Is there really a proportional relationship between VO2max and body weight? A review article

Maximum oxygen uptake (VO2max) is a “gold standard” in aerobic capacity assessment, playing a vital role in various fields. However, ratio scaling (VO2maxbw), the present method used to express relative VO2max, should be suspected due to its theoretical deficiencies. Therefore, the aim of the study was to revise the quantitative relationship between VO2max and body weight (bw). Dimensional analysis was utilized to deduce their theoretical relationship, while linear or nonlinear regression analysis based on four mathematical models (ratio scaling, linear function, simple allometric model and full allometric model) were utilized in statistics analysis to verify the theoretical relationship. Besides, to investigate the effect of ratio scaling on removing body weight, Pearson correlation coefficient was used to analyze the correlation between VO2maxbw and bw. All the relevant data were collected from published references. Dimensional analysis suggested VO2max be proportional to bw23. Statistics analysis displayed that four mathematical expressions were VO2max = 0.047bw (p<0.01, R2 = 0.68), VO2max = 0.036bw+0.71 (p<0.01, R2 = 0.76), VO2max = 0.10bw0.82 (p<0.01, R2 = 0.93) and VO2max = 0.23bw0.66–0.48 (p<0.01, R2 = 0.81) respectively. Pearson correlation coefficient showed a significant moderately negative relation between VO2maxbw and bw (r = -0.42, p<0.01), while there was no correlation between VO2maxbw0.82 and bw (r = 0.066, p = 0.41). Although statistics analysis did not fully verify the theoretical result, both dimensional and statistics analysis suggested ratio scaling distort the relationship and power function be more appropriate to describe the relationship. Additionally, we hypothesized that lean mass, rather than body weight, plays a more essential role in eliminating the gap between theoretical and experimental b values, and is more appropriate to standardize VO2max, future studies can focus more on it.

An Allometric Model Based Approach For Estimating Biomass In Seven Indian Bamboo Species In Western Himalayan Foothills, India

The rapid growth rate, high biomass production, and annual harvesting, makes bamboo as suitable species for commercial production. Allometric equations for many broadleaf and conifer tree species are available. However, knowledge on biomass production and allometric equations of bamboos are limited. This study aims at developing species specific allometric models for predicting biomass and synthetic height values as a proxy variable for seven bamboo species in Himalayan foothills. Two power form based allometric models were used to predict above ground and culm biomass using Diameter at breast height (D) alone and D in combination with culm height (H) as independent variable. This study also extended to establishing H-D allometric model that can be used to generate synthetic H values as proxy to missing H. In the seven bamboo species studied, among three major biomass component (culm, branch and foliage), culm is the most important component with highest share (69.56 to 78.71%).Distribution of percentage (%) share of culm, branch and foliage to above ground fresh weight varies significantly between different bamboo species. D. hamiltonii has highest productivity for above ground biomass components. Ratio of dry to fresh weight of seven bamboo species was estimated for culm, branch, foliage and above ground biomass to convert fresh weight to dry weight.

Exploring the Relationship between Forest Canopy Height and Canopy Density from Spaceborne LiDAR Observations

Forest structure is a useful proxy for carbon stocks, ecosystem function and species diversity, but it is not well characterised globally. However, Earth observing sensors, operating in various modes, can provide information on different components of forests enabling improved understanding of their structure and variations thereof. The Ice, Cloud and Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS), providing LiDAR footprints from 2003 to 2009 with close to global coverage, can be used to capture elements of forest structure. Here, we evaluate a simple allometric model that relates global forest canopy height (RH100) and canopy density measurements to explain spatial patterns of forest structural properties. The GLA14 data product (version 34) was applied across subdivisions of the World Wildlife Federation ecoregions and their statistical properties were investigated. The allometric model was found to correspond to the ICESat GLAS metrics (median mean squared error, MSE: 0.028; inter-quartile range of MSE: 0.022–0.035). The relationship between canopy height and density was found to vary across biomes, realms and ecoregions, with denser forest regions displaying a greater increase in canopy density values with canopy height, compared to sparser or temperate forests. Furthermore, the single parameter of the allometric model corresponded with the maximum canopy density and maximum height values across the globe. The combination of the single parameter of the allometric model, maximum canopy density and maximum canopy height values have potential application in frameworks that target the retrieval of above-ground biomass and can inform on both species and niche diversity, highlighting areas for conservation, and potentially enabling the characterisation of biophysical drivers of forest structure.

Hubungan panjang-berat dan faktor kondisi julung-julung (Hemirhamphodon pogonognathus) di Aek Mailil Kabupaten Labuhanbatu Sumatera Utara Indonesia

Julung-julung (Hemirhamphodon pogonognathus) merupakan salah satu spesies ikan asli Indonesia. Aek Mailil merupakan salah satu habitat ikan julung-julug (H. pogonognathus) yang berada di Kabupaten Labuhanbatu. Penelitian bertujuan untuk mendapatkan hubungan panjang-berat dan faktor kondisi ikan julung-julung (H. pogonognathus) yang hidup di Aek Mailil. Pengambilan data dilakukan mulai November 2020 hingga Januari 2021 dengan alat tangkap durung. Titik sampling ditetapkan atas informasi dari masyarakat Desa Bandar Kumbul. Hubungan panjang-berat dihitung dengan Linear Allometrik Model (LAM), sedangkan faktor kondisi dihitung dengan rumus Fulton (K) dan berat relatif (Wr). Pola pertumbuhan ikan julung-julung (H. pogonognathus) mendapatkan hasil alometrik negatif dengan nilai b 2,9371 (b<3). Nilai koefisien Fulton (K) 2,57 dan koefisien berat relatif (Wr) 103,07. Hal ini menunjukkan bahwa pola pertumbuhan ikan julung-julung (H. pogonognathus) allometrik negatif dengan panjang tubuh lebih cepat dibandingkan berat tumbuh. Nilai (K) menunjukkan bahwa Aek Mailil masih dalam keadaan seimbang dan baik untuk mendukung kehidupan ikan julung-julung (H. pogonognathus). Kata kunci: faktor kondisi; Hemirhamphodon pogonognathus; pola pertumbuhan ABSTRACTLong-Weight relationship and condition factors of Julung-Julung (Hemirhamphodon pogonognathus) in Aek Mailil, Labuhanbatu Regency, North Sumatera, Indonesia. Hemirhamphodon pogonognathus is one of Indonesia's native fish species. Aek Mailil is one of the habitats for julung-julung (H. pogonognathus) in Labuhanbatu Regency. This study aimed to determine the relationship between length-weight and condition factors of julung-julung (H. pogonognathus) living in Aek Mailil. Sampling was carried out from November 2020 to January 2021 using durung fishing gear. The sampling points were determined based on information from the local community of Bandar Kumbul Village. The relationship of length-weight is calculated using the Linear Allometric Model (LAM), while the condition factor is calculated using the Fulton formula (K) and relative weight (Wr). The growth pattern of julung-julung (H. pogonognathus) got a negative allometric result with a b value of 2.9371 (b <3). The value of the Fulton coefficient (K) 2.57 and the relative weight coefficient (Wr) 103.07. This means that Aek Mailil's waters are in a balanced state and can support the (H. pogonognathus) live.Keywords: condition factor; Hemirhamphodon pogonognathus; growth pattern

Allometric model to estimate biomass and carbon of seedling in Pangarengan mangrove forest, Cirebon, West Java

Ekosistem mangrove di Desa Pangarengan, Kabupaten Cirebon memberikan manfaat jasa lingkungan, diantaranya sebagai penjerap dan penyimpan karbon. Umumnya, pendugaan simpanan karbon hutan mangrove menggunakan persamaan alometrik. Namun demikian, persamaan alometrik yang tersedia saat ini masih disusun dari tahapan pertumbuhan pancang, tiang, dan pohon. Tujuan penelitian ini adalah menyusun model alometrik untuk semai di hutan mangrove. Penelitian dilaksanakan pada bulan Juni 2021 di hutan mangrove Desa Pangarengan, Kabupaten Cirebon. Alat yang digunakan dalam penelitian adalah kaliper, pita ukur, timbangan digital, dan gunting tanaman. Bahan penelitian berupa semai mangrove jenis Rhizophora mucronata, Avicennia marina, dan Sonneratia caseolaris sebanyak 25 sampel. Model alometrik terbaik dalam menduga biomassa berat kering dengan prediktor diameter pangkal adalah Y = 35,013 Dp1,860 (R2 adj = 0,873; SEE = 0,472) dengan menggunakan prediktor diameter ujung adalah Y = 249,573 Du2,276 (R2 adj = 0,524; SEE = 0,710), sedangkan alometrik penduga kandungan karbon semai adalah Y = 5,835 Dp1,804 (R2 adj = 0,831; SEE = 0,528) dan Y = 35,750 Du2,107 (R2 adj = 0,607; SEE = 0,805). Model alometrik power dengan prediktor diameter pangkal cukup baik dalam menduga biomassa berat kering dan kandungan karbon semai di hutan mangrove Desa Pangarengan. Kata kunci: akuntansi karbon, mitigasi, iklim, regresi

Allometric Models for Aboveground Biomass of Six Common Subtropical Shrubs and Small Trees

Background: The aboveground biomass (AGB) of shrubs and small trees is the main component for the productivity and carbon storage of understory vegetation in subtropical natural secondary forests. However, few allometric models exist for shrubs and small trees, even though they can accurately evaluate understory vegetative biomass. Methods: To estimate the ABG of six common shrub and small tree species, we utilized harvesting to sample 206 individuals, and developed species-specific and multi-species allometric models based on four predictors including height (H), stem diameter (D), crown area (Ca), and wood density (ρ). Results: As expected, these six shrub and small tree species possessed greater biomass in their stems in contrast to branches, with the lowest biomass in the leaves. Species-specific allometric models that employed D and the combined variables of D2H and ρDH as predictors, could accurately estimate the components and total AGB, with R2 values ranging from between 0.602 and 0.971. A multi-species shrub allometric model revealed that ρDH was the best predictor, with R2 values ranging from between 0.809 and 0.890. Conclusions: These results indicated that H and D were effective predictors for the models to estimate the AGB of the six shrub and small tree species, and the introduction of ρ improved their accuracy. The optimal model selected in this study could be applied to estimate the biomass of shrubs and small trees in the subtropical regions.