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Tree allometry plays a crucial role in tree survival, stability, and timber quantity and quality of mixed-species plantations. However, the responses of tree allometry to resource utilisation within the framework of interspecific competition and complementarity remain poorly understood. Taking into consideration strong- and weakspace competition (SC and WC), as well as N2-fixing and non-N2-fixing tree species (FN and nFN), a mixed-species planting trial was conducted for Betula alnoides, a pioneer tree species, which was separately mixed with Acacia melanoxylon (SC + FN), Erythrophleum fordii (WC + FN), Eucalyptus cloeziana (SC + nFN) and Pinus kesiya var. langbianensis (WC + nFN) in southern China. Six years after planting, tree growth, total nitrogen (N) and carbon (C) contents, and the natural abundances of 15N and 13C in the leaves were measured for each species, and the mycorrhizal colonisation rates of B. alnoides were investigated under each treatment. Allometric variations and their relationships with space competition and nutrient-related factors were analyzed. The results showed a consistent effect of space competition on the height-diameter relationship of B. alnoides in mixtures with FN or nFN. The tree height growth of B. alnoides was significantly promoted under high space competition, and growth in diameter at breast height (DBH), tree height and crown size were all expedited in mixtures with FN. The symbiotic relationship between ectomycorrhizal fungi and B. alnoides was significantly influenced by both space competition and N2 fixation by the accompanying tree species, whereas such significant effects were absent for arbuscular mycorrhizal fungi. Furthermore, high space competition significantly decreased the water use efficiency (WUE) of B. alnoides, and its N use efficiency (NUE) was much lower in the FN mixtures. Structural equation modeling further demonstrated that the stem allometry of B. alnoides was affected by its NUE and WUE via changes in its height growth, and crown allometry was influenced by the mycorrhizal symbiotic relationship. Our findings provide new insights into the mechanisms driving tree allometric responses to above- and belowground resource competition and complementarity in mixed-species plantations, which are instructive for the establishment of mixed-species plantations. [ABSTRACT FROM AUTHOR]

Background and aims: Coastal wetland types have been severely altered by human reclamation activities and Spartina alterniflora invasion. However, how these changes impact C-N-P stoichiometry and nutrient allocation of coastal plants remain unclear. Methods: We investigated C, N, and P contents and ratios in leaf, stem, and root from 30 sites with adjacent natural wetlands (as control, dominated by native Phragmites australis), reclaimed wetlands (dominated by native P. australis), and invasive wetlands (dominated by exotic S. alterniflora) across eastern coast of China. Results: C content and N:P ratio remained constant, N and P contents decreased significantly, but C:N and C:P ratios increased with increasing latitude in natural wetlands. While the direction or magnitude of these latitudinal patterns in reclaimed and invasive wetlands were extremely changed at both individual and organ level. Interestingly, leaf had significant higher C, N, and P contents but lower C:N and C:P ratios than stem and root in each wetland. Compared with natural wetlands, both reclaimed and invasive wetlands had significant lower C and N contents and N:P ratio but higher C:N ratio, invasive wetlands also had significant higher leaf P content. P. australis enhanced the homeostasis for N:P, strength allometric relationship of N and P in leaf, but exhibited a isometric relationship of N and P at individual level after reclamation. S. alterniflora had strict homeostasis for N, P and N:P in most organs and strong ability to decouple the allometric relationship of N and P in leaf, and N changed faster than P at individual level. Conclusions: Importantly, large-scale observations showed that reclamation and especially S. alterniflora invasion significantly decreased N:P ratio in each organ, which might highly affect below- and above-ground trophic chains in the future. Our study provides practical insights in understanding species-specific and multiorgan biogeochemical process and the nutrient allocation strategies of plants under reclaimed and invasive pressures in coastal salt marshes. [ABSTRACT FROM AUTHOR]

Exploring the allometric relationship between carbon emission and economic development can provide guidance for policy-makers who hope to accelerate carbon emission reduction and achieve high-quality development. First, based on the established DMSP/OLS and NPP/VIIRS nighttime light datasets, this study simulated the carbon emissions of the Yangtze River Delta from 2000 to 2020. Second, our research analyzed the spatiotemporal evolution characteristics of carbon emissions. Third, adopting allometric growth model, we explored the allometric relationship between economic development and carbon emissions in Yangtze River Delta. The main conclusions are as follows. First, four prediction models, namely, linear fitting, support vector machine, random forest, and CNN-BiLSTM deep learning, were compared to simulate the accuracy of carbon emissions. Consequently, the CNN-BiLSTM deep learning estimation model presented the best accuracy. Second, both the carbon emissions in YRD as a whole showed an increasing trend, with the largest growth rate appearing in Shanghai and the smallest growth rate occurring in Lishui. Moreover, the high-carbon emission areas were mainly distributed in the core city cluster, which are enclosed by Shanghai, Nanjing, and Hangzhou. Finally, the allometric relationship between economic development and carbon emissions was dominated by one-level negative during the sample period, and the relative growth rate of carbon emissions is lower than that of the economic development, which made the YRD at a basic coordinate stage of weak expansion of economy. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cortex radius (CR) and stele radius (SR) are important functional traits associated with the nutrient acquisition and transport functions of fine roots, respectively. However, for developmental and anatomical reasons, the resource acquisition–transport relationship of fine roots is expected to be different for different root orders. To address this issue, critical fine root anatomical traits were examined for the first three orders of roots of 59 subtropical woody plants. Designating the most distal fine roots as order one, SR scaled isometrically with respect to root radius (RR) (i.e., SR ∝ RR1.0) in the three root orders, whereas CR scaled allometrically with respect to RR (i.e., CR ∝ RR>1.0) with the numerical values of scaling exponents increasing significantly with increasing root orders thereby indicating a disproportional increase in CR with increasing root orders. There were also differences between normalized root tissue (CR/RR and SR/RR) and RR in different root orders. A negative isometric relationship (i.e., SR/RR ∝ RR−1.0) existed between SR/RR and RR in three order roots, whereas the allometric exponent between CR/RR and RR increased with root order (from 0.88 to 1.55). Collectively, the data indicate that root anatomical and functional traits change as a function of RR and that these changes need to be considered when modeling fine root resource acquisition–transport functions. [ABSTRACT FROM AUTHOR]

Accurate estimates of tree height (H) are critical for forest productivity and carbon stock assessments. Based on an extensive dataset, we developed a set of generalized mixed-effects height–DBH (H–D) models in a typical natural mixed forest in Northeastern China, adding species functional traits to the H–D base model. Functional traits encompass diverse leaf economic spectrum features as well as maximum tree height and wood density, which characterize the ability of a plant to acquire resources and resist external disturbances. Beyond this, we defined expanded variables at different levels and combined them to form a new model, which provided satisfactory estimates. The results show that functional traits can significantly affect the H–D ratio and improve estimations of allometric relationships. Generalized mixed-effects models with multilevel combinations of expanded variables could improve the prediction accuracy of tree height. There was an 82.42% improvement in the accuracy of carbon stock estimates for the studied zone using our model predictions. This study introduces commonly used functional traits into the H–D model, providing an important reference for forest growth and harvest models. [ABSTRACT FROM AUTHOR]

Carbon (C), nitrogen (N), and phosphorus (P) stoichiometry and their allometric relationships in soil and plants are hot topics that attract a lot of attention, while those rocks that form soils are often neglected. Weathering is a common geological phenomenon that may significantly influence the nutrient composition and release of nutrients from rock and its inherent soils. This study presents C, N, and P concentrations data as well as microscope petrological photographs of fresh and weathered sandstones from Longhushan World Geopark in SE China, in an attempt to investigate C, N, and P stoichiometry of rocks before and after weathering and discuss the driving mechanisms. The results show that weathering significantly decreased rock C, C/N, and C/P concentrations, slightly decreased N and N/P concentrations, and slightly increased P concentration. Microscope observations show that fresh sandstones contain calcite, apatite, microplagioclase, and organic matter, while weathered sandstones feature apatite and organic matter. The flexible allometric relationships and mineral changes before and after rock weathering indicate that chemical mechanisms, such as dissolution of carbonate and hydration of microplagioclase, have changed the existence form of C, N, P and, thus, significantly influence rock C, N, and P stoichiometry. This stoichiometry feature can be in turn used to reflect the regulation effect of rock weathering. [ABSTRACT FROM AUTHOR]

Copyright of Naturaliste Canadien is the property of La Societe Provancher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Allometric growth equations help to describe the correlation between the variables of tree biological characteristics (e.g., diameter and height, diameter and canopy width) and estimate tree dynamics at a given tree dimension. Allometric models of common tree species within urban forests are also important to relate ecosystem services to common urban tree measurements such as stem diameter. In this study, allometric growth models were developed for common tree species used for urban greening on the streets of seven municipal districts in Qingdao city of eastern China. A sampling survey was constructed on an urban–rural gradient to obtain the data of tree diameter, crown width, height to live crown base, and tree height. From these measurements, the crown volume and crown projection area of tree species were calculated. The allometric relationship between two variables was established using quantile regression models (95%, 50%, and 5%) to explore its correlation and the influence of tree species characteristics on urban tree allometry. Our results showed that the correlation of allometric growth of different tree species varied largely due to their own characteristics, and the allometric growth of the same tree species was significantly different as well under the fitting of different quantiles. We found that the relationship between crown width and diameter was stronger than that between tree height and diameter. Moreover, the allometric relationship between crown projection area–diameter and crown width–diameter showed similar fitting. The allometric relationship analysis provide theoretical models and a way to use common field data to support urban forestry management and for the subsequent evaluation and prediction of tree functions and ecosystem services. [ABSTRACT FROM AUTHOR]

Understanding how a plant allocates biomass for reproduction and the effect of location position on twigs' biomass partitioning provides essential information on how to maximise fruit yields through pruning. Fengdan (Paeonia ostii) is a variety of oil Peony newly developed in China. In this paper, the pattern of biomass allocation and allometric growth of the modules within twig (fruit twigs) of five populations of Fengdan were investigated by using standardised major axis (SMA) analyses. The ANOVA results showed that the biomass of stem, seed, husk and fruit per twig significantly varied among populations and among twigs growing at different positions within an individual plant. The top twig had the largest stem and fruit biomass. Twig showed an allometric growth relationship between reproduction and growth (SMA slope b ≠ 1). An obvious trade‐off was found between seed number and 100‐seed weight in fruits. These findings demonstrate that the seated position of the Fengdan twig significantly influences its resource allocation pattern and fruit (seed) yield, implying the efficiency of creating a suitable growth environment and optimising tree architecture in increasing oil Peony yield. [ABSTRACT FROM AUTHOR]

Biomass of seedlings at different developing stages of growth is important information for studying the response of species to site conditions. The objectives of this study was to explore the distribution characteristics of AGB (above-ground biomass) and BGB (below-ground biomass) of Abies georgei var. smithii seedlings of different ages, and investigate the effects of topography (slope aspect, altitude), plant community characteristics (crown density, species diversity, etc.), and soil properties (soil physical and chemical properties) on the biomass and its allocation. Seedlings in five age classes (1–2, 3–4, 5–6, 7–8, and 9–10 years old) were collected by full excavation from 6 elevations (3800 m, 3900 m, 4000 m, 4100 m, 4200 m, 4300 m) on the north and south slopes of Sejila Mountain in Tibet. 15 seedlings of each age class were investigated at one altitude. The individual effects of seedling age (SA) and the interaction effects of SA, slope aspect (SL), and elevation (EG), namely, SL×EG, SL×SA, EG×SA, and SL×EG×SA, had significant effects on the AGB of the seedlings (p<0.05), whereas BGB was only significantly affected by SA (p<0.001). The AGB and BGB of the seedlings showed a binomial growth trend with the increase in seedling age, and had an allometric relationship at different elevations, α (allometric exponential) varied from 0.913 to 1.046 in the northern slope, and from 1.004 to 1.268 in the southern slope. The biomass of seedlings on the northern slope was remarkably affected by stand factors, with a contribution rate of 47.8%, whereas that on the southern slope was considerably affected by soil factors with a contribution rate of 53.2%. The results showed that age was the most important factor affecting seedling biomass. The allometric pattern of seedling biomass was relatively stable, but in a high-altitude habitat, A. georgei var. smithii seedlings increased the input of BGB. Understanding seedling biomass allocation and its influencing factors is useful for evaluating plants' ability to acquire resources and survival strategies for adaptation to the environment in Tibet Plateau. [ABSTRACT FROM AUTHOR]

Accurate estimates of forest aboveground biomass (AGB) are essential for global carbon cycle studies and have widely relied on approaches using spectral and structural information of forest canopies extracted from various remote sensing datasets. However, combining the advantages of active and passive data sources to improve estimation accuracy remains challenging. Here, we proposed a new approach for forest AGB modeling based on allometric relationships and using the form of power-law to integrate structural and spectral information. Over 60 km² of drone light detection and ranging (LiDAR) data and 1,370 field plot measurements, covering the four major forest types of China (coniferous forest, sub-tropical broadleaf forest, coniferous and broadleaf-leaved mixed forest, and tropical broadleaf forest), were collected together with Sentinel-2 images to evaluate the proposed approach. The results show that the most universally useful structural and spectral metrics are the average values of canopy height and spectral index rather than their maximum values. Compared with structural attributes used alone, combining structural and spectral information can improve the estimation accuracy of AGB, increasing R² by about 10% and reducing the root mean square error by about 22%; the accuracy of the proposed approach can yield a R² of 0.7 in different forests types. The proposed approach performs the best in coniferous forest, followed by sub-tropical broadleaf forest, coniferous and broadleaf-leaved mixed forest, and then tropical broadleaf forest. Furthermore, the simple linear regression used in the proposed method is less sensitive to sample size and outperforms statistically multivariate machine learning-based regression models such as stepwise multiple regression, artificial neural networks, and Random Forest. The proposed approach may provide an alternative solution to map large-scale forest biomass using space-borne LiDAR and optical images with high accuracy. [ABSTRACT FROM AUTHOR]

The petiole–lamina relationship is central to the functional tradeoff between photosynthetic efficiency and the support/protection cost. Understanding environmental gradients in the relationship and its underlying mechanisms remains a critical challenge for ecologists. We investigated the possible scaling of the petiole–lamina relationships in three dimensions, i.e., petiole length (PL) vs. lamina length (LL), petiole cross sectional area (PCA) vs. lamina area (LA), and petiole mass (PM) vs. lamina mass (LM), for 325 Qinghai–Tibetan woody species, and examined their relation to leaf form, altitude, climate, and vegetation types. Both crossspecies analysis and meta-analysis showed significantly isometric, negatively allometric, and positively allometric scaling of the petiole–lamina relationships in the length, area, and mass dimensions, respectively, reflecting an equal, slower, and faster variation in the petiole than in the lamina in these trait dimensions. Along altitudinal gradients, the effect size of the petiole–lamina relationship decreased in the length and mass dimensions but increased in the area dimension, suggesting the importance of enhancing leaf light-interception and nutrient transport efficiency in the warm zones in petiole development, but enhancing leaf support/protection in the cold zones. The significant additional influences of LA, LM, and LA were observed on the PL–LL, PCA–LA, and PM–LM relationships, respectively, implying that the single-dimension petiole trait is affected simultaneously by multidimensional lamina traits. Relative to simple-leaved species, the presence of petiolule in compound-leaved species can increase both leaf light interception and static gravity loads or dynamic drag forces on the petiole, leading to lower dependence of PL variation on LL variation, but higher biomass allocation to the petiole. Our study highlights the need for multidimension analyses of the petiole–lamina relationships and illustrates the importance of plant functional tradeoffs and the change in the tradeoffs along environmental gradients in determining the relationships. [ABSTRACT FROM AUTHOR]

Background - Shrublands are receiving increasing attention because of climate change. However, knowledge about biomass allocation of shrublands at the community level and how this is regulated by climate is of limited availability but critical for accurately estimating carbon stocks and predicting global carbon cycles. Methods - We sampled 50 typical shrublands along a climate gradient in China and investigated the biomass allocation of shrubland at the community level and the effect of climate on biomass allocation. Shrub biomass was estimated using species-specific allometric relationships and the biomass of understory herbs was collected by excavating the whole plant. Regression analysis was used to examine the relationships between the biomass and the climate factors. RMA were conducted to establish the allometric relationships between the root and the shoot biomass at the community level. Key results - Shoot, root, and total biomass of shrub communities across different sites were estimated with median values of 206.5, 145.8, and 344.5 g/m2, respectively. Shoot, root, and total biomass of herb communities were estimated at 68.2, 58.9, and 117.2 g/m2, respectively. The median value of the R/S ratio of shrub communities was 0.58 and that of herb communities was 0.84. The R/S ratio of the shrub community showed a negative relationship with mean annual temperature and mean annual precipitation and a positive relationship with total annual sunshine and the aridity index. The R/S ratio of the herb community however showed a weak relationship with climate factors. Shoot biomass of the shrub community was nearly proportional to root biomass with a scaling exponent of 1.17, whereas shoot biomass of the herb community was disproportional to root biomass with a scaling exponent of 2.1. Conclusions - In shrublands, root biomass was more affected than shoot biomass by climate factors and this is related to water availability as a result of biomass allocation change of the shrub community. The understory herb community was less affected by climate due to the modification of the overstory-understory interaction to the climate-induced biomass allocation pattern. Shoot biomass of shrubs scales isometrically with root biomass at the community level, which supports the isometric theory of above-ground and belowground biomass partitioning. [ABSTRACT FROM AUTHOR]

Background: Larch (Larix Mill.) forests are widely distributed in the upper parts of mountainous areas in China, playing vital roles in constructing mountain landscapes and maintaining mountain environments. Despite their importance, our knowledges on the large-scale patterns of structure characteristics and the relationships between different structure variables are unclear. In this paper, we investigated 155 plots from 11 natural larch forest types across the country to explore the biogeographic patterns of the structure characteristics and the allometric relationships between different structure variables for Chinese larch forests. Results: The structure characteristics were significantly different among larch forest types. For different larch forest types, the power function fits the relationships between tree height and diameter at breast height (DBH), average DBH and stem density, and taper and stem density well, but with different exponents among larch forest types. The power exponents of the allometric relationships between tree height and DBH for different larch forest types varied from 0.61 to 0.93 (mean = 0.86) by standard major axis regression (SMA), and from 0.51 to 0.78 (mean = 0.56) by ordinary least square regression (OLS). The 50%, 75% and 95% quantile regression (QR) and OLS indicated that the average DBH and taper of the L. gmelinii forests, L. gmelinii var. principis-rupprechtii forests, and L. sibirica forests were significantly correlated with stem density. Conclusions: The relationship between tree height and DBH showed a power function relationship for all larch forest types in China, but with different exponents. Overall, stem density was negatively correlated with average DBH and taper. The Sect. Larix forests exhibited stand density effect. Our findings provide an important basis for recognizing the biogeographic patterns of structure factors and for the management of larch forests in China. [ABSTRACT FROM AUTHOR]

Triploid organisms, in particular oysters, are widely used in marine aquaculture. However, the advantage of triploid oysters compared to diploids has not been proven in all cases. Comparative morphological analysis of Pacific oysters Crassostrea gigas of different ploidy levels allows evaluating the benefits of raising triploids in the Black Sea. First, the morphological characteristics of diploid and triploid Pacific oysters C. gigas farmed in the Black Sea were studied. Allometric ratios of weight (W, g) and shell height (H, mm) of oysters were obtained, which are described by the equations W2n = 4 x 10-4 x H2n 2.56, R² = 0.86 and W3n = 9 x 10-5 x H3n 2.90, R² = 0.91. Triploids showed positive allometry and had more biomass at smaller shell height than diploid oysters. A clear linear relationship of the height and length of oyster shells was established. Significant differences in linear parameters between 2n and 3n C. gigas farmed in Donuzlav Liman are not seen. Based on these results, it is assumed that the advantage of the growth of 3n mollusks is less evident in farms located at high latitudes. The environmental factors and farm technology have probably affected the growth of oysters to a greater degree than their ploidy. [ABSTRACT FROM AUTHOR]

Flightless birds were once the largest and heaviest terrestrial fauna on many archipelagos around the world. Robust approaches for estimating their population parameters are essential for understanding prehistoric insular ecosystems and extinction processes. Body mass and population density are negatively related for extant flightless bird species, providing a method for quantifying densities and population sizes of extinct flightless species. Here we assemble an updated global data set of body mass and population densities for extant flightless birds and estimate the relationship between these variables. We use generalised least squares models that account for phylogenetic relatedness and incorporate the effects of limiting factors (e.g. habitat suitability) on population density. We demonstrate the applicability of this allometric relationship to extinct species by estimating densities for each of the nine species of moa (Dinornithiformes) and generating a combined spatially explicit map of total moa density across New Zealand. To compare our density estimates with those previously published, we summed individual species' abundances to generate a mean national density of 2.02–9.66 birds km−2 for low‐ and high‐density scenarios, respectively. Our results reconcile the extreme bimodality of previous estimates (< 2 birds km−2 and > 10 birds km−2) and are comparable to contemporary densities of large herbivorous wild mammals introduced into New Zealand about 150 yr ago. The revised moa density has little effect on the harvest rates required to bring about extinction within 150–200 yr, indicating that rapid extinction was an inevitable response to human hunting, irrespective of the initial population of moa. [ABSTRACT FROM AUTHOR]

The morphological structures of organisms may be subject to divergence when exposed to varied nutritive conditions, due to the occurrence of developmental plasticity and its fixation due to the process of genetic accommodation. The allometric relationship of traits with respect to each other and to the whole body defines the shape of an individual. Developmental plasticity in different nutritional regimes affects the absolute value of traits and its relative scaling with respect to body size. We investigated the diversification in wing dimensions and body size in Drosophila ananassae by utilizing isofemale lines of Bilaspur and karyotypically characterized stocks of Varanasi, by rearing flies in nutritional regimes having differences in protein and carbohydrate compositions. The effect of dietary protein variations on plasticity of absolute size of body and wing dimensions was found to be highly genotype‐dependent as compared to sucrose, in both the sexes and in both the populations. This suggests that variation in proteins in natural environment may induce greater selective pressure on traits and may lead to diversification in morphological structures due to the process of genetic accommodation. We found highly significant genetic variation in plasticity for allometric relationship in Bilaspur population for variations in protein as well as carbohydrate in dietary media. However, constraints in plasticity of allometric slopes for wing dimensions in karyotypic stocks of Varanasi were found in response to both the nutritional variations. The analysis of reaction norms also suggested that there is involvement of alpha inversion present in 2L chromosome of Varanasi population, in adapting to different nutritional environmental conditions due to changes in static allometry of different wing dimensions. Overall, this study reveals that the nutritional ecology and evolutionary allometry govern the morphological divergence of traits size and shape in a genotypic‐dependent manner, thereby resulting in morphological evolutions. [ABSTRACT FROM AUTHOR]

Copyright of Bosque (03048799) is the property of Facultad de Ciencias Forestales, Universidad Austral de Chile and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crop residue is recognized as a potential feedstock for biofuels and a sustainable substitute for fossil energy sources. Expanding the acreage of biofuel crops, it is important to establish a crop residue retention regime to conserve soil fertility and prevent soil erosion. This paper presents simple linear and power equations between stubble biomass ratio (SBR, i. e. percentage of stubble biomass to whole plant biomass) and stubble height ratio (SHR, i. e. percentage of stubble height to maximum plant height) for a wide range of field crops of rice, wheat, oat, corn, sorghum, sunflower, canola, soybean and cotton, using data collected from 15 sites in production fields in 11 provinces across China from 2009 to 2012. Simple linear regressions for the crops were associated with highly significant coefficients of determination (R²) for all crops. Validation with independent datasets also showed high R² values, indicating model goodness-of-fit. Mean relative error (MRE) and root mean square error (RMSE) values showed good fit for the two allometric relationships for each field crop studied. These results could be used to assess stubble mass for sustainable residue removal in bio-based energy systems. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Key message : This work demonstrates that the Olive tree, which is managed and pruned as a fruit tree, can be treated as a forest tree using allometric equations, to estimate both biomass production and volumes. Abstract: The Olive tree ( Olea europaea L.) is an evergreen tree that can grow and accumulate a relatively high amount of dry matter, even in dry environmental conditions common in the Mediterranean basin and typical of traditional rain-fed agriculture. The objective of this research was to develop a tool to predict woody biomass and tree component volume for the olive tree, to be used for different agricultural and environmental purposes. The study was carried out in six olive groves across three locations in Italy, collecting data on the 'Leccino' cultivar, which is spread worldwide. Models for volume and biomass were developed for the whole tree and its different components. Basal diameter and a diameter of 80 cm of the trunk height were explored as independent variables for modeling. The results of this study demonstrate a high correlation between the two selected variables and total biomass, above and below-ground biomass and tree component volumes. The same variables show high correlation with total leaf area, but no correlation with the root/shoot ratio, and Leaf Area Index. [ABSTRACT FROM AUTHOR]

In forest ecosystem studies, tree stem structure variables (SSVs) proved to be an essential kind of parameters, and now simultaneously deriving SSVs of as many kinds as possible at large scales is preferred for enhancing the frontier studies on marcoecosystem ecology and global carbon cycle. For this newly emerging task, satellite imagery such as WorldView-2 panchromatic images (WPIs) is used as a potential solution for co-prediction of tree-level multifarious SSVs, with static terrestrial laser scanning (TLS) assumed as a ‘bridge’. The specific operation is to pursue the allometric relationships between TLS-derived SSVs and WPI-derived feature parameters, and regression analyses with one or multiple explanatory variables are applied to deduce the prediction models (termed as Model1s and Model2s). In the case ofPicea abies,Pinus sylvestris,Populus tremulandQuercus roburin a boreal forest, tests showed that Model1s and Model2s for different tree species can be derived (e.g. the maximumR2 = 0.574 forQ. robur). Overall, this study basically validated the algorithm proposed for co-prediction of multifarious SSVs, and the contribution is equivalent to developing a viable solution for SSV-estimation upscaling, which is useful for large-scale investigations of forest understory, macroecosystem ecology, global vegetation dynamics and global carbon cycle. [ABSTRACT FROM AUTHOR]

The diversity and community composition of ground arthropods is routinely analyzed by pitfall trap sampling, which is a cost‐ and time‐effective method to gather large numbers of replicates but also known to generate data that are biased by species‐specific differences in locomotory activity. Previous studies have looked at factors that influence the sampling bias. These studies, however, were limited to one or few species and did rarely quantify how the species‐specific sampling bias shapes community‐level diversity metrics. In this study, we systematically quantify the species‐specific and community‐level sampling bias with an allometric individual‐based model that simulates movement and pitfall sampling of 10 generic ground arthropod species differing in body mass. We perform multiple simulation experiments covering different scenarios of pitfall trap number, spatial trap arrangement, temperature, and population density. We show that the sampling bias decreased strongly with increasing body mass, temperature, and pitfall trap number, while population density had no effect and trap arrangement only had little effect. The average movement speed of a species in the field integrates body mass and temperature effects and could be used to derive reliable estimates of absolute species abundance. We demonstrate how unbiased relative species abundance can be derived using correction factors that need only information on species body mass. We find that community‐level diversity metrics are sensitive to the particular community structure, namely the relation between body mass and relative abundance across species. Generally, pitfall trap sampling flattens the rank‐abundance distribution and leads to overestimations of ground arthropod Shannon diversity. We conclude that the correction of the species‐specific pitfall trap sampling bias is necessary for the reliability of conclusions drawn from ground arthropod field studies. We propose bias correction is a manageable task using either body mass to derive unbiased relative abundance or the average speed to derive reliable estimates of absolute abundance from pitfall trap sampling. [ABSTRACT FROM AUTHOR]

Key message : We present comparisons about biomass allocation between males and hermaphrodites of androdioecious Acer tegmentosum Maxim.. Different biomass allocation patterns were found, and males were shown to have a larger investment into coarse roots and foliage. Context: Sexual dimorphism in differences of reproductive costs between genders has been widely reported for trees, but we still know little about allometric relationships between tree components in both genders. Aims: We present biomass allocation patterns and relationships between components of the androdioecious A. tegmentosum in a broad-leaved mixed forest in northeastern China. The objectives of this study were to examine how gender affects the biomass structure of androdioecious species and how the gender-related reproductive efforts affect the allometric relationships. Methods: We harvested 31 hermaphrodite and 29 male A. tegmentosum trees and opted for diameter at breast height, tree height, and crown length as the independent variables and various biomass components as the dependent variables. Five types of function were used to model allometry equations. Results: Biomass allocation between genders was different, and the best biomass model for each biomass component varies between genders. Males have a higher investment in foliage and coarse root biomass than hermaphrodites, and hermaphrodites invested more in reproduction than males. Conclusion: Biomass equations are strongly gender-related. Males tended to invest a larger fraction of the vegetative biomass into leaves and coarse roots. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) reconstruction of plants is time-consuming and involves considerable levels of data acquisition. This is possibly one reason why the integration of genetic variability into 3D architectural models has so far been largely overlooked. In this study, an allometry-based approach was developed to account for architectural variability in 3D architectural models of oil palm (Elaeis guineensis Jacq.) as a case study. Allometric relationships were used to model architectural traits from individual leaflets to the entire crown while accounting for ontogenetic and morphogenetic gradients. Inter- and intra-progeny variabilities were evaluated for each trait and mixed-effect models were used to estimate the mean and variance parameters required for complete 3D virtual plants. Significant differences in leaf geometry (petiole length, density of leaflets, and rachis curvature) and leaflet morphology (gradients of leaflet length and width) were detected between and within progenies and were modelled in order to generate populations of plants that were consistent with the observed populations. The application of mixed-effect models on allometric relationships highlighted an interesting trade-off between model accuracy and ease of defining parameters for the 3D reconstruction of plants while at the same time integrating their observed variability. Future research will be dedicated to sensitivity analyses coupling the structural model presented here with a radiative balance model in order to identify the key architectural traits involved in light interception efficiency. [ABSTRACT FROM AUTHOR]

The leaf area index (LAI) is an important vegetation biophysical parameter, which plays a critical role in gas-vegetation exchange processes. Several studies have recently been conducted to estimate vegetation LAI using airborne discrete-return Light Detection and Ranging (LiDAR) data. However, few studies have been carried out to estimate the LAI of low-statue vegetation, such as the maize. The objective of this research is to explore the potential of estimating LAI for maize using airborne discrete-return LiDAR data. The LAIs of maize were estimated by a method based on the Beer–Lambert law and a method based on the allometric relationship, respectively. In addition, a new height threshold method for separating ground returns from canopy returns was proposed to better estimate the LAI of maize. Moreover, the two LAI estimation methods were also evaluated using the leave-one-out cross-validation method. Results indicate that the new height threshold method performs better than the traditional height threshold method in separating grounds returns from LiDAR returns. The coefficient of variation of detrended return heights within a field was a good parameter to estimate the LAI of maize. In addition, results also indicate that the method based on the Beer–Lambert law (R2 = 0.849, RMSE = 0.256) was more accurate than the method based on the allometric relationship (R2 = 0.779, RMSE = 0.315) in low-LAI regions, while only the method based on the allometric relationship is suitable for estimating the LAI of maize in high-LAI regions. [ABSTRACT FROM PUBLISHER]

Tomato (Solanum lycopersicum L.) is an important vegetable crop and often cultivated in regions exposed to salinity and high temperatures (HT) which change plant architecture, decrease canopy light interception and disturb physiological functions. However, the long-term effects of salinity and HT combination (S+HT) on plant growth are still unclear. A dynamic functional-structural plant model (FSPM) of tomato was parameterized and evaluated for different levels of S+HT combinations. The evaluated model was used to quantify the contributions of morphological changes (architectural effects) and physiological disturbances (non-architectural effects) on the reduction of shoot dry mass under S+HT. The model predicted architectural variables with high accuracy (>85%), which ensured the reliability of the model analyses. HT enhanced architectural effects but reduced non-architectural effects of salinity on dry mass production. The stronger architectural effects of salinity under HT could not be counterbalanced by the smaller non-architectural effects. Therefore, long-term influences of HT on shoot dry mass under salinity were negative at the whole plant level. Our model analysis highlights the importance of plant architecture at canopy level in studying the plant responses to the environments and shows the merits of dynamic FSPMs as heuristic tools. [ABSTRACT FROM AUTHOR]

Rodents are known to perform post-dispersal seed predation in tropical rain forest, but there is little information on the identity of these seed predators and how they select their seeds. Using cafeteria experiments, we found that seed mass, rodent body mass, and the ratio of seed/rodent mass were determinants of seed consumption. [ABSTRACT FROM AUTHOR]

Aquatic invertebrate biomass estimations are often important in ecological and biological studies. Biomass may be determined by regression models between body and case dimensions and dry mass. Using linear, exponential and power regressions we analyzed the relationship between body and case dimensions and the biomass of Phylloicus elektoros Prather, 2003. Furthermore, we used cross-validation to evaluate the predictions of our models and of the models developed for Phylloicus sp. from southeastern Brazil. We measured four body dimensions (head capsule width, interocular distance, body and pronotum length) of 152 larvae and two case dimensions (width and length) of 45 cases. Case width provided better fit with biomass than case length in all model classes. Body length provided the best biomass prediction. Biomass predictions using models proposed in the literature were 75% lower than the observed values. The power model provided the best fit between body and case dimensions with biomass. However, exponential models also provided good biomass estimates. We observed a close fit between body and case dimensions and biomass, but the predictive power of the models was low (~40%). The predictive power of models proposed in the literature was much worse than those built from local data and thus we do not recommend their use to predict the biomass of organisms from different regions. [ABSTRACT FROM AUTHOR]

Background and Aims Biomass accumulation and allocation patterns are critical to quantifying ecosystem dynamics. However, these patterns differ among species, and they can change in response to nutrient availability even among genetically related individuals. In order to understand this complexity further, this study examined three ephemeral species (with very short vegetative growth periods) and three annual species (with significantly longer vegetative growth periods) in the Gurbantunggut Desert, north-western China, to determine their responses to different nitrogen (N) supplements under natural conditions. Methods Nitrogen was added to the soil at rates of 0, 0·5, 1·0, 3·0, 6·0 and 24·0 g N m−2 year−1. Plants were sampled at various intervals to measure relative growth rate and shoot and root dry mass. Key Results Compared with annuals, ephemerals grew more rapidly, increased shoot and root biomass with increasing N application rates and significantly decreased root/shoot ratios. Nevertheless, changes in the biomass allocation of some species (i.e. Erodium oxyrrhynchum) in response to the N treatment were largely a consequence of changes in overall plant size, which was inconsistent with an optimal partitioning model. An isometric log shoot vs. log root scaling relationship for the final biomass harvest was observed for each species and all annuals, while pooled data of three ephemerals showed an allometric scaling relationship. Conclusions These results indicate that ephemerals and annuals differ observably in their biomass allocation patterns in response to soil N supplements, although an isometric log shoot vs. log root scaling relationship was maintained across all species. These findings highlight that different life history strategies behave differently in response to N application even when interspecific scaling relationships remain nearly isometric. [ABSTRACT FROM AUTHOR]

The present investigation deals with the assessment of fecundity and gonadosomatic index (GSI) of Schizothorax plagiostomus collected from the river Jhelum, Kashmir. The mean value of fecundity was estimated as 14599 (SD 9219.7) eggs with a mean total length of 34.340 (SD 6.86) and a mean total body weight of 440.60 (SD267.62). The relationship of fecundity with other parameters such as total length, total weight, ovary length and ovary weight were found to be linear and the value of correlation coefficient (r) was 0.965, 0.961, 0.933 and 0.972 respectively. The highest value of GSI was recorded in the month of May 12.56 (SD1.81). [ABSTRACT FROM AUTHOR]

We investigate evapotranspiration, sap flow and top soil water content variations in a wax myrtle-tree heath (‘fayal-brezal’ in Spanish) cloud forest in the Garajonay National Park (La Gomera, Canary Islands) over a 1-year period. We provide transpiration estimates for one of the representative species, the shrubby needle-like Erica arborea L., present in this relict subtropical forest. An ad hoc tree up to the stand scaling method that combines the sap flow and auxiliary reference evapotranspiration data is illustrated, showing to be useful when sap flow in a limited number of trees has been monitored. Individual daily-based scaling curves of the Gompertz type were necessary to explain the observed sap flow variability in E. arborea during the 1-year period investigated (r2 ≥ 0.953 with mode of r2 = 0.9999). The mean daily sap flow of an E. arborea individual amounted to 8.37 ± 5.65 kg day−1 tree−1, with a maximum of 20.48 kg day−1 tree−1, yielding an annual total of 3052.89 kg tree−1. A comparison of the computed daily transpiration with the continuous micrometeorological time series monitored in the studied plot suggested that solar radiation was the main driving force of transpiration in E. arborea (cross correlation index = 0.94). Fog may also affect tree transpiration via its reduction of radiation and temperature, such that during foggy periods the mean daily water loss estimate of E. arborea was 5.35 ± 4.30 kg day−1 tree−1, which sharply contrasted with the 2.4-fold average transpiration values obtained for fog-free days, i.e., 12.81 ± 4.33 kg day−1 tree−1. The annual water balance rendered a 288 mm year−1 water input to the forest and evidenced the need for accurately quantifying the contribution of fog water dripping from the canopy. [ABSTRACT FROM PUBLISHER]

Domestication of animals has resulted in phenotypic changes by means of natural and human-directed selection. Body composition is important for farm animals because it reflects the status of energy reserves. Thus, there is the possibility that farm animals as providers of food have been more affected by human-directed selection for body composition than laboratory animals. In this study, an analysis was conducted to determine what similarities and differences in body composition occur between farm and laboratory animals using literature data obtained from seven comparative slaughter studies (n = 136 observations). Farm animals from four species (cattle, goats, pigs and sheep) were all castrated males, whereas laboratory animals from three species (dogs, mice and rats) comprised males and/or females. All animals were fed ad libitum. The allometric equation, Y = aXb, was used to determine the influence of species on the accretion rates of chemical components (Y, kg) relative to the growth of the empty body, fat-free empty body or protein weights (X, kg). There were differences between farm and laboratory animals in terms of the allometric growth coefficients for chemical components relative to the empty BW and fat-free empty BW (P < 0.01); farm animals had more rapid accretion rates of fat (P < 0.01) but laboratory animals had more rapid accretion rates of protein, water and ash (P < 0.01). In contrast, there was no difference in terms of the allometric growth coefficients for protein and water within farm animals (P > 0.2). The allometric growth coefficients for ash weight relative to protein weight for six species except sheep were not different from a value of 1 (P > 0.1), whereas that of sheep was smaller than 1 (P < 0.01). When compared at the same fat content of the empty body, the rate of change in water content (%) per unit change in fat content (%) was not different (P > 0.05) across farm animal species and similar ash-to-protein ratios were obtained except for dogs. The fraction of empty body energy gain retained as fat increased in a curvilinear manner, and there was little variation among farm animals at the same fat content of the empty body. These findings may provide the opportunity to develop a general model to predict empty body composition across farm animal species. In contrast, there were considerable differences of chemical body composition between farm and laboratory animals. [ABSTRACT FROM PUBLISHER]

Context: While many woody perennials grow and reproduce in varying environments, their ability to modify their reproductive allocation under varying resource availability is unclear. Aims: This study aimed to demonstrate the occurrence of plasticity of reproductive allocation in a pioneer woody species ( Ulex europaeus). Methods: We studied seed production in 144 plants under different irradiance and population densities. We measured their basal area, their whole shoot biomass and photosynthetic biomass, and their reproductive output (number of fruits per individual and number of seeds per fruit). Results: We found that newly produced photosynthetic biomass was influenced by environmental variation, which in turn determined its reproductive output. In addition, in low light conditions investment in reproduction was more reduced than investment in growth indicating plasticity of reproductive allocation. Conclusion: These results provide the first evidence for plasticity of reproductive allocation of a woody plant. It may lead to the ability of this pioneer species to survive and to continue to reproduce even at low rates in non-optimal shady habitats and to maintain a non-empty seed bank in forest systems with long unfavourable periods between two disturbances. [ABSTRACT FROM AUTHOR]

We propose a conceptual (generic) allometric (power function) relationship between tree-size-related forest inventory attributes (e.g. biomass, volume, basal area, quadratic mean diameter, Lorey's height) and canopy height (CH) as estimated from first-return airborne light detection and ranging (LiDAR) pulses. A data-driven estimation of the parameters in the power function is complicated, so we recommend an alternative approximation obtained via a linearisation step. Only two predictors appear in the approximation: the mean CH and the variance of CHs within the spatial domain supported by field data. The proposed model eliminates an otherwise complex search for the best predictors amongst a large number of candidate LiDAR metrics. It also facilitates model comparisons and interpretation. Fit statistics estimated for volume, basal area, quadratic mean diameter and Lorey's height – using three separate datasets from Norway – were compelling. [ABSTRACT FROM AUTHOR]

Premise of the study: In a previous paper, we questioned the traditional interpretation of the advantages and disadvantages of high wood density (Functional Ecology 24: 701-705). Niklas and Spatz (American Journal of Botany 97: 1587-1594) challenged the biomechanical relevance of studying properties of dry wood, including dry wood density, and slated that we erred in our claims regarding scaling. Methods: We first present the full derivation of our previous claims regarding scaling. We then examine how the fresh modulus of rupture and the elastic modulus scale with dry wood density and compare these scaling relationships with those for dry mechanical properties, using almost exactly the same data set analyzed by Niklas and Spatz. Key results: The derivation shows that given our assumptions that the modulus of rupture and elastic modulus are both proportional to wood density, the resistance to bending is inversely proportional to wood density and strength is inversely proportional with the square root of wood density, exactly as we previously claimed. The analyses show that the elastic modulus of fresh wood scales proportionally with wood density (exponent 1.05, 95% CI 0.90-1.11) but that the modulus of rupture of fresh wood does not, scaling instead with the 1.25 power of wood density (Cl 1.18-1.31 ). Conclusions: The deviation from proportional scaling for modulus of rupture is so small that our central conclusion remains correct: for a given construction cost, trees with lower wood density have higher strength and higher resistance to bending. [ABSTRACT FROM AUTHOR]

Density effects on the growth of self-thinning Eucalyptus urophylla stands were examined for 7 years. Tree height and stem diameter at breast height were measured during the experimental period. Stems, branches, leaves, bark and roots of 45 E. urophylla trees were sampled in three different density stands in order to establish their biomass equations. Change trends of the biological time τ and density ρ were described used corresponding equations. The stem weight ratio increased and leaf weight ratio decreased, whereas those of branch, bark and root were relatively steady from 2 years after the planting. The competition-density (C-D) effect equation of mean organ weight w was derived by combining the allometric power relationship between mean tree weight w and w with the C-D effect equation of self-thinning stands. The equations of the C-D effect for w and ρ and for w and ρ were used to describe the C-D effects in tree and organs during course of self-thinning, respectively, and showed a good fit to the data. Leaf biomass of different density stands reached a more or less constant level with time elapse. High density produced the greatest biomass and stem biomass, so that it is the best choice in silvicultural practice. [ABSTRACT FROM AUTHOR]

The allometric relationships between mean weights of components, such as stems, branches and leaves and tree weight as well as their time-trajectories, were studied with data of self-thinning Pinus densiflora stands with different densities. The allometric relationships existed between the weights of stems, branches and leaves and the tree weight during the course of self-thinning. The stem weight ratio increased with increasing tree weight because the allometric coefficient in stem was higher than unity, whereas the branch weight ratio and the leaf weight ratio decreased because the allometric coefficients in branches and leaves were less than unity. An allometric power relationship existed between mean component weight and mean tree weight during the course of self-thinning. The time-trajectory of mean component weight ( w) and density (ρ) in the early growth stage was expressed as a mathematical model which incorporates the allometric power relationship into the Tadaki's model, whereas the model for describing w-ρ trajectory in the later growth stage was derived by combining the allometric power relationship with 3/2 power law. The two models, Tadaki's model and 3/2 power law, showed a good fit to data from P. densiflora stands. The time-trajectories of mean tree weight ( w)-density (ρ) or w-ρ initially almost moves nearly vertically in the low-density stand, moves along a steep curve and an inclined curve in the medium- and high-density stands, respectively, and gradually approaches self-thinning line in the early stage of stand development, whereas they reached and moved along the self-thinning line in the later stage of stand development. The self-thinning exponents were determined to be 1.71, 1.19 and 1.13 for the trees, 2.38, 1.33 and 1.20 for the stem, 3.16, 1.55 and 1.46 for the branches, 2.66, 1.39 and 1.35 for the leaves in the low-, medium- and high-density stands, respectively. The 3/2 power law of self-thinning is derived on the basis of simple geometric model of space occupation by growing trees, but allometric growth of tree and components can make the slope of the self-thinning line being different from −3/2. The reasons that the self-thinning exponents of components in the low-density stand were greater than those in the medium- and high-density stands were discussed. [ABSTRACT FROM AUTHOR]

The importance of sexual reproduction for clonal plant species has long been underestimated, perhaps as a consequence of the difficulty in identifying individuals, preventing the study of their population dynamics. Such is the case for Empetrum hermaphroditum, an ericaceous species, which dominates the ground vegetation of subarctic ecosystems. Despite abundant seed production, seedlings are rarely observed. Therefore, prevalent seedling recruitment on a subarctic dune system provided an opportunity to study the population dynamics and spatial pattern of the colonization phase of this species. We established a 6 – ha grid on the dune systems that extended from the shoreline to be fixed dunes and mapped and measured all E. hermaphroditum individuals in the grid. Moreover, we sampled 112 individuals just outside the grid to identify any allometric relationship between the size and age of the individuals, which allowed us to reconstruct population expansion. The overall size structure suggests that the populations is still expanding. In the last 50 yr. E. hermaphroditum advanced more than 200 m in the dune system. Expansion started in the 1960s simultaneously at different distances from the shoreline. Colonization did not proceed gradually from the fixed dune toward the shoreline but instead individuals established earlier in the troughs between the dunes, with and increasingly clumped spatial pattern as the population filled in with time. [ABSTRACT FROM AUTHOR]

Few tree size/leaf area correlations have been produced for hardwoods, where the extrapolation from individual branches to the whole tree is less straightforward than in conifers with more regular branching patterns. We used randomized branch sampling to estimate leaf area of European beech ( Fagus sylvatica L.) trees of different stands, ages and areas in Austria. Cross-sectional areas (CSA) predicted 87–92% of leaf area variation, the best predictor being the sum of branch CSA. Leaf area was somewhat better correlated with CSA at breast height than at the base of the crown, and using sapwood instead of total CSA made little difference. While there was no effect of growth area, a stepwise regression model showed that dominant trees in pole-stage had, for unclear reasons, significantly higher leaf area/CSA relationships. A comparison with regressions produced from smaller beech trees in other parts of Europe suggests that the leaf area/basal area regression is generally valid for beech in central Europe. [ABSTRACT FROM AUTHOR]

Biomass and aboveground net primary production (ANPP) in a monospecific pioneer stand of a mangrove Kandelia obovata (S., L.) Yong were quantified. The estimated biomasses in leaves, branches, stems, roots, aboveground and total were 5.61 (3.68%), 28.8 (18.9%), 46.1 (30.2%), 71.8 (47.2%), 80.5 (52.8%) and 152 Mg ha−1 (100%), respectively. Stem phytomass increment per tree was estimated using allometric relationships and stem analysis. Stem volume without bark of harvested trees showed a strong allometric relationship with D H ( D0.1, diameter at a height of one-tenth of tree height H) ( R2 = 0.924). Annual stem volume increment per tree showed a strong allometric relationship with D H ( R2 = 0.860). Litterfall rate ranges from 3.87 to 56.1 kg ha−1 day−1 for leaves and 0.177 to 46.2 kg ha−1 day−1 for branches. Seasonal changes of litterfall rate were observed, which showed a peak during wet season (August–September). Total annual litterfall was estimated as 10.6 Mg ha−1 year−1, in which 68.2% was contributed by the leaves. The ANPP in the K. obovata stand was 29.9–32.1 Mg ha−1 year−1, which is ca. 2.8–3.0 times of annual litterfall. The growth efficiency (aboveground biomass increment/LAI) was 5.35–5.98 Mg ha−1 year−1. The low leaf longevity (9.3 months) and high growth efficiency of K. obovata makes it a highly productive mangrove species. [ABSTRACT FROM AUTHOR]

Root biomass and root distribution were studied in Entisols derived from the thick deposition of volcanic pumice on Hokkaido Island, Japan, to examine the effect of soil conditions on tree root development. The soil had a thin (<10 cm) A horizon and thick coarse pumiceous gravel layers with low levels of available nutrients and water. Two stands were studied: a Picea glehnii– Abies sachalinensis stand (PA stand) and a Larix kaempferi– Betula platyphylla var. japonica stand (LB stand). The allometric relationships between diameter at breast height (DBH) and aboveground and belowground biomass of these species were obtained to estimate stand biomass. The belowground biomass was small: 30.6 Mg ha−1 for the PA stand and 24.3 Mg ha−1 for the LB stand. The trunk/root ratios of study stands were 4.8 for the PA stand and 4.3 for the LB stand, which were higher than those from previous studies in boreal and temperate forests. All species developed shallow root systems, and fine roots were spread densely in the shallow A horizon, suggesting that physical obstruction by the pumiceous layers and their low levels of available water and nutrients restricted downward root elongation. The high trunk/root ratios of the trees may also have resulted from the limited available rooting space in the study sites. [ABSTRACT FROM AUTHOR]

The allometric relationships for plant daily biomass production rates, different measures of body size (dry weight and length) and photosynthetic biomass per plant are reported for two mutants of Arabidopsis thaliana ( abi1-1, insensitive to ABA; era1-2, hypersensitive to ABA). Scaling relationships, such as daily rate of growth ( G) vs body mass ( M), plant body length or plant height ( L) vs body mass ( M), photosynthetic biomass ( M p ) vs non-photosynthetic biomass ( M n ), and daily rate of growth ( G) vs. photosynthetic biomass ( M p ) were significantly different in abi1-1 and era1-2. It is implied that the sensitivity to abscisic acid may change the scaling relationships for plant biomass production rate and body size in Arabidopsis thaliana. Because these scaling relationships are closely related to sensitivity to abscisic acid, they are of importance for phytohormonal ecology. [ABSTRACT FROM AUTHOR]

Ecological data analysis often involves fitting linear or nonlinear equations to data after transforming either the response variable, the right side of the equation, or both, so that the standard suite of regression assumptions are more closely met. However, inference is usually done in the natural metric and it is well known that retransforming back to the original metric provides a biased estimator for the mean of the response variable. For the normal linear model, fit under a log-transformation, correction factors are available to reduce this bias, but these factors may not be generally applicable to all model forms or other transformations. We demonstrate that this problem is handled in a straightforward manner using a Bayesian approach, which is general for linear and nonlinear models and other transformations and model error structures. The Bayesian framework provides a predictive distribution for the response variable so that inference can be made at the mean, or over the entire distribution to incorporate the predictive uncertainty. [ABSTRACT FROM AUTHOR]

Questions: How do biological invasion patterns of Larix kaempferi seedlings change with different microhabitats along an elevational gradient on a volcano? How are seedling attributes such as establishment, competitive ability and morphological plasticity, advantageous to the invasion of stressful disturbed areas? Location: Mount Koma, Hokkaido, Japan. Methods: Seed sowing experiments and natural seedling censuses were conducted with L. kaempferi and the dominant native tree Betulaermanii. Seed germination, seedling survival and allocation were investigated on three microhabitats (bare ground, Salix reinii patch and Larix understorey) in three elevational zones for three years. Results: Seed germination was higher in Larix understorey than in bare ground and Salix patches, but did not differ between elevations. Survival rates were not different between elevations and microhabitats. Larix had a higher survival rate than Betala. Larix showed the highest natural seedling density in Sa/ix patches, independent of elevational differences, while Betu/a density was nearly zero. Larix seedlings changed allocations between microhabitats, while the ratio of leaf to total biomass was constant. In bare ground Larix was more stunted and branched and increased its allocation to the roots. This form is adaptive to windy, nutrient-poor environments. Larix seedlings were taller and more slender in Salix patches, indicating that the priority was light acquisition in shaded habitats. Little change in Betula allocation was detected. Conclusion: Invasive species establish themselves more efficiently than native species in every microhabitat investigated, especially at higher elevations, by having higher survival and growth rates derived from superior seedling performance. Plant communities on and above the tree line are modified by the biological invasion. [ABSTRACT FROM AUTHOR]

The article presents a study of a framework to examine the response of a regional group of species to land-use change or habitat alterations. The framework has the components of a demographic model, a regional database of life-history traits, and a sensitivity analysis of the model predictions. The model predicts the minimum area of native habitat that allows for persistence of a species, and was applied to the regional community of species of avifauna of Costa Rica.

Estimates of biomass and leaf area index (LAI) are important variables in ecological and climate models. However, very little is known about the biomass and LAI of the vegetation in the Scandinavian mountain area. In this study, extensive field data consisting of diameter at breast height for 13 000 trees and height for 550 trees were collected. Furthermore, biomass and leaf area (LA) measurements for 46 mountain birch trees [ Betula pubescens ssp . czerepanovii (Orlowa) Hämet-Ahti] and biomass and LA measurements for shrubs (e.g. Salix spp., Betula nana ) at 36 sample plots were carried out. Multiplicative linear models for trees were fitted to tree biomass and LA measurements using basal area at breast height, height, crown diameter and diameter at stump height as explanatory variables. Additive linear models were fitted to shrub biomass and LAI measurements using coverage of shrubs, topographic variables and soil type as explanatory variables. The functions were then used to predict the biomass and LAI for trees and shrubs for the entire test area, which covers an area of 84 km 2 and is located at latitude 68° N. The mean total biomass estimates were 27 493 kg ha -1 for the forest and 7650 kg ha -1 for snow-protected heath and meadow vegetation. The LAIs were 2.06 and 0.52, respectively. For monitoring biomass and LAI in the Scandinavian mountain area, the functions could also be applied to data from traditional field-based inventories and the estimates might further be improved by combining the estimates from the test area with auxiliary information such as remote sensing images. [ABSTRACT FROM AUTHOR]