Seasonal dynamics of water use efficiency of typical forest and grassland ecosystems in China

We selected four sites of ChinaFLUX representing four major ecosystem types in China—Changbaishan temperate broad-leaved Korean pine mixed forest (CBS), Dinghushan subtropical evergreen broadleaved forest (DHS), Inner Mongolia temperate steppe (NM), and Haibei alpine shrub-meadow (HBGC)—to study the seasonal dynamics of ecosystem water use efficiency (WUE = GPP/ET, where GPP is gross primary productivity and ET is evapotranspiration) and factors affecting it. Our seasonal dynamics results indicated single-peak variation of WUE in CBS, NM, and HBGC, which were affected by air temperature (Ta) and leaf area index (LAI), through their effects on the partitioning of evapotranspiration (ET) into transpiration (T) (i.e., T/ET). In DHS, WUE was higher at the beginning and the end of the year, and minimum in summer. Ta and soil water content affected the seasonal dynamics of WUE through their effects on GPP/T. Our results indicate that seasonal dynamics of WUE were different because factors affecting the seasonal dynamics and their mechanism were different among the key ecosystems.     

土地利用方式对湖泊洲滩湿地植物生物量的影响——以西洞庭湖国家级自然保护区为例

【目的】为了解土地利用方式对西洞庭湖洲滩湿地生态系统服务功能的影响,探索土壤含水率和物种丰富度在湿地恢复过程中所起的作用,进而为今后西洞庭湖湿地恢复工程提供指导。【方法】于2015年冬季通过收割法和生物量模型对杨树种植区域、退林还湿区域、天然洲滩这3个区域间的土壤含水率、物种丰富度和植物地上生物量差异及土壤含水率和物种丰富度与地上生物量相关性进行了初步探究。【结果】1)不同土地利用方式下洲滩土壤含水率与物种丰富度差异显著;天然洲滩土壤含水率最高,退林还湿区最低,杨树种植区和退林还湿区物种丰富度高于天然洲滩。2)不同土地利用方式下洲滩植被地上生物量差异显著;杨树林种植区的植物地上生物量高于天然洲滩,而退林还湿区与天然洲滩无差异;草本植物地上生物量呈现出天然洲滩区最高、杨树林种植区最低的规律。3)不同土地利用方式下土壤含水率与草本植物地上生物量呈正相关,物种丰富度与草本植物地上生物量呈负相关。【结论】利用和恢复工程对洲滩湿地土壤含水率和物种丰富度存在影响;土地利用方式对洲滩湿地生态系统功能存在影响;土壤含水率和物种丰富度对于修复退化湿地及生态系统功能具有重要意义。后续退林还湿工程开展可考虑人为增加土壤含水率以及移植苔草等优势物种等人工辅助措施,以促进退林还湿区域向天然洲滩湿地的演替。     

河南省西平县杨树人工林碳贮量及其分配特征研究

基于对西平县杨树人工林植被生物量,土壤容重和碳含量的调查,估算杨树林生态系统碳贮量。研究表明:杨树林的乔木层碳密度波动在0.489~0.512g/g,杨树各器官的碳密度大小依次是树叶>树干>树枝>树根,整个植被层碳贮量大小依次是乔木层>林下植被层>凋落物层,与其各自生物量所占比例相当;土壤层的碳密度以0~20 cm的最高,往下逐渐降低;整个杨树林的碳贮量为164.29 t/hm2,乔木层碳贮量在整个植被层碳贮量中处于主导地位,占整个植被层碳贮量的97.36%。     

Response of nitrogen mineralization dynamics and biochemical properties to litter amendments to soils of a poplar plantation

Understanding the impact of plant litters on soil nitrogen(N) dynamics could facilitate development of management strategies that promote plantation ecosystem function.Our objective was to evaluate the effects of different litter types on N mineralization and availability,microbial biomass, and activities of L-asparaginase and odiphenol oxidase(o-DPO) in soils of a poplar(Populus deltoides) plantation through 24 weeks of incubation experiments.The tested litters included foliage(F), branch(B), or root(R) of poplar trees, and understory vegetation(U) or a mixture of F, B, and U(M).Litter amendments led to rapid N immobilization during the first 4 weeks of incubation, while net N mineralization was detected in all tested soils from 6 to 24 weeks of incubation, with zeroorder reaction rate constants(k) ranging from 7.7 to9.6 mg N released kg~(-1) soil wk~(-1).Moreover, litter addition led to increased microbial biomass carbon(C) 49–128% and increased MBC:MBN ratio by 5–92%,strengthened activities of L-asparaginase and o-DPO by14–74%; Up to about 37 kg N ha~(-1) net increase in mineralized N in litter added soils during 24 weeks of incubation suggests that adequate poplar and understory litter management could lead to reduced inputs while facilitate sustainable and economic viable plantation production.     

Response of soil respiration to a severe drought in Chinese <Emphasis Type="Italic">Eucalyptus</Emphasis> plantations

Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values (100.9 mg C–CO₂ m^?2 h^?1) recorded in June and the lowest values (28.7 mg C–CO₂ m^?2 h^?1) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83–91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90–99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6–10%. Soil water was strongly related to changes in soil parameters (i.e., bulk density, pH, soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid–base properties and soil texture, and affected soil nutrient availability.     

章古台地区樟子松人工林土壤水分物理性质的研究

以章古台地区樟子松人工林地土壤为研究对象,依照不同立地、不同林龄、不同林型和不同林分密度研究了樟子松人工林改良土壤水分物理性质状况和林地土壤含水率。结果表明:不同林龄林地土壤含水率有明显区别:0～20年生林分土壤含水率较高,至27年生林分林地土壤含水率为最低,27年生以后林分土壤含水率有所回升。甸子地樟子松固沙林改善土壤水分物理性质优于坨子地樟子松固沙林。不同林龄间土壤水分物理性质区别不明显,但较裸沙地要好。从改良土壤水分物理性质效果来看:樟杨混交是较好造林类型,600～800株/hm2是章古台樟子松固沙林适宜的林分密度。     

Root order-dependent seasonal dynamics in the carbon and nitrogen chemistry of poplar fine roots

Fine roots play an important role in above- and belowground carbon (C) allocation in forest ecosystems. However, few studies have focused on the seasonal dynamics of fine roots with different branching orders. The objective of this study is to provide insight to the seasonal heterogeneity in roots of different orders within root hierarchies of poplar trees under different soil conditions. Three plots were established in high (plantation A) and low (plantation B) soil nutrient conditions. Fine roots were sampled in each of four seasons throughout one year. All sampled roots were classified into one to five groups depending on their branching order, and the dry biomass of living roots and the concentrations of C, nitrogen (N) and total non-structural carbohydrate (TNC) were examined. Low order (first- to second-order) roots demonstrated more significant seasonal dynamics than high order roots, and the biomass of first-order fine roots was positively influenced by soil temperature and moisture while the biomass of second-order fine roots was negatively affected by soil nutrient conditions. The different responses of fine roots to environmental fluctuations implied a high division of root function, even within low order roots. The C and N chemistry of poplar fine roots also differed significantly with branching order; element concentrations were lower in low order roots. Principal component analysis indicated that root order explained 98.2% of the variation in fine root chemistry. Moreover, the first-order roots in plantation A had greater C but less TNC concentrations than those in plantation B, suggesting that C allocation in low order roots may be more responsive to soil nutrient conditions. The allocation of C and N also exhibited significant seasonal dynamics (p < 0.05); the TNC concentration was highest in winter, whereas C:N ratios were significantly lower in the summer and fall in each order of fine roots (p < 0.05). All these results suggest that branching order may be related to root growth and photoassimilate allocation, which should receive greater attention in future studies on C and N fluxes in forest ecosystems.     

滩地钉螺种群消长与杨树人工林关系的研究

在南洞庭湖和西洞庭湖的滩地杨树人工林内采取定位观测为主的研究方法，对滩地的地下水位、土壤含水率、螺情的变化规律及其与滩地杨树人工林的相关关系进行了定量研究，揭示了杨树人工林内钉螺种群消长的内在规律和环境因子的偶发效应，显示出滩地杨树人工林生态系统抑螺机制的有效性和持续性，体现了滩地杨树抑螺林的血防安全意义。     

High-frequency analysis of the complex linkage between soil CO(2) fluxes, photosynthesis and environmental variables

High-frequency soil CO(2) flux data are valuable for providing new insights into the processes of soil CO(2) production. A record of hourly soil CO(2) fluxes from a semi-arid ponderosa pine stand was spatially and temporally deconstructed in attempts to determine if variation could be explained by logical drivers using (i) CO(2) production depths, (ii) relationships and lags between fluxes and soil temperatures, or (iii) the role of canopy assimilation in soil CO(2) flux variation. Relationships between temperature and soil fluxes were difficult to establish at the hourly scale because diel cycles of soil fluxes varied seasonally, with the peak of flux rates occurring later in the day as soil water content decreased. Using a simple heat transport/gas diffusion model to estimate the time and depth of CO(2) flux production, we determined that the variation in diel soil CO(2) flux patterns could not be explained by changes in diffusion rates or production from deeper soil profiles. We tested for the effect of gross ecosystem productivity (GEP) by minimizing soil flux covariance with temperature and moisture using only data from discrete bins of environmental conditions (±1 °C soil temperature at multiple depths, precipitation-free periods and stable soil moisture). Gross ecosystem productivity was identified as a possible driver of variability at the hourly scale during the growing season, with multiple lags between ~5, 15 and 23 days. Additionally, the chamber-specific lags between GEP and soil CO(2) fluxes appeared to relate to combined path length for carbon flow (top of tree to chamber center). In this sparse and heterogeneous forested system, the potential link between CO(2) assimilation and soil CO(2) flux may be quite variable both temporally and spatially. For model applications, it is important to note that soil CO(2) fluxes are influenced by many biophysical factors, which may confound or obscure relationships with logical environmental drivers and act at multiple temporal and spatial scales; therefore, caution is needed when attributing soil CO(2) fluxes to covariates like temperature, moisture and GEP.     

Effects of soil fauna on leaf litter decomposition under different land uses in eastern coast of China

Soil fauna decompose litter, whereas land use changes may significantly alter the composition and structure of soil fauna assemblages. However, little is known of the effects of land-use on the contribution of soil fauna to litter decomposition. We studied the impacts of soil fauna on the decomposition of litter from poplar trees under three different land uses (i.e. poplar-crop integrated system, poplar plantation, and cropland), from December 2013 to December 2014, in a coastal area of Northern Jiangsu Province. We collected litter samples in litterbags with three mesh sizes (5, 1 and 0. 01 mm, respectively) to quantify the contribution of various soil fauna to the decomposition of poplar leaf litter. Litter decomposition rates differed significantly by land use and were highest in the cropland, intermediate in the poplar-crop integrated system, and lowest in the poplar plantation. Soil fauna in the poplar-crop integrated system was characterized by the highest numbers of taxa and individuals, and highest Margalef’s diversity, which suggested that agro-forestry ecosystems may support a greater quantity, distribution, and biodiversity of soil fauna than can single-species agriculture or plantation forestry. The individuals and groups of soil fauna in the macro-mesh litterbags were higher than in the meso-mesh litterbags under the same land use types. The average contribution rate of meso- and micro-fauna to litter decomposition was 18.46%, which was higher than the contribution rate of macro-fauna (3.31%). The percentage of remaining litter mass was inversely related to the density of the soil fauna (P < 0.05) in poplar plantations; however, was unrelated in the poplar-crop integrated system and cropland. This may have been the result of anthropogenic interference in poplar-crop integrated systems and croplands. Our study suggested that when land-use change alters vegetation types, it can affect species composition and the structure of soil fauna assemblages, which, in turn, affects litter decomposition.     

Carbon dioxide fluxes across the Sierra de Guadarrama, Spain

Understanding the spatial and temporal variation in soil respiration within small geographic areas is essential to accurately assess the carbon budget on a global scale. In this study, we investigated the factors controlling soil respiration in an altitudinal gradient in a southern Mediterranean mixed pine–oak forest ecosystem in the north face of the Sierra de Guadarrama in Spain. Soil respiration was measured in five Pinus sylvestris L. plots over a period of 1 year by means of a closed dynamic system (LI-COR 6400). Soil temperature and water content were measured at the same time as soil respiration. Other soil physico-chemical and microbiological properties were measured during the study. Measured soil respiration ranged from 6.8 to 1.4 μmol m^?2 s^?1, showing the highest values at plots situated at higher elevation. Q ₁₀ values ranged between 1.30 and 2.04, while R ₁₀ values ranged between 2.0 and 3.6. The results indicate that the seasonal variation of soil respiration was mainly controlled by soil temperature and moisture. Among sites, soil carbon and nitrogen stocks regulate soil respiration in addition to soil temperature and moisture. Our results suggest that application of standard models to estimate soil respiration for small geographic areas may not be adequate unless other factors are considered in addition to soil temperature.     

间伐对祁连山青海云杉人工林土壤水分的影响

利用EM50土壤水分监测仪,在样地尺度上,测定了祁连山青海云杉天然林、无间伐和间伐强度为20%的人工林地生长季节的土壤水分,对比分析间伐对人工林土壤水分的影响。结果表明:未间伐人工林林地表层(10 cm)土壤含水量显著高于间伐强度为20%的人工林和天然林,间伐导致了人工林林地表层土壤水分下降;而对于深层土壤含水量而言,间伐措施又显著提高了深层60 cm处的土壤含水量。与天然林地土壤含水量相比,无间伐人工林深层60 cm和80 cm处的土壤体积含水量仅为天然林的49.7%和52.1%,深层土壤已经出现旱化现象,间伐措施能够减缓这种旱化现象。     

Temperature has more effects than soil moisture on biosynthesis of flavonoids in Ginkgo (Ginkgo biloba L.) leaves

The flavonoids content and its composition in Ginkgo (Ginkgo biloba L.) leaves are affected by environmental factors such as temperature and soil moisture. Here we performed experiments in phytotron using 2-year-old Ginkgo seedlings to explore the effects of temperature and soil moisture on flavonoids content, enzymes related to flavonoids biosynthesis such as phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and p-coumarate CoA ligase (4CL), soluble sugar and protein content. We found that temperature and lower soil moisture had significant effects on these parameters. The effects of temperature on flavonoids content, the activity of C4H and 4CL and soluble sugar content were greater than that of soil moisture. The total flavonoid content, the activity of PAL, C4H and 4CL, soluble sugar content were higher in lower temperature regime 15 °C (daytime)/5 °C (nighttime) and lower soil moisture (30–35 % of field capacity), but higher temperature was beneficial to the accumulation of soluble protein. This indicates that increasing of soluble sugar content and the activity of PAL, C4H and 4CL are beneficial to flavonoids biosynthesis and accumulation in the Ginkgo leaves, while increasing of soluble protein is adverse to flavonoids biosynthesis. Because lower temperature and soil moisture are favorable to flavonoids biosynthesis, we can take some silvicultural steps to increase flavonoids production in Ginkgo plantation, such as establishing leaf-harvest plantation at lower temperature zone, reducing irrigating before harvesting leaves.     

Variation of soil enzyme activity and microbial biomass in poplar plantations of different genotypes and stem spacings

To improve the productivity of poplar plantations, a field experiment of split-plot design with four tree spacings and three poplar clones was established, and four soil enzyme activities and microbial biomass were monitored in the trial.Soil enzyme activities, in most cases,were significantly higher in topsoil(0–10 cm) than in lower horizons(10–20 cm).Soil cellulase, catalase and protease activities during the growing season were higher than during the non-growing season, while invertase activity followed the opposite trend.Soil invertase, cellulase and catalase activities varied by poplar clone but soil protease activity did not.Cellulase and protease activities in the plantation at 5×5 m spacing were significantly higher than in the other spacings.The highest catalase activity was recorded at 6×6 m spacing.At the same planting density, invertase activity was greater in square spacings than in rectangular spacings.Soil microbial biomass was also significantly affected by seedling spacing and poplar clone.The mean soil MBC was significantly lower in topsoil than in the lower horizon, while MBN showed the opposite pattern.Significantly positive correlations were observed among soil cellulase, protease and catalase activities(p0.01), whereas soil invertase activity was negatively and significantly correlated with cellulase, protease and catalase activities(p0.01).Soil microbial biomass and enzyme activities were not correlated except for a significantly negative correlation between soil MBC and catalase activities.Variations in soil enzyme activity and microbial biomass in different poplar plantations suggest that genotype and planting spacing should be considered when modeling soil nutrient dynamics and managing for long-term site productivity.     

Combined surface drip irrigation and fertigation significantly increase biomass and carbon storage in a <Emphasis Type="Italic">Populus</Emphasis> × <Emphasis Type="Italic">euramericana</Emphasis> cv. Guariento plantation

Fast-growing poplar plantations are considered of great benefit to both timber production and carbon (C) sequestration, and are increasingly planted for multiple purposes worldwide. Irrigation and fertilization are common management practices in plantations in semiarid regions. However, quantitative investigation of the integrative effect of surface drip irrigation and fertigation (SDIF) on biomass and C storage in poplar plantations remains limited. In this study, we conducted a field experiment on a fast-growing poplar cultivar (Populus × euramericana cv. Guariento) plantation to compare the combination of surface drip irrigation and fertigation in growing seasons with conventional management (control; CK). Experiments repeated over 2 years showed that SDIF significantly increased biomass and C storage in both trees and soil in the plantation compared with the CK. Tree biomass C in SDIF-treated and CK stands after the first year of the experiment (age 5) was 6.20 and 4.05 t C ha^?1, respectively, and the difference further increased, i.e., 15.18 and 8.63 t C ha^?1, respectively, after the second year of the experiment (age 6). There was 53 and 76 % higher C storage in SDIF-treated trees than in the CK trees after the first and second years of the experiment, respectively. The SDIF increased the soil C concentration, especially in the surface soil at 0- to 40-cm depth. Soil organic C at a depth of 0–60 cm under the SDIF treatment was 45.42, 50.87 and 61.32 t C ha^?1 in the 1st, 2nd and 3rd years, respectively, with annual increases of 12 and 21 % between the first and second, and second and third year, respectively. The corresponding soil organic C in the CK was 43.08, 43.57 and 47.92 t C ha^?1 in the 1st, 2nd and 3rd years; the annual increases were only 1 and 10 %, respectively. The results confirmed the significant effect of the combined management on C storage in poplar plantations, thus we suggest it can be applied in forestry management, even though it generally did not change C concentrations of tree components.     

The effects of experimental warming and CO<Subscript>2</Subscript> concentration doubling on soil organic carbon fractions of a montane coniferous forest on the eastern Qinghai-Tibetan Plateau

To explore the effects of elevated temperature (ET), elevated atmospheric CO₂ concentration (EC) and ET plus EC (ETC) on different fractions of soil organic carbon (SOC) is significant for understanding the interactions between SOC and environmental variables. Up to date, little information is available in montane forests of the eastern Qinghai-Tibetan Plateau, which is a key region for studying global climate change especially for high altitude areas. This work applied an automatic gas exchange system to investigate the responses of different fractions of SOC to these factors (ET: + 2.5 °C; EC: + 350 ppm; ETC: + 2.5 °C + 350 ppm) after two and a half years’ treatments. Results showed that both ET and EC significantly increased the average amount of SOC and not-readily oxidizable carbon (NROC), while significantly decreased the readily oxidizable carbon (ROC) in soil. The dramatic contrast between the content of NROC and ROC provided evidence that trees exposed to either ET or EC would employ more labile nutrient to meet their growth demands. Soil microbial biomass carbon (SMBC) was significantly related to the amount of ROC. Unlike ROC, the trends of particulate organic carbon (POC) and mineral-associated organic carbon (MOC) under different treatments were consistent with that of SOC. Under ET, EC and ETC, the alterations of %ROC were more obvious than that of %POC, and positive correlations were observed between SOC, POC, MOC and NROC, with the exception of ROC and SMBC. These results indicated that the biotical and chemical labile components were more sensitive than the physical active fraction of soil organic matter. Meanwhile, the physical protection and chemical recalcitrance effects were important protection mechanisms from the response to global climate change.     

沙地杨树人工林生物量特征研究

以科尔沁沙地杨树人工林为研究对象,实地测定了造林5年、8年、18年杨树人工林的树木生物量、枯落物生物量、草本生物量和根系生物量,并分析其特征。结果表明：5年人工林地上总生物量和0—60cm土层根系生物量分别为725kg／667m^2和260．66kg／667m^2;8年的分别为1086．62kg／667m^2和147．27kg／667m^2;18年的分别为1690．70kg／667m^2和297．75kg／667m^2。同时,随着林龄的增长,树木生物量、枯落物生物量逐渐增加,而草本生物量和根系生物量占林木总生物量的比例有所下降。     

Assessing water use and soil water balance of planted native tree species under strong water limitations in Northern Chile

Some forest plantations with native species are established in semiarid central Chile to compensate for industrial activities such as those of mining. Two of those operational forest plantations were monitored from age 1 to 3 years-old (2014–2016). Some plant attributes and soil volumetric water content (VWC) were monitored for eight native tree species (Acacia caven, Schinus polygamus, Porlieria chilensis, Lithraea caustica, Quillaja saponaria, Cryptocarya alba, Drimys winteri and Maytenus boaria), and a water balance model fitted to assess plant water use. Site preparation comprised planting holes of 40 cm?×?40 cm by 50 cm in depth dug with a backhoe. Substrate was removed and mixed with compost in proportion 70:30 before mixing it in the planting hole. Planting holes acted as water reservoirs over the study period with soil VWC generally increasing with soil depth being also less variable deeper than in the upper soil layers. The ratio of adaxial (upper leaf side) to abaxial (lower leaf side) stomatal conductance approximately followed a species gradient from xeric to mesic. Irrigation represented about 26% and 53% of the total water input for the sclerophyll and the D. winteri plantation, respectively. At the plant level (0.4?×?0.4 m), soil evaporation and transpiration of D. winteri (273 and 232 mm year^?1, equivalent to 43.7 and 37.1 L plant^?1, respectively) were about twofold the values for the sclerophyllous/malacophyllous plantation (138 and 128 mm year^?1, 22.1 and 20.5 L plant^?1, respectively). We suggest the water budget for the sclerophyll/malacophyllous plantation was tight but feasible to be adjusted while for D. winteri irrigation was excessive, could be drastically reduced, and suppressed altogether if planted in gullies. We believe water balance models and soil moisture content sensors could be used to better plan and manage irrigation frequency and amounts in compensation forest plantations in semiarid central Chile.     

Provenance variation in survival, growth and dry matter partitioning of Parkia biglobosa (Jacq.) R.Br. ex G.Don seedlings in response to water stress

The effects of drought stress on growth and dry matter partitioning of seven provenances of Parkia biglobosa were assessed in a nursery experiment. Three different water regimes were applied: soil high, medium and low water content (HWC, MWC and LWC) corresponding respectively to 100, 75 and 50 % of field capacity. A split-plot experimental design was applied with the provenance as main plot and the water regime as sub-plot, replicated three times. Each provenance was represented by 30 seedlings in each replication, corresponding to three test periods with ten seedlings each (6, 12 and 18 months after water stress started). There were significant interactions between provenance and water regime for survival rate and the relative growth rates of diameter and height. After 18 months, the dry matter mean was 20.00 ± 0.65 g for the HWC regime, 11.50 ± 2.90 g for the MWC regime while all plants in the LWC regime died. After 6 months, the accumulated water use efficiency (WUE) showed significant differences between water regimes, but not between provenances. Seedlings from the LWC regime showed higher WUE than those from the MWC regime. However, the HWC regime displayed the highest mean value of WUE. Despite differences between provenances, it was not possible to clearly separate them according to the geographical position or climatic parameters, based on the growth performance or both fresh to dry weight and shoot to root dry weight ratios.     

杉木人工林伐后2种恢复模式碳储量的比较

[目的]为了探讨恢复模式对森林生态系统碳库的影响,[方法]利用定位研究方法,对比分析了湖南会同杉木人工林皆伐后2种恢复模式(自然恢复和人工恢复)20年时森林生态系统碳储量及其空间分布。[结果]表明:(1)自然恢复植被层碳储量明显大于人工恢复,自然恢复的乔木层碳储量比人工恢复的高22.56%。自然恢复的乔木层各器官碳储量的分配比为干﹥枝﹥根﹥叶﹥皮,而人工恢复为干﹥根﹥枝﹥皮﹥叶。林下植被层和凋落物层碳储量所占比例非常小,自然恢复的灌木层、草本层和凋落物层碳储量分别为人工恢复的3.99、5.94、1.14倍。(2)自然恢复的土壤层碳储量比人工恢复的小;自然恢复表层(0 10 cm)土壤碳含量和碳储量均比人工恢复的大,但其它土层则相反;2种恢复模式的土壤碳含量、碳储量均随土层深度的增加而减少,不同恢复土壤各层碳储量所占分配比差异明显。(3)自然恢复各组分碳储量为乔木层﹥土壤层﹥凋落物层﹥灌木层﹥草本层,而人工恢复为土壤层﹥乔木层﹥凋落物层﹥灌木层﹥草本层。[结论]自然恢复模式更有利于伐后林地植被层碳储量的恢复,而人工恢复模式更有利于伐后林地土壤层碳储量的恢复。从整个森林生态系统看,杉木人工林皆伐后林地自然恢复模式固碳能力高于人工恢复模式,恢复模式对碳储量在生态系统各组分的分配也产生了一些影响。