Calculation of uneven-aged stand structures with the negative exponential diameter distribution and Sterba's modified competition density rule

Abstract Depending on Sterba's modified Competition Density Rule [Sterba, H., 1975. Assmann's theorie der grundflachenhaltung die “Competition Density Rule” det Japaner Kira, Ando und Tadaki. Cbl. f.d. ges. Forstw. 92, 46–62], the maximum basal area ( G max ), quadratic mean diameter ( d G max ), and stem numbers ( N G max ), for uneven-aged stands of Abies nordmanniana in the Black Sea Region in Turkey were calculated. Then, an exponential diameter distribution as a function of dominant height for these stands was obtained by solving nonlinear system of equations, which uses the maximum basal area ( G max ) and the stem numbers ( N G max ) as input values, and gives diminution coefficient ( q ) and the number of stems in the largest diameter class ( N 1 ) as outputs. The results are in accordance to Sterba and Monserud's findings [Sterba, H., Monserud, R.A., 1993. The maximum density concept applied to uneven-aged mixed species stands. For. Sci. 39 (3), 432–452] on the slope of the maximum density line, and with Susmel's [Susmel, L., 1956. Laws and the variation of the parameters in uneven-aged normal forests. L’Italia Forestale e Montana XI (3), 3–14] concept of decreasing q with increasing dominant height.