【作者】 李燕；

【导师】 张建国；

【作者基本信息】 中国林业科学研究院 ， 森林培育， 2010， 博士

【摘要】 本文以福建邵武28年生杉木(Cunninghamia lanceolata)密度试验林为研究对象,通过林木实测数据拟合优选生物量估算模型,结合生态系统中乔木(叶、枝、去皮干、干皮、根蔸和根)、灌木、草本、凋落物和土壤的有机碳含量以及林分调查数据,系统研究了杉木成熟林生态系统的碳储量、空间分布格局及其与林分初植密度和立地指数的关系。取得了三个方面的重要结果:1.生物量估算模型的拟合与优选采用11种生物量模型,分别对杉木幼林龄(7年生)、中龄林(16年生)、成熟林(28年生)和不分林龄的单木各器官(叶、枝、干皮、去皮干、根蔸和根)和全株生物量进行拟合,共得到生物量估算模型308个。结果表明:(1)11种生物量模型都能较好的模拟杉木单木生物量,其中幂函数模型( W1 = aDb、( )W = a DHb和( )W = a D H)拟合效果最优,其次为指数模型( ( )W 8 = a expbD、W 9 = a exp(b D2)、( )W1 0 = a expbDH、W1 1 = a expbD H),再次之为多项式模型( W 4= a + bD + cD2、W 5= a + bD 2 + cD4、W 6= a + bDH + c DH、( )2 22W 7= a + bD H + c D H);共选出估算杉木幼林龄、中龄林和成熟林各器官和全株生物量的最优模型21个(18个器官模型,3个全株模型),不分林龄的杉木单木各生物量的最优模型7个(6个器官模型,1个全株模型),均为幂函数模型;(2)不同林龄的单木生物量最优模型的通用性较差,而不分龄林的单木生物量最优模型具有一定的通用性,精度较高,可用于估算不同林龄的单木生物量;(3)应用福建邵武单木生物量模型对江西28年生的成熟林单木各生物量的预测效果显示,不分林龄的大样本生物量模型精度比较高,可在较大范围应用。而区域小样本模型仅限于区域小范围应用。2.不同立地不同密度杉木成熟林土壤碳储量基于75个土壤剖面(0～100 cm)的数据,分析了不同密度(5个初植密度)和立地指数级(6个立地指数级)杉木成熟林土壤有机碳密度及其分布特征。结果表明:(1)不同初植密度和立地林分土壤有机碳含量存在显著差异(P<0.05),各林分整个土层(0～100 cm)的平均有机碳含量为0.9126%～1.3886%,其中初植密度为6667株·hm-220立地指数级的林分最高,初植为密度10000株·hm-214立地指数级的林分最低。土壤有机碳含量整体随深度增加而降低,但各林分的降幅不同,其中初植密度为5000株·hm-216立地指数级的杉木成熟林降幅最大,达84.22%。(2)不同初植密度和立地林分土壤有机碳密度差异极显著(P<0.01),其各土层的平均有机碳密度变化范围为4.9591～35.7399 Mg·hm-2。75个土壤剖面土壤碳密度随深度增加而降低,各林分整个土层(0～100 cm)平均土壤碳密度为114.2279～187.2361 Mg·hm-2,总平均值为150.3215 Mg·hm-2。(3)林分土壤有机碳表层富集明显,0～30 cm土层土壤碳储量占整个土层(0～100 cm)的57.08%。研究发现,土壤表层0～10 cm的碳密度与林地立地指数呈显著正相关关系(P<0.05),这一结论对林地质量评价和土壤管理具有重要意义。(4)林分密度和林地立地质量是影响土壤碳汇水平的主要因素。从碳汇林地经营角度考虑,在低立地指数级(SI≤14 m)林地造林时建议采用高初植密度≥6667株·hm-2),中等及以上立地指数级(SI≥16 m)的林地应采用低初植密度≤6667株·hm-2。3.杉木成熟林生态系统的碳储量及其空间分布特征福建邵武15个样地28年生的杉木各器官和成熟林生态系统各组分的含碳量和碳储量的研究结果表明:(1)杉木不同器官的有机碳含量差异极显著(P<0.01),各器官的平均有机碳含量变化范围为49.1829%～53.4352%,其由大到小为:叶(53.4352%)>去皮干(53.2206%)>根蔸(51.6617%)>枝(51.1115%)>干皮(50.9420%)>根(49.1829%)。各器官的有机碳含量的差异可能与杉木的生长规律有关,因此,应对林木分器官测定有机碳含量,以达到精确估算杉木成熟林碳储量的目的。研究发现,杉木去皮干的有机碳含量在树高垂直分布上差异不明显,可视为垂直均匀分布。林下地被物各层的有机碳含量由大到小为:凋落物层(47.6355%～52.8923%,平均为50.6268%)>灌木层(39.8711%～46.5126%,平均为44.0429%)>草本层(35.9797%～43.9649%,平均为40.5909%)。(2)不同初植密度和立地指数级的杉木成熟林各器官碳储量的平均值和分配率为:去皮干(78.8943 Mg·hm-2,58.0832%～64.6194%)>地下部分(22.8704 Mg·hm-2,16.0528%～20.9624)>干皮(13.1020 Mg·hm-2,9.3927%～10.7423%)>枝(7.0874 Mg·hm-2,4.0841%～7.5481%)>叶(5.5873 Mg·hm-2,3.0739%～5.6319%)。相同初植密度且林分密度相差不大的杉木成熟林,立地指数越高,杉木各器官的碳储量越大,其中79.0376%～83.9472%的碳储存于地上部分器官;相同初植密度和立地的杉木成熟林林分的碳储量的差异主要是由林分密度不同造成的。杉木单木各器官的碳储量是单木的生长状况和林分密度共同作用的结果。(3)不同初植密度和立地杉木成熟林生态系统各组分碳储量的平均值和分配率排序为:土壤(150.3215 Mg·hm-2,45.4608%～63.7434%)>乔木层(127.5417 Mg·hm-2,33.4074%～52.0212%)>凋落物层(4.8947 Mg·hm-2,1.0893%～2.2838%)>草本层(0.7065 Mg·hm-2,0.0797%～0.4246%)>灌木层(0.2103 Mg·hm-2,0.0070%～0.2685%)。高立地指数且单木生物量较高的林分,其乔木层的碳储量高于土壤层,立地指数级为20 m初植密度为1667和6667株·hm-2的林分以及立地指数级为22 m初植密度为1667和5000株·hm-2的林分,均为此类林分。在同一初值密度,林分密度相差不大的情况下,立地指数级正向影响乔木层及各组分总的碳储量。更多还原

【Abstract】 Optimal biomass models were used to estimate biomass of Cunninghamia lanceolata mature plantation ecosystems (28-year old) in Shaowu, Fujian Province, with the measured data of trees’ biomass. Carbon storage of mature plantation ecosystems was estimated with stand survey data and organic carbon contents of tree layer(including leaf, branch, peeled stem, bark, root head and root),shrub layer,herbaceous layer, litter and soil of the mature forest ecosystems. Carbon storage of mature plantation ecosystems and its spatial distribution was studied, as well the relationship between it and planting density-site index class. The main results were as follows:1. Selection of biomass estimate models for Chinese fir plantationIn this paper, 11 kinds of biomass models were used to estimate the single-tree biomasses in a young (7-year old), middle-aged (16-year old), mature Chinese fir plantation (28-year old) and the mixed-age Chinese fir stand, respectively. There were 308 biomass models fitted totally. The results showed that: (1) The power function models( W1 = aDb、( )bW = a D H) present the best fitting results followed by exponential models( ( )W 8 = a expbD、W 9 = a exp(b D2)、( )W1 0 = a expbDH、( )W1 1 = a expbD H) and the polynomial models ( W 4= a + bD + cD2、W 5= a + bD 2 + cD4、( )W 6= a + bDH + c DH、2 22W 7= a + bD H + c D H)with the least effective fitting results. 21 optimal biomass models for individual organ of tree and total single-tree in young, middle-aged and mature Chinese fir plantation were chosen, including 18 for organ and 3 for total single-tree. 7 optimal biomass models of individual tree regardless of ages were chosen, which contained 6 for organ and 1 for total single-tree. All of the optimal biomass models were in the form of power function ones; (2) The optimal biomass models of single-tree with different ages had poor generality, but the ones regardless of ages had a certain generality with high accuracy, which can be used for estimating the biomasses of single-tree with different ages; (3) To predict single-tree biomass of mature Chinese fir plantation (28-year old) in Jiangxi Province, optimal biomass models of single-tree in Shaowu, Fujian Province, which was based on a large sample of forest biomass, showed relatively high accuracy and can be applied in a large range. The regional model with small sample is limited to small application area.2. Soil organic carbon storage and vertical distribution of mature Chinese fir plantation with different planting density and site indexThere were 5 planting densities and 6 site index classes in mature Chinese fir plantation. Based on 75 soil profiles (0～100 cm), the storage and distribution of soil organic carbon for the plantation was studies. The results were as follow: (1) Soil organic carbon contents in different planting density-site index class levels were significantly different among stands (P<0.05). The average soil organic carbon content of the whole soil section (0～100 cm) for the stands was 0.9126%～1.3886%. The average soil organic carbon content was the highest in the stand with planting density 6667 hm-2 and Site Class 20 m, and the lowest with planting density 10000 hm-2 and Site Class 14 m. Soil organic carbon contents generally decreased with depth, but decreasing amplitude was different for the stands, and decreasing amplitude of the stand with planting density 5000 hm-2 and Site Class 16 m, is highest (84.22 %). (2) Soil organic carbon densities in different planting density-site index class levels were significantly different among stands (P<0.01). The average soil carbon density in every soil layer of the stands changed greatly, with a range of 4.9591～35.7399 Mg·hm-2. Soil carbon density decreased generally with the depth, too. For the whole soil section (0～100 cm), the average soil carbon density in the stands varied from 114.2279～187.2361 Mg·hm-2, their total mean values were 150.3215 Mg·hm-2. (3) The soil organic carbon assembled obviously in surface layer soils. The carbon storage contribution rate of the soil layer 0～30 cm was up to 57.08%. Carbon density of soil surface 0～10 cm and site index showed significant positive correlation (P<0.05). The conclusion played an important role in the evaluation of woodland quality and soil management. (4) Planting density and site quality were the main factors, which effected on soil carbon sink levels. If the management purpose was to have large carbon sink capacity of the plantations, the suitable planting density should be chosen with site quality. Low site index classes (SI≤14 m) of woodland should be combined with high planting density (≥6667 hm-2), medium and high classes (SI≥16 m) with low density (≤6667 hm-2).3. Characteristics of carbon storage and the spatial distribution in Chinese fir plantation ecosystemCarbon content and storage of different organs and components of ecosystem were studied in 15 plots of a 28-year old Chinese fir plantation in Shaowu, Fujian. The results showed that: (1) Organic carbon densities in different organs of Chinese fir were significantly different (P<0.01). The average organic carbon contents in different organs were in the range of 49.1829%~ 53.4352%, the descending order: leaf (53.4352%)> peeled stem (53.2206%)> root head (51.6617%)> branch (51.1115%)> bark (50.9420%)> root (49.1829%). Organic carbon content of various organs may be related to differences in the growth pattern of the fir. Therefore, the response to measure organic carbon content of each organ, was in order to estimate accurately carbon storage of mature Chinese fir plantation. Peeled stem in vertical distribution of organic carbon content was no significant difference, which could be regarded as uniformly distributed vertically. The organic carbon contents in different layers of the forest floor were in the order as: litter layer (47.6355%~52.8923%, an average of 50.6268%)>shrub layer (39.8711%~ 46.5126%, an average of 44.0429%)>herb layer (35.9797%~43.9649%, an average of 40.5909%).(2) The means and distribution sequence of the carbon storage in each organ of plantation ecosystem with different initial planting densities and site index classes was that peeled stem (78.8943 Mg·hm-2, 58.0832%~64.6194%)>underground parts (22.8704 Mg·hm-2, 16.0528%~20.9624)>bark (13.1020 Mg·hm-2, 9.3927%~ 10.7423%)>branch (7.0874 Mg·hm-2, 4.0841%~7.5481%)>leaf (5.5873 Mg·hm-2, 3.0739%~5.6319%). With the same planting density and stand densities difference little among the plantations, the higher the site index class of the plantation, the greater carbon storage of different organs in the one. 79.0376%~83.9472% of carbon stored in aboveground organs; differences of carbon storage in mature fir plantations with the same planting density and site index class were mainly caused by the stand density. Carbon storage of Chinese fir plantation in different organs was the result of the interaction of individual growth and plant stand density.(3) The means and distribution sequence of the carbon storage in each component of plantation ecosystem with different initial planting densities and site index classes was that soil (150.3215 Mg·hm-2, 45.4608%~63.7434%)>tree layer(127.5417 Mg·hm-2, 33.4074%～52.0212%)>litter layer (4.8947 Mg·hm-2, 1.0893%～2.2838) >herb layer (0.7065 Mg·hm-2, 0.0797%～0.4246%)>shrub layer (0.2103 Mg·hm-2, 0.0070%～0.2685%). The carbon storage in tree layer was larger than one in the soil of plantation ecosystem, which was high site index class with high biomass of individual tree. Such stand were studied in this paper, including site index class of 20 m with the initial planting density of 1667 hm-2, site index class of 20 m with the initial planting density of 6667 hm-2, site index class of 22 m with the initial planting density of 1667 hm-2 and site index class of 22 m with the initial planting density of 5000 hm-2. With the same planting density and stand densities difference little among the plantations, the higher the site index class of the plantation, the greater carbon storage of tree layer and total layers in the one.更多还原