عنوان مقاله [English]
Quantification of forest structure and its various components helps to better understand the forest ecosystem and supports its improved management. Here, the Gini index were used as a spatial distribution index for evaluating the structural diversity. The main objective was to analyse the stand structure and determine the necessary factors for the structural heterogeneity and homogeneity. This study was conducted in compartments 305, 306, 309, 310 and 311 in Gorazbon district, Kheyrud forest by means of a full calipering method. Then Gini index was calculated and finally the Lorenz curve was derived by using frequencies of stems, diameter class, as well as cumulative relative frequencies of trees and their basal area. The results showed Gini index values of 39.5%, 66%, 44%, 82% and 74% for compartments 305, 306, 309, 310 and 311, respectively. In addiiton, the diameter structure for 305 and 309 compartments was shown to be close to homogeneity, whereas it was close to medium for compartment 306 and close to heterogeneity for compartments 310 and 311. Finally the use of Gini index and Lorenz curve was concluded to he helpful in reclecting the near-real structural diversity in natural beech stands.
- Bilek, L., Remes, J. and Zahradnik, D., 2011. Managed vs. unmanaged. Structure of beech forest stands (Fagus sylvatica L.) after 50 years of development, Central Bohemia. Forest Systems, 20(1): 122-138.
- Binkley, D., 2004. A hypothesis about the interaction of tree dominance and stand production through stand development. Forest Ecology and Management, 190(2-3): 265-271.
- Chivulescu, E., Badea, O., Tomescu, R., Silaghi, D., Leca, T. and Turcu, D., 2014. Structural features of virgin beech forests in Semenic Mountains. The dynamic structure of virgin beech forest p20 Semenic between 2005-2013. Proceedings of the Romanian Academy Series B, 16(2): 115-124.
- Clark, P.J. and Evans, F.C., 1954. Distance to nearest neighbor as a measure of spatial relationships in populations. Ecology, 35(4): 445-453.
- Dixon, P.H., Weiner, J., Mitchelle-Olds, T. and Woodley, R., 1987. Bootstrapping the Gini coefficient of inequality. Ecology, 68(5): 1548-1551.
- Duduman, G., 2011. A forest management planning tool to create highly diverse uneven-aged stands. Forestry, 84(3): 301-314.
- Gini, C.,1912. Variabilita e Mutabilita: Contributo allo Studio delle Distribuzioni e delle Relazioni Statistiche. Tipografia di Paolo Cuppin, Bologna, Italy, 158p.
- Hall, J.S., Harris, D.J, Medjibe, V. and Ashton, P.M.S., 2003. The effects of selective logging on forest structure and tree species composition in a Central African forest: implications for management of conservation areas. Forest Ecology and Management, 183(1-3): 249-264.
- Lee, W.K., Von Gadow, K. and Akça, A., 1999. Waldstruktur und Lorenz-modell. Allgemeine Forst- und Jagdzeitung, 170(12): 220-223.
- Lexerǿd, N.L. and Eid, T., 2006. An evaluation of different diameter diversity indices based on criteria related to forest management planning. Forest Ecology and Management, 222 (1–3): 17-28.
-Linares, J.C., Carreira, J.A. and Ochoa, V., 2011. Human impacts drive forest structure and diversity. Insights from Mediterranean mountain forest dominated by Abies pinsapo (Boiss.). European Journal of Forest Resource, 130(4): 533-542.
- Lorenz, M.O., 1905. Methods of measuring the concentration of wealth. Journal of the American Statistical Association, 9(70): 209-219.
- Marvie Mohadjer, M.R., Zobeiri, M., Etemad, V. and Jour Gholami, M., 2009. Performing the single selection method at compartment level and necessity for full inventory of tree species (Case study: Gorazbon district in Kheroud Forest). Iranian Journal of Natural Resources Research, 61(4): 889-908.
- Neumann, M. and Starlinger, F., 2001. The significance of different indices for stand structure and diversity in forests. Forest Ecology and Management, 145(1-2): 91-106.
- Pach, M. and Podlaski, R., 2015.Tree diameter structural diversity in Central European forests with Abies alba and Fagus sylvatica: managed versus unmanaged forest stands. Ecological Research, 30(2): 367-384.
- Pielou, E.C., 1961. Segregation and symmetry in two-species populations as studied by nearest- neighbour relationships. Journal of Ecology, 49(2): 225-269.
- Sterba, H., 2004. Equilibrium curves and growth models to deal with forests in transition to uneven-aged structure - application in two sample stands. Silva Fennica, 38(4): 413-423.
- Sterba, H., 2008. Diversity indices based on angle count sampling and their interrelationships when used in forest inventories. Forestry, 81(5): 587-597.
- Shannon, C.E. and Weaver, W., 1949. The Mathematical Theory of Communication. University of Illinois Press, Urbana, New York, 117p.
- Valbuena, R., Packalén, P., Martín-Fernández, S. and Maltamo, M., 2012. Diversity and equitability ordering profiles applied to study forest structure. Forest Ecology and Management, 276: 185-195.