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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]

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]

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]

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]

The filtration rate of the soft clam Mya arenaria was measured as the volume of water cleared of algal cells ( Rhodomonas sp.) in two ways, by means of the clearance method and the suction method. Both methods allow measurements on undisturbed clams buried in the sediment. The filtration rate (F, ml min -1 individual -1 ) of Mya arenaria as a function of temperature (T, °C) could be expressed as: F = 1.78T + 13.35 in the temperature-tolerance interval of 4-22 °C where the opening state of the siphons remain unchanged. After a 22 day exposure period to a lower constant temperature of 14 °C, the filtration rate was subsequently measured as a function of temperature and expressed as: F = 2.19T + 29.15. Based on the slopes of the regression lines as well as on the observed linear increase in filtration rate during the acclimation period (mainly due to growth), it is concluded that only minor, or possibly no, temperature acclimation may take place in soft clams (and presumably other bivalves). The filtration rate (F, l h -1 ; 11 °C) as a function of dry weight of soft parts (W, g) and shell length (L, mm) could be described by means of the allometric equations: F = 4.76 W 0.71 and F = 0.0007L 2.47 . [ABSTRACT FROM AUTHOR]