Stand Biomass Research Articles

Plantation species-specific adjustment functions for the Forest Carbon Predictor in New Zealand

BackgroundNew Zealand’s planted forest area is dominated by radiata pine (90%), but also includes Douglas-fir (6%), and a range of minor species including eucalypts and cypress. Carbon sequestration in planted forest is currently estimated using yield tables from the Forest Carbon Predictor (FCP), which was designed to estimate dry matter in live biomass and dead organic matter pools in radiata pine stands. Stand variables required as model inputs include basal area, mean top height, stocking, and tending regime. In addition, wood density needs to be measured or estimated. When the FCP is applied to plantation species other than radiata pine, dry matter estimates may need to be adjusted to remove bias.MethodsTo test for and remove bias, existing biomass studies were compiled and additional biomass data collected to fill gaps. Measured dry matter stock estimates were compared with predictions from the FCP model. Species assessed included Pseudotsuga menziesii (10 stands), Cupressus lusitanica (2), Eucalyptus regnans (7), E. nitens (5), E. saligna (7), E. botryoides (2), E. fastigata (2), and Acacia dealbata (2).ResultsStem bark and crown components were higher in Douglas-fir than predicted by the FCP, whereas crown components were appreciably lower in hardwood species than predicted. Root biomass estimates in Douglas-fir and hardwood species were similar to predictions from the FCP. Dead organic matter stock estimates were similar in Douglas-fir to predictions from the FCP. Dry matter predictions from the model were adjusted by species or species group, to help reduce model prediction error when the FCP is applied to these species. Model bias for Douglas-fir averaged 4.1% for aboveground live biomass, with a root mean square error of 12.9%. Model bias for hardwood species averaged − 0.11% for aboveground live biomass, with a root mean square error of 16.1%. Owing to data limitations, model bias was poorly estimated for dead organic matter pools.ConclusionsThis study has shown that forest carbon models that have been developed for well-studied plantation species can be adapted with some degree of certainty and applied to other species with suitable, albeit limited, biomass data in order to improve the accuracy of predictions of stand biomass and carbon sequestration.

Tree- and Stand-Level Biomass Estimation in a Larix decidua Mill. Chronosequence

Carbon pool assessments in forests is one of the most important tasks of forest ecology. Despite the wide cultivation range, and economical and traditional importance, the aboveground biomass of European larch (Larix decidua Mill.) stands is poorly characterized. To increase knowledge about forest biomass accumulation and to provide a set of tools for aboveground biomass estimation, we studied a chronosequence of 12 larch forest stands (7–120 years old). From these stands, we measured the biomass of 96 sample trees ranging from 1.9 to 57.9 cm in diameter at breast height. We provided age-specific and generalized allometric equations, biomass conversion and expansion factors (BCEFs) and biomass models based on forest stand characteristics. Aboveground biomass of stands ranged from 4.46 (7-year-old forest stand) to 445.76 Mg ha−1 (106-year-old). Stand biomass increased with increasing stand age, basal area, mean diameter, height and total stem volume and decreased with increasing density. BCEFs of the aboveground biomass and stem were almost constant (mean BCEFs of 0.4688 and 0.3833 Mg m−3, respectively). Our generalized models at the tree and stand level had lower bias in predicting the biomass of the forest stands studied, than other published models. The set of tools provided fills the gap in biomass estimation caused by the low number of studies on larch biomass, which allows for better estimation of forest carbon pools.

ESTIMASI BIOMASSA DAN AKUMULASI HARA TEGAKAN JATI (TECTONA GRANDIS L.F) DI TELUK PANDAN, KUTAI TIMUR, KALIMANTAN TIMUR

Biomass studies are important because they are closely related to other study interests. Estimation of the amount of forest stand biomass is highly relevant to the study of biogeochemical cycles. This study aims to determine the amount of biomass and macro nutrient content in teak stands. By calculating the biomass estimation and analyzing the nutrient content it will be known the amount of nutrient accumulation in biomass. The results of this study are: Total of teak stand biomass of 39,26 ton / ha, including stem component as much as 21,64 ton / ha (55%), branch + twig 11,79 ton / ha (30%), bark component 3.71 ton / ha (9%) and leaf component 2.13 ton / ha (5%). The highest N concentration of nutrients in leaf components, for the highest P in branches + twigs, whereas K, Ca and Mg were highest in the bark component. The highest accumulation of nutrient biomass is Ca (194.4 kg / ha), followed by K (189.7 kg / ha), P (92.4 kg / ha), N (53.5 kg / ha) and Mg (48.4 kg / ha).

ESTIMASI BIOMASSA DAN AKUMULASI HARA TEGAKAN JATI (TECTONA GRANDIS L.F) DI TELUK PANDAN, KUTAI TIMUR, KALIMANTAN TIMUR

Biomass studies are important because they are closely related to other study interests. Estimation of the amount of forest stand biomass is highly relevant to the study of biogeochemical cycles. This study aims to determine the amount of biomass and macro nutrient content in teak stands. By calculating the biomass estimation and analyzing the nutrient content it will be known the amount of nutrient accumulation in biomass. The results of this study are: Total of teak stand biomass of 39,26 ton / ha, including stem component as much as 21,64 ton / ha (55%), branch + twig 11,79 ton / ha (30%), bark component 3.71 ton / ha (9%) and leaf component 2.13 ton / ha (5%). The highest N concentration of nutrients in leaf components, for the highest P in branches + twigs, whereas K, Ca and Mg were highest in the bark component. The highest accumulation of nutrient biomass is Ca (194.4 kg / ha), followed by K (189.7 kg / ha), P (92.4 kg / ha), N (53.5 kg / ha) and Mg (48.4 kg / ha).

Biomass and carbon stocks in mangrove stands of Kadalundi estuarine wetland, south-west coast of India

Mangroves are keystone ecosystems which provide numerous environmental services. Mangroves assume significance as standing stores of sequestered atmospheric carbon and are therefore, important in the light of climate change mitigation. In this study, we attempted to assess the biomass of mangroves in the Kadalundi wetland, south-west coast of India and evaluated the potential of these mangroves to sequester and store carbon. The C-stocks of above-ground and root biomass were 83.32±11.06 t C ha-1 and 34.96±4.30 t C ha-1 respectively, while the C-stock in sediment was estimated to be 63.87±8.67 t C ha-1. The estimates of mean combined C-stocks in the mangrove biomass and sediment of Kadalundi shows that this estuarine mangrove wetland stored 182.15 t C ha-1, which was equivalent to 668.48 t CO2 ha-1. The mangroves which cover an area of 13.23 ha in the Kadalundi wetland is assumed to have a potential to sequester and store a substantial quantity of 2,409.84 t C which is equivalent to 8,844.11 t CO2. The study underscores the importance of these intertidal forests for climate change mitigation and stresses the importance of protecting the mangroves which provide many other important ecosystem services that benefit communities.

Net primary production in plantations of Pinus taeda and Eucalyptus cloeziana compared with a mountain miombo woodland in Mozambique

Planting monocultures of fast-growing non-native (exotic) species is one way to slow or reverse deforestation and forest degradation in tropical zones. This study compared the effects on total net primary production (NPP) of first-rotation monoculture (34-year-old) plantations of Pinus taeda and Eucalyptus cloeziana and adjacent mountain miombo woodland in Mozambique. Total NPP was defined as the sum of annual carbon (C) sequestration in total aboveground tree biomass, belowground coarse root biomass, fine roots (≤2 mm) and fine litterfall.Field measurements were conducted over one year in three 30 m × 30 m permanent sampling plots for each forest type and involved monitoring litterfall and fine root production using in-growth cores and stem diameter growth. Carbon increment in aboveground tree biomass and belowground coarse root biomass was determined using allometric equations, for P. taeda, E. cloeziana, and root-to-shoot ratio, for miombo woodland.Major findings were that total NPP in P. taeda (14.1 Mg C ha−1 yr−1) and E. cloeziana (19.7 Mg C ha−1 yr−1) stands was significantly higher than in miombo woodland stands (5.9 Mg C ha−1 yr−1). These differences were largely attributable to lower basal area and presumably lower leaf biomass in miombo stands. There were several indications that the miombo stands studied had been degraded by selective cutting and other forms of use of forest resources. The difference in total NPP was also reflected in differences in patterns of C sequestration. Carbon in litterfall was the largest component of total NPP in miombo stands (41%), whereas C increment in aboveground tree biomass was the largest component of total NPP in plantation stands (44% in P. taeda and 51% in E. cloeziana).If the aim of forest management is to increase NPP and C sequestration in biomass of degraded miombo stands, our results indicate that replacement with plantations of P. taeda or E. cloeziana can be a useful management option, provided that the plantations are protected from anthropogenic disturbances, particularly fire. However, this aim needs to be balanced against other environmental aims and the socio-economic needs of local communities, since miombo woodland provides a wide range of unique economic, social and ecological benefits.

Resolving Variables Influencing the Residence Time of Biomass in the Old-Age Forest across Climate Gradients

Standing biomass stocks represent a balance between a number of processes that lead to biomass accumulation or to biomass loss. The average time of biomass residence (ATr) of an ecosystem is the average period of time that carbon is locked up in the living biomass before it is transferred to the litter pool and is an important variable influencing the process leading to biomass loss. Variation in terrestrial ATr with climate is thought to originate from a direct influence of temperature and precipitation on plant mortality. However, variation in ATr may also result from an indirect influence of climate by means of plant age and growing season length. To identify the relative importance of direct and indirect climate effects, we analyzed published data of ecosystem woody biomass and productivity from forest plots across climate gradients, using three approaches: bayesian linear regression, multiple regression, and structural equation modeling. The three approaches provided special insights and they converged in supporting climate as an indirect driver of ATr across climate gradients. Notably, age and growing season length explained most of the variation in ATr, whereas mean annual temperature and precipitation explained almost none, suggesting that climate indirectly influenced ATr. Our analyses provide novel evidence not only supporting that the old-age forests could be a carbon sink with a longer time of biomass residence at a large scale, but also modifying the key drivers of ecosystem processes for vegetation dynamic models.

The simulation of the vine biomass at different planting ages in Ningxia vineyards using DNDC model

The vine total biomass of different planting ages from plants in vineyard (1–12 years) was investigated by analysing biomass in stands with various ages and also simulated using the denitrification-decomposition (DNDC) model in the east Helan Mountains, Ningxia in 2011. The results indicated that the DNDC model accurately simulated the total biomass at different planting ages in the studied vineyard; the simulated results were approximately 93.6% of the measured results, and the biomass determination coefficient R2 between the model simulation and the in situ observations was 0.948 (p < 0.01), representing a significant correlation. Under the simulation, the vine biomass accumulation was found to be sensitive to the changes of fertilisation depth, soil organic carbon content, pH and other factors, and would effectively increase by appropriate increase of the fertilisation amount and decrease of the irrigation amount at the same time. Therefore, the DNDC model is applicable for simulating biomass in Ningxia vineyards and it has the potential to be widely applied to assess crop biomass variations under different climate conditions or management methods.

Nutrient cycling and biomass flows in a low-quality forest stand improvement system in the Lesser Khingan Range of China

ABSTRACTThe material flow and bulk internal flow analyses were used to establish a material accumulation and cycling model for a low-quality forest stand improvement system and a series of processes were considered. The model was applied in a one-hectare low-quality forest plot in the Lesser Khingan Range of China. Results showed that during 1997–2007, the stands absorbed 270.19 kg of N, 74.28 kg of P, and 124.39 kg of K from soils, 51.82 kg of N and 2.38 kg of P were directly absorbed by foliage, and 16.25 kg of K was released to soils by eluviation. Until 2007, the accumulated nutrients in the stands included 236.91 kg of N, 65.28 kg of P, and 108.55 kg of K. When horizontal strip clearcutting was applied in 2007, 50% accumulated nutrients in the stands were shifted due to harvesting operations, and 212.74 kg of N, 26.97 kg of P, and 98.88 kg of K were accumulated in soils, declining by 9.47% for N, 3.68% for P, and 17.60% for K, respectively, compared with year 1997. 94.61 t per hectare of biomass was generated, of which the biomass in stands accounted for 87.36%. The felled tree biomass was 36.89 t per hectare, of which 84.90% and 10.03% of biomass were utilized in terms of logs and other means, and the rest was left on site.

Tree biomass allometry during the early growth of Norway spruce (Picea abies) varies between pure stands and mixtures with European beech (Fagus sylvatica)

In this paper, we report an investigation of how forest stand mixture may affect biomass allometric relationships in Norway spruce (Picea abies (L.) Karst.). Analysis of aboveground biomass data was conducted for 50 trees: 25 sample trees from a pure Norway spruce stand and 25 from a mixed stand of Norway spruce with European beech (Fagus sylvatica L.). ANCOVA results demonstrated that individual-tree biomass allometry of the pure stand significantly differed from that of the mixed stand. Allometric characteristics depended on the biomass component recorded and the type of biomass predictor used. When predicted by diameter at breast height and (or) height, the total aboveground biomass of mixed-stand trees was significantly less than that for pure-stand trees. This “apparent” lower aboveground biomass was attributed to the lower branch and needle biomass proportions of trees growing in mixed stand. The findings indicate that caution should be exercised when applying biomass allometric models developed from pure stands to predict tree biomass in mixed stands (and vice versa), as such data treatment may introduce significant bias.

Above-ground biomass estimation for Quercus rotundifolia using vegetation indices derived from high spatial resolution satellite images

ABSTRACTThe estimation of vegetation parameters, such as above-ground biomass, with high accuracy using remote sensing data, represents a promising approach. The present study develops models to estimate and map above-ground biomass of Mediterranean Quercus rotundifolia stands using one QuickBird satellite image in pan-sharpened mode, with four multispectral bands (blue, green, red and near infrared) and a spatial resolution of 0.70 m. The satellite image was orthorectified, geometrically and radiometrically corrected. Object-oriented classification methods and multi-resolution segmentation were used to derive a vegetation mask per forest species. Data from forest inventory (24 plots) and vegetation indices (NDVI, EVI, SR and SAVI) derived from high spatial resolution satellite images were used for an area of 133 km2, in southern Portugal. The statistical analysis included correlation, variance analysis and linear regression. The linear regression models fitted included the arithmetic mean and the median values of the vegetation indices per inventory plot as explanatory variables. The overall results of the fitted models show a trend of better performance for those with the median value of the vegetation index as the explanatory variable. The best fitted model (R2 = 75.3) was associated with the Simple Ratio (SR) median value as an explanatory variable. A Quercus rotundifolia above-ground biomass map was produced.

Aboveground biomass and carbon stock assessment in forest stands of Gmelinaarborea Roxb. in Mizoram, North-East India

Aboveground biomass and carbon stock in tropical forest play an important role in global carbon cycle. Assessment of biomass and carbon pool in different forest stands may provide information in making decisions about the carbon management within the forest. Gmelina arborea , a fast growing species that is widely distributed and an important timber species of Mizoram has been chosen to assess its biomass and carbon stock. The present study was carried out to estimate the aboveground biomass and carbon stock in G. arborea in different forest stands of Mamit District, Mizoram, north-east India. The result shows that the total aboveground biomass ranged between 66-108 Mg ha -1 and carbon stock (30.00-53.20 mg C ha -1 ). The aboveground biomass and carbon stock was maximum in forest stands (site-III) with highest tree density and diameter class of 30-40cm and 40-50cm indicating the forest site was mature and undisturbed. The result demonstrates that G. arborea contribute in carbon sequestration and helps in mitigating global warming. Further, the aboveground biomass and carbon sequestration potential was greatly affected by the tree composition, population pressure and anthropogenic activities. Keywords: Aboveground biomass, carbon stock, diameter class,Gmelina arborea, tropical forest.

Short-term effects of prescribed burning on litterfall biomass in mixed stands of Pinus nigra and Pinus pinaster and pure stands of Pinus nigra in the Cuenca Mountains (Central-Eastern Spain)

Fire severity, defined as the magnitude of fire effects in an ecosystem, is a key factor to consider in planning management strategies for protecting forests against fire. Although prescribed burning has been used as a fuel reduction tool in forest ecosystems, it is quite limited in the Mediterranean region. Furthermore, little is known about how tree crowns are affected by prescribed underburning aimed at reducing fire severity in conifer stands. As part of an ongoing study to assess the effects of prescribed burning on the tree canopy, litterfall is currently being monitored in a network of experimental plots located in mixed (Pinus nigra and Pinus pinaster) and pure (P. nigra) conifer stands in the Cuenca Mountains (Castilla La Mancha, Spain). A total of 12 study plots (30m×30m) were established in a completely randomized experimental design to determine the effect of burning, with 2 treatments: no burning (control) and burning (i.e. with three replicate plots for each treatment and site). Burning was conducted in May 2016. In each plot, 8 litterfall collectors were installed at regular intervals, according to international protocols (ICP Forests), and all biomass falling into the collectors is being monitored monthly. The specific objective of this study is to assess how prescribed burning affects the rate of generation of foliar and non-foliar litterfall biomass due to the fire. In addition, the Leaf Area Index was estimated before burning and one year later to verify possible changes in the structure of the stands. This information could be used to help minimize the negative impacts of prescribed underburning on litterfall. To our knowledge, this study represents the first attempt to evaluate the effect of prescribed burning on litterfall biomass in Europe.

How do tree stand parameters affect young Scots pine biomass? – Allometric equations and biomass conversion and expansion factors

Abstract Due to the impact of climate change and rising atmospheric carbon dioxide concentrations, assessment of forest carbon pools becomes a crucial task for forest ecology. One of the scientific gaps in this task is the assessment of young tree stands, not included in forest inventories, due to lack of merchantable volume. We aimed to provide a comprehensive set of allometric equations (AEs) and biomass conversion and expansion factors (BCEFs) for young Scots pine tree stands and to develop models of tree stand biomass based on stand features easy-measurable by remote sensing: height and density. We used data collected in 77 tree stands of Scots pine ranging in age from 3 to 20 years in Western and Central Poland, covering forest, post-agricultural and post-industrial sites. Our dataset included 423 sample trees. Our study resulted in collection of 256 site-specific AEs, 12 generalized AEs and equations allowing for dynamic BCEF calculation. Due to lack of BCEF applicability for young trees, we also provided age- and height-dependent functions allowing for precise biomass estimation at the tree-stand level. It was found that tree-stand biomass increased with tree-stand age, height and volume, and decreased with increasing density in the chronosequence. BCEFs decreased with tree-stand age, height and volume and increased with increasing density. Using these relationships we provided stand-level equations based on BCEFs and on tree height – the stand characteristic which is easily obtained from airborne data. These two models did not show a big difference in accuracy. Thus, height-based models are expected to be useful for extensive assessments of young tree stand biomass and carbon sequestration, allowing for better estimation of forest carbon pools. Moreover, our models, in comparison with IPCC guidelines, give more precise values of carbon pools and biomass of young Scots pine tree stands.

東京大学千葉演習林,秩父演習林のモミ,ツガを主林木とした天然生林における林分現存量,生長量およびリターの生産量

東京大学千葉演習林,秩父演習林のモミ,ツガを主林木とした天然生林における林分現存量,生長量およびリターの生産量

Conifer proportion explains fine root biomass more than tree species diversity and site factors in major European forest types

Abstract Fine roots (diameter ≤ 2 mm) contribute significantly to the forest carbon cycle and are essential for resource acquisition from the soil. We conducted a study to assess the relationships between tree and ground vegetation fine root biomass and tree species diversity (monocultures compared to 2–5 species mixtures), conifer proportion and other site factors (stand basal area, soil carbon stocks and C:N ratio) in the six major European forest types, boreal forest in Finland, temperate forests in Poland, Germany and Romania, thermophilous deciduous forests in Italy, and Mediterranean forests in Spain. We sampled the fine roots of trees and ground vegetation to the depth of 20 cm in the mineral soil and allocated the fine root biomass to individual tree species using near-infrared reflectance spectroscopy (NIRS). We did not find any general positive effects of tree species diversity on the fine root biomass of trees or ground vegetation across the forest types and tree species combinations. However, our results suggest that tree fine root biomass increases with tree species diversity in pure broadleaf forests, but not in pure conifer forests. Species diversity explained 7% of the variation in tree fine root biomass in the broadleaf stands. The narrow tree species diversity gradient (1–2 species) in the conifer forests compared to the broadleaf forests (1−4) may have decreased the probability of conifer species combinations with below-ground functional traits conducive to over-yielding. Some evidence of diversity-mediated changes in the vertical rooting patterns of broadleaf trees and ground vegetation were found within the entire organic and 0–20 cm mineral soil layer although the weighted mean depth of fine root biomass was not affected. Negative diversity effects were found in the organic layer and positive diversity effects in the 0–10 cm mineral soil layer for broadleaf tree fine root biomass. Diversity effects were negative for ground vegetation fine root biomass in the 0–10 cm mineral soil layer. There was a general positive effect of conifer proportion on total fine root biomass in the organic layer, but not in the mineral soil layers. In general conifer proportion and site factors explained more of the variation in tree fine root biomass than tree species diversity. More research covering the annual variation in fine root biomass and deeper soil layers is needed before recommending managing species-rich forest for increasing below-ground biomass and carbon pools.

Biomass, spacing and planting design influence cut-and-chip harvesting in hybrid poplar

Hybrid poplar is a woody crop grown for the production of bioenergy, biofuels and bioproducts. Harvesting is often the largest single cost in the production system and the development and optimization of equipment is evolving. The objective of this study was to evaluate the performance of a single-pass, cut-and-chip harvesting operation in commercial plantings that included four cultivars, two spacing treatments, and two coppice planting designs (dedicated, and interplanted with sawtimber). Approximately 15 h of harvesting using a New Holland 9080 forage harvester equipped with a purpose-built coppice header was monitored over four days. Stand biomass ranged between 34 and 78 Mg ha−1of fresh biomass and effective material capacity (Cm) of the harvester ranged from 10 to 78 Mg h−1of fresh biomass excluding headland activities. Tree spacing had a significant effect on Cm but cultivar and planting design did not. The treatments did not have discernible effects on machine fuel consumption (mean 83 L h−1; ơ 16.4) or crop-specific fuel consumption for fresh biomass (mean 1.34 L Mg−1; ơ 0.31). Crop-specific fuel consumption was positively correlated with engine load, and negatively correlated with standing biomass; this result was statistically significant but negligible (<1%) in terms of liters of fuel used for each additional Mg ha−1 of stand biomass for engine loads ranging between 30% and 110%.

Biomass conversion and expansion factors in Douglas-fir stands of different planting density: variation according to individual growth and prediction equations

Aim of study: We built biomass expansion factors (BCEFs) from Douglas-fir felled trees planted with different planting densities to evaluate the differences according tree size and planting density.Area of study: The Douglas-fir plantation under study is located on the northern coastal chain of Calabria (Tyrrhenian side) south Italy.Materials and methods: We derived tree level BCEFs, relative to crown (BCEFc), to stem (BCEFst = basic density, BD) and total above-ground (BCEFt) from destructive measurements carried out in a Douglas-fir plantation where four study plots were selected according to different planting densities (from 833 to 2500 trees per hectare). The measured BCEFs were regressed against diameter at breast height and total height, planting density, site productivity (SP) and their interactions to test the variation of BCEFs. Analysis of variance (ANOVA) and the post hoc Tukey comparison test were used to test differences in BCEFt, BCEFc and in BD between plots with different planting density.Main results: BCEFs decreased with increasing total height and DBH, but large dispersion measures were obtained for any of the compartments in the analysis. An increasing trend with planting density was found for all the analyzed BCEFs, but together with planting density, BCEFs also resulted dependent upon site productivity. BCEFt average values ranged between 1.40 Mg m-3 in planting density with 833 trees/ha (PD833) to 2.09 Mg m-3 in planting density with 2500 trees/ha (PD2500), which are in the range of IPCC prescribed values for Douglas-fir trees.Research highlights: Our results showed that the application of BCEF to estimate forest biomass in stands with different planting densities should explicitly account for the effect of planting density and site productivity.

Allometric scaling, biomass accumulation and carbon stocks in different aged stands of thin-walled bamboos Schizostachyum dullooa, Pseudostachyum polymorphum and Melocanna baccifera

In recent decades, bamboos have become globally important biomass resources in tropical regions. However, bamboo stands have uneven age structure, and often differently aged culms are found distributed throughout a stand. This makes estimation of their biomass and carbon stocks more complicated than forest trees. Therefore, the present study was undertaken to: (i) determine whether or not growth and biomass accumulation in thin-walled bamboos follow simple height-diameter (H-D) relationships and allometric scaling rules, and (ii) develop models for estimation of biomass and carbon stocks in different aged stands of the bamboos Schizostachyum dullooa, Pseudostachyum polymorphum and Melocanna baccifera in North East India. The H-D relationships and allometric scaling between above-ground biomass (AGB), culm height (H) and diameter at breast height (D) were examined using various models. The results demonstrate that H, D and AGB are allometrically related in the different aged bamboo stands. However, these relationships significantly deviated from theoretical predictions. The common functions used for modelling H-D relationships also gave significantly differing estimates of the asymptotic height (Hmax) highlighting large uncertainty in the choice of H-D functions. Our findings indicate that use of volume provides better biomass prediction in the three species than either D or H alone. Aboveground biomass carbon densities of the bamboo forests were estimated at 23Mgha–1 for S. dullooa, 21Mgha–1 for P. polymorphum and 58Mgha–1 for M. baccifera forests. The estimated carbon density of M. baccifera was comparable with values reported for thick walled bamboos in North East India and elsewhere. Although S. dullooa and P. polymorphum had lower carbon densities, the ability of these species to grow fast after forest disturbance indicates their potential for abating land degradation and carbon management by preventing losses from forest degradation. These species also hold great potential for biomass production given the local tradition of planting them in home gardens.

Carbon stocks in selected tree plantations, as compared with semi-deciduous forests in centre-west Côte d’Ivoire

Reducing emissions from deforestation and forest degradation (REDD+) is receiving increasing political and scientific attention as a climate change mitigation approach. Agroforestry systems are credited for stocking significant amounts of carbon and hence have a potential to mitigate greenhouse gas emissions. Forestry-based carbon storage projects are currently being introduced in many tropical countries, but assessment of carbon storage is difficult due to a lack of species-level information.The research addressed in this paper assessed above, belowground and litter biomass of Theobroma cacao (cocoa) and Tectona grandis(teak) plantations relative to secondary forests in two sites in mid-western Côte d'Ivoire. Allometric equations for tropical trees relating to diameter at breast height (DBH) were used to estimate carbon storage potential. The main findings reveal that teak plantations have an appreciably much greater mean carbon storage capacity than secondary forests and cocoa plantations. The aboveground biomass of teak stands contained the highest carbon stock (214.7MgCha-1) while litter and root displayed 2.8 and 35.6MgCha-1, respectively. Cocoa plantations have the lowest carbon storage potential in the aboveground biomass,estimated at 18.6MgCha-1, but a considerable amount of carbon stored in the litter (4.7MgCha-1). With teak plantations’ annual mean storage rate of 19.5MgCha-1 year-1, corresponding to 70.6Mg CO2 ha-1year-1, the results demonstrate teak's potential of carbon sequestration and mitigation of the greenhouse gas emission effect.