茂兰退化喀斯特森林植被自然恢复中生态系统碳吸存特征

为了了解退化喀斯特森林自然恢复中生态系统碳吸存趋势,采用空间代替时间的方法,研究了茂兰退化喀斯特森林自然恢复中生态系统碳吸存特征。结果表明:总体上植被生物量随恢复进程递增,其中乔木层与其变化一致,草本层、灌木层则相反;喀斯特植被的地上与地下生物量之比较低,尤其灌木层的地上与地下生物量之比最低;加权平均含碳率随恢复进展递增;随恢复进程,植被乔木层碳密度递增,草本层、灌木层碳密度递减;总体上生态系统及其植被、土壤的碳密度由恢复早期(草本阶段、草灌阶段)经中期(灌木阶段、灌乔阶段)至后期(乔木阶段、顶极阶段)呈增加趋势,而凋落物的相反。在贵州茂兰国家级自然保护区喀斯特森林的恢复进程中,植被对生态系统碳库的影响最大,尤其是木本植被,而土壤的影响较小,因此,加强植被恢复对喀斯特地区生态系统碳汇具有极重要的意义。     

贵州中部喀斯特山地不同植被生态系统细根生态特征及养分储量

为了解喀斯特生态系统退化过程中树木细根生物量和土壤养分的变化,选择贵州中部喀斯特山地乔木林、灌木林和灌草丛3种植被生态系统,比较分析不同深度(0～5 cm、5～10 cm和10～15 cm)土壤细根数量及其养分情况.结果表明:树木细根主要分布在0～10 cm土层,并随土层加深而减少.在0～10 cm土层中,乔木林、灌木林和灌草丛的活细根生物量分别占0～15 cm总细根生物量的42.78%、56.75%和53.38%,总活细根生物量的83.36%、86.91%和93.79%.不同植被下优势种植物细根生物量存在差异.0～5 cm土层乔木林活细根氮素和磷素储量均显著高于灌草丛和灌木林(P0.05),但灌木林和灌草丛间没有差异;5～10 cm土层乔木林活细根氮和磷储量显著高于灌草丛和灌木林(P0.05),灌木林下又显著高于灌草丛下(P0.05).0～10 cm土层的活细根生物量与植株地上部分生物量呈正相关,植物叶片氮、磷养分含量与细根比根长呈显著的负相关,说明细根的养分储量对地上生物量的建成和生态系统功能的发挥具有重要作用.     

黄土丘陵区退耕还林地刺槐人工林碳储量及分配规律

采用样地调查与生物量实测方法,研究了甘肃黄土丘陵区不同坡向(阳坡、阴坡)和退耕年限(退耕5a、8a和11a)刺槐人工林乔木不同器官、灌草层、枯落物层和土壤层的碳含量,以及刺槐人工林乔木层、灌草层、枯落物层和土壤层碳储量及其分配特征。结果表明:刺槐不同器官碳含量均值变化范围为43.02%—50.89%%,从高到低排列顺序为树干细枝中枝粗枝叶根桩大根粗根小根中根树皮细根;灌木层碳含量为35.76%—42.74%;草本层碳含量为35.83%—43.64%;枯落物层碳含量为39.55%—41.77%;土壤层(0—100 cm)碳含量均值变化范围0.22%—0.99%,随退耕年限增加而增大,土壤深度的增加而逐渐下降。刺槐人工林生态系统碳库空间分布序列为土壤层(0—100 cm)植被层枯落物层。阳坡和阴坡退耕5a、8a、11a刺槐林生态系统碳储量分别为52.52、58.93、73.72 t/hm2和49.95、61.83、79.03 t/hm2。退耕年限和坡向是影响刺槐人工林碳储量增加的主要因素。刺槐人工林具有良好的固碳效益,是黄土丘陵区的理想树种。     

黄土丘陵区油松人工林生态系统碳密度及其分配

以子午岭林区油松(Pinus tabulaeformis)人工林为研究对象,通过野外调查与室内分析,探讨了幼龄9a、中龄23a、近熟33a和成熟47a等不同林龄林分的生物量、含碳率、碳密度及其时空分布特征。结果表明:(1)油松林各群落平均生物量大小排序为:乔木层(76.12 t/hm2)枯落物层(14.56 t/hm2)林下植被层(3.66 t/hm2)。乔木层生物量随林龄增大而持续增加,各器官中树干所占比例最大(38%—46%),其次为叶和根,枝和皮所占比例最小;林下植被层生物量随林龄增大呈先降低后增加趋势;枯落物层生物量随林龄增大则明显增加。(2)油松乔木、林下灌木、草本、枯落物平均含碳率依次为50.2%、44.5%、43.8%和40.6%。林龄对乔木各器官含碳率无显著影响,不同器官之间含碳率存在显著性差异,具体表现为叶(53.3%)枝(51.4%)皮(50.6%)干(49.8%)根(47.3%);灌木各器官含碳率表现为枝(46.0%)叶(44.8%)根(42.5%),草本则是地上(45.2%)地下(40.2%)。土壤(0—100 cm)含碳率在0.3%—2.7%之间,且具有明显的垂直分布特征:表层含碳率高,并随土壤深度的增加逐渐降低。(3)9、23、33和47年生油松林生态系统碳密度分别为70.49、100.48、167.71和144.26 t/hm2,其空间分布序列表现为土壤层植被层枯落物层,且植被层和土壤层是油松人工林的主要碳库。林龄是影响油松林木及群落碳密度积累的主导因子之一。随林龄增加,土壤碳密度所占生态系统碳密度份额逐渐降低,乔木层和枯落物层则逐渐增加。     

长沙市区马尾松人工林生态系统碳储量及其空间分布

采用样方法和取样法,研究了长沙市区13年生马尾松林生态系统碳含量、碳储量及其空间分布特征。结果表明:马尾松林木各器官平均碳含量为511.17 g/kg,从高到低排列顺序为叶>干>根>皮>枝;林下灌木层、草本层、枯落物层的平均碳含量分别为531.66、465.53、393.92g/kg。林地土壤层有机碳含量为9.40—24.73 g/kg,各层次碳素含量分布不均,表层(0—15cm)土壤碳素含量较高,并随土壤深度的增加而逐渐下降。生态系统碳库的空间分布序列为土壤层>植被层>枯落物层。植被层的碳储量为34.50t/hm2,占整个生态系统碳总储量的21.57%;乔木层碳储量占整个生态系统的20.27%,占植被层碳储量的93.97%。乔木层碳储量中,树干的碳储量最高,占乔木层碳储量的65.52%,其次为根,占乔木层碳储量的19.15%,树皮最少,仅占2.10%;枯落物层碳储量为3.81 t/hm2,仅占整个生态系统碳储量的2.38%;林地土壤层(0—60cm)碳储量相当可观,为121.62 t/hm2,占系统碳储量的76.05%。马尾松林年净生产力为4.88 t.hm-.2a-1,有机碳年净固定量为2.50 t.hm-.2a-1,折合成CO2的量为9.16 t.hm-.2a-1。     

六盘山四种森林生态系统的碳氮储量、组成及分布特征

碳和氮是森林生态系统的重要组成元素,其含量有很大时空差异,并和立地及森林特征关系很大,需做大量的积累性调查才能得到其变化规律,尤其是加强在过去较少研究的西北地区的调查。在宁夏六盘山区选择华北落叶松(Larix principisrupprechtii)人工林、华山松(Pinus armandii)次生林、桦木(Betula platyphylla)次生林和野李子(Prunus salicina)灌丛4种典型森林,测定了乔木层(分不同器官)、灌木层、草本层、枯落物层、根系层(0—100 cm土壤)的碳、氮含量,分析了生态系统的碳、氮储量及成分组成和层次分布特征。结果表明,碳含量在不同乔木树种及其不同器官之间的差异不明显;但氮含量存在显著的树种差别和器官差异,以树叶的最高、树干的最低。灌木层和草本层的碳氮含量均表现为地上部分地下部分。各森林样地的乔木层、灌木层、草本层的碳含量依次降低,但氮含量依次增高;枯落物层的碳含量低于各植被层,但氮含量高于各植被层;根系层土壤的碳、氮含量则随土层增深而递减。包括活植被层、枯落物层和根系层土壤在内的华北落叶松人工林、华山松次生林、桦木次生林、野李子灌丛的生态系统碳储量依次为364.56、450.98、640.02、196.55 t/hm2,氮储量依次为27.86、36.19、47.02、15.99 t/hm2。所有4种森林生态系统的根系层土壤的碳氮储量均占整个生态系统总储量的绝大部分,其比例对碳储量为84.69%—93.92%,氮储量为98.09%—98.64%。从乔木层、灌木层、草本层、枯落物层到根系层(土壤),呈现出C/N比依次减小的趋势;根系层土壤和整个生态系统的C/N比分别为华北落叶松林的11.84和13.12、华山松林的10.76和12.56、桦木林的12.48和13.52、野李子灌丛的11.70和12.29。     

土壤微生物群落对枯落物输入的响应

枯落物分解在陆地生态系统物质循环能量流动中起着关键性作用,明确枯落物输入对土壤微生物群落的影响有助于理解土壤微生物生物多样性和陆地生态系统功能的相互关系。本文采用整合分析方法,以中国为研究区域,以不添加枯落物为对照组,探究土壤微生物(真菌、细菌、放线菌)及微生物生物量碳、生物量氮对枯落物输入的响应。结果表明:与不添加枯落物相比,添加枯落物后土壤微生物生物量碳、生物量氮分别显著增加3.9%和4.4%;土壤真菌PLFA、细菌PLFA及总微生物PLFA分别增加4.0%、3.1%和2.4%。枯落物输入对土壤微生物的影响受到气候条件、年降水量、植被类型及土壤酸碱度等因素的显著影响;不同气候类型下,土壤微生物对枯落物输入的响应呈现出亚热带季风气候区>温带季风气候区>温带大陆气候区的趋势,以及随着年降水量的增加呈现出先升高后降低的趋势;不同植被类型下,土壤微生物对枯落物输入的响应呈现出阔叶林>草地≈混交林>针叶林的趋势。     

喀斯特风水林和荒山生态系统碳储量的研究

所研究的风水林和荒山属于喀斯特地貌。喀斯特森林是一种脆弱的低生物量生态系统,土壤贫瘠,自我修复能力低,易受人为因素干扰。风水林指人们居住地附近的一片茂盛的森林,认为有神居住而崇拜,严禁被砍伐和破坏。荒山是喀斯特森林植被在人为干扰后出现岩石裸露产生的石漠化现象。该研究通过野外调查、实验室分析、数理统计等对广西罗城喀斯特风水林和荒山生态系统碳储量进行对比性研究。结果表明:喀斯特风水林植被、土壤和枯落物碳储量分别是荒山的7.42倍、5.9倍和1.1倍,风水林和荒山生态系统碳储量分别为137.06、93.73 t·hm~(-2),其中土壤碳库贡献率最高,而林下植被和枯落物却较低,表明风水林森林生态系统碳储量明显高于荒山。通过风水林和荒山的碳储量比较研究,为评价风水林碳汇提供依据,为制定森林管理政策、保护村社水平的植被提供数据参考。此外,还探讨了少数民族朴素的生态伦理思想在保护森林和增汇方面的作用,丰富了生态伦理学内容,对传承和弘扬少数民族传统文化、恢复生态具有重要意义。     

不同林龄杨树人工林碳储量研究

基于盐城市东台林场杨树人工林的生物量调查和土壤碳测定,探讨了不同发育阶段杨树人工林碳储量的时空变化规律。结果表明,随林龄的增加,杨树人工林生态系统碳储量增加,群落总碳储量的空间分布序列是:土壤层(130.87 t·hm-2)乔木层(56.32 t·hm-2)枯落物层(1.2 t·hm-2)林下植被层(0.37 t·hm-2);乔木层碳储量和林木各器官碳储量均随林龄的增加而总体呈上升趋势;林下植被层和枯枝落叶层碳储量呈先上升后下降的趋势;土壤层碳储量先增加后下降,但其占杨树人工林总碳储量的比例逐渐降低。研究认为杨树人工林固碳潜力巨大,且不同发育阶段的杨树人工林碳储量差异主要是由乔木层碳储量差异引起的。     

湖北省主要森林类型生态系统生物量与碳密度比较

利用野外调查数据对湖北省封山育林下的次生林、次生林、人工林森林生态系统碳密度进行了分析,结果表明:封山育林下的次生林、次生林和人工林生态系统乔木层平均碳密度分别为133.87、73.42和111.62t·hm-2,灌木层平均碳密度分别为1.65、1.40和1.52t·hm-2,草本层平均碳密度分别为0.13、0.09和0.13t·hm-2,枯落物层平均碳密度分别为0.47、1.34和0.93t·hm-2,乔木层碳密度作为生态系统碳储量的主要贡献者占总生物碳密度的98.35%、96.29%和97.74%,林下植被(灌木层和草本层)碳密度分别占1.31%、1.95%和1.44%,凋落物层碳密度分别占0.34%、1.76%和0.82%。土壤(0～100cm)碳密度平均值分别为57.04、66.92和54.12t·hm-2,土壤碳密度的60%储存在0～40cm土壤中,并随土层深度增加,各层次土壤碳密度逐渐减少。森林生态系统的乔木层、灌木层、草本层、凋落物层生物量和土壤层碳密度均表现出:封山育林下的次生林、次生林大于人工林。封山育林下的次生林、次生林和人工林碳密度分布序列为土壤(0～100cm)>乔木层>灌木层>草本层>枯落物层。可见,封山育林下的次生林更有助于提高森林碳汇,实施近自然林经营是提升该区域森林碳汇能力的重要途径。     

Review of root dynamics in forest ecosystems grouped by climate,climatic forest type and species

Patterns of both above- and belowground biomass and production were evaluated using published information from 200 individual data-sets. Data sets were comprised of the following types of information: organic matter storage in living and dead biomass (e.g. surface organic horizons and soil organic matter accumulations), above- and belowground net primary production (NPP) and biomass, litter transfers, climatic data (i.e. precipitation and temperature), and nutrient storage (N, P, Ca, K) in above- and belowground biomass, soil organic matter and litter transfers. Forests were grouped by climate, foliage life-span, species and soil order. Several climatic and nutrient variables were regressed against fine root biomass or net primary production to determine what variables were most useful in predicting their dynamics. There were no significant or consistent patterns for above- and belowground biomass accumulation or NPP change across the different climatic forest types and by soil order. Similarly, there were no consistent patterns of soil organic matter (SOM) accumulation by climatic forest type but SOM varied significantly by soil order—the chemistry of the soil was more important in determining the amount of organic matter accumulation than climate. Soil orders which were high in aluminum, iron, and clay (e.g. Ultisols, Oxisols) had high total living and dead organic matter accumulations-especially in the cold temperate zone and in the tropics. Climatic variables and nutrient storage pools (i.e. in the forest floor) successfully predicted fine root NPP but not fine root biomass which was better predicted by nutrients in litterfall. The importance of grouping information by species based on their adaptive strategies for water and nutrient-use is suggested by the data. Some species groups did not appear to be sensitive to large changes in either climatic or nutrient variables while for others these variables explained a large proportion of the variation in fine root biomass and/or NPP.     

A quantitative study of the forest floor biomass,litter fall and nutrient return in a Pinus roxburghii forest in Kumaun Himalaya

The present paper reports on the forest floor biomass, litter fall, nutrient return and turnover of organic matter in a Pinus roxburghii forest in Kumaun Himalaya. Peak values of fresh leaf litter, partially decomposed litter and wood litter on the forest floor occurred in April, May and September, respectively. The relative contribution of partially decomposed material to total forest floor biomass remained greatest throughout the annual cycle. The biomass of herbaceous vegetation was maximal in September with a total annual net production of 151 g m^-2. The total annual litter fall was 895 g m^-2, of which tree, shrub and herb litters accounted for 82.4%, 0.6%, and 16.8%, respectively. Annual nutrient return in kg ha^-1 through litter fall amounted to 278.6 ash, 73.9 N, 5.5 P, 79.7 Ca, 15.1Mg, 20.7 K and 3.6Na. The turnover rate for tree litter was 48% and that for various nutrients on the forest floor ranged between 40–79%.     

广西马山岩溶次生林群落生物量和碳储量

岩溶植被在岩溶生态系统碳循环和全球碳平衡中具有重要的作用。通过对马山县岩溶次生林年龄序列(幼龄林、中龄林和老龄林)3个演替阶段9个样地(20 m×50 m)的系统取样调查,研究了停止人为干扰后岩溶次生林生物量和碳储量的变化。结果表明:沿幼林、中林和老林群落的顺向演替发展,群落生物量显著增加(P0.05),从幼林群落的48.17 t/hm2、到中林群落113.47 t/hm2,再到老林群落242.59 t/hm2。老林生态系统的碳储量较高,平均为236.69 t/hm2,中林和幼林较低且非常相近,分别为225.17 t/hm2和224.76 t/hm2,各次生林生态系统的碳储量差异不显著(P0.05)。土壤碳储量的大小顺序为幼林(198.44 t/hm2)中林(167.39 t/hm2)老林(113.43 t/hm2)。沿群落正向演替,各次生林生态系统中植物碳储量和土壤碳储量的比例发生明显的变化。幼林的土壤碳储量占生态系统碳储量的88.29%,植物碳储量只占11.71%;中林相应为74.34%和25.66%;而老林为47.92%和52.08%。可见,随着岩溶植被的正向演替,土壤碳转变为植物碳的趋势十分明显,这是岩溶森林不同于酸性土森林的一个显著特征。     

Variation in biomass and carbon storage by stand age in pine (Pinus tabulaeformis) planted ecosystem in Mt. Taiyue,Shanxi, China

Forest ecosystems play dominant roles in global carbon budget because of the large quantities stored in live biomass, detritus, and soil organic matter. Researchers in various countries have investigated regional and continental scale patterns of carbon (C) stocks in forest ecosystems; however, the relationship between stand age in different components (vegetation, forest floor detritus, and mineral soil) and C storage and sequestration remains poorly understood. In this paper, we assessed an age sequence of 18-, 20-, 25-, 38-, and 42-year-old Pinus tabulaeformis planted by analyzing the vertical distribution of different components biomass with similar site conditions on Mt. Taiyue, Shanxi, China. The results showed that biomass of P. tabulaeformis planted stands was ranged from 88.59 Mg ha^?1 for the 25-year-old stand to 231.05 Mg ha^?1 for the 42-year-old stand and the major biomass was in the stems. Biomass of the ground vegetation varied from 0.51 to 1.35 Mg C ha^?1 between the five stands. The forest floor biomass increased with increasing stand age. The mean C concentration of total tree was 49.94%, which was higher than C concentrations of ground vegetation and forest floor. Different organs of trees C concentration were between 54.14% and 47.74%. C concentrations stored in the mineral soil for each stand experienced decline with increasing soil depth, but were age-independent. Total C storage of five planted forests ranged from 122.15 to 229.85 Mg C ha^?1, of which 51.44–68.38% of C storage was in the soil and 28.46–45.21% in vegetation. The study provided not only with an estimation biomass of P. tabulaeformis planted forest in Mt. Taiyue, Shanxi, China, but also with accurately estimating forest C storage at ecosystem scale.     

Experimental litterfall manipulation drives large and rapid changes in soil carbon cycling in a wet tropical forest

Global changes such as variations in plant net primary production are likely to drive shifts in leaf litterfall inputs to forest soils, but the effects of such changes on soil carbon (C) cycling and storage remain largely unknown, especially in C‐rich tropical forest ecosystems. We initiated a leaf litterfall manipulation experiment in a tropical rain forest in Costa Rica to test the sensitivity of surface soil C pools and fluxes to different litter inputs. After only 2 years of treatment, doubling litterfall inputs increased surface soil C concentrations by 31%, removing litter from the forest floor drove a 26% reduction over the same time period, and these changes in soil C concentrations were associated with variations in dissolved organic matter fluxes, fine root biomass, microbial biomass, soil moisture, and nutrient fluxes. However, the litter manipulations had only small effects on soil organic C (SOC) chemistry, suggesting that changes in C cycling, nutrient cycling, and microbial processes in response to litter manipulation reflect shifts in the quantity rather than quality of SOC. The manipulation also affected soil CO ₂ fluxes; the relative decline in CO ₂ production was greater in the litter removal plots (?22%) than the increase in the litter addition plots (+15%). Our analysis showed that variations in CO ₂ fluxes were strongly correlated with microbial biomass pools, soil C and nitrogen (N) pools, soil inorganic P fluxes, dissolved organic C fluxes, and fine root biomass. Together, our data suggest that shifts in leaf litter inputs in response to localized human disturbances and global environmental change could have rapid and important consequences for belowground C storage and fluxes in tropical rain forests, and highlight differences between tropical and temperate ecosystems, where belowground C cycling responses to changes in litterfall are generally slower and more subtle.     

岩溶地区不同石漠化程度下草地细根对土壤养分的贡献

细根分解和周转是土壤有机质和养分的重要来源。为探明不同石漠化程度天然草地细根对土壤养分的贡献,于2017年3月至次年1月,采用土柱法和分解袋法,研究不同石漠化程度下天然草地的细根生物量、分解和养分释放动态及对石漠化的响应。结果表明:3种不同石漠化程度下草地的细根生物量随季节均呈现先增加后降低的趋势,随石漠化程度的加剧均呈现逐渐降低的趋势,潜在、中度和强度石漠化草地的细根生物量分别为3355.65、2944.02 g/m~2和1806.80 g/m~2。细根分解速率呈现先快后慢的趋势,分解300天后的残留率均低于50%。细根有机碳、全氮、全磷和全钾的释放过程具有显著不同,释放模式最终均表现为"释放",潜在、中度和强度石漠化草地细根的有机碳、全氮、全磷、全钾的年归还量分别为32.46—161.08、0.24—3.88、0.08—0.32、0.15—2.78 g/m~2。随石漠化程度的加剧,细根生物量和分解率呈现逐渐降低趋势,土壤有机碳、全氮归还量呈现逐渐增加趋势。     

喀斯特峰丛洼地不同生态系统的土壤肥力变化特征

基于喀斯特峰丛洼地坡耕地、草丛、灌丛、人工林、次生林、原生林6种典型生态系统的土壤主要养分、矿质养分和微生物这3组变量共计20个指标的调查、取样和分析,运用多重比较分析、主成分分析和典范相关分析探讨了其土壤肥力变化特征、主要影响因子及两两之间的相互关系。结果表明,喀斯特峰丛洼地土壤pH值为6.60—7.75,土壤主要养分、微生物种群数量和微生物生物量明显高于同纬度地区地带性红壤,矿质养分含量相对较低,其中SiO2、Al2O3、Fe2O3占矿质全量的90%以上。土壤肥力的总体趋势为原生林>次生林>灌丛>草丛>坡耕地>人工林。喀斯特石漠化地区实行林草结合的退耕还林还草模式更有利于土壤生态系统的环境改善,坡耕地应多施有机肥和氮肥,人工林应多施氮肥。原生林植物与养分之间达到了良好的平衡状态,主要应加强森林抚育管理,改善森林环境,保障植物、土壤养分及微生物之间的良好协调关系。确保土壤资源的合理利用,促进喀斯特峰丛洼地乃至整个西南喀斯特区域植被的迅速恢复和生态重建。     

Organic Carbon Storage in Four Ecosystem Types in the Karst Region of Southwestern China

Karst ecosystems are important landscape types that cover about 12% of the world''s land area. The role of karst ecosystems in the global carbon cycle remains unclear, due to the lack of an appropriate method for determining the thickness of the solum, a representative sampling of the soil and data of organic carbon stocks at the ecosystem level. The karst region in southwestern China is the largest in the world. In this study, we estimated biomass, soil quantity and ecosystem organic carbon stocks in four vegetation types typical of karst ecosystems in this region, shrub grasslands (SG), thorn shrubbery (TS), forest - shrub transition (FS) and secondary forest (F). The results showed that the biomass of SG, TS, FS, and F is 0.52, 0.85, 5.9 and 19.2 kg m⁻², respectively and the corresponding organic cabon storage is 0.26, 0.40, 2.83 and 9.09 kg m⁻², respectively. Nevertheless, soil quantity and corresponding organic carbon storage are very small in karst habitats. The quantity of fine earth overlaying the physical weathering zone of the carbonate rock of SG, TS, FS and F is 38.10, 99.24, 29.57 and 61.89 kg m⁻², respectively, while the corresponding organic carbon storage is only 3.34, 4.10, 2.37, 5.25 kg m⁻², respectively. As a whole, ecosystem organic carbon storage of SG, TS, FS, and F is 3.81, 4.72, 5.68 and 15.1 kg m⁻², respectively. These are very low levels compared to other ecosystems in non-karst areas. With the restoration of degraded vegetation, karst ecosystems in southwestern China may play active roles in mitigating the increasing CO₂ concentration in the atmosphere.     

Forest floor biomass,litter fall and nutrient return in Central Himalayan oak forests

The seasonal dynamics of forest floor biomass, pattern of litter fall and nutrient return in Central Himalayan oak forests are described. Fresh and partially decomposed litter layers occur throughout the whole year in addition to herbaceous vegetation. The highest leaf litter value is found in April and May and the minimum in September. Partially and largely decomposed litter tended to increase from January to May with a slight decline in June. The wood litter peaked in March and April. The relative contribution of partially decomposed litter to the forest floor remains greatest the year round. The maximum herbaceous vegetation development was found in September with a total annual net production of 104.3 g m^-2yr^-1. The total calculated input of litter was 480.8 g m^-2yr^-1. About 68% of the forest floor was replaced each year with a subsequent turnover time of 1.47 yr. The total annual input of litter ranged from 664 (Quercus floribunda site) –952 g m^-2 (Q. lanuginosa site), of which tree, shrub and herbaceous litter accounted for respectively 72.0–86.3%, 6.4 – 19.4% and 5.2 – 8.6%. The annual nutrient return through litter fall amounted to (kg ha^-1) 178.0 – 291.0 N, 10.0 – 26.9 P, 176.8 – 301.6 Ca, 43.9 – 64.1 K and 3.98 – 6.45 Na. The tree litter showed an annual replacement of 66.0 – 70.0%, for different nutrients the range was 64 and 84%.