Showing papers on "Cunninghamia published in 2013"

Ecosystem carbon storage and soil organic carbon stability in pure and mixed stands of Cunninghamia lanceolata and Michelia macclurei

Abstract: Across the world, about 264 million ha forest plantations are monospecific. This practice has been found to cause site productivity and soil fertility decline in the regions where forests have been harvested several times. To mitigate these problems, mixed-species plantations, especially with broadleaved and coniferous species, are preferred. Understanding the effects of introducing broadleaved tree in monospecific coniferous plantation on ecosystem carbon (C) storage and soil organic C (SOC) stability is critical to improve our understanding of forest C sequestration and C cycle. Plots were established in subtropical plantations with a randomized block design to examine the influence of introducing Michelia macclurei trees into pure Cunninghamia lanceolata plantation on biomass C storage, SOC storage of total, labile, and recalcitrant fractions (0–40 cm depth), and SOC stability. Introducing M. macclurei trees increased biomass C by 17.9 % and 14.2 % compared with monospecific C. lanceolata and M. macclurei plantations, respectively. Storage of different SOC fractions was not significantly different between monospecific C. lanceolata and mixed plantations. SOC stability in bulk soils was not affected, although it differed in 10–20 cm and 20–40 cm soil depth among three plantations. Mixed species plantations can increase C sequestration, and in the subtropical forest ecosystem examined this was mainly attributed to an increase in biomass C.

Aboveground biomass and corresponding carbon sequestration ability of four major forest types in south China

Abstract: We estimated aboveground biomass carbon (T ABC) and net carbon accumulation rates (T NEP) for trees in four major forest types based on national forest inventory data collected in 1994–1998 and 1999–2003. The four types were Pinus massoniana forest, Cunninghamia lanceolata forest, hard broad-leaved evergreen forest and soft broad-leaved evergreen forest. We analyzed variations in T ABC and T NEP for five stand ages (initiation, young, medium, mature and old). In both time periods, estimated T ABC in all four forest types increased consistently with forest stand age and the oldest stage had the largest T ABC compared with other stages. Broad-leaved forests (hard and soft) had higher T ABC than needle-leaved forests (Pinus massoniana and Cunninghamia lanceolata) for each of the five age stages. The difference of T ABC between broad-leaved and needle-leaved forests increased with forest stand age. Comparison of estimated T NEP by age category indicated T NEP increased from the initiation stage to the young stage, and then decreased from the mature stage to old stage in all four forest types. T NEP for any particular stage depended on the forest type; for instance, broad-leaved forests at both the mature and old stages had greater T NEP than in needle-leaved forests. A logistic curve was applied to fit the relationship between T ABC and forest stand age. In each period, correlations in all four forest types were all statistically significant (P < 0.01) with R 2 > 0.95. T ABC was therefore predicted by these regression functions from 2000 to 2050 and the mean T NEP during the predicted period was estimated to be about 41.14, 31.53, 75.50 and 75.68 g C m−2 a−1 in Pinus massoniana forest, Cunninghamia lanceolata forest, hard broad-leaved forest and soft broad-leaved forest, respectively. Results from both forest inventory and regression prediction suggest broad-leaved forests are greater carbon sinks, and hence have greater carbon sequestration ability especially in the mature and old stages when compared to needle-leaved forests. Broad-leaved forests should have high levels of carbon sequestration when compared with needle-leaved forests in south China.

Development and characterization of 28 polymorphic EST-SSR markers for Cunninghamia lanceolata (Taxodiaceae) based on transcriptome sequences

Abstract: Abstract The Chinese fir (Cunninghamia lanceolata) is a very important plantation species that is mainly distributed in Southern China. However, genomic analyses of C. lanceolata have lagged significantly behind those of other conifer species due to a lack of suitable markers. To address this issue, we examined 27,666,670 reads from C. lanceolata transcriptome sequences recorded in the SRA database. Assembly produced 35,633 contigs, 1,822 (5.11%) of which contained one or more SSRs. In total, 2,156 SSRs were identified, giving an average SSR density of 68.4 SSRs/Mb. The most common SSR types were tri-SSRs (41.7%), followed by hexa-(29.8%), penta- (12.7%), di-(11.1%) and tetra-(4.7%) SSRs. EST-SSR markers based on the 1,822 SSR-containing contigs were developed using the CMiB pipeline and primer pairs were designed to target 35 loci. Polymorphism was observed in 28 of these loci, for which the number of alleles per locus ranged from 3 to 12 over 16 plus-tree individuals. The observed heterozygosity (Ho), expected heterozygosity (He) and fixation index (FIS) values for the targeted loci ranged from 0.125 to 0.938, 0.225 to 0.891 and -0.368 to 0.456, respectively. The corres - ponding PIC values ranged from 0.210 to 0.881, with an average of 0.573. Some of these markers have since been used in our ongoing genetic diversity analyses of C. lanceolata. To our knowledge, this is the first analysis of SSRs and EST-SSR markers in C. lanceolata, and the identified EST-SSR markers will be useful in future genetic analyses of C. lanceolata and related species.

Plus Tree Resource Survey and Genebank Construction for Cunninghamia lanceolata

Abstract: Based on a large-scale investigation into Cunninghamia lanceolata stands in Lechang area of Guangdong Province,a total of 104 plus trees of C.lanceolata were screened out,and the trait indexes including height,DBH,form index,standing volume,wood quality and growth properties of the plus trees were measured and analyzed.The results showed that the average values of tree height,DBH,and standing volume of the plus tree population were all significantly(P0.01) higher than those of the sample plot population,whose phenotype level was above 77.0.Further analyses revealed that the real gain of tree height,DBH,and standing volume indexes of the plus trees could achieve to 0.4%-97.1%,32.3%-131.8%,and 82.6%-712.5% respectively.The height-DBH ratio and the crown-DBH diameter ratio ranged from 38.9 to 76.5,and from 8.7 to 21.9 individually.The basic wood density(DEN),red-heartwood ratio(RHR),shrinkage(SH) and hygroscopicity(HY) of the plus trees changed in amplitudes of 0.251 1-0.3 931 g/cm3,29.2%-72.3%,0.8%-32.4%,and 189.0%-332.9% respectively.Notably,the trait of SH varied most significantly among the plus trees with phenotypic variation coefficient(CV) of 100%,while the DEN index varied much less with a CV of 11%.By using the mean-trees as controls,a considerable number of plus trees with qualified wood were herein identified.Currently,the germplasm resources of C.lanceolata plus trees were well conserved by both in situ and ex situ methods.The compacted ex situ conservation ratio appeared to be 98.1%.

Dynamic changes of biomass and its allocation in Cunninghamia lanceolata plantations of different stand ages

Abstract: Based on the investigation data from a total of 15 plots(20 m×50 m) in Cunninghamia lanceolata plantations of different stand ages(6,16,23,32,and 50 years old) in Guangxi of South China,and by using the data of 15 sample trees of different ages and diameter at breast height(DBH),the biomass regression equation with DBH as the single variable was established.The biomass in the tree layer and in the shrub,herb,and litter layers of the plantations was calculated by regression analysis and quadrat harvest method,respectively,and the change trends of the biomass and its allocation in the plantations of different stand ages were analyzed.Except that the stands of 16 and 23 years old had a slight decrease in biomass due to intermediated thinning,the total biomass of the other stands increased with stand age.The biomass of the stands of 6,16,23,32,and 50 years old was 62.73,172.51,141.65,192.30,and 247.32 Mg·hm-2,respectively,of which,living biomass made up 95.76%-98.39%.Tree layer predominated in biomass,occupying 89.77%-96.55% of the total biomass,and the change trend of tree layer biomass with stand age was as the same as that of the total biomass.The biomass of litter layer was the second,occupying 1.61%-4.24%;while the biomass of shrub and herb layers was the least,accounting for 0.01%-4.26% and 0.27%-4.07%,respectively.The biomass in shrub layer was the largest in 6 years old stand,while that in herb layer was the largest in 23 years old stand.In tree layer,trunk had the greatest proportion of biomass,accounting for 54.89%-75.97%,followed by root,accounting for 11.91%-12.66%.The biomass of both trunk and root was increased with stand age.The proportion of branch-and leaf biomass was 11.86-15.19%,and 4.80%-13.17%,respectively,and decreased with stand age.In shrub layer,the biomass allocation was in the order of branch root leaf,except for leaf branch in 50 years old stand,and root branch in 23 and 50 years old stands.In herb layer,as compared with underground part,aboveground part had greater biomass in 6 and 23 years old stands,but was the opposite in other age stands.The biomass of tree organs and in different layers as well as the whole biomass could be well fitted by growth models.As compared with other plantations,32 years old C.lanceolata plantation had a medium-high level total biomass,suggesting that C.lanceolata would be a fast-growing and high-yielding forestation tree species with high photosynthetic efficiency and high carbon sequestration potential.

Two New Lignans from the Wood of Cunninghamia konishii

Abstract: Two new lignans, (8S,8′S)-4,3′-dihydroxy-3,4′,5′-trimethoxylignan-9′,9-olide (1) and trans–4′,8,8′-trihydroxy-3′-methoxy-3,4-methylenedioxylignan-9′,9-olide (2), were isolated from the wood of Cunn...

Stand basal area model for Cunninghamia lanceolata (Lamb.) Hook. plantations based on a multilevel nonlinear mixed-effect model across south-eastern China

Abstract: Based on a multilevel nonlinear mixed-effect model approach, a stand basal area model was developed for Cunninghamia lanceolata (Lamb.) Hook. plantations belonging to the National Forest Inventory in China. The database consists of 583 plots embracing 18 different blocks within three seed source sites in this study. Of the plots, 80% were randomly selected for model fitting and 20% were carried out for model validation. The modified Chapman–Richards and Schumacher models were evaluated to find a basic model. The explanatory variables included stand dominant height, stand age and total number of stems per hectare. After selection of the basic model, the fitting and predictive ability of a multilevel nonlinear mixed-effect model was analysed. Site-, block- and plot-level random-effects terms were assessed for their contributions to improve model prediction over the ordinary least squares (OLS) method widely used in forest management. In addition, within-plot variance–covariance structure was taken into acco...

The coarse root biomass of eight common tree species in subtropical evergreen forest

Abstract: Though coarse root biomass is an important part in biomass of forest ecosystems, few studies were found in subtropical area. In this study, whole digging method was used to determine the biomass of coarse root (diameter>2 mm) of 175 trees of 8 species in subtropical evergreen forests. The 8 species includes Castanopsis fargesii , Castanopis sclerophylla , Schima superba , Pinus massoniana , Cunninghamia lanceolata , Liquidambar formosana , Sassafras tzumu , Alniphyllum fortunei . Also, the lost roots during excavation were corrected by developing scaling relationship between biomass of root and diameter. Then, four kinds of allometric models for each species and combined trees were fitted to link stem diameter at breast height (dbh) and height ( H ) to coarse root biomass. The results showed that all the scaling relationship between biomass of root and diameter of roots were significant ( P P R 2 values than the height-coarse root biomass. The results also indicate that dbh is an adequate estimator for coarse root biomass of subtropical evergreen trees. The results in this study provide important information to estimate the coarse root biomass in subtropical evergreen forests.

Effects of broadleaf plantation and Chinese fir (Cunninghamia lanceolata) plantation on soil carbon and nitrogen pools

Abstract: A comparative study was conducted on the soil C and N pools in a 19-year-old broadleaf plantation and a Chinese fir (Cunninghamia lanceolata) plantation in subtropical China, aimed to understand the effects of tree species on the soil C and N pools. In the broadleaf plantation, the C and N stocks in 0-40 cm soil layer were 99.41 Mg.hm-2 and 6. 18 Mg.hm-2, being 33.1 % and 22. 6 % larger than those in Chinese fir plantation, respectively. The standing biomass and the C and N stocks of forest floor in the broadleaf plantation were 1.60, 1.49, and 1.52 times of those in Chinese fir plantation, respectively, and the differences were statistically significant. There was a significant negative relationship between the forest floor C/N ratio and the soil C and N stocks. In the broadleaf plantation, the fine root biomass in 0-80 cm soil layer was 1.28 times of that in the Chinese fir plantation, and the fine root biomass in 0-10 cm soil layer accounted for 48. 2 % of the total fine root biomass. The C and N stocks in the fine roots in the broadleaf plantation were also higher than those in the Chinese fir plantation. In 0-10 cm soil layer, its C stock had a significant positive relationship with the fine root C stock. It was suggested that as compared with Chinese fir plantation, the soil in broadleaf plantation had a greater potential to accumulate organic carbon.

Study on carbon storage of main forest types in southeast part of Guizhou province

Abstract: The carbon storages of the main forest types in southeast of Guizhou province were investigated based on the biomass data collected from field surveys and the carbon contents of each tree organ with potassium dichromate method.The results show that the carbon storages of main forest types were from 334.32 to 566.79 t.hm-2,and the contents from the maximum to minimum was: Pinus massoniana plantation(566.79 t.hm-2),Cunninghamia lanceolata plantation(403.74 t.hm-2),deciduous broad-leaved forest(374.07 t.hm-2),evergreen broad-leaved forest(352.35 t.hm-2),coniferous and broad-leaved mixed forest(34.32 t.hm-2);in the similar forest ecosystems,the carbon storages in soil layer was the largest,with the value from 286.66 to 481.49 t.hm-2,the next was the canopy,being 15.23 ～ 74.58 t.hm-2,the third was the litter layer,while the shrubs layer and herbaceous layer were the minimum;The carbon storage in arborous layer of P.massoniana plantation was the biggest(74.58 t.hm-2),that in C.lanceolata plantation was the least(15.23 t.hm-2);the carbon storages differences among in layer of litter,shrubs and herbaceous were relatively small and not that far away;the average annual carbon sequestration of young and half-mature forests ranked by magnitude: coniferous and broad-leaved mixed forest P.massoniana plantation deciduous broad-leaved forest C.lanceolata plantation evergreen broad-leaved forest;the average annual carbon sequestration in different forest types gradually declined with the increment of the soil thickness.The carbon content rates in top soil showed that: P.massoniana plantationsconiferous and broad-leaved mixed forestevergreen broad-leaved forestdeciduous broad-leaved forestC.lanceolata plantations.The soil layer and canopy layer were the largest carbon pool in the whole forest ecosystem in the southeast of Guizhou province.

The coarse root biomass of eight common tree species in subtropical evergreen forest

Abstract: Though coarse root biomass is an important part in biomass of forest ecosystems,few studies were found in subtropical area.In this study,whole digging method was used to determine the biomass of coarse root(diameter2 mm) of 175 trees of 8 species in subtropical evergreen forests.The 8 species includes Castanopsis fargesii,Castanopis sclerophylla,Schima superba,Pinus massoniana,Cunninghamia lanceolata,Liquidambar formosana,Sassafras tzumu,Alniphyllum fortunei.Also,the lost roots during excavation were corrected by developing scaling relationship between biomass of root and diameter.Then,four kinds of allometric models for each species and combined trees were fitted to link stem diameter at breast height(dbh) and height(H) to coarse root biomass.The results showed that all the scaling relationship between biomass of root and diameter of roots were significant(P0.001),which indicated that the biomass of lost roots during digging could be estimated by the diameter of broken points.All allometric models for coarse root biomass using breast height or height as predictors were significant(P0.001),but the dbh-coarse root biomass equations had higher R2 values than the height-coarse root biomass.The results also indicate that dbh is an adequate estimator for coarse root biomass of subtropical evergreen trees.The results in this study provide important information to estimate the coarse root biomass in subtropical evergreen forests.

Study on selection of main fuel-wood forest tree species in South China and combustion characteristics of wood pellets of fuel-wood trees

Abstract: According to the biomasses and calorific values of main fuel-wood tree species in South China, the trees were clustered by type, and comprehensively evaluated by taking into account their biological and ecological characteristics and planting and extending status. Then five kinds of excellent fuel-wood and energy tree species, which grew fast, yielded highly, had calorific values, planted widely and was suitable for planting in South China, were selected as the preferential kinds to plant for the fuel forest in the South china, such as poplar, willow, masson pine, Cunninghamia lanceolata, slash pine. The combustion characteristics of the wood pellet fuels made of 5 kinds of selected trees were analyzed according to Swedish Biofuel Standards(SS187120). The results show that the characteristics of 5 kinds of wood pellets(moisture content, calorific value and net density etc. have reached international level. However, after burned, the ash contents of 5 kinds of wood pellets were all higher than that of the reference values of Swedish Biofuel Standards(SS187120), excepting Chinese fir pellets other trees' pellets all are fusibility ash, so other wood pellets are ease of slagging during combustion.

Study on evaluation index system of Cunninghamia lanceolata scenic and recreational forests based on analytic network process

Abstract: So far,there is no evaluation index system of Cunninghamia lanceolata scenic and recreational forests by analytic network process.Based on the data of scenic and recreational forests at home and abroad,by taking C.lanceolata forests as studying objects,an evaluation index system of Cunninghamia lanceolata scenic and recreational forests was set up by analytic network process.The results show that in the first grade indexes,the weighting of forest aesthetics index was the biggest,that of other indexes followed by: forest measurement,stand spatial structure,Characteristics of surface cover,forest’s health.In the second grade indexes,the weightings ordered by magnitude: slope,tree height,transparency distance,DBH,life form,canopy density,crown width,density of trees number,show degree of trunk,height of shrub,green quantity,proportion of coniferous trees and broadleaved trees,fallen dead wood,height of grass,coverage,distribution of grass and shrub,stem form,color diversity,forest tree distribution,litter distribution,mean height under first alive branch.This study provides basis data for city forest planning,management and further research.

Individual crown diameter prediction for Cunninghamia lanceolata forests based on mixed effects models.

Abstract: 以湖南省黄丰桥国有林场103块样地共2461株杉木为例,建立单木冠幅模型.由于所调查数据是在不同立地条件下相同样地中重复观察得到,数据间存在明显相关性,为解决此问题,将考虑立地指数和样地对冠幅生长的随机影响,即建立嵌套2水平非线性混合冠幅模型.从12个常用林分模型中选出较好的冠幅直径模型作为构建混合模型的基础模型.除胸高直径外,还考虑其他17个林分或树木因子对冠幅的影响.通过指标AIC(akaike information criterion)和对数似然确定最佳形式参数随机效应组合类型,用指数函数、幂函数以及常数加幂函数3种形式的残差方差模型消除异方差,最后对混合模型和传统回归模型进行比较及评价.结果表明:逻辑斯蒂形式的冠幅直径模型[模型(13)]拟合效果较好,选择为基础模型;胸径、冠底高、树高和样地优势高是影响冠幅的主要因子;幂函数消除异方差效果最好;与立地指数相比,立地指数与样地的嵌套效应对冠幅影响更大;模型(15)的嵌套2水平比总体平均水平和立地指数水平预测精度高,相比于模型(13)有明显改进.本文主要为方法研究,对于其他树种可以用相似方法构建冠幅模型.

Cunninghamia lanceolata cultivation compound substrate and preparation method for same

Abstract: The invention discloses a cunninghamia lanceolata cultivation compound substrate and a preparation method for the same. The substrate comprises the following raw materials in parts by weight: 200 parts of cunninghamia lanceolata skin powder, 200-220 parts of tung bran, 0.1-1.2 parts of corn flour, 10-11 parts of rice bran, 0.07-0.08 parts of slaked lime powder, 0.04-0.05 parts of enzyme microorganism agent, 0.01-0.02 parts of suillus bovines agent, 0.01-0.02 parts of coletus luridus, 10-11 parts of calcium magnesium phosphate fertilizer, 2.0-2.5 parts of urea, and 0.01 part of 95% dexon wettable powder. The preparation method comprises the following steps of: crushing cunninghamia lanceolata skins, performing fermentation and adsorption treatments, performing ectotrophic mycorrhiza amplification, compounding, and thus obtaining the cunninghamia lanceolata cultivation compound substrate. With the adoption of the substrate, wood processing remains can be adequately utilized, thus being environment-friendly and reducing seedling culture cost; the use of quick-acting fertilizers and pesticides is reduced, thus reducing pollution, avoiding soil hardening and salinization, enhancing the biological activity of soil system, and building up fertility; seedlings are fast in growth, nursery stocks are good in quality, and the survival rate of afforestation is high; and the substrate is good in economic benefits, social benefits and ecological benefits.

Comparison of several soil nutritions in pure Cunninghamia lanceolata plantations and mixed forests, and relationship between nutrition and growth factors

Abstract: After comparing the soil nutritions in pure Cunninghamia lanceolata plantations and mixed forests of C.lanceolata and Pinus massoniana,Phyllostachys heterocycla,Michelia macclurel,Schima superba and Vernicia fordii,the correlation analysis on soil nutrition content and C.lanceolata growth factor was conducted.The results are as followings: ⑴ The nitrogen,phosphorus and organic matter contents raised and the soil pH decreased in mixed forests of C.lanceolata and Pinus massoniana;the nitrogen and potassium contents increased in mixed forests of C.lanceolata and P.heterocycla;the nitrogen and organic matter contents increased and the soil pH decreased in mixed forests of C.lanceolata and V.fordii;the soil pH raised in mixed forests of C.lanceolata and S.superba.⑵ There were significantly influences of soil pH,organic contents on DBH,height of C.lanceolata.And there was a significantly influence of nitrogen content on height of C.lanceolata.The stimulative influences of five forest stand types on growth factors of C.lanceolata ordered from high to low as following: P.massoniana V.fordii P.heterocycla M.macclurel.And the mixed forests of C.lanceolata and S.superba can’t improve the growth of C.lanceolata.

Construction of tree volume equations for Chinese fir plantations in Guizhou Province, southwestern China

Abstract: Forest volume, the major component of forest biomass, is an important issue in forest resource monitoring. It is estimated from tree volume tables or equations. Based on tree volume data of 1840 sample trees from Chinese fir (Cunninghamia lanceolata) plantations in Guizhou Province in southwestern China, parallel one- and two-variable tree volume tables and tree height curves for central and other areas were constructed using an error-in-variable modeling method. The results show that, although the one-variable tree volume equations and height curves between the central and other areas were significantly different, the two-variable volume equations were sufficiently close, so that a generalized two-variable tree volume equation could be established for the entire province.

Arbor Biomass in Eight Types of Forest Communities of Tianmushan National Nature Reserve

Abstract: Investigations were conducted on arbor biomass in eight types of forest communities,including Cunninghamia lanceolata,Pinus massoniana,mixed coniferous and broadleaf forest,evergreen broad-leaved forest(EBF),Phyllostachys heterocycla cv.pubescens,mixed evergreen and deciduous broad-leaved forest(MF),deciduous broad-leaved forest(DBF) and deciduous broad-leaved shrub in Tianmushan National Nature Reserve.Stand density,species,dominant tree species and biomass in the tree layer of different forest community types were evaluated and estimated.Results showed that biomass was as following: MF DBF mixed coniferous and broadleaf forest C.lanceolata EBF P.massoniana Phyllostachys heterocycla cv.pubescens deciduous broad-leaved shrub.Biomass showed little change in five types of forest communities below 1000 meters.Species richness had positive relation with elevation(above 1000 meters),but biomass showed reveres variation.

Comprehensive Discussion on Low-function Ecological Forest Reconstruction Technology of Cunninghamia lanceolata and Pinus massoniana in Anhui Northern Subtropics Region

Abstract: The causes for lower ecological benefit of pure coniferous forests were analyzed from many aspects such as biodiversity,soil conservation,net primary productivity,and so on.And,these Cunninghamia lanceolata and Pinus massoniana pure forests could be reconstructed into conifer-broadleaf mixed forests which have higher ecological benefit,if we take follow measures: intermediate cutting,closing mountain,replanting broadleaf trees,and so on.

Determination of root system biomass of matured Cunninghamia lanceolata plantation in Tianjingshan Forest Farm, Guangdong province

Abstract: The root system biomasses of 8 normal sample trees with different dominance and diameter at breast height(D) in matured Cunninghamia lanceolata plantation in Tianjingshan Forest Farm, Guangdong Province were measured by total root excavating methods.The root system biomass regression models were set up by using parameters of D and D2H, and also the root biomass allocation pattern in different forest layers and in various diameter classes were analyzed. The results indicate that:(1) Adding H factor as the second independent variable slightly improved the predictive power of the allometric equation compared to the equation only involving D; so,it was suggested that the cubic equation should be the first choice to estimate the root system biomass, then the quadratic and power equation next.(2) The total underground root biomass of the plantation was 29.27 t·hm-2, and the biomasses in arbor, shrub, herb layer took up 96.04%, 0.38%, 3.59% respectively; and 57.3%, 15.8%, 17.0%, 4.76%, 1.97% of arbor biomass were distributed in root stump(W ST), coarse root(W C), larger root(W L), middle root(W M), small root(W S), fine root(W F) respectively; the root biomasses for more than 2.0 cm root diameter occupied 90.1% of total root biomass.(3) The root biomasses of tree layer in different diameter class showed the skewed distribution as same as aboveground biomass, and the crest values appeared in the 18~22 cm diameter class, that inferred larger diameter trees had more contribution to root biomass of matured Chinese fir plantation.(4) As decreasing of tree dominance, the biomass proportion of the roots for supporting tree body decreased, and that of small and fine roots for absorbing and transferring water and nutrient increased significantly. And also, the required root amount for per unit weight of branch and leaf increased obviously as the decrease of tree dominance. The phenomenon is called "resource stress stimulates tree to produce more roots", and is a suitable mechanism for non-dominant trees when they face increasing stress of canopy growth space, light and soil nutrient competition. The phenomenon can be explained by resource competition effect.

Analysis of Stand Spatial Structure of Cunninghamia lanceolata-Broadleaved Mixed Plantation

Abstract: To analyze the stand spatial structure of Cunninghamia lanceolata-broadleaved mixed plantation,the plantation predominated by C. lanceolata and Schima superba in mid-subtropical zone was taken as the study object,and three structure parameters( mingling degree,neighborhood comparison and uniform angle index) and two tree species composition( Ⅰand Ⅱ) were used. The results showed that the mingling degree of C. lanceolata and S. superba was mainly relatively weak and moderate mixture,the average mingling in the stand were 0. 45 and 0. 52 respectively,showing the relatively simple spatial allocation and poor mixing of different tree species in this plantation. The proportions of neighborhood comparison of C. lanceolata,S. superba and Castanopsis sclerophylla distributed uniformly,the mean value was about 0. 50. But the differentiation between dominant species( Paulownia,Pinus massoniana and Castanopsis fargesii) and suppressed species( Schima argentea,Toxicodendron verniciflua,Liquidambar formosana,Cyclobalanopsis glauca and Daphniphyllum oldhamii) was obviously,the mean values ranged from 0 to0. 88,indicating the stand growth was mainly medium state,and tree species in the arborous layer was instable. As for uniform angle index,considering the spatial units,the distribution of uniform angle index changed with a fluctuant pattern and the forest plantation presented an aggregating distribution pattern. In order to improve plantation quality and play its function better,this study aimed to provide scientific basis for guiding selective cutting management and spatial structure optimization of C. lanceolata-broadleaved mixed plantation.

Characteristics of content and density of soil organic carbon in Eucalptus grandis×E. urophylla forest and the other three forest types in northern Guangxi

Abstract: Based on the soil horizons of 0-60cm of Eucalptus grandis×E.urophylla forest,Cunninghamia lanceolata forest,Pinus massoniana forest and Phyllostachys edulis forest planted in northern Guangxi,which the distribution characteristics of the soil organic carbon content and soil organic carbon density had studied.The results showed that the maximum value and minimum value of soil organic carbon content were occurred at the soil horizons of 0-15 cm [(49.49±1.16) g·kg-1] of the Phyllostachys edulis forest and at the soil horizons of 45-60 cm [(4.50 ±0.52) g·kg-1] of the Pinus massoniana forest,respectively.The average value of the soil organic carbon content at the soil horizons of 0-60cm of the four forest types arranged as the following order: Phyllostachys edulis forest(28.16 g·kg-1) Cunninghamia lanceolata forest(25.10 g·kg-1) Eucalptus grandis×E.urophylla forest(14.52 g·kg-1) Pinus massoniana forest(9.56 g·kg-1).The proportion of soil organic carbon content at the soil horizons of 0-15cm of the Eucalptus grandis×E.urophylla forest,Cunninghamia lanceolata forest,Pinus massoniana forest and Phyllostachys edulis forest were 28.29%,39.14%,55.44% and 43.94%,respectively.The maximum value and minimum value of the soil organic carbon density were occurred at the soil horizons of 0-15 cm [(6.71±1.72) kg·m-2] of the Cunninghamia lanceolata forest and at the soil horizons of 45-60 cm [(1.14±0.11) kg·m-2] of the Pinus massoniana forest,respectively.The average value of the soil organic carbon density at the soil horizons of 0-60cm of the four forest types arranged as the following order: Cunninghamia lanceolata forest(19.60 kg·m-2) Phyllostachys edulis forest(18.85 kg·m-2) Eucalptus grandis×E.urophylla forest(12.91 kg·m-2) Pinus massoniana forest(8.47 kg·m-2).The proportion of the soil organic carbon density at the soil horizons of 0-15 cm of the Eucalptus grandis×E.urophylla forest,Cunninghamia lanceolata forest,Pinus massoniana forest and Phyllostachys edulis forest were 25.12%,34.25%,52.07% and 32.64%,respectively.The soil organic carbon content and the soil organic carbon density of the four forest types had a decreased trend with the soil horizons increasing.

Aboveground Biomass of 27-year-old Cunninghamia lanceolata Plantation in Tianjingshan Forest Farm,Guangdong Province

Abstract: Aboveground biomass(AGB) of Cunninghamia lanceolata plantation(27 a) was measured using the normal tree method in Tianjingshan Forest Farm,Guangdong ProvinceThe distribution pattern of AGB among different forest layers and organs were investigated,and biomass regression models using parameters of tree height(H) and diameter at breast height(D) were also set up in this paperThe results indicated that:(1) Adding H factor as the second independent variable slightly improved the predictive power of the allometric equation compared to the equation only involving DThe Quadratic,Cubic and Power equations were suggested to be used for estimating trees' aboveground(Wa) and stem(Ws) biomass;the best biomass equation of bark(Wbark),branch-leaf(Wb + l) must be Quadratic and Cubic equations(2) Total AGB of the plantation was 14102 t/hm2,and biomass of arbor,herb,shrub and litter layer took up 9520%,028%,033% and 423% of AGB,respectively,and 8178%,1079%,743% of arbor biomass were allocated in the stem,branch-leaf,bark,respectively(3) The tree density in different diameter class showed Gaussian distribution,but the biomass showed skewed distribution and larger diameter class had more biomass

Study on water-holding function of main forest types in southeast of Guizhou province

Abstract: The main forest types in southeast of Guizhou Province were selected to test their water conservation capacity.The results showed that the average interception rate of different forest types varied f rom 9.98 % to 28.46 %.The best forest type for the effect of canopy interception were Pinus massoniana plantation and broad-leaved mixed forest.The water retention characteristics in shrubs layer from the maximum to minimum was: broad-leaved mixed forest,Pinus massoniana plantation,deciduous broad-leaved forest,Cunninghamia lanceolata plantation,evergreen broad-leaved forest.while herbaceous layer in shrubs layer from the maximum to minimum was:Pinus massoniana plantation,evergreen broad-leaved forest,Cunninghamia lanceolata plantation,broad-leaved mixed forest,deciduous broad-leaved forest.and the water retention characteristics in litter layer:broad-leaved mixed forest Pinus massoniana plantation deciduous broad-leaved forest Cunninghamia lanceolata plantation evergreen broad-leaved forest.The soil bulk density of surface soil in deciduous broad-leaved forest was least(0.84g/cm3),and the Effect of soil bulk density for the Soil improvement in deciduous broad-leaved forest was obvious,surface soil static water storage capacity was the most large in main forest types in southeast of Guizhou Province.The ability of soil infiltration and dynamics of Soil water storage in broad-leaved mixed forest was much matter than other forest types in southeast of Guizhou Province.

Litterfall production and its relationship with climatic factors in a Cunninghamia lanceolata (Lamb.) Hook. plantation

Abstract: In order to investigate the relationships between litterfall(production,composition and dynamics) and climatic factors,a 7-year-long field experiment was conducted in a Cunninghamia lanceolata(Lamb.) Hook.plantation in Shaxian,Fujian Province.Results showed that the ranges of litterfall production from 2005 to 2011 were from 1 051.83-2 407.80 kg · hm-2,with the mean value of 1 493.14 kg · hm-2 · y-1.Litterfall production reduced significantly from 2005 to 2006,while in the next 6 years,litterfall production increased followed by decreasing,and increased again finally,but its change scope was smooth.The litterfall proportions of leaves,branches,fruits,barks,rags were 62.9%、16.6%、7.63%、3.16% and 9.73%,respectively.The monthly dynamics of litterfall production showed a type of two peaks,which appeared in February(maximum) and July,accounting for 62.3% of the total annual production.The relationships between litterfall production and meteorological factors were examined by using Pearson and Spearman methods.The results showed that precipitation and wind speed were the most sensitive factors in C.lanceolataplantations(P0.05),followed by the temperature and sunshine hours.

Estimating Technology of Carbon Harvest for Cunninghamia lanceolata Plantation

Abstract: By defining the concepts of carbon harvest and carbon harvest table and then using the second orthogonal rotation design to set standards plots of Cunninghamia lanceolata plantation in Fujian Province and by investigating and then measuring the carbon contents in different parts of a sampling tree and carbon stocks in different forest stands in the representative Cunninghamia lanceolata plantation,carbon harvest model of individual tree based on the relative growth equation with the independent variables of DBH,tree height and wood volume and stand carbon harvest table of variable density with the independent variables of average DBH,average tree height,density index and stand volume were respectively established in Cunninghamia lanceolata plantation in order to reveal the relationships between forest carbon harvest and forest stand of plantation especially Cunninghamia lanceolata plantation in Fujian Province from the point of view of yield prediction.The estimating accuracies of the carbon harvest models and the stand carbon harvest tables in Cunninghamia lanceolata plantation were high,both of which were more than 95% upon testing.In addition,the influences of single wood volume and stand forest stock volume on carbon harvest were fully considered by the models and tables.There are good application values in forest carbon sink estimation as the models and tables have excellent compatibility and strong operability.When the established carbon harvest models and tables of Cunninghamia lanceolata plantation were applied to estimate carbon harvest of a single wood or a forest stand in a reality Cunninghamia lanceolata plantation,the results were perfect with high accuracy.Especially,the proportional error was only 4.70% in the carbon harvest model of a single wood which indicated that the carbon harvest models and stand carbon harvest tables established in the paper could be used to estimate carbon storage or stock of a single tree and a forest stand in a Cunninghamia lanceolata plantation in Fujian Province,which would enrich the content of dynamic prediction of forest resources,provide reference for the monitoring of forest resources in the province and accumulate basic data for other relevant researches.