Variation of Tree-size Scaling in A Forest Community across Multiple Scales

Thu, 02 Jul 2026 00:33:04 +0000

Forest structure is important for species diversity and the distribution of physical force. A general scaling of tree size with fixed parameters is often used, but variation in scaling across scales is unknown. It is necessary to characterize patterns of tree size structure in forests using inventory data to advance canopy science and forest sustainability. This study analyzed a dataset of each tree, including position, tree diameter, height, and canopy diameter, across a 1-ha forest community at multiple scales. The results indicated no correlation between the number of tree species and the accumulated tree-occupying volume (the space occupied by a tree) at different scales. The frequency distribution of tree-occupying volume followed power laws across different scales, but the exponents varied by locations at the same scale. Polynomial functions of degree 2 can also fit the frequency distribution of the tree-occupying volume. Taylor’s power laws held in the tree-occupying volumes at different scales with varying exponents. Across different tree species, the distribution of tree-occupying volume followed power laws within their populations. For the distribution of tree canopy diameter, both power laws in frequency and Taylor’s law were observed across scales with varied exponents. A significant relationship existed between canopy diameters and tree-occupying volumes, with the scaling exponents of about 3.0 only at some sites. Power laws also held between canopy projection areas and tree-occupying volumes, with the exponents around 3/2 in some areas. These results provided insights into variation in tree structure and scaling within a forest community, which could serve as a basis for sustainable forest management.

Modeling of Yield Stability and Genotype by Environment Interaction Effect on Early and Medium Duration Genotypes of Cowpea (Vigna unguiculata (L.) Walp.)

Sat, 29 Aug 2026 02:29:05 +0000

The study modeled the yield stability of selected early- and medium-duration cowpea genotypes across six locations in northern Ghana to identify the most stable and winning genotype(s). The models employed in the study included a combined analysis of variance (ANOVA), the Additive Main Effects and Multiplicative Interaction (AMMI) model, the Genotype + Genotype-by-Environment (GGE) biplot model, and non-parametric statistical models. The yield stability and adaptability measure SARI-2-50-80 indicated that the genotypes SARI-2-50-80, IT86D-610, IT10K-837-1, and SARI-6-2-6 are high-yielding and stable among medium-duration cowpea lines across environments. The study also found that genotypes SARI-3-11-80 (0.227 t/ha) and the checker cultivar KIRKHOUSE-BENGA (0.145t/ha) had relatively lower ASV (AMMI Stability Value) values, indicating higher stability in medium-duration cowpea lines. Genotypes SARI-3-11-80 (0.0696t/ha) and SARI-1-3-90 (0.0952t/ha), SARI-13-17-2 and IT07K-299-6IT07K-299-6, demonstrated lower MASI (Mean Absolute Standard Index) values, suggesting higher stability and adaptability. Genotypes SARI-3-11-80 (0.442t/ha) and KIRKHOUSE-B (0.581 t/ha) exhibited relatively lower MASV (Mean Absolute Standard Values /Modified AMMI stability Value)) values, indicating higher stability and adaptability. Damongo, Yendi, and Manga were identified as the most promising environments for most of the lines. Yield stability was significantly predicted by genotype, environment and genotype by environment interactive effect. The ANOVA for confirmation, AMMI and GGE for decomposition and visualization, and non-parametric models for robust validation represent a highly accurate and comprehensive approach to MET (Multi-Environment Trial) analysis. The AMMI model derived the calculated stability metrics which were used for the accurate identification of the high-yielding and stable genotypes.

Journal of Plant Studies, Issue: Vol.15, No.1

Variation of Tree-size Scaling in A Forest Community across Multiple Scales

Modeling of Yield Stability and Genotype by Environment Interaction Effect on Early and Medium Duration Genotypes of Cowpea (Vigna unguiculata (L.) Walp.)