Allometric equation Research Papers - Academia.edu (original) (raw)

Leaf area index (LAI) is one of the most frequently used parameters for the analysis of canopy structure and it has also been shown to be an important structural characteristic of the forest ecosystem and forest productivity. The objectives of this study were: (1) to calibrate optical estimates of PAI (plant area index) from the LAI-2000 using leaf area index derived from allometric models for six different tropical tree species and (2) to explore the corresponding relationship of calibrated LAI-2000 with stand productivity indices and environmental factors along a strong environmental gradient in the southern region of Costa Rica. From sixteen 6-year-old pure stand plantations (trees spaced 3 m Â 3 m) of four fast growing native species (Terminalia amazonia, Vochysia ferruginea, Vochysia guatemalensis and Hieronyma alchorneoides) and two introduced species (Pinus caribaea var hondurensis and Gmelina arborea), the plant area index (PAI) was estimated indirectly using the LAI-2000 plant canopy analyzer (LI-COR, Lincoln, NE), under cloudy sky conditions at a fixed height of 1.3 m above the ground with a 458 view cap. In addition, leaf area index (LAI) was estimated allometrically by felling four selected trees and measuring the area and biomass of leaves. The specific leaf area (SLA) showed typical values for each tree species that ranged between 81 cm 2 g À1 (V. ferruginea) and 106 cm 2 g À1 (G. arborea). Based on the characteristic SLA, for all tree species, the leaf area per tree could be estimated by allometric equations using the dbh (diameter at 1.3 m) as the independent variable. The calibration of the LAI-2000 PAI data versus the allometric estimate of leaf area showed strong and unbiased relationship for the species: T. amazonia, V. guatemalensis, H. alchorneoides and P. caribaea. In the case of G. arborea and V. ferruginea the LAI-2000 PAI values underestimated and overestimated the allometric measurements of LAI. For all tree species, calibrated LAI-2000 values were used as an independent variable in highly significant regression equations to estimate dominant tree height in each stand (in m) and stand yield in m 3 ha À1 year À1 , implying that calibrated LAI-2000 can be used to evaluate site quality and stand productivity. The generalized relationships for all species, between average calibrated LAI-2000 with stands yield or dominant tree height among four Eco-regions, indicated that as soil nutrient and water supply become optimal for tree growth, maximum LAI, dominant stand height and yield values are obtained.

- by
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- Costa Rica, Biological Sciences, Environmental Sciences, Leaf Area Index

Moist tropical forests in Africa and elsewhere store large amounts of carbon and need accurate allometric regressions for their estimation. In Africa the absence of species-specific or mixed-species allometric equations has lead to broad use of pan moist tropical equations to estimate tree biomass. This lack of information has raised many discussions on the accuracy of these data, since equations were derived from biomass collected outside Africa. Mixed-species regression equations with 71 sample trees using different input variables such as diameter, diameter and height, product of diameter and height, and wood density were developed to estimate total aboveground biomass and biomass of leaves and branches for a Cameroon forest. Our biomass data was added to 372 biomass data collected across different moist tropical forests in Asia and South America to develop new pan moist tropical allometric regressions. Species-specific and mixed-species height diameter regression models were also developed to estimate heights using 3833 trees. Using only diameter as input variable, the mixed-species regression model estimates the aboveground biomass of the study site with an average error of 7.4%. Adding height or wood density did not improve significantly the estimations. Using the three variables together improved the precision with an average error of 3.4%. For general allometric equations tree height was a good predictor variable. The best pan moist tropical equation was obtained when the three variables were added together followed by the one which includes diameter and height. This study provides height diameter relationships and wood density of 31 species. The pan moist tropical equation developed by Chave et al. (2005), estimates total aboveground biomass across different sites with an average error of 20.3% followed by equations developed in the present study with an average error of 29.5%.

- by Adamou Ibrahima
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- Forestry, Biomass, Forest Ecology, Biological Sciences

Four tree species were harvested periodically over a 13-year period from plantations in the humid lowlands of Costa Rica: Cedrela odorata, Cordia alliodora, Hyeronima alchorneoides, and Euterpe oleracea. The soil was a well-drained, volcanic alluvium, and high fertility coupled with 4m of annual rainfall and high temperatures led to rapid growth rates; at age 13 many individual were >30cm dbh

- by John Ewel
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- Biomass, Biological Sciences, Growth, Environmental Sciences

Uncertainties in biomass estimates in Amazonian forests result in a broad range of possible magnitude for the emissions of carbon from deforestation and other land-use changes. This paper presents biomass equations developed from trees directly weighed in open forest on fertile soils in the southern Amazon (SA) and allometric equations for bole volume estimates of trees in both dense and open forests. The equations were used to improve the commonly used biomass models based on large-scale wood-volume inventories carried out in Amazonian forest. The biomass estimates from the SA allometric equation indicate that equations developed in forests on infertile soils in central Amazonia (CA) result in overestimates if applied to trees in the open forests of SA. All aboveground components of 267 trees in open forests of SA were cut and weighed, and the proportion of the biomass stored in the crowns of trees in open forest was found to be higher than in dense-forest. In the case of inventoried wood volume, corrections were applied for indentations and hollow trunks and it was determined that no adjustment is needed for the form factor used in the RadamBrasil volume formula. New values are suggested for use in models to convert wood volume to biomass estimates. A biomass map for Brazilian Amazonia was produced from 2702 plots inventoried by the RadamBrasil Project incorporating all corrections for wood density and wood volume and in factors used to add the bole volume of small trees and the crown biomass. Considering all adjustments, the biomass map indicates total biomass of 123.1 Gt (1 Gt = 1 billion tons) dry weight (aboveground + belowground) for originally forested areas in 1976 in the Brazilian Legal Amazon as a whole (102.3 Gt for aboveground only) at the time of the RadamBrasil inventories, which were carried out before intensive deforestation had occurred in the region. Excluded from this estimate are 529,000 km 2 of forest lacking sufficient RadamBrasil inventory data. After forest losses of 676,000 km 2 by 2006not counting 175,000 km 2 of this deforested area lacking RadamBrasil data-the estimated dry biomass stock was reduced to 105.4 and 87.6 Gt (aboveground + belowground and only above-ground). Thus, at the 2006 time the carbon storage in forested areas in Brazilian Amazonia as a whole will be around 51.1 Gt (assuming 1 Mg dry biomass = 0.485 Mg C). Biomass estimates by forest type (aggregated into 12 vegetation classes) are provided for each state in the Brazilian Legal Amazon.

- by Euler Nogueira
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- Botany, Climate Change, Conservation Biology, Biomass

The regrowth capacity after pollarding of a short-rotation plantation of Acacia saligna (Labill.) H. Wendl. was investigated in a field trial. This shrub has been proposed as a provider of biomass (fuelwood and fodder) in an arid environment, using local marginal water resources such as surface runoff and brackish groundwater. The specific objective of this study was to examine the

- by Jhonathan Ephrath
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- Water quality, Water Availability, Brackish Water, Low Frequency

Commercial and research scale plantings of short-rotation woody crops require reliable and efficient estimations of biomass yield before time of harvest. Biomass equations currently exist but the accuracy and efficiency of estimation... more

- by Lawrence Abrahamson
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- Engineering, Technology, Nonlinear Regression, Prediction error

Fractal branching models can provide a non-destructive and generic tool for estimating tree shoot and root length and biomass, but field validation is rarely described in the literature. We compared estimates of above ground tree biomass for four indigenous tree used on farm in the Philippines based on the WanFBA model tree architecture with data from destructive sampling. Allometric equations for the four species varied in the constant (biomass at virtual stem diameter 1) and power of the scaling rule (b in Y = aD b), deviating from the value of 8/3 that is claimed to be universal. Allometric equations for aboveground biomass were 0.035 D 2.87 for Shorea contorta, 0.133 D 2.36 for Vitex parviflora, 0.063 D 2.54 for Pterocarpus indicus and 0.065 D 2.28 for Artocarpus heterophyllus, respectively. Allometric equations for branch biomass had a higher b factor than those for total biomass (except in Artocarpus); allometric equations for the leave ? twig fraction a lower b. The performance of the WanFBA model was significantly improved by introduction of a tapering factor ''s'' for decrease of branch diameter within a single link. All statistical tests performed on measured biomass versus biomass predicted from the WanFBA results confirm the viability of the WanFBA model as a non-destructive tool for predicting above-ground biomass equations for total biomass, branch biomass and the leaf ? twig fraction.

- by Fernando Santos Martin
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- Agroforestry, Aboveground biomass, Tree Architecture, Statistical Test

Body masses of some South American dinosaurs are estimated. The sauropod Argentinosaurus huinculensis reached 73 tonnes, and therefore, is the largest of all land animals whose mass has been rigorously obtained. Another sauropod, Antarctosaurus giganteus, was the second largest, at nearly 69 tonnes, while Antarctosaurus wichmannianus reached 34 tonnes. A third sauropod, the bizarre-looking Amargasaurus cazaui, was much smaller, with a body mass of only 2.5 tonnes. Among theropods, the body mass of the strangely looking, horned Carnotaurus sastrei, was volumetrically estimated at 1.5 tonnes, while allometric equations on limb measurements yielded overestimations. Moreover, the holotype specimen of Giganotosaurus carolinii (MUCPv-CH-1) was about as large as the average-sized Tyrannosaurus rex, and only marginally smaller than "Sue", the largest specimen. However, a new dentary of Giganotosaurus (MUCPv-95) is 8% longer than that of the holotype. Assuming geometric similarity, that individual must have had a body mass above 8 tonnes and hence must have been the largest theropod ever found.

- by Gerardo Mazzetta
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- Evolutionary Biology, Geology, Ecology, Body Size

A reference guide for the effects of chemicals on crustaceans.

- by Francisco Sánchez-bayo
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- Crustacea, Environmental Monitoring, Risk assessment, Daphnia

The crown architectures of 11 Psychotria species native to Barro Colorado Island, Panama were reconstructed from field measurements of leaf and branch geometry with the three-dimensional simulation model Yplant. The objective was to assess the role of species differences in architecture in light capture and carbon gain in their natural understory environment. When species were grouped according to their putative light environment preference, the shade tolerant species were found to have a small but significantly higher efficiency of light capture for both diffuse and direct light as compared to the light demanding species. Within each grouping, however, there were few significant differences in light capture efficiency among species. The lower efficiencies of light demanding species was due to slightly higher self-shading and slightly lower angular efficiencies. Simulations of whole plant assimilation showed that light demanding species had greater daily assimilation in both direct and diffuse light due to the significantly greater light availability in the sites where light demanding species were found, as compared to those where shade tolerant species occurred. Among light demanding species, the above ground relative growth rate measured over a 1-year period by applying allometric equations for mass versus linear dimensions, was positively correlated with diffuse PFD and with mean daily assimilation estimated from Y-plant. For the shade tolerant plants, there was no significant correlation between RGR and mean daily assimilation or with any measure of light availability, probably because they occurred over a much narrower range of light environments. Overall, the results reveal a strong convergence in light capture efficiencies among the Psychotria species at lower values than previously observed in understory plants using similar approaches. Constraints imposed by other crown functions such as hydraulics and biomechanical support may place upper limits on light capture efficiency. Keywords Crown architecture. Self shading. Daily photosynthesis. Leaf longevity. Forest gaps Abbreviations E a : Efficiency of light absorption (dimensionless). E a dir: Efficiency of direct light absorption (dimensionless). E a dif: Efficiency of diffuse light absorption (dimensionless). D E : Display efficiency (dimensionless). P E : Projection efficiency (dimensionless). CosI: Mean cosine of incidence (dimensionless). aLAR e : Effective leaf area ratio (m 2 g −1). A tot : Daily assimilation (mmol m −2 day −1). A dir : Daily assimilation in direct PFD (mmol m −2 day −1). A dif : Daily assimilation in diffuse PFD (mmol m −2 day −1

- by Fernando Valladares
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- Functional Analysis, Carbon, Biology, Ecology

Uncertainty in biomass estimates is one of the greatest limitations to models of carbon flux in tropical forests. Previous comparisons of field-based estimates of the aboveground biomass (AGB) of trees greater than 10 cm diameter within Amazonia have been limited by the paucity of data for western Amazon forests, and the use of site-specific methods to estimate biomass from inventory data. In addition, the role of regional variation in stand-level wood specific gravity has not previously been considered. Using data from 56 mature forest plots across Amazonia, we consider the relative roles of species composition (wood specific gravity) and forest structure (basal area) in determining variation in AGB. Mean stand-level wood specific gravity, on a per stem basis, is 15.8% higher in forests in central and eastern, compared with northwestern Amazonia. This pattern is due to the higher diversity and abundance of taxa with high specific gravity values in central and eastern Amazonia, and the greater diversity and abundance of taxa with low specific gravity values in western Amazonia. For two estimates of AGB derived using different allometric equations, basal area explains 51.7% and 63.4%, and stand-level specific gravity 45.4% and 29.7%, of the total variation in AGB. The variation in specific gravity is important because it determines the regional scale, spatial pattern of AGB. When weighting by specific gravity is included, central and eastern Amazon forests have significantly higher AGB than stands in northwest or southwest Amazonia. The regional-scale pattern of species composition therefore defines a broad gradient of AGB across Amazonia.

- by David A Neill
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- Carbon, Global Change Biology, Biological Sciences, Global change

An increase in woody plant abundance in regions historically dominated by grasses is a recent land cover change in grasslands worldwide. In tallgrass prairies of North America, this increase in woody plant cover includes the development of dense stands of eastern redcedar (Juniperus virginiana L.). To evaluate the consequences of this ongoing land cover change for ecosystem functioning, we developed allometric equations, using data from Kansas and Oklahoma, to estimate aboveground biomass and productivity in closed-canopy redcedar stands. We then applied these equations to three closed-canopy redcedar stands, 35-80 years old, which developed on sites formerly dominated by tallgrass prairie in eastern Kansas. Aboveground plant biomass for these redcedar-dominated sites ranged from 114 100 kg/ha for the youngest stand to 210 700 kg/ha for the oldest. Annual aboveground net primary productivity (ANPP) ranged from 7250 to 10 440 kg•ha-1 •year-1 for the oldest and younger redcedar stands, respectively. Estimates of ANPP in comparable tallgrass prairie sites in this region average 3690 kg•ha-1 •year-1 indicating a large increase in C uptake and aboveground storage as a result of the change from prairie to redcedar forests. Therefore, the widespread occurrence of redcedars across the woodland-prairie ecotone suggests that this land-cover change may have important consequences for regional net C storage. Résumé : L'augmentation de l'abondance des plantes ligneuses dans des régions historiquement dominées par les graminées est un changement récent de type de couvert des prairies à l'échelle mondiale. Dans les prairies à herbes hautes de l'Amérique du Nord, cette augmentation du couvert des plantes ligneuses inclut le développement de peuplements denses de genévrier de Virginie (Juniperus virginiana L.). De façon à évaluer les conséquences de ce changement progressif de type de couvert pour le fonctionnement de l'écosystème, nous avons développé des équations allométriques à partir de données provenant du Kansas et de l'Oklahoma pour estimer la biomasse épigée et la productivité de ces peuplements à couvert fermé de genévrier. Nous avons ensuite appliqué ces équations à trois peuplements fermés de genévrier, âgés entre 35 et 80 ans et qui se sont développés dans des sites anciennement dominés par la prairie à herbes hautes dans l'est du Kansas. La biomasse aérienne de ces sites dominés par le genévrier variait de 114 100 kg/ha pour le peuplement le plus jeune à 210 700 kg/ha pour le plus vieux. La productivité primaire nette annuelle de la biomasse aérienne (PPNA) oscillait entre 7250 et 10 440 kg•ha-1 •an-1 respectivement pour le plus vieux et le plus jeune peuplement. Les estimés de la PPNA dans des sites de prairie à herbes comparables atteignent en moyenne 3690 kg•ha-1 •an-1 , ce qui indique une forte augmentation de la fixation du carbone et de son stockage aérien par la conversion des prairies en forêts de genévrier. Par conséquent, la présence abondante de genévriers dans l'écotone prairie-forêt semble indiquer que ce changement de type de couvert peut avoir des conséquences importantes pour le stockage régional net de carbone.

- by Loretta Johnson
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- Earth Sciences, Canadian, Environmental Sciences, Land cover change

Many studies have analyzed the benefits, costs, and carbon storage capacity associated with urban trees. These studies have been limited by a lack of research on urban tree biomass, such that estimates of carbon storage in urban systems have relied upon allometric relationships developed in traditional forests. As urbanization increases globally, it is becoming important to more accurately evaluate carbon

- by Indy Burke
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- Biomass, Ecology, Protein Structure and Function, Carbon Storage

Accurate estimation of biomass is becoming vital for selling carbon into national and international markets. Being a dry continent, Australia's natural forest has several shrub species. However, because of limited availability of methodology and difficulty in estimation they are unaccounted for in many cases. This paper has three objectives: (a) to address the major problem in multiple regressions, (b) to develop the best allometric equation for the biomass estimation of a popular shrub species, wild raspberry (Rubus probus) and (c) to prepare a teaching tool, by following systematic and logical steps, for biomass estimation using ForecastX TM software. We identified the possible explanatory variables, by discussing with experts and citing literature, for shrub biomass and then measured them by destructive sampling at Taabinga, near Kingaroy, Queensland. Our research suggests that careful analysis of correlation matrices gives very important clues to which variables we should select and which we should not for the models. High multicollinearity among the independent variables is a major problem in multiple regressions. This study shows that this problem could easily be solved by using basic scientific formula and applying a single variable instead of applying many highly correlated variables in the model. Unlike most statistical books, our analysis does not suggest to reject that variable from the model whose coefficient is not statistically significantly different from zero as it could be highly influential in another set of combination. Similarly, we recommend using the 'intercept' even if its value is not significantly different with zero as it does not cost extra money to be included but it does help the predictive power of the model. Although we developed a range of biomass prediction models (for wild raspberry) that can be used in different circumstances, our first recommendation is for the model which is based on girth and crown volume. Where cost is the major issues, we prefer the model which employs girth and crown area, as it gives a good result and needs only three variables to be measured. These findings can be helpful in teaching the practical applications of multiple regression in courses such as Data Analysis and Business Forecasting.

- by Tek Maraseni
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- Data Analysis, International Marketing, Teaching Methods, Multiple Regression
- by IAEES Publications
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- Regression, Biomass Utilization, Landsat, Carbon Stock

Two phylogenetic comparative methods, independent contrasts and generalized least squares models, can be used to determine the statistical relationship between two or more traits. We show that the two approaches are functionally identical and that either can be used to make statistical inferences about values at internal nodes of a phylogenetic tree (hypothetical ancestors), to estimate relationships between characters, and to predict values for unmeasured species. Regression equations derived from independent contrasts can be placed back onto the original data space, including computation of both confidence intervals and prediction intervals for new observations. Predictions for unmeasured species (including extinct forms) can be made increasingly accurate and precise as the specificity of their placement on a phylogenetic tree increases, which can greatly increase statistical power to detect, for example, deviation of a single species from an allometric prediction. We reexamine published data for basal metabolic rates (BMR) of birds and show that conventional and phylogenetic allometric equations differ significantly. In new results, we show that, as compared with nonpasserines, passerines exhibit a lower rate of evolution in both body mass and mass-corrected BMR; passerines also have significantly smaller body masses than their sister clade. These differences may justify separate, clade-specific allometric equations for prediction of avian basal metabolic rates.

- by Theodore Garland
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- Biology, Medicine, Biological Sciences, Statistical Inference

Prediction of pig performance from data on nutrient intake and animal properties makes it easier to obtain a better productivity. It provides tools to arrive at desired outputs, or to calculate required inputs. Thus it enables production to be flexible, safe and less erratic. It is to be expected that the results will give a more profitable pig production. In practice, different types of models are used, mostly by feed producers, but also in farm management programmes. Each of these existing models was designed to meet a certain objective. The classification of different types of models, and the benefits of using them, are presented in the literature overview of the thesis. After a general overview of modelling, a critical evaluation was provided on existing models. It was concluded from the literature, that a comprehensive model, which predicts the chemical composition in different parts of the body, like in lean or in the meat, does not exist. It was also concluded that mechanisti...

- by Veronika Halas
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- Energy Metabolism, Body Composition, Global Optimization, Factorial Design

Fixation of river flow passages and riverbed degradation may facilitate the development of higher floodplains with the establishment of exotic species such as black locust (Robinia pseudoacacia L.). We quantitatively evaluated the relationship between nitrogen (N) levels in black locust trees and in sediments under different flood disturbance regimes in a riparian area of the Chikuma River. In this study, allometric equations were developed for relating leaf N content to diameter at breast height of black locust. The amount of leaf N in black locust increased with distance from the river, reaching 159 kg N ha-1 at 180 m from the river. There was a small difference in N content between green and fallen leaves (0.2%), and so the leaf N was almost equivalent to N input to riparian sediments. Fine sediments accumulated on the riparian area, where the amount of sediments N increased with distance from the river, ranging from 1091 ± 767 to 4953 ± 2953 kg N ha-1. The N accumulation rates also increased with distance from the river, corresponding with the amount of leaf N in black locust per unit area, but the former exceeded the latter. The sediment N accumulation might be accelerated by sediment trapping effect due to riparian vegetation itself. A large input of N provided by invaded black locust might alter nutrient dynamics and native plant community structure in the riparian area.

- by Hideshige Toda
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- Exotic Species, Allometry, Nitrogen, Community Structure

Leaf area index (LAI) of Teak (Tectona grandis) and Bamboo (Dendrocalamus strictus) grown in Shoolpaneshwar Wildlife Sanctuary of Narmada District, Gujarat, India was obtained by destructive sampling, photo-grid method and by litter trap method. An allometric equation (between leaf area by litter trap method and canopy spread area) was developed for the determination of LAI. Results show that LAI value

- by Dhaval vyas
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- Forestry, Tropical forest, Teak, Root-Mean Square Error

Parasitic cowbirds lay eggs in the nests of other species and dupe them into caring for their young. Unlike other brood parasites, cowbirds have not developed egg mimicry or bizarre chick morphology. However, most of them parasitize a large number of hosts. Several features of cowbirds have been proposed as more general adaptations to brood parasitism. In this study, we used a recent molecular phylogeny as a historical framework to test the possible adaptations of the parasitic cowbird, including egg size, eggshell thickness and energy content of the eggs, length of the incubation period, and growth pattern of cowbird nestlings. We used a recently developed extension of independent contrasts to test whether the five cowbird species deviate from general allometric equations. We generated prediction intervals for a nonparasite that evolved in the place of the cowbirds. By using these prediction intervals, we found that parasitic cowbirds had not reduced weight or energy content of their eggs, nor their incubation period over evolutionary time. Cowbird chicks and those of nonparasitic relatives had similar growth pattern. The only characteristic that separated parasitic cowbirds from their nonparasitic relatives was an increase in eggshell thickness. All these findings were robust and resisted the use of three models of character evolution. The fact that most traits exhibited by cowbirds were inherited from a nonparasitic ancestor does not rule out that they are advantageous for parasitism. Future research should focus on such traits of cowbird relatives and on how these traits preadapted a particular lineage to become parasites.

- by Juan Francisco Ornelas and +1
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- Evolutionary Biology, Zoology, Life history, Ecology

The quantitative and qualitative estimation of aboveground biomass production is essential for short-rotation forestry. Indirect methods of biomass estimation have been developed based on the establishment of regressions between biomass components and tree dimensions as well as canopy architecture. The difficulty encountered with this method is to know whether, and to what degree, the obtained equations can be used under contrasting environmental conditions and for different genetic backgrounds. In the present study, allometric equations were developed linking tree dry weight (stem, branch and aboveground tree dry weight) with stem circumference, stem height and number of sylleptic branches for five 2-yearold intra-as well as interspecific poplar (Populus) families growing at three contrasting sites in Europe, i.e. Northern Italy, Central France and Southern UK. The multiple regression method was used to find the most precise biomass equation which represents the genetic variation for each family at each site, independently, as well as a common equation involving all families and sites. The two F 1 P. deltoides Â P. trichocarpa families and the F 1 P. alba Â P. alba family were the most productive families irrespective of site. However, different patterns in biomass accumulation were observed between these crosses. The F 1 P. alba Â P. alba family accumulated significantly more biomass in branches than in the stem as compared to both other families. In most cases, different transformations of the dependent variables were needed to improve the linear equations. Stem circumference was superior in predicting tree dry weight, but stem height and number of sylleptic branches were often needed to optimize the equations dependent on family and site. A standardized equation combining the five families and the three sites explained more than 95% of the observed variation for tree dry weight. However, there was a significant family effect, and at the UK site, a severe rust attack could have affected the relationships among the three predictors resulting in a significantly different equation for this site. When the UK site was excluded from the model, no overall site effect was observed. Thus, a single equation might be applied at family level regardless of the environmental conditions when stand density, age and plantation management are comparable.

- by Matthieu PINEL
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- Plant Biology, Forest Ecology And Management, Ecology, Forest Ecology

Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were:

- by Eduardo Brondizio
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- Earth Sciences, Biogeochemistry, Biomass, Biological Sciences
- by neil stuart
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- Geology, Biomass, Earth, Carbon Sequestration

Sub-Saharan Africa has a great diversity of local coppicing species which are exploited in traditional short coppice systems for firewood. Biomass yield and profitability of these systems as well as their responses to silvicultural improvement are little known. This study evaluated the firewood yield and the profitability of a traditional Daniellia oliveri short-rotation coppice on fallow lands in central Benin. Two weed management options were considered: (1) the weedy option, usually practiced by locals, which experienced grass competition and bushfires, and (2) the weed-free option, which consisted in periodic removal of grasses and other species. Destructive measurements and allometric equations were used to estimate biomass yield in 12 plots over 42 months. A cost-benefit analysis model based on the net present value and the benefit-cost ratio was used to compare the profitability of the two management options. Biomass accumulation rate averaged 1.08 AE 0.20 tonnes of dry matter ha À1 year À1 (t DM ha À1 year À1) in weedy conditions. Weed removal improved 3.5 times this rate in weed-free plots (3.83 AE 0.47 t DM ha À1 year À1). After 42 months, total biomass reached 3.67 AE 0.65 t DM ha À1 in weedy plots and 11.63 AE 0.76 t DM ha À1 in weed-free plots. Most of the biomass (!88%) was marketable in local markets. Coppice exploitation was profitable after 24 months for both management options. Weed removal improved the profits three times. A sensitivity analysis showed that both options were still profitable with up to 25% increase of labour and transport costs, 25% decrease of biomass price and 12% increase of the discount rate.

- by Achille Assogbadjo
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- Engineering, Mathematics, Technology, Biomass

- by Achille Assogbadjo
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- Engineering, Mathematics, Technology, Biomass

Land management in tropical woodlands is being used to sequester carbon (C), alleviate poverty and protect biodiversity, among other benefits. Our objective was to determine how slash-and-burn agriculture affected vegetation and soil C stocks and biodiversity on an area of miombo woodland in Mozambique, and how C stocks and biodiversity responded once agriculture was abandoned. We sampled twenty-eight 0.125 ha plots that had previously been cleared for subsistence agriculture and had been left to re-grow for 2 to $25 years, and fourteen 0.25 ha plots of protected woodlands, recording stem diameter distributions and species, collecting wood for density determination, and soil from 0 to 0.3 m for determination of %C and bulk density. Clearance for agriculture reduced stem wood C stocks by 19.0 t C ha À1. There were significant relationships between period of re-growth and basal area, stem numbers and stem biomass. During re-growth, wood C stocks accumulated at 0.7 t C ha À1 year À1. There was no significant difference in stem C stocks on woodlands and on abandoned farmland 20-30 years old. Soil C stocks in the top 0.3 m on abandoned land had a narrower range (21-74 t C ha À1) than stocks in woodland soils (18-140 t C ha À1). There was no discernible increase in soil C stocks with period of re-growth, suggesting that the rate of accumulation of organic matter in these soils was very slow. The re-growing plots did not contain the defining miombo species, and total stem numbers were significantly greater than in woodland plots, but species richness and diversity were similar in older abandonments and miombo woodlands. Wood C stocks on abandoned farmland were capable of recovery within 2-3 decades, but soil C stocks did not change on this timescale. Woodland soils were capable of storing >100 t C ha À1 , whereas no soil on a re-growing area exceeded 74 t C ha À1 , so there is a potential for C sequestration in soils on abandoned farmland. Management should focus on identifying C-rich soils, conserving remaining woodlands to protect soil C and preserve defining miombo species, and on investigating whether fire control on recovering woodland can stimulate accumulation of soil C and greater tree biomass, and restore defining miombo species.

- by JennyRose Fernando
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- Land management, Forest Ecology And Management, Biology, Carbon Sequestration

Pools and annual fluxes of carbon (C) were estimated for a mature Eucalyptus pauciflora (snowgum) forest with and without phosphorus (P) fertilizer addition to determine the effect of soil P availability on allocation of C in the stand. Aboveground biomass was estimated from allometric equations relating stem and branch diameters of individual trees to their biomass. Biomass production was calculated from annual increments in tree diameters and measurements of litterfall. Maintenance and construction respiration were calculated for each component using equations given by Ryan (1991a). Total belowground C flux was estimated from measurements of annual soil CO 2 efflux less the C content of annual litterfall (assuming forest floor and soil C were at approximate steady state for the year that soil CO 2 efflux was measured). The total C content of the standing biomass of the unfertilized stand was 138 t ha 1 , with approximately 80% aboveground and 20% belowground. Forest floor C was 8.5 t ha 1. Soil C content (0-1 m) was 369 t ha 1 representing 70% of the total C pool in the ecosystem. Total gross annual C flux aboveground (biomass increment plus litterfall plus respiration) was 11.9 t ha 1 and gross flux belowground (coarse root increment plus fine root production plus root respiration) was 5.1 t ha 1. Total annual soil efflux was 7.1 t ha 1 , of which 2.5 t ha 1 (35%) was contributed by litter decomposition. The short-term effect of changing the availability of P compared with C on allocation to aboveground versus belowground processes was estimated by comparing fertilized and unfertilized stands during the year after treatment. In the P-fertilized stand annual wood biomass increment increased by 30%, there was no evidence of change in canopy biomass, and belowground C allocation decreased by 19% relative to the unfertilized stand. Total annual C flux was 16.97 and 16.75 t ha 1 yr 1 and the ratio of below-to aboveground C allocation was 0.43 and 0.35 in the unfertilized and P-fertilized stands, respectively. Therefore, the major response of the forest stand to increased soil P availability appeared to be a shift in C allocation; with little change in total productivity. These results emphasise that both growth rate and allocation need to be estimated to predict changes in fluxes and storage of C in forests that may occur in response to disturbance or climate change.

- by Heather Keith
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- Biological Sciences, Phosphorus, Environmental Sciences, Steady state

The objective of this study is to analyze JERS-1 backscattering coeficient to characterize vegetation cover and its relationship with the aerial biomass data of primary forest and secondary successions. In support to this analysis, spectral data from optical TM-Landsat bands have also been used in combination with JERS-1 data, to establish a regression model that best fits to the field

- by Manfred Keil
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- Optical Imaging, Data Collection, Multiple Regression, Secondary Forest

This study was conducted to determine biomass dynamics, carbon sequestration and plant nitrogen immobilization in multispecies riparian buffers, cool-season grass buffers and adjacent crop fields in central Iowa. The seven-year-old multispecies buffers were composed of poplar (Populus × euroamericana 'Eugenei') and switchgrass (Panicum virgatum L.). The cool-season grass buffers were dominated by non-native forage grasses (Bromus inermis Leysser., Phleum pratense L. and Poa pratensis L). Crop fields were under an annual corn-soybean rotation. Aboveground non-woody live and dead biomass were determined by direct harvests throughout two growing seasons. The dynamics of fine (0-2 mm) and small roots (2-5 mm) were assessed by sequentially collecting 35 cm deep, 5.4 cm diameter cores (125 cm deep cores in the second year) from April through November. Biomass of poplar trees was estimated using allometric equations developed by destructive sampling of trees. Poplar had the greatest aboveground live biomass, N and C pools, while switchgrass had the highest mean aboveground dead biomass, C and N pools. Over the two-year sampling period, live fine root biomass and root C and N in the riparian buffers were significantly greater than in crop fields. Growing-season mean biomass, C and N pools were greater in the multispecies buffer than in either of the crop fields or cool-season grass buffers. Rates of C accumulation in plant and litter biomass in the planted poplar and switchgrass stands averaged 2960 and 820 kg C ha −1 y −1 , respectively. Nitrogen immobilization rates in the poplar stands and switchgrass sites averaged 37 and 16 kg N ha −1 y −1 , respectively. Planted riparian buffers containing native perennial species therefore have the potential to sequester C from the atmosphere, and to immobilize N in biomass, therefore slowing or preventing N losses to the atmosphere and to ground and surface waters.

- by Aydin Tufekcioglu
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- Carbon Sequestration, Populus, Seasonality, Surface Water

Protected areas play a significant role in carbon storage in arid and semi-arid land. In the central region of Argentina, there are three nature reserves located along a West to East rainfall gradient between two different phytogeographical provinces: the Monte and the Arid Chaco. The aims of this work were: (1) to quantify carbon storage in the three nature reserves and (2) to compare the different vegetation communities in the internal structure, expressed as canopy cover, diversity and relative abundance of woody plant functional types in each of the nature reserves. The combination of remote sensing data with a detailed inventory and local biomass allometric equations models were found to be appropriate tools for the estimation of carbon storage in each nature reserve. In general, canopy cover and carbon storage tends to increase from west to east and, within each nature reserve, from shrubland into mature forest community. Total carbon storage in mature woodlands ranged from 48 to 95 Mg ha À1 , in open and mixed woodlands from 21 to 36 Mg ha À1 , and in shrublands from 8 to 19 Mg ha À1. On the other hand, many similarities were observed between the mixed woodlands of the wetter Reserve and the mature forest of the more arid Reserve of the Arid Chaco, based on the organization of plant functional types, canopy cover and carbon storage. This knowledge of carbon storage would thus be a useful input for the development of strategies for reducing CO 2 emissions caused by deforestation and forest degradation and, in particular, it is significant for planning policies to mitigate desertification in arid and semiarid lands.

The difficulties in separating forest type vegetation using optical images led this research group to seek for a solution by merging radar and optical images. The objective of this study is to evaluate the potential use of JERS-1 images to separate the gradient physiognomies of the Cerrado biome, using data from a BIOTA project. One of the main problems in the use of optical images is the high spatial heterogeneity presented by this gradient, which changes in both horizontal and vertical structure. This study took place initially in two pilot areas: one of the areas is a conservation unit of cerrado vegetation and the other one comprises remnants located within private properties which present all Cerrado physiognomies, besides Seasonal Semideciduous Forest (SSForest). That calibration provided enough information to classify the different physiognomies of Cerrado along the São Paulo State. Thus, merging NDVI images (from LANDSAT and MODIS) and JERS-1 images, 206 cerrado polygons were analysed in order to discriminate their physiognomies. These image observations were corroborated with data collected by the botany team who visited those remnants. The SAR images demonstrated to be a good physiognomy indicator in areas with different wood biomass, such as cerrado s.s., cerradão, and SSForest. In the other pilot area, the aboveground woody biomass was estimated using allometric equations (using the diameter at breast height and height of 800 trees, in 10 sample sites with different density). The biomass values were related to the backscattering within each sample site in the JERS-1 images. The result is an equation (R 2 = 0,812), that permits to estimate woody biomass using backscattering values registered in JERS-1 images, in any similar wood physiognomy.

- by Marisa Bitencourt
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- Optical Imaging, Seasonality, Spatial Heterogeneity, Data Collection

- by Euler Nogueira
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- Earth Sciences, Biogeochemistry, Biomass, Biological Sciences
- by José Guilherme
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- Energy Metabolism, Biological Sciences, Body Size, Oscillations

We conducted a study of the breeding biology of the Thorn-tailed Rayadito (Aphrastura spinicauda) in secondary forests on the continental island of Chiloé (42Њ S), southern Chile. Rayaditos are small insectivorous furnariids inhabiting the south-temperate forests of Chile and Argentina. We followed the reproduction of rayadito pairs breeding in nest-boxes. Rayaditos build their nests mainly of rhizomes and stems of epiphytic vines, grasses, and hairs during periods of at least a week, and show a marked population asynchrony in laying dates of more than two months (October-December). Rayaditos lay clutches of 3-6 eggs with a mode of 4 and laying occurs on alternate days. Eggs are 50% larger and hatchlings are 30% larger than expected from allometric equations. Most broods hatch synchronously. Nestling growth curves adjust well to logistic functions and at 2 weeks nestlings attain masses similar to asymptotic values. Nestling growth, which occurs over 3 weeks, is 27% slower than expected from allometry. Fledglings attain adult size with respect to tarsus length, but have less developed plumage and higher body mass than adults. Rayaditos exhibit clutch and brood reduction, suggesting possible food limitation. The protracted breeding periods may preclude second breeding attempts for most pairs in Chiloé. There is evidence for declines in parental quality with season. The low seasonal fecundity, large eggs, and prolonged dependence periods of a truly south-temperate species like the Thorntailed Rayadito reflect a 'slow' life history similar to that of tropical passerines.

- by Santiago Merino
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- Zoology, Life history, Seasonality, Temperate Rainforest

Abstract. Ecosystems net primary production quantification can be done by means of allometric equations. Carbon sequestration studies also involve the quantification of growth dry biomass, knowing the carbon percentage of dry biomass.... more

- by Jose Aranha
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- Carbon Sequestration, Mathematical Model, North East, Pinus Pinaster
- by Philip Fearnside
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- Biomass, Forest Ecology And Management, Brazil, Amazonia
- by Philip Fearnside
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- Earth Sciences, Soil Science, Biogeochemistry, Tropical Ecology

- by Daniel Metcalfe
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- Earth Sciences, Soil Science, Biogeochemistry, Tropical Ecology

Purpose: Allometry is a method to express the relationship between physiological and anatomical
variables. It can be used to measure the vital capacity through mathematical equations. This study
aimed at evaluating lung function indices to estimate the maximal aerobic power by respiratory
gas analysis device and the allometric equation.
Methods: This study was a descriptive and correlational research. A total of 80 subjects were
chosen by convenience sampling method. Then, their anthropometric characteristics and
dimensions of chest circumference (diameter and depth of the chest) were measured, and Bruce
test was used to measure maximal aerobic power. The Pearson correlation coefficient and
multivariate regression analysis were performed using SPSS 16.
Results: There is a positive and significant relationship between vital capacity and maximal
aerobic power (r=0.229, P=0.041) and also between the device vital capacity and formula vital
capacity (r=1.00, P=0.00). Accordingly, the following model was developed (chest circumfer
ence×0.284)+(age×0.319)+(vital capacity×1.761)+inclination=Maximal oxygen consumption.
Conclusion: According to the study results, there is a significant correlation between device vital
capacity and formula vital capacity. Thus, in order to predict the maximal oxygen consumption,
in the absence of any other experimental methods, allometric equation can be used.

- by José Claudio Mura
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- Environmental Science, Remote Sensing, Brazilian Amazon, Landscape change
- by David Jupp
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- Near Infrared, Remote, Data Collection, Geomatic Engineering

We developed allometric equations to predict whole-tree leaf area (A l), leaf biomass (M l) and leaf area to sapwood area ratio (A l :A s) in five rain forest tree species of Costa Rica: Pentaclethra macroloba (Willd.) Kuntze (Fabaceae/ Mim), Carapa guianensis Aubl. (Meliaceae), Vochysia ferruginea Mart. (Vochysiaceae), Virola koshnii Warb. (Myristicaceae) and Tetragastris panamensis (Engl.) Kuntze (Burseraceae). By destructive analyses (n = 11-14 trees per species), we observed strong nonlinear allometric relationships (r 2 ≥ 0.9) for predicting A l or M l from stem diameters or A s measured at breast height. Linear relationships were less accurate. In general, A l :A s at breast height increased linearly with tree height except for Pentaclethra, which showed a negative trend. All species, however, showed increased total A l with height. The observation that four of the five species increased in A l :A s with height is consistent with hypotheses about tradeoffs between morphological and anatomical adaptations that favor efficient water flow through variation in the amount of leaf area supported by sapwood and those imposed by the need to respond quickly to light gaps in the canopy.

- by Julio Calvo
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- Model Theory, Photosynthesis, Plant Biology, Ecology

RESUMO O objetivo deste trabalho foi ajustar equações para estimar o carbono presente no fuste de árvores individuais de eucalipto eo estoque de carbono, por unidade de área, em diferentes condições de plantio. Para isso, foram... more

- by Carlos Pedro Boechat Soares
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- Mathematics, Site index, Forestry Sciences, Carbon Stock

With increasing CO 2 in the atmosphere, there is an urgent need of reliable estimates of biomass and carbon pools in tropical forests, most especially in Africa where there is a serious lack of data. Information on current annual increment (CAI) of carbon biomass resulting from direct field measurements is crucial in this context, to know how forest ecosystems will affect the carbon cycle and also to validate eddy covariance flux measurements. Biomass data were collected from 25 plots of 13 ha spread over the different vegetation types and land uses of a moist evergreen forest of 772,066 ha in Cameroon. With site-specific allometric equations, we estimated biomass and aboveground and belowground carbon pools. We used GIS technology to develop a carbon biomass map of our study area. The CAI was estimated using the growth rates obtained from tree rings analysis. The carbon biomass was on average 264 ± 48 Mg ha −1. This estimate includes aboveground carbon, root carbon and soil organic carbon down to 30 cm depth. This value varied from 231 ± 45 Mg ha −1 of carbon in Agro-Forests to 283 ± 51 Mg ha −1 of carbon in Managed Forests and to 278 ± 56 Mg ha −1 of carbon in National Park. The carbon CAI varied from 2.54 ± 0.65 Mg ha −1 year −1 in Agro-Forests to 2.79 ± 0.72 Mg ha −1 year −1 in Managed Forests and to 2.85 ± 0.72 Mg ha −1 year −1 in National Park. This study provides estimates of biomass, carbon pools and CAI of carbon biomass from a forest landscape in Cameroon as well as an appropriate methodology to estimate these components and the related uncertainty.

- by gode gravenhorst
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- Forestry, Biomass, Carbon Cycle, Forest Ecology

- by gode gravenhorst
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- Environmental Science, Chemistry, Forestry, Biomass

We show the regression equations that relate the head width of 10 freshwater insect species or the length of the first thoracic segment of 2 amphipods with their dry mass in 3 reaches along a small stream in northern Spain. Spatial differences in size-mass relationships were found. Organisms stored in alcohol showed lower dry mass than those specimens that were dried immediately after collection. The use of both size measures for dry mass estimation in field samples is discussed. It is recommended that the size-mass relationships be constructed using non-preserved organisms. Furthermore, great care is required when such allometric equations are taken from the literature.

- by Ana Basaguren
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- Earth Sciences, Biomass, Biology, Morphometry

Estimates of tree biomass are useful in assessing forest structure and condition (Chave et al., 2003; Houghton and Goodale, 2004); forest productivity, carbon stocks and fluxes based on sequential biomass measurements (Clark et al., 2001); and sequestration of carbon in biomass components, including wood, leaves, and roots; as well as being a useful indicator of site productivity. Several generalized biomass prediction equations have been developed for tropical species (Brown et al., 1989; Chambers et al., 2001; Chave et al., 2005; Overman et al., 1994). For temperate species, Ter-Mikaelian and Korzukhin (1997) reported a list of biomass equations for 66 North American tree species. However, single species and mixtures of species differ in allometry, wood density, and architecture, all of which can affect the relationship between the measurements taken during forest inventories and the biomass of individual trees (Chave et al., 2003). Therefore,

- by Jose Navar
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- Applied Mathematics, Forestry, Carbon, Biomass

Cerrado is a biome that occupies about 25% of the Brazilian territory and is characterized by a gradient of grassland to savanna and forest formations and by high species richness. It has been severely affected by degradation and deforestation and has been heavily fragmented over the past 4-5 decades. Despite the recognized overall ecological importance of the Cerrado, there are only few studies focusing on the quantification of biomass in this biome. We conducted such a case study in the SouthEast of Brazil in a cerrado sensu stricto (cerrado s.s.) with the goal to produce estimates of above-and belowground biomass and to develop allometric equations. A number of 120 trees from 18 species were destructively sampled and partitioned into the components: leaves, branches and bole. Five models with DBH (D), height (H), D 2 H and wood density (WD) as independent variables were tested for the development of allometric models for individual tree aboveground biomass (leaves + branches + bole). One model based on basal area (BA) as a stand parameter was also tested as an alternative approach for predicting aboveground biomass in the stand level. Belowground biomass was estimated by subsampling on 10 sample plots. Mean aboveground tree biomass (bole, branches and leaves) was estimated to be 62,965.5 kg ha À1 (SE = 14.6%) and belowground biomass accounted for 37,501.8 kg ha À1 (SE = 23%). The best-fit equation for the estimation of individual tree aboveground biomass include DBH and wood density as explanatory variables (R 2 = 0.898; SEE = 0.371) and is applicable for the diameter range of this study (5.0-27.6 cm) and in environments with similar conditions of the cerrado s.s. sampled. In the stand level, the model tested presented a higher goodness of fit than the single tree models (R 2 = 0.934; SEE = 0.224). Our estimates of aboveground biomass are higher than reported by other studies developed in the same physiognomy, but the estimates of belowground biomass are within the range of values reported in other studies from sites in cerrado s.s. Both biomass estimates, however, exhibit relatively large standard errors. The root-toshoot ratio of the sample trees is in the magnitude of reported values for savanna ecosystems, but smaller than estimated from other studies in the cerrado s.s.

Forty five Prosopis stems of 2.5-18.0 cm diameter at breast height (DBH) were sampled at Nadapal along the Turkwel riverine forest for development of biomass and volume prediction equations for naturally established stands. Basal diameter (D30), DBH and heights were measured, felled trees and their volumes, fresh and dry weights determined. Linear and power models were evaluated for volume and biomass prediction through regression analysis of measured tree parameters. Power models yielded better results than linear models in volume and biomass prediction, with D30 and DBH being more reliable than height. Validation of models at two sites in Marigat and Bura, revealed strong significant correlations between predicted and measured tree biomass and volumes, suggesting effectiveness of the models in biomass prediction across sites. Subsequently, model development and model validation data were pooled to develop national models. Basal diameter was found to be the best variable in the dev...

- by Gabriel Muturi
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- Horticulture, Linear Model, Model validation, Regression Analysis