The self-thinning line in overcrowded stands of the mangrove, Bruguiera gymnorrhiza, Okinawa Island, Japan

• Published in: Tropics Vol. 20; no. 3; pp. 71 - 77
• Main Authors: Deshar, Rashila, Sharma, Sahadev, Hoque, A.T.M. Rafiqul, Wu, Min, Mouctar, Kamara, Hagihara, Akio
• Format: Journal Article
• Language: English
• Published: JAPAN SOCIETY OF TROPICAL ECOLOGY 2011
• Subjects: 3/2 power law of self-thinning; self-thinning exponent; simple geometric model; Weller’s allometric model
• ISSN: 0917-415X; 1882-5729
• DOI: 10.3759/tropics.20.71

Using Weller’s allometric model, i.e. the allometric relationships of mean tree height H (=gθ•wθ) and mean aboveground mass density d (=w /( s•H )=gδ•wδ, where s is the mean area occupied by a tree, i.e. the reciprocal population density (1/ρ = gφ • wφ ), to w, the self-thinning line (w=K•ρ-α) of overcrowded Bruguiera gymnorrhiza stands was studied. Mean population tree height increased with increasing w. The values of the allometric constant θ and the multiplying factor gθbetween H and w were 0.2605 and 2.868 m kg-θ, respectively. Simultaneously, the allometric constant sigma; and the multiplying factor g sigma; between d and w were 0.05894 and 1.934 m-3 kg1-δ, respectively. The δ-value was not significantly different from zero, showing that d remains constant regardless of an increase in w. The self-thinning exponent α based on the θ- and δf-values, and the multiplying factor K based on the gθ, g δ-, and φ-values were 1.469 and 12.39 kg m–2α, respectively. The value of θ+δ was 0.319, which was not significantly different from 1/3 (t = 0.253, df = 82, p = 0.801). Thus, the self-thinning exponent α was not significantly different from 3/2, which means that the self-thinning line of the present overcrowded B. gymnorrhiza stands can be explained using the simple geometric model.