Estimating net primary productivity of Chinese pine forests based on forest inventory data

Forest inventory data (FID) include forest resources informationat large spatial scale and long temporal scale. They are importantdata sources for estimating forest net primary productivity(NPP) and carbon budget at landscape and regional scales. Inthis study, more than 100 datasets of biomass, volume, NPP andstand age for Chinese pine forests (Pinus tabulaeformis) fromthe literature were synthesized to develop regression equationsbetween biomass and volume, and between NPP and biomass as wellas stand age. Using these regression equations and the fourthFID surveyed by the Forestry Ministry China from 1989 to 1993,NPP values of Chinese pine forests were estimated. The meanNPP of Chinese pine forests was 4.35 Mg ha^–1 yr^–1.NPP varied widely among provinces, ranging from 1.5 (Neimenggu)to 13.73 Mg ha^–1 yr^–1 (Guizhou). Total NPP of Chinesepine was 10.87 Tg yr^–1 (1 Tg = 10¹² g). NPP values ofChinese pine forests were not distributed evenly across differentprovinces in China. This study may be useful not only for estimatingforest carbon of other forest types but also for evaluatingterrestrial carbon balance at regional and global levels.     

Assessment of biomass and net primary productivity of a dry tropical forest using geospatial technology

This study quantifies biomass, aboveground and belowground net productivity, along with additional environmental factors over a 2-3 year period in Barnawapara Sanctuary of Chhattisgarh, India through satellite remotesensing and GIS techniques. Ten sampling quadrates20×20, 5×5 and 1×1 m were randomly laid for overstorey (OS), understorey (US) and ground vegetation(GS), respectively. Girth of trees was measured at breast height and collar diameters of shrubs and herbs at 0.1 m height. Biomass was estimated using allometric regression equations and herb biomass by harvesting. Net primary productivity (NPP) was determined by Ssumming biomass increment and litter crop values. Aspect and slope influenced the vegetation types, biomass and NPP in different forests. Standing biomass and NPP varied from 18.6 to101.5 Mg ha^-1 and 5.3 to 12.7 Mg ha^-1 a^-1, respectively,in different forest types. The highest biomass was found in dense mixed forest, while net production recoded in Teak forests. Both were lowest in degraded mixed forests of different forest types. OS, US and GS contributed 90.4, 8.7and 0.7%, respectively, for the total mean standing biomass in different forests. This study developed spectral models for the estimation of biomass and NPP using Normalized Difference Vegetation Index and other vegetation indices.The study demonstrated the potential of geospatial tools for estimation of biomass and net productivity of dry tropical forest ecosystem.     

Estimating and mapping forest biomass in northeast China using joint forest resources inventory and remote sensing data

Being able to accurately estimate and map forest biomass at large scales is important for a better understanding of the terrestrial carbon cycle and for improving the effectiveness of forest management. In this study, forest plot sample data, forest resources inventory(FRI) data, and SPOT Vegetation(SPOT-VGT) normalized difference vegetation index(NDVI) data were used to estimate total forest biomass and spatial distribution of forest biomass in northeast China(with 1 km resolution). Total forest biomass at both county and provincial scales was estimated using FRI data of 11 different forest types obtained by sampling 1156 forest plots, and newly-created volume to biomass conversion models. The biomass density at the county scale and SPOT-VGT NDVI data were used to estimate the spatial distribution of forest biomass. The results suggest that the total forest biomass was 2.4 Pg(1 Pg = 10~(15) g), with an average of 77.2 Mg ha~(-1), during the study period. Forests having greater biomass density were located in the middle mountain ranges in the study area. Human activities affected forest biomass at different elevations, slopes and aspects. The results suggest that the volume to biomass conversion models that could be developed using more plot samples and more detailed forest type classifications would be better suited for the study area and would provide more accurate biomass estimates. Use of both FRI and remote sensing data allowed the down-scaling of regional forest biomass statistics to forest cover pixels to produce a relatively fineresolution biomass map.     

基于CASA模型的瓦屋山林场植被净初级生产力估算

在地理信息系统和遥感技术支持下,利用改进的CASA模型,并结合Landsat TM遥感影像、气象数据和林班数据,估算出瓦屋山林场2008—2009年的植被净初级生产力(PNPP),并通过实测植被生物量和生产力的关系,验证CASA模型在研究地区估算结果。结果表明:CASA模型估测植被PNPP与实测结果有较好的一致性,能够适用于瓦屋山林场植被净生产力估算;CASA模型估算结果主要植被类型年均PNPP区别明显,从高到低依次是:中国山杨、麻栎、板栗、马尾松、湿地松、灌木、杉木和池杉;瓦屋山林场植被PNPP季节变化显著,夏季贡献率最大,其次是春季和秋季,冬季最少,主要由于不同季节环境因素不同,其中又以太阳辐射最为重要。     

Tree diversity and timber productivity in planted forests: Pinus patula versus mixed cloud forest species

New Forests - Planted forests contribute to maximizing timber production but their role as valuable habitat for diversity is of increasing concern, particularly in tropical montane cloud forest...     

Estimation of aboveground biomass in mangrove forests using high-resolution satellite data

Mangroves play important roles in providing a range of ecosystem services, mitigation of strong waves, protection of coastlines against erosion, maintenance of water quality, and carbon sink in the context of global warming. For trees in mangrove forests in southern Ranong Province, Thailand, we investigated the allometric relationship between crown area derived from high-resolution satellite data and stem diameter and used the resulting model to estimate aboveground biomass. We used QuickBird panchromatic and multispectral data acquired for the study area on 15 October 2006 as the high-resolution satellite data. Individual tree crowns were extracted from the satellite image of panchromatic data by using the watershed method, and the species were identified by using the maximum-likelihood method for the multispectral data. Overall classification accuracy for species identification was 88.5 %. The biomass derived from our field survey was plotted against aboveground biomass in the sample plots, estimated from the QuickBird data. The regression line through the origin between the satellite-estimated biomass and biomass based on the field data had a slope of 1.26 (R ² = 0.65). Stand aboveground biomass estimated from the high-resolution satellite data was underestimated because of a lack of data on the biomass of suppressed trees and inappropriate segmentation of crowns of large trees into two or more trees.     

鄂尔多斯高原油蒿灌丛群落生物量和净初级生产力研究(英文)

应用标准株收获法对鄂尔多斯高原油蒿灌丛群落生物量和净初级生产力进行了一个生长季(6月~10月)的研究。结果表明:(1)生长季内不同月份之间相同株型单株油蒿地上和地下生物量差异不显著(p>0.1),而地上当年生部分生物量差异显著(p<0.01);(2)油蒿群落中,地上和地下总生物量为699.76~1246.40gm-2,年地上部分NPP值为224.09 gm-2y-1;(3)单株油蒿生物量和 NPP 与灌丛体积具有较好的相关性,应用幂指数方程能够达到较好的拟合效果。     

Variability in net primary production and carbon storage in biomass across Oregon forests—an assessment integrating data from forest inventories,intensive sites,and remote sensing

We used a combination of data from USDA Forest Service inventories, intensive chronosequences, extensive sites, and satellite remote sensing, to estimate biomass and net primary production (NPP) for the forested region of western Oregon. The study area was divided into four ecoregions differing widely in climatic conditions and management regime. The forest age distributions (as derived from inventory data) differed by ecozone with fewer old stands in the Coast Range and the East Cascades, and a relatively uniform distribution of ages from 0 to 815 in the Cascade Mountains. Age distributions also differed by land ownership, with fewer old stands on non-federal lands than on national forest lands. Estimated biomass increased rapidly in early stand development and tended to stabilize after about 200 years. Peak biomass in the semi-arid East Cascades was about one-third that of the other ecoregions (median biomass at asymptote ∼9 and ∼25 kg C m⁻², respectively). The timing and magnitude of maximum net primary production also varied by ecoregion, with the high productivity Coast Range forests reaching a maximum NPP before 30 years of age (median ∼1 kg C m⁻² y⁻¹), and the low productivity East Cascades reaching a maximum NPP between 80 and 100 years (median ∼0.3 kg C m⁻² y⁻¹). Productivity was generally lower in older stands with the exception of the East Cascades ecoregion where, contrary to the paradigm of age-related decline in forest growth, the oldest stands had the highest NPP. The East Cascades also differed from the other ecoregions in that the proportion of NPP allocated belowground decreased rather than increased with stand age. This study demonstrates the value of combining data from intensive and extensive measurement sites for improved estimates of carbon stocks and fluxes as well as improved parameterization of process models used in scaling carbon flux over broad regions.     

Below- and above-ground biomass and net primary production in a paleotropical natural forest (Sulawesi,Indonesia) as compared to neotropical forests

Data on the biomass and productivity of southeast Asian tropical forests are rare, making it difficult to evaluate the role of these forest ecosystems in the global carbon cycle and the effects of increasing deforestation rates in this region. In particular, more precise information on size and dynamics of the root system is needed. In six natural forest stands at pre-montane elevation (c. 1000 m a.s.l.) on Sulawesi (Indonesia), we determined above-ground biomass and the distribution of fine (d < 2 mm) and coarse roots (d > 2 mm), estimated above- and below-ground net production, and compared the results to literature data from other pre-montane paleo- and neotropical forests. The mean total biomass of the stands was 303 Mg ha⁻¹ (or 128 Mg C ha⁻¹), with the largest biomass fraction being recorded for the above-ground components (286 Mg ha⁻¹) and 11.2 and 5.6 Mg ha⁻¹ of coarse and fine root biomass (down to 300 cm in the soil profile), resulting in a remarkably high shoot:root ratio of c. 17. Fine root density in the soil profile showed an exponential decrease with soil depth that was closely related to the concentrations of base cations, soil pH and in particular of total P and N. The above-ground biomass of these stands was found to be much higher than that of pre-montane forests in the Neotropics, on average, but lower compared to other pre-montane forests in the Paleotropics, in particular when compared with dipterocarp forests in Malesia. The total above- and below-ground net primary production was estimated at 15.2 Mg ha⁻¹ yr⁻¹ (or 6.7 Mg C ha⁻¹ yr⁻¹) with 14% of this stand total being invested below-ground and 86% representing above-ground net primary production. Leaf production was found to exceed net primary production of stem wood. The estimated above-ground production was high in relation to the mean calculated for pre-montane forests on a global scale, but it was markedly lower compared to data on dipterocarp forests in South-east Asia. We conclude that the studied forest plots on Sulawesi follow the general trend of higher biomasses and productivity found for paleotropical pre-montane forest compared to neotropical ones. However, biomass stocks and productivity appear to be lower in these Fagaceae-rich forests on Sulawesi than in dipterocarp forests of Malesia.     

基于森林资源二类调查数据的江苏省林地落界工作主要问题处理探析

森林资源二类调查以普查森林资源为目的,而林地落界以落实规划林地为宗旨,2者之间的目的、要求和标准存在一定区别.文章分析2者数据之间衔接的5个方面问题,并以ArcGIS为平台,提出了衔接2者数据的具体方法.     

Above- and belowground biomass and net primary production in a 73-year-old Scots pine forest

We estimated above- and belowground biomass and net primary production (NPP) of a 73-year-old Scots pine (Pinus sylvestris L.) forest stand in the Belgian Campine region. Total biomass for the stand was 176 Mg ha(-1), of which 74.4% was found in stems. The root system contained 12.6% of total biomass, most of it in coarse roots (> 5 mm). Fine roots (< 5 mm) comprised only about 1.7% of total biomass, and more than 50% of fine root biomass was retrieved in the litter layer and the upper 15 cm of the mineral soil. The ratio of belowground biomass to aboveground biomass was 0.14, which is lower than that of other Scots pine forests and other coniferous forests. Between 1995 and 2001, mean annual NPP was 11.2 Mg ha(-1) year(-1), of which 68.7% was allocated to aboveground compartments. Stems, needles and cones made relatively high contributions to total NPP compared with branches. However, branch NPP was possibly underestimated because litterfall of big branches was neglected. The proportion of total NPP in belowground components was 31.3%. Coarse root NPP (2% of total) was low compared with its biomass. Fine root NPP was 3.3 Mg ha(-1) year(-1), representing about 29.5% of total NPP; however, the estimate of fine root NPP is much more uncertain than NPP of aboveground compartments. The ratio NPP/GPP (gross primary production) was 0.32, which was low compared with other coniferous forests.     

Estimation of biomass and carbon stocks in plants,soil and forest floor in different tropical forests

An accurate characterization of tree carbon (TC), forest floor carbon (FFC) and soil organic carbon (SOC) in tropical forest plantations is important to estimate their contribution to global carbon stocks. This information, however, is poor and fragmented. Carbon contents were assessed in patula pine (Pinus patula) and teak (Tectona grandis) stands in tropical forest plantations of different development stages in combination with inventory assessments and soil survey information. Growth models were used to associate TOC to tree normal diameter (D) with average basal area and total tree height (H_T), with D and H_T parameters that can be used in 6–26 years old patula pine and teak in commercial tropical forests as indicators of carbon stocks. The information was obtained from individual trees in different development stages in 54 patula pine plots and 42 teak plots. The obtained TC was 99.6 Mg ha⁻¹ in patula pine and 85.7 Mg ha⁻¹ in teak forests. FFC was 2.3 and 1.2 Mg ha⁻¹, SOC in the surface layer (0–25 cm) was 92.6 and 35.8 Mg ha⁻¹, 76.1 and 19 Mg ha⁻¹ in deep layers (25–50 cm) in patula pine and teak, respectively. Carbon storage in trees was similar between patula pine and teak plantations, but patula pine had higher levels of forest floor carbon and soil organic carbon. Carbon storage in trees represents 37 and 60% of the total carbon content in patula pine and teak plantations, respectively. Even so, the remaining percentage corresponds to SOC, whereas FFC content is less than 1%. In summary, differences in carbon stocks between patula pine and teak trees were not significant, but the distribution of carbon differed between the plantation types. The low FFC does not explain the SOC stocks; however, current variability of SOC stocks could be related to variation in land use history.     

Estimation of shrub biomass by airborne LiDAR data in small forest stands

The presence of shrub vegetation is very significant in Mediterranean ecosystems. However, the difficulty involved in shrub management and the lack of information about behavior of this vegetation means that these areas are often left out of spatial planning projects. Airborne LiDAR (Light Detection And Ranging) has been used successfully in forestry to estimate dendrometric and dasometric variables that allow to characterize forest structure. In contrast, little research has focused on shrub vegetation. The objective of this study was to estimate dry biomass of shrub vegetation in 83 stands of radius 0.5 m using variables derived from LiDAR data. Dominant species was Quercus coccifera, one of the most characteristic species of the Mediterranean forests. Density of LiDAR data in the analyzed stands varied from 2 points/m² to 16 points/m², being the average 8 points/m² and the standard deviation 4.5 points/m². Under these conditions, predictions of biomass were performed calculating the mean height, the maximum height and the percentile values 80th, 90th, and 95th derived from LiDAR in concentric areas whose radius varied from 0.50 m to 3.5 m from the center of the stand. The maximum R² and the minimum RMSE for dry biomass estimations were obtained when the percentile 95th of LiDAR data was calculated in an area of radius 1.5 m, being 0.48 and 1.45 kg, respectively. For this radius, it was found that for the stands (n = 39) where the DTM is calculated with high accuracy (RMSE lower than 0.20 m) and with a high density of LiDAR data (more than 8 points/m²) the R² value was 0.73. These results show the possibility of estimating shrub biomass in small areas when the density of LiDAR data is high and errors associated to the DTM are low. These results would allow us to improve the knowledge about shrub behavior avoiding the cost of field measurements and clear cutting actions.     

Aboveground biomass and net primary production of semi-evergreen tropical forest of Manipur, north-eastern India

The aboveground biomass dynamics and net primary productivity were investigated to assess the productive potential of Dipterocarpus forest in Manipur, Northeast India. Two forest stands (stand I and II) were earmarked randomly in the study site for the evaluation of biomass in the different girth classes of tree species by harvest method. The total biomass was 22.50 t·ha-1 and 18.27 t·ha-1 in forest stand I and II respectively. Annual aboveground net primary production varied from 8.86 to 10.43 t·ha-1 respectively in two forest stands (stand I and II). In the present study, the values of production efficiency and the biomass accumulation ratio indicate that the forest is at succession stage with high productive potential.     

Organic carbon stocks and stock changes of forest biomass in Belgium derived from forest inventory data in a spatially explicit approach

? Carbon sequestration in forest ecosystems is an important though still uncertain process in the global greenhouse gas balance.

? We computed biomass organic carbon (BOC) stocks of spatially explicit forested landscape units (LSU) in Belgium based on data collected in the regional forest inventories of 1984 (Wallonia region only) and 2000 (Wallonia and Flanders). C stock changes between 1984 and 2000 were estimated for Wallonia.

? The total BOC pool stored in Belgian forests in 2000 amounts to 57.8 Mt C in 6222 km², or 10.0 kg C m^?2 in broadleaf, 9.5 kg C m^?2 in coniferous and 8.7 kg C m^?2 in mixed forest. Based on previous soil organic carbon (SOC) analysis for the same LSU, BOC and SOC stock per LSU appeared only weakly correlated. The total BOC sequestration between 1984 and 2000 equals 5.7 Mt C over an area of 5 107 km², resulting in a flux of 0.07 kg C m^?2 y^?1. The BOC content of broadleaf forest in Wallonia increased with 6%, of coniferous forest with 32% and of mixed forest with 11%.

? The observed regional differences in BOC stocks and in BOC sequestration rates are explained by the forest age-class distribution and site productivity. The strength of the spatially explicit approach lies in the fact that BOC and SOC data originating from diverse sampling strategies can be combined for spatial or temporal comparison of C stocks.

     

Predicting natural forest regeneration: a statistical model based on inventory data

Regenerating forest stands through natural seedlings is a commonly accepted silvicultural strategy in Germany. To plan for and increase natural regeneration within a given stand, foresters must be able to estimate whether the stand in its current state can produce sufficient saplings to replace the overstory. In this paper, we present two approaches to building a model that can estimate the probability of natural regeneration occurring, based on variables that are typically readily available from forest inventories. To estimate model parameters we used the large database of the third National Forest Inventory, which covers forest stands and sites across the whole of Germany, as well as weather and soil data. We examined how these variables impact the emergence of natural regeneration, ultimately fitting a model that can predict the occurrence of natural regeneration in 72% of cases. The influence of the variables on the predicted occurrence of natural regeneration was mixed, with most stand variables contributing only minor impact and most likely influencing natural regeneration via complex interactions. The exception was vertical structure (number of stand layers), which accounted for a large proportion of the goodness-of-fit of the model. An important finding was that forest ownership structure is a key variable for the prediction of the presence of regeneration. Data from this study support the assumption that some forest owners manage their stands in a way that fosters natural regeneration.     

Trends in bole biomass accumulation, net primary production and tree mortality in Pseudotsuga menziesii forests of contrasting age

Although it is generally accepted that the rate of accumulation of biomass declines as forests age, little is known about the relative contributions to this decline of changes in net primary production (NPP) and tree mortality. We used 10-15 years of observations of permanent plots in three small watersheds in and near the H.J. Andrews Experimental Forest, Oregon, to examine these issues. The three watersheds are of similar elevation and potential productivity and support young (29 years at last measurement), mature (approximately 100 years) and old (approximately 400 years) forest dominated by Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. Accumulation of tree bole biomass was greatest in the young stand, reaching approximately 7 Mg ha-1 year-1 in the last measurement interval. Bole biomass accumulation was relatively constant (approximately 4-5 Mg ha-1 year-1) in the mature stand, and there was no net accumulation of bole biomass in the old-forest stand. The NPP of boles increased with time in the young stand, from approximately 3 to approximately 7 Mg ha-1 year-1, but was nearly constant in the mature and old-forest stands, at approximately 6 and 3-4 Mg ha-1 year-1, respectively. Mortality increased slowly in the young stand (from < 0.1 to 0.3 Mg ha-1 year-1), but fluctuated between 1-2 and 2-6 Mg ha-1 year-1 in the mature and old-forest stands, respectively. Thus, declining biomass accumulation with stand age reflects, in approximately equal amounts, both decreasing NPP and increasing mortality.     

Modeling topographic effects on net ecosystem productivity of boreal black spruce forests

Current regional estimates of net primary productivity (NPP) of boreal black spruce overlook the large variation in NPP caused by small-scale topographic effects on soil water, temperature and nutrient availability. Topographic effects on black spruce NPP could likely be modeled by simulating the lateral and vertical movement of water, and its effects on soil nutrient transformation and uptake, through three-dimensional watersheds defined by aspects and slopes of their topographic positions. To examine this likelihood, the ecosystem model 'ecosys' was run for 120 years on a transect that included upper- and lower-slope positions and a basin in which a basal water table was set 0.5 m below the soil surface. For the run, we used soil properties and weather conditions recorded at the 115-year-old BOREAS Southern Old Black Spruce site. Short-term model performance was tested by comparing diurnal and annual carbon (C) transfers simulated under 1994 weather conditions during the 115th year of the model run with those measured at this site during 1994 by eddy covariance, surface chambers and allometry. After 115 years, annual spruce NPP simulated at the upper-slope positions was twice that at the basin (350 versus 170 g C m-2), whereas accumulated wood C was almost three times as large (6.8 versus 2.4 kg C m-2). In the model, increases in NPP and wood growth in upper-slope positions were caused by lower soil water contents, higher soil temperatures, and more rapid O2 uptake that accelerated heterotrophic respiration and hence nutrient mineralization and uptake. Modeled differences in wood growth with topographic position were quantitatively consistent with measurements of boreal black spruce at several research sites differing in water table depth. Modeled differences also agreed with differences in wood growth rates derived from allometric measurements at boreal black spruce sites differing in productivity indices as a result of differences in subsurface hydrology. The magnitude of these differences clearly indicates the importance of accounting for subsurface hydrology in regional estimates of boreal forest productivity.     

Comparison of temporal and spatial changes in three major tropical forests based on MODIS data

Numerous studies have shown that intact tropical forests account for half of the total terrestrial sink for anthropogenic carbon dioxide.Here,we analyzed and compared changes in three main tropical forest regions from 2000 to 2014,based on time-series analysis and landscape metrics derived from moderate-resolution imaging spectroradiometer data.We examined spatialpattern changes in percentage of tree cover and net primary production(NPP)for three tropical forest regions—Amazon basin,Congo basin,and Southeast Asia.The results show that:the Amazon basin region had the largest tropical forest area and total NPP and a better continuity of TC distribution;the Southeast Asia region exhibited a sharp decrease in NPP and had comparatively separate spatial patterns of both TC and NPP;and the Congo basin region exhibited a dramatic increase in NPP and had better aggregation of forest NPP distribution.Results also show that aggregative patterns likely correlate with high NPP values.