水杉人工林细根和粗根碳氮磷计量特征对N添加的响应

目的 研究水杉细根和粗根碳（C）、氮（N）、磷（P）计量特征对N添加的响应,揭示细根和粗根N、P养分分配格局的变化,为科学认识水杉对N沉降的适应策略提供参考。 方法 在江苏省东台市林场水杉人工林进行长期N添加试验,设置对照（CK,0 kg·hm−2·a−1）、低N（LN,56 kg·hm−2·a−1）、中N（MN,168 kg·hm−2·a−1）、高N（HN,280 kg·hm−2·a−1）4个N添加处理,测定水杉细根（直径<2 mm）和粗根（2 mm≤直径≤5 mm）C、N、P含量及土壤理化性质指标。 结果 （1）N添加对水杉人工林土壤有机碳和水解氮含量存在明显促进作用,且随着N添加量增加,这种促进作用有所减弱。N添加对土壤全磷含量、有效磷含量和pH均无显著影响。（2）随着N添加量的增加,水杉细根和粗根N含量、C:P、N:P显著增加,P含量和C:N显著下降。此外,细根和粗根N含量、C:N和N:P在HN处理下对N添加的响应存在明显差异,表现为细根N含量、C:N和N:P在HN处理下对N添加响应减弱。（3）水杉粗根N含量和C:N可塑性响应在HN处理下显著高于细根,粗根N:P可塑性响应在MN和HN处理下显著高于细根。 结论 水杉细根和粗根C、N、P计量特征对N添加的响应较为一致,分析发现粗根N含量、C:N、N:P的可塑性响应在HN处理下显著高于细根。研究结果为认识N沉降持续增加背景下林木地下部分养分分配策略提供新的思路,也为沿海防护林养分管理措施的制定提供科学依据。     

长宁苦竹种群结构和地上生物量研究

本文研究了长宁苦竹的种群结构和地上部分生物量。结果表明：（1）人工经营和未经营的苦竹种群都为增长型种群，但人工经营苦竹种群落结构简单；（2）人工经营苦竹种群径级结构偏大；地上部分生物量较大；（3）在种群水平，长宁苦竹地上部分生物量为37．58t／hm^2，随径级增大而增大；（4）在构件水平，1a生苦竹的地上生物量为1074．20g／株，2a生的为2041．86g／株；（5）1a生苦竹竿、枝和叶的含水率普遍高于2a生。     

Functions for estimating aboveground biomass of birch in Norway

A suite of regional allometric aboveground biomass functions were derived for Betula pubescens and Betula pendula for Norwegian conditions. The data consisted of 67 trees sampled throughout Norway. A total of 14 component functions were developed for total aboveground, total stem, stemwood, stem bark, live crown, live branch, leaf, and dead branch biomass using combinations of diameter at breast height and height as predictor variables. Application of the derived functions to existing local southern Norwegian mountain birch and regional Swedish biomass datasets indicated an overall good predictive ability of the developed functions. However, the functions produced slight underestimates, suggesting that the respective birch populations had differing biomass allocation patterns. When the developed functions were applied to Norwegian National Forest Inventory data, they produced slightly higher biomass stock and stock change estimates than what is obtained using existing Swedish functions. The higher estimates were evident in the north, central, and western part of Norway, while estimates were similar in southeastern Norway where growing conditions are most similar to Swedish conditions. The analysis indicates that the derived functions are the best available for regional birch biomass stock and stock change estimation in Norway.     

Allometric relationship for estimating above-ground biomass of Aegialitis rotundifolia Roxb. of Sundarbans mangrove forest, in Bangladesh

Tree biomass plays a key role in sustainable management by providing different aspects of ecosystem. Estimation of above ground biomass by non-destructive means requires the development of allometric equations. Most researchers used DBH (diameter at breast height) and TH (total height) to develop allometric equation for a tree. Very few species-specific allometric equations are currently available for shrubs to estimate of biomass from measured plant attributes. Therefore, we used some of readily measurable variables to develop allometric equations such as girth at collar-height (GCH) and height of girth measuring point (GMH) with total height (TH) for A. rotundifolia, a mangrove species of Sundarbans of Bangladesh, as it is too dwarf to take DBH and too irregular in base to take Girth at a fixed height. Linear, non-linear and logarithmic regression techniques were tried to determine the best regression model to estimate the above-ground biomass of stem, branch and leaf. A total of 186 regression equations were generated from the combination of independent variables. Best fit regression equations were determined by examining co-efficient of determination (R2), co-efficient of variation (CV), mean-square of the error (MSerror), residual mean error (Rsme), and F-value. Multiple linear regression models showed more efficient over other types of regression equation. The performance of regression equations was increased by inclusion of GMH as an independent variable along with total height and GCH.     

Functions for estimating belowground and whole tree biomass of birch in Norway

Obtaining accurate estimates of national belowground and whole tree biomass is important to better understand the global carbon cycle and to quantify biomass stocks and changes. However, the availability of individual tree belowground biomass functions is generally low due to the difficulty of extracting roots. Allometric birch (Betula pubescens Ehrh. and Betula pendula Roth) biomass functions were derived from 67 trees for belowground and whole tree biomass using diameter at breast height (dbh) and height as the independent variables. The sampled trees spanned a dbh range from 4.0 to 45.5?cm and the functions provided a good fit to the data (RMSE?=?14.2?kg for BG and 40.7?kg for whole tree with dbh as predictor). Belowground, total stem, live crown, and dead branch biomass comprised 29.2%, 52.2%, 18.1%, and 0.5% of the whole tree biomass, respectively. Observed root-to-shoot ratios were between 0.21 and 0.88 with a mean of 0.42. Comparisons with existing belowground birch biomass functions from Fennoscandia indicated considerable differences in estimates between existing functions. The derived data-set for belowground birch biomass is the largest in Fennoscandia and the developed functions are likely the best available for estimating national birch biomass stock and stock change in Norway.     

An allometric equation for estimating stem biomass of Acacia auriculiformis in the north-eastern region of Bangladesh

Tree biomass plays an important role in sustainable management and in estimating forest carbon stocks. The objective of this study was to select the best model for measuring stem biomass of Acacia auriculiformis in the study area. Data from five hillocks and 120 individual trees from each hillock were used in this study. Twelve different forms of linear, power and exponential equations were compared in this study to select the best model. Two models (VI and XI) were selected based on R ², adjusted R ², the Akaike information criterion, F-statistics and the five assumptions of linear regression. Model VI was discarded based on the Durbin-Watson value of autocorrelation of the residuals, then the ARIMA (2, 0, 1) model was used to remove the autocorrelation from the model and the final bias-corrected model XI was derived. The model was validated with a test data set having the same range of DBH and stem height of the training data set on the basis of linear regression, Morisita's similarity index, and t-test for mean difference between predicted and expected biomass. A comparison between the best logarithmic and non-linear allometric model shows that the non-linear model produces systematic biases and overestimates stem biomass for larger trees. The overall results showed that the bias-corrected logarithmic model XI can be used efficiently for estimating stem biomass of A. auriculiformis in the northeastern region of Bangladesh.     

Relationship between species diversity and biomass of eucalyptus plantation in Guangxi, south China

To reveal the relationship between species diversity and biomass in a eucalyptus (Eucalyptus urophylla × E. grandis) plantation located in the Dongmen State Forestry Farm of Guangxi, south China, 18 sample plots were established and the total biomass, arbor layer biomass and undergrowth biomass of communities were subsequently harvested. The results were as follows: 1) Species richness in eucalypt plantation had remarkable positive correlation with biomass of arbor layer, undergrowth and community (α = 0.001), its correlation coefficients were 0.6935, 0.7028 and 0.7106 respectively. 2) Leaf area index (LAI) had remarkable positive correlation with species richness and undergrowth biomass (α = 0.001). Its correlation coefficients were 0.7310 and 0.6856, respectively. 3) Arbor layer biomass had remarkable correlation with soil organic matter and hydrolysable N, its correlation coefficients was 0.6416 and 0.6203 respectively. Species richness had remarkable correlation with soil organic matter and correlation coefficient was 0.6359. Among them, the correlation was significant at the 0.1 level. Undergrowth biomass had little correlation with nine soil nutrients and correlation coefficients were under 0.4. To sum up, species diversity was advantageous to the promotion of the biomass of the eucalyptus plantation, and the variation of LAI and soil nutrient in small-scales could result in the difference of species diversity and biomass in different sample plots. Translater from Scientia Silvae Sinicae, 2008, 44(4): 14–19 [译自: 林业科学]     

沼液施肥对杨树林地土壤微生物量碳氮的影响

沼液是沼气发酵过后的液体残留物,是一种优质的有机肥料。研究了不同沼液施肥对杨树林地土壤微生物量碳氮的影响。结果表明:施用沼液可以提高土壤微生物量碳、氮的含量,微生物量碳、氮含量增加范围分别为4.29%~61.62%和6.08%~76.10%,土壤微生物量碳氮含量随沼液施用量增加逐渐提高。土壤微生物量碳氮呈正相关。土壤微生物量碳氮比随沼液施用量增加逐渐下降,其变化范围为9.92~10.81,土壤微生物量碳氮比与微生物量碳、氮含量负相关。     

桂西北西南桦人工林生长规律和生物生产力

以广西天峨县林朵林场12年生西南桦人工林为研究对象,研究其生长过程和生物生产力特征。结果表明:西南桦在桂西北具有较强的生长适应性,12年生平均胸径(去皮)、平均树高和平均蓄积量分别达到15.6 cm,16.8 m,170.10 m3/hm2;西南桦树高和胸径生长均以前5 a最快,随后随林龄的增长而下降;材积生长在8年生时达到峰值,之后开始下降但仍然保持较高的年生长量。12年生西南桦人工林林分生物量为130.86 t/hm2,其中乔木层、灌木层、草本层和凋落物层生物量依次为122.38,2.35,1.87和4.26 t/hm2,分别占93.52%,1.80%,1.43%和3.26%。林分乔木层年净生产力为10.20 t/(hm2·a),不同器官净生产力大小次序为树干、树叶、树枝、树根、树皮。     

Allometric models for estimation of aboveground biomass of Gmelina arborea Roxb. in pulpwood plantations of Bangladesh

Gmelina arborea Roxb. is a fast-growing, deciduous tree species native to Bangladesh. It has been widely planted since 1992 for commercial production of pulpwood in hilly areas of Bangladesh. The purpose of this study was to derive well-fitting allometric models for estimation of aboveground biomass, and carbon and nutrient (nitrogen, phosphorus and potassium) stocks in G. arborea to ensure sustainable production and management of this species. Eight linear models with 64 regression equations were tested for estimation of aboveground biomass, carbon and nutrient stocks in different parts (leaves, branches, bark and stem) of the plant. The best-fitting allometric models were selected in accordance with various relevant statistical criteria.     

Estimation of shoot biomass productivity in Estonian Salix plantations

Shoot biomass production was estimated in two Estonian short rotation forest (SRF) plantations during the first rotation cycle (1994–1997). The plantations were established with six clones of Salix viminalis and one clone of Salix dasyclados in 1993. The plantation, located on well-composed organic soil, was characterised by higher productivity (6.2 t DM ha⁻¹ per year) compared with the plantation on poor mineral soil (5.2 t DM ha⁻¹ per year). Fertilisation of the latter plantation increased its productivity to 11.0 t DM ha⁻¹ per year, which is the value close to a predicted maximum for Swedish climatic conditions. In fertilised plots, clone 81090 of S. dasyclados was characterised by the highest productivity among all clones, but also by high stool mortality. Clones 78021 and 78183 of S. viminalis had the most stable and relatively high productivity and can therefore be recommended as promising planting material for SRF in Estonia.

When estimating production, the use of proper allometric relations between shoot dry weight and diameter is of crucial importance. Additional measurements on 1-year-old shoots in 1998 showed that besides shoot age also clone and fertilisation are significant factors influencing allometric relations. The dry weight of fertilised shoots was about 10% lower than that of non-fertilised shoots of the same height and diameter. Older shoots were heavier than younger shoots with a similar diameter.     

Forest natural regeneration and biomass production after slash and burn in a seasonally dry forest in the Southern Brazilian Amazon

This study estimates the aboveground biomass accumulation after forest clearing and slash burning and describes the structure and successional development of the secondary forest in the seasonally dry southern Amazon. The original burn study was conducted in four land clearings in 1997, 1998, and 1999. The size of the clearings varied from 1 to 9 ha. The native forest was felled, allowed to dry for approximately three months and then burned by the end of the dry season. A census was conducted in the central 1-ha forest on each site prior to the area's felling and burn. The aboveground biomass (AGB) and structure were similar to other primary tropical forests. However, the high density of Cecropia spp. before the forest felling and burn treatment indicates past low intensity disturbances. Seven and eight years after the fire, the fallow forests were still in an early successional stage dominated by Cecropia spp. The four areas had a high biomass accumulation during the studied period, varying from 7.5 to 15.0 Mg ha⁻¹ year⁻¹. The lower biomass accumulation in one plot was an effect of a higher fire severity, produced by the one-year difference in time between slash and burn of the forest, slowing the natural regeneration of Cecropia spp. The time needed for this forest to recover to the pre-fire AGB levels ranged from 20 to 30 years, assuming the current AGB accumulation rates are maintained. Considering these results, the maintenance of regenerating secondary forests in the Amazon would be a significant contribution to soil and watershed protection, minimizing biodiversity losses and perhaps mitigating climatic changes effects in the region.     

连栽对巨尾桉人工林生物量和生产力的影响

对不同连栽代数的巨尾桉人工林的生物量和生产力进行研究。按径级标准木法,测定3年生不同连栽代数的巨尾桉人工林生物量,建立其估算模型,计算出3年生不同连栽代数巨尾桉人工林分的生物量和生产力。结果表明：第1,2,3代巨尾桉人工林年生物量分别为37.81,37.02,26.59 t/ hm2;林分年净生产力分别为12.60,12.34,8.86 t/（hm2·a）;干材年生产力分别为6.12,6.14,4.33 t/（hm2·a）。随着连栽代数的增加,林分的生物量和生产力下降趋势不明显,第2代林干材生产力高于第1,3代林。     

Additive prediction of aboveground biomass for Pinus radiata (D. Don) plantations

A general and two country-specific systems of additive equations were developed to predict aboveground biomass of Pinus radiata plantations from stand variables that are routinely measured in inventory plots and predicted by conventional growth and yield models. The data for this work consisted of 319 plot-based biomass estimates that were derived from individual tree biomass equations developed in situ. These plot-based biomass estimates were compiled from studies reported in the forestry and ecological literature since 1960 and also from personal communications. They represent more than 60 sites worldwide with a majority in Australia and New Zealand. The systems of additive biomass equations developed from these data provide an alternative and addition to the current methods of estimating the aboveground biomass of P. radiata plantations. They also provide a direct linkage between forest inventory measures, outputs from conventional growth and yield models and biomass and carbon stock estimates at the same spatial scale. This direct linkage provides a new basis for scaling to a remote sensing image from which biomass and carbon stocks across the landscape can be mapped. Comparisons of prediction accuracies between this approach and other methods such as scaling up from individual tree biomass estimates and biomass expansion factors highlighted considerable methodological differences in the estimates of aboveground biomass and associated uncertainties over a range of stand age and conditions. These differences should be carefully evaluated before adopting a particular method to estimate aboveground biomass and carbon stocks of P. radiata plantations at a local, regional or national scale.     

不同林龄阶段杉木人工林生物量和碳储量的分布特征

通过对湖南省绥宁县堡子岭国有林场4个不同林龄阶段杉木人工林的调查,研究了不同林龄阶段杉木人工林生物量和碳储量的分布特征.结果表明:不同林龄阶段杉木林单株各器官之间存在极显著性差异(P<0.001),杉木林及单株各器官生物量和碳储量随着林龄的增长而增加,树干、树根和树枝在碳累积方面优势较大,成熟林和近熟林的乔木层碳储量较...     

Aboveground biomass of three conifers in the Qianyanzhou plantation, Jiangxi Province, China

Regressive models of the aboveground biomass for three conifers in subtropical China—slash pine (Pinus elliottii), Masson pine (P. massoniana) and Chinese fir (Cunninghamia lanceolata)—were established. Regression analysis of leaf biomass and total biomass of each branch against branch diameter (d), branch length (L), d ³ and d ² L was conducted with functions of linear, power and exponent. A power law equation with a single parameter (d) was proved to be better than the rest for Masson pine and Chinese fir, and a linear equation with parameter (d ³) is better for slash pine. The canopy biomass was derived by adopting the regression equations to all branches of each individual tree. These kinds of equations were also used to fit the relationship between total tree biomass, branch biomass, foliage biomass and tree diameter at breast height (D), tree height (H), D ³ and D ² H, respectively. D ² H was found to be the best parameter for estimating total biomass. However, for foliage biomass and branch biomass, both parameters and equation forms showed some differences among species. Correlations were highly significant (P<0.001) for foliage biomass, branch biomass and total biomass, among which the equation of the total biomass was the highest. With these equations, the aboveground biomass of Masson pine forest, slash pine forest and Chinese fir forest were estimated, in addition to the allocation of aboveground biomass. The above-ground biomass of Masson pine forest, slash pine forest and Chinese fir forest was 83.6, 72.1 and 59 t/hm² respectively, and the stem biomass was more than the foliage biomass and the branch biomass. The underground biomass of these three forests which estimated with others’ research were 10.44, 9.42 and 11.48 t/hm², and the amount of carbon-fixed were 47.94, 45.14 and 37.52 t/hm², respectively. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(8): 1382–1388 [译自: 应用生态学报]     

Estimating biomass and macronutrient content of some commercially important plantation species in South Africa

The removal of biomass, in any combination of stemwood, bark or branch harvesting, can cause a significant increase in nutrient loss from commercial timber plantations. Ensuring long-term site productivity of forest plantations is a key issue for forestry management. Managers need to secure a continued supply of tree biomass components, while understanding the impact of various harvesting operations on plantation nutrient reserves. It is imperative to quantify the biomass and nutrient stocks and their removal during silvicultural operations, such as harvesting, burning and various forms of site preparation. At present, there are no simple methods to estimate inherent site nutrient reserves, or nutrient gains through processes such as atmospheric deposition or rock weathering, or the quantities of nutrients lost through silvicultural operations (harvesting, burning and site preparation). The aim of this work was to construct simple multipliers that can be used in conjunction with plantation timber volumes to estimate stem, branch and bark biomass and nutrient contents. The multipliers were developed from data existing for Eucalyptus spp., Pinus patula and Acacia mearnsii stands throughout the summer rainfall region of South Africa and Swaziland. Due to limited data unique nutrient multipliers were not developed for each productivity range and the multipliers were assumed to be consistent across all productivity ranges. The ratios may underestimate on fertile sites where luxury consumption of nutrients may occur and not accurately predict where stand management practices have altered wood density, allometry or canopy architecture. Although genus and species impacted on the quantity of nutrients held in the plantation biomass, productivity and harvesting intensity were the biggest driver of nutrient removal. Although the multipliers developed here have value in creating a general estimate of nutrient content they are from a limited dataset and need to be expanded upon across species, site and age ranges before being able to precisely estimate nutrient contents. Although harvesting is a major component of nutrient export, natural additions and losses of nutrients, and site nutrient reserves need to be known in order to gain a complete understanding of the impact of nutrient loss on site nutrient reserves.     

不同林分密度楠木人工林生物量初步研究

对福建省顺昌埔上国有林场不同林分密度的37年生楠木人工纯林的生物量及分配进行调查和分析,结果表明:低密度林分(1 500~1 650株.hm-2)楠木单株标准木的平均生物量为56.52 kg.株-1,是高密度林分(2200~2400株.hm-2)的1.39倍。单株标准木各器官的平均生物量均随林分密度的增加而减小;楠木人工林乔木层生物量随林分密度的增加而增大,乔木层总平均生物量在干材中的分配基本不受林分密度的影响(低密度的为53.59%,高密度的为53.72%),在根、皮中的分配比例随林分密度的增大略有增大,而在枝与叶中的分配比例则随密度的增加而下降。各器官生物量均存在干材>根>皮>枝>叶这一规律,其中干材生物量占总物量的比例最大,均超过了50%,最大达到61.11%。     

洞庭湖区短轮伐期杨树人工林生物量调查

为实现杨树人工林的分类经营,提高杨树人工林的经济效益,采用标准木法对洞庭湖区杨树人工林中不同径阶林木生物量进行了测定。结果表明:7年生杨树人工林的径阶集中分布在14~20 cm。不同径阶杨树单株不同器官生物量均遵循树干树枝树根(含桩)树皮树叶的分配规律;随着径阶的增长,树干在单株、林分内所占的比例均呈增长趋势;小于5 cm的主干、树枝和根的生物量与地上部分的胸径和树高均成幂函数关系,相关系数分别为0.839 4、0.940 5和0.994 7。     

Root biomass and productivity in dominant plantation populations in the mountainous area in western Sichuan

This study investigated root biomass and productivity in dominant populations in western Sichuan, China. A total of 4 plots (Picea balfouriana plantation for 22 age in Maerkang, 9 trees, mean DBH of population for 10.4 cm and height for 10.5 m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0 cm and height for 13.8 m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1 cm and height for 11.9 m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5 m; a 20 m×25 m plot located on each of the 4 types in western Sichuan, China) were randomly selected and excavated to a depth of 60 cm for each of the 4 plantation types. To estimate the root biomass of an individual tree using D ² H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm² varied among plantation population types following the order: L. kaempferi (37.832 t/hm²) > A. fabri (24.907 t/hm²) > L. maxteriana (18.320 t/hm²) > P. balfouriana (15.982 t/hm²). The biomass fractions of a given root size class compared to the total root biomass differed among plantation population types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g., 97.88% for P. balfouriana population, 96.78% for L. maxteriana, 95.65% for A. fabri, and 99.72 for L. kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for P. balfouriana, 77.13% for L. maxteriana, 65.02% for A. fabri and 80.66% for L. kaempferi, respectively. The root allocation in the 0–20, 20–40, and 40–60 cm soil layers gave ratios of 34:12:1 for P. balfouriana, 24:6:1 for L. maxteriana, 15:7:1 for A. fabri, and 64:4:1 for L. kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/(hm²·m) for P. balfouriana, 8.230 t/hm²·m) for L. maxteriana, 24.546 t/(hm²·m) for A. fabri, and 13.211 t/(hm²·m) for L. kaempferi population, respectively. The root biomass productivity was found to be 0.57 t/(hm²·year) for P. balfouriana, 0.83 t/(hm²·year) for L. maxteriana, 0.71 t/(hm²·year) for A. fabri and 1.64 t/(hm²·year) for L. kaempferi population, respectively. __________ Translated from Acta Ecologica Sinica, 2006, 26(2): 542–551 [译自: 生态学报, 2006, 26(2): 542–551]