通过用静态碱吸收法对中亚热带福建三明格氏栲自然保护区内的格氏栲天然林和33年生的格氏栲人工林及杉木人工林的土壤呼吸进行为期2年的定位研究，结果表明，三种森林土壤呼吸速率季节变化均呈单峰曲线，最大峰值出现在5月至6月，最小值出现在12月至1月。格氏栲天然林、格氏栲人工林和杉木人工林土壤呼吸速率1年中变化范围分别在403.47～1001.12mg CO2m-2h-1、193.89～697.86mg CO2m-2h-1和75.97～368.98mg CO2m-2h-1之间。2002 年土壤呼吸速率主要受土壤温度影响，但在极端干旱的2003 年则主要受土壤湿度的影响。双因素关系模型（R=aebTWc）拟合结果优于仅考虑土壤温度或土壤湿度的单因素关系模型，土壤温度和土壤湿度共同解释不同年份不同森林土壤呼吸速率季节变化的80%～96%。杉木林土壤呼吸对气候变化敏感性高于格氏栲天然林和人工林。格氏栲天然林、格氏栲人工林和杉木人工林土壤呼吸年通量分别为13.742、9.439 和4.543tC·hm-2·a-1，前者分别约是后二者的1.5倍和3.0倍。森林转换对土壤呼吸通量的影响可能与枯落物数量和质量、根系呼吸、土壤有机质数量和质量的变化有关。

应用密闭室碱吸收法对杉木人工林皆伐后的土壤呼吸及各分室呼吸进行为期1年定位研究，结果表明，杉木林皆伐后前4个月土壤呼吸显著高于对照（未伐地）的，皆伐6个月后则显著低于对照的，但伐后1年内的平均土壤呼吸则与对照的无显著差异。皆伐地枯枝落叶层呼吸和矿质土壤呼吸在伐后的5个月和6个月内均显著高于对照的，但此后则与对照的无显著差异。皆伐地根系呼吸除在伐后当月显著高于对照的外，第3个月迅速降低至消失。皆伐地土壤呼吸、枯枝落叶层呼吸和矿质土壤呼吸最大值出现时间均较对照的有所提前。伐后1年内皆伐地枯枝落叶层呼吸、矿质土壤呼吸和根系呼吸占土壤呼吸的比例分别为34.5%、63.9%和1.6%，而对照的则分别为23.4%、50.1%和26.5%。双因素关系模型拟合结果表明，土壤温度和土壤湿度共同解释皆伐和对照土壤呼吸速率变化的54%和90%。皆伐地土壤呼吸及各分室呼吸对土壤温度的敏感性低于对照的，但对土壤湿度的敏感性则高于对照的。皆伐地土壤呼吸、矿质土壤呼吸和枯枝落叶层呼吸的Q10分别为1.42、1.53 和1.34，而对照的土壤呼吸、矿质土壤呼吸、枯枝落叶层呼吸和根系呼吸的Q10则分别为2.42、1.81、2.40和4.41。

通过用静态碱吸收法对中亚热带福建三明格氏栲自然保护区内的格氏栲天然林和33年生的格氏栲人工林及杉木人工林的土壤异养呼吸进行为期2年的定位研究。结果表明，三种森林枯枝落叶层呼吸和无根土壤呼吸速率季节变化均呈单峰曲线，最大峰值出现在5月至6月，最小值出现在12月至1月。格氏栲天然林、格氏栲人工林和杉木人工林枯枝落 叶层呼吸速率平均值分别为CO279.88、44.37和21.02mgm-2h-1，无根土壤呼吸速率平均值分别为CO2217.4、85.85和94.04mgm-2h-1。2002 年枯枝落叶层呼吸速率和无根土壤呼吸速率主要受土壤温度影响，但在极端干旱的2003年则主要受土壤湿度的影响。双因素关系模型（R=aebTWc）拟合结果优于仅考虑土壤温度或土壤湿度的单因素关系模型，土壤温度和土壤湿度共同解释不同年份枯枝落叶层呼吸和无根土壤呼吸速率季节变化的82%～85%和85%～92%。不同森林枯枝落叶层呼吸对土壤温度和湿度的敏感性均高于无根土壤呼吸的。格氏栲天然林、格氏栲人工林和杉木人工林枯枝落叶层呼吸年通量分别为C3.76、2.63和1.23thm-2a-1，无根土壤呼吸年通量则分别为C3.44、2.79和1.49thm-2a-1。不同森林土壤异养呼吸通量的差异主要与枯落物数量和质量、土壤有机质数量和质量的差异有关。杉木林枯枝落叶层呼吸对干旱敏感性高于格氏栲（天然林和人工林）的，而人工林（杉木和格氏栲）的土壤有机C对干旱敏感性则要高于格氏栲天然林。

通过用挖壕沟+静态碱吸收法对福建三明格氏栲天然林及33年生格氏栲和杉木人工林的根系呼吸进行为期2年定位研究。不同森林根系呼吸速率季节变化均呈单峰曲线，最大值出现在春末或夏初，最小值出现在冬季。1年中格氏栲天然林、格氏栲人工林和杉木人工林根系呼吸速率变化范围分别在157.76mg CO2m-2h-1～480.40mg CO2m-2h-1、53.03 mg CO2m-2h-1～339.45mg CO2m-2h-1和16.66mg CO2m-2h-1～228.02mg CO2m-2h-1之间。在近似正常气候状况的2002 年，不同森林根系呼吸主要受土壤温度影响（R2=0.52～0.72）；而土壤温度和土壤湿度共同则可解释根系呼吸速率季节变化的81%～90%。在极端干旱的2003年，根系呼吸受土壤温度或湿度的影响较小，土壤温度和土壤湿度共同仅能解释根系呼吸变化的24～60%，这与根系在持续干旱期间长期处于近休眠状态有关。根系呼吸对土壤温度和土壤湿度的敏感性大小顺序均为杉木人工林>格氏栲人工林>格氏栲天然林。格氏栲天然林根系呼吸占土壤呼吸比例（47.6%）均高于格氏栲和杉木人工林的（42.5%和40.2%），不同森林根系呼吸占土壤呼吸比例均以冬季最低，而以5月或6月最高。格氏栲天然林、格氏栲人工林和杉木人工林根系呼吸年通量分别为6.537、4.013 和1.828tC·hm-2·a-1。

通过对福建三明格氏栲天然林及在其采伐迹地上营造的33年生格氏栲人工林和杉木人工林粗木质残体现存量与季节动态、C库及养分库的研究表明，格氏栲天然林、人工林和杉木人工林枯枝落叶层现存量分别为1.32、0.46和0.23t·hm-2.3种林分粗木质残体现存量的季节变化模式均为夏季>冬季>秋季>春季。格氏栲天然林粗木质残体C贮量0.78 t·hm-2，分别是格氏栲人工林和杉木人工林的4.11倍和7.09倍；格氏栲天然林粗木质残体C库与两种人工林间差异显著（P<0.05）。格氏栲天然林、格氏栲人工林和杉木人工林粗木质残体养分贮量分别为14.16、2.90和0.95kg·hm-2；格氏栲天然林粗木质残体中各种养分贮量均最高。与人工林相比，天然林粗木质残体现存量、C和养分贮量均最大。

通过对福建三明36a生的格氏栲人工林和杉木人工林林木地下C分配（TBCA）进行研究，结果表明，由分室累加法直接测定的格氏栲和杉木人工林的TBCA分别为8.426 和4.040tC·hm-2·a-1。在格氏栲和杉木人工林TBCA组成中，根系净生产量和根系呼吸各约占50%；在根系年净生产量中，细根年净生产量和粗根年净生产量各约占75%和25%。而格氏栲和杉木人工林的细根年C归还量则均约占各自TBCA的1/3（分别为33%和36%）。在假设地下C库处于稳定状态时，由C平衡法计算的格氏栲和杉木人工林的TBCA（分别为6.039 和2.987tC·hm-2·a-1）低于分室累加法，这与两种人工林地下C库尚未达到稳定状态有关。利用Raich and Nadelhoffer（1989）全球模式方程推算的格氏栲和杉木人工林的TBCA（分别为9.771和5.344tC·hm-2·a-1）则高于分室累加法，这与全球模式方程只是一种全球尺度规律有关。

The soil properties were investigated in the sites where different generations of Chinese fir (Cunninghamia lanceolata) were cultivated in order to show the impact of a repeated monoculture regime on site productivity. Compared with the stand of first generation (FG), the soil structure became destroyed in the stands of the second generation (SG) and the third generation (TG). For instance, the destroyed rate of ped was 55%-115% in the SG and the TG than that in the FG. The soil nutrient storage and its availability decreased in the SG and the TG. For the top soils (0-20cm), the content of organic matter, total N and P, and available N and P decreased by 3%-20% than those in the FG. For many soil parameters, the difference was statistically significant between three stands. Furthermore, with an increase in planting generation of Chinese fir, total quantity of soil microbes appeared to evidently decline, the soil enzyme activity weakened, and the soil biological activityreduced. In order to maintain sustainable site productivity, the new silvicultural measurements need to be developed in Chinese fir plantation management.

For the last several decades, native broad-leafed forests in many areas of south China have been converted into plantations of more productive forest species for timber use. This paper presents a case study examining how this forest conversion affects ecosystem carbon storage by comparing 33 year-old plantations of two coniferous trees, Chinese fir (Cunninghamia lanceolata, CF) and Fokienia hodginsii (FH) and two broadleaved trees, Ormosia xylocarpa (OX) and Castanopsis kawakamii (CK), with an adjacent relict natural forest of Castanopsis kawakamii (NF150 year old) in Sanming, Fujian, China. Overall estimates of total ecosystem carbon pools ranged from a maximum of 399.1 Mg ha-1 in the NF to a minimum of 210.6Mg ha-1 in the FH. The combined tree carbon pool was at a maximum in the NF where it contributed 64% of the total ecosystem pool, while the OX had the lowest contribution by trees at only 49%. Differences were also observed for the carbon pools of undergrowth, forest floor and standing dead wood, but that these pools together represent at the most 5% of the ecosystem C stock. Total C storage in the surface 100cm soils ranged from 123.9Mg ha-1 in the NF to 102.3Mg ha-1 in the FH. Significant differences (P<0.01) in SOC concentrations and storage between native forest and the plantations were limited to the surface soils (0-10cm and 10-20cm), while no significant difference was found among the plantations at any soil depth (P>0.05). Annual aboveground litterfall C ranged from 4.51Mg ha-1 in the CK to 2.15Mg ha-1 in the CF, and annual belowground litterfall (root mortality) C ranged from 4.35 Mg ha-1 in the NF to 1.25Mg ha-1 in the CF. When the NF was converted into tree plantations, the vegetation C pool (tree plus undergrowth) was reduced by 27-59%, and the detritus C pool (forest floor, standing dead wood, and soils) reduced by 20-25%, respectively. These differences between the NF and the plantations may be attributed to a combination of factors including more diverse species communities, more C store types, higher quantity and better quality of above-and belowground litter materials under the NF than under the plantations and site disturbance during the establishment of plantations.

A Chinese fir forest (Cunninghamia lanceolata, CL) and a secondary evergreen broadleaved forest (BF) located in Fujian Province, south-eastern China, were examined before clear-cutting to compare their ecosystem carbon and nitrogen pools (above-and below-ground tree, understorey vegetation and forest floor biomass + 0-100cm mineral soil layer). The ecosystem pools of C and N in the CL before clear-cutting were 257 Mg ha−1 and 8605 kg ha−1, respectively. The corresponding values for the BF were 336 Mg ha−1 of C and 10,248 kg ha−1 of N. For the two forests, most of the C was in the trees, whereas most of the N pool was in the soil. C and N pools in understorey vegetation and forest floor were small in the two forests (about 2% of ecosystem pools). During clear-cutting, 117 Mg ha−1 C and 307 kg ha−1 N in stem wood with bark and coarse branches (>2 cm) were removed from the CL compared to 159 Mg ha−1 C and 741 kg ha−1 N from the BF. Two days after slash burning, C removal from logging residues (including forest floor material) was estimated at 10 Mg ha−1 for CL and 23 Mg ha−1 for BF, and N removal was 233 and 490 kg ha−1 in the CL and BF, respectively. Compared with the pre-burn levels in the CL, contents of topsoil organic C and total N 2 days after burning were reduced by 17 and 19%, respectively. In the BF, the corresponding proportions were 27% (C) and 25% (N). Our results indicate that clear-cutting and slash burning had caused marked short-term changes in ecosystem C and N in the two forests. How long these changes will persist needs further study.

通过对格氏栲（Castanopsis kawakamii）和杉木（Cunninghamia lanceolata）人工林新近凋落物、半分解层（F层）和分解层（H层）凋落物室内模拟淋洗实验，研究了凋落物淋溶过程中溶解有机碳（DOC）浓度变化及紫外-可见（UV-Vis）光谱特征。结果表明，格氏栲和杉木人工林新近凋落物淋出液的DOC浓度较低，F层淋出液的DOC浓度较高；格氏栲凋落物淋出液的DOC浓度基本上随淋溶次数的增加而降低，杉木的则先升后降。淋出液溶解有机物（DOM）的紫外吸收值均随波长的增加而减小，且UV-Vis吸收曲线均在200nm附近出现吸收峰，不同来源DOM 的E240/E420存在显著差异；同一样品各次淋出液的DOC浓度与E200有很好的线性关系（R2>0.90），据此，可用E200值估算DOC浓度。