林体系的保护与重建提供参考依据。【方法】采用时间动态分析法,在南亚热带滨海沙地区域选取高山榕/假苹婆天然林(FS)、红鳞蒲桃天然林(SH)、马占相思人工林(AM)为研究对象,使用收集网和分解袋法,测定各林分的凋落物量、残留量及凋落物碳(C)、氮(N)、磷(P)初始含量,分析各林分凋落物总量和叶、枝、花果及杂物组分占比、凋落物总量的月动态变化情况及分解速率,通过Olson模型和相关性分析分别研究凋落物周转期和分解率与凋落物初始养分的相关性。【结果】3种林分类型的年凋落量为8645.74~23404.07 kg/hm2,排序为FS>SH>AM;凋落叶量占林分凋落物总量的比重最大,为84.24%~94.98%,AM的凋落叶量与FS和SH间存在显著差异(P<0.05,下同),凋落物总量及各组分凋落量均表现为2种天然林高于人工林。3种林分年凋落物量的月动态变化均呈现3峰型,峰值分别出现在5月、8月和10月或11月,总体在5月达到全年凋落量最高峰但具体波动幅度存在差异。在时间序列上,FS和SH的凋落物分解速率变化趋势均表现为先快后慢,AM表现为慢—快—慢;试验结束时,各林分的干物质残留量排序为AM(66.30%)>SH(46.90%)>FS(23.90%)。3种林分凋落物分解符合Olson模型,预测分解的半衰期为0.423~1.472 a,分解周转期为AM(6.360 a)>SH(4.016 a)>FS(1.827 a)。凋落物分解速率与初始C含量呈极显著负相关(P<0.01),与C/N呈显著负相关。【结论】滨海沙地FS和SH 2种天然林分的年凋落物量大、分解率快和周转期短,具有较高改善滨海沙地土壤结构和维持土壤肥力的能力。在滨海沙地的植被恢复和防护林体系建设中,应优先从当地的天然林分中选择建群树种和伴生树种构建近自然的混交林或复层林,增加林分的生物多样性和凋落物组成的复杂性,提高林分对土壤养分的贡献率,对海岸带生态系统可持续的保护和治理具有重要意义。

三工河流域两种琵琶柴群落凋落物分解与周转研究

凋落物是植物与土壤间物质和能量转换的载体,是陆地生态系统养分循环的重要环节。本文于2010年和2011年生长季(5月—10月)内,利用凋落物收集器和分解袋法研究三工河流域两处长势不同的琵琶柴群落凋落物的生产、分解和周转对土壤因子的响应。结果表明,两个群落凋落物的月产量呈先增加后降低的趋势,分别在7月和8月达到最大值。群落1和群落2的年凋落物年产量差异显著,分别为25.42 g·m^(–2)·a^(–1)和34.05 g·m^(–2)·a^(–1),凋落物对土壤有机碳的补充量分别为11.81 g·m^(–2)·a^(–1)和17.65 g·m^(–2)·a^(–1)。两个群落的凋落物均在初期分解较快,随后分解速率不断降低,群落1和群落2的分解1年后的残留率分别为71.81%和75.60%。当凋落物分解量达到50%和95%时,群落1分别需要2.52年和14.64年,群落2分别需要3.69年和20.13年。群落1和群落2的周转速率分别为1.21次·a^(–1)和0.98次·a^(–1)。本研究结果预示,土壤含水量、pH和容重是影响凋落物分解的主导因子。

模拟氮沉降对华西雨屏区苦竹林凋落物养分输入量的早期影响

凋落物养分输入量是营养元素通过凋落物归还土壤的库流量,也是土壤肥力的主要来源,旨在探究凋落物及其养分元素输入量对N沉降增加的早期响应,以期为竹林生态系统的物质循环和能量流动提供基础数据。2007年11月至2010年12月对华西雨屏区苦竹人工林进行了模拟氮(N)沉降试验,氮沉降水平分别为:对照(0 g N·m-2·a-1),低氮(5 g N·m-2·a-1),中氮(15 g N·m-2·a-1),高氮(30 g N·m-2·a-1)。在氮沉降2 a后,于2010年1月开始收集各样方的凋落物样品,连续收集12个月,测定凋落物量和养分输入量。结果表明:氮沉降显著增加了凋落物量;同时显著增加了凋落叶中的N、P、K、Ca、Mg元素含量和这几种养分元素的年输入量。研究表明模拟氮沉降处理增加了凋落物对土壤养分的输入量,这对于维持苦竹林地肥力与保持苦竹林分的长期生长力具有重要的作用。

森林凋落物研究进展

对森林凋落物的概念、研究方法及主要研究内容作了阐述 ,特别就凋落物收集面积和分解袋孔径大小、凋落量时空动态和凋落物分解速率等问题进行了综合分析。目前森林凋落物研究的重要结论有 :海拔和纬度因子是通过对光、温、水等生态因子的再分配来影响凋落量 ,其中主导气候因子是年均温。凋落物的分解与化学组成和环境因子有关 ,C/N和N含量在凋落物分解过程中起着重要作用。土壤水分是影响凋落物分解主要环境因子之一 ;土壤微生物对凋落物的影响 ,前期是通过真菌破碎凋落物表层使内居性动物得以侵入凋落物内部 ,后期则以细菌降解有机物为主。凋落量、凋落物分解的影响因子 。

西双版纳原始热带湿性季节雨林生物量及净初级生产

应用生物量回归模型和生产力方程，研究了西双版纳原始热带湿性季节雨林生物量及净初级生产量（NPP）。雨林总生物量为692．590t·hm-2，总生物量分配为：乔木层占98．66％、灌木层占0．76％、木质藤本层占0．50％、草本层占0．09％，生物量主要集中于乔木层。雨林年平均NPP为25．764t·hm-2·a－1，其中各层次的NPP分别为（t·hm-2·a－1）：乔木层23．972（占总NPP的93．04％）、灌木层0．749（占2．91％）、木质藤本层0．431（占1．67％）和草本层0．612（占2．38％）。乔木层NPP分配为（t·hm－2·a-1）：凋落量11．566、叶虫食量0．694和生物量增量11．712。结果表明：西双版纳虽地处热带北缘，当地原始热带湿性季节雨林同样具有典型热带雨林一样高的生物量和NPP。