Estimation beech (Fagus Orientalis L) and hornbeam (Carpinus betulus L) trees height using nonlinear models and mixed-effects model

Document Type : Research Paper

Authors

1 Gorgan University of Agricultural Sciences and Natural Resources, Gorgan

2 Gorgan University of Agricultural Sciences and Natural Resources

Abstract

The aim of this study was to develop the Mixed-effects model and compare it with nonlinear models for estimating beech (Fagus Orientalis Lipsky) and hornbeam (Carpinus betulus L.) heights in the Shast-kalateh forests (district 1 and 2) of Gorgan. We applied a systematic sampling method to collect the field data within a 150×200 m network (308 circular plots) and in each plot, tree species were identified and height and diameter at breast height (DBH) of all trees were measured. Model fitting was done in two stages: Fixed-effect approach was used in the first stage wherein candidate models where height (dependent variable) and DBH (independent variable). These were refitted in the second stage using a mixed-effect approach. The adjusted coefficient of determination and root mean square error, were used to assess the models. The results of fitting nonlinear models showed that for the beech, Curtis and Naslund models had the highest coefficient of determination of 0.76 and the lowest root mean square error of 3.35 and 3.40, respectively. For hornbeam, Naslund and Michailoff models with the coefficient of determination of 0.40 and the root mean square error of 2.95 and 2.90 were selected as the best models. The results of nonlinear mixed effects model showed that the R2 for beech and hornbeam species increased by 10% and 30% respectively, and the RMSE improved about 0.65 for beech and 0.6 for hornbeam.

Keywords


[1]. FAO, (2020). The State of the World’s Forests, FAO, 46pp.
[2]. IUFRO, (2004). Improvement and Silviculture of Beech. In: Proceedings of the 7th International Beech Symposium. Tehran, 10.–20. Tehran, Research Institute of Forests and Rangelands: 186.
[3]. Alemi, A., Oladi, J., Fallah, A., and Maghsodi, Y. (2021). Evaluating of Different Height-Diameter Nonlinear Models for Hornbeam in Uneven-Aged Stands (Case Study: Golestan Rezaeian Forest). Ecology of Iranian Forest, 8(16): 29-38.
[4]. Gadow, K., Real, P., and Álvarez-González, J.G. (2001). Modelización del crecimiento y la evolución de los bosques. IUFRO World Series vol. 12. Vienna, Austria.
[5]. Castano-Santamaria, J., Crecente-Campo, F., Fernandez-Martinez, J.L., Barrio-Anta, M., and Obeso, J.R. (2013). Tree height prediction approaches for uneven-aged beech forests in northwestern Spain. Forest Ecology and Management, 307: 63-73.
[6]. Dorado, F.C., Diéguez-Aranda, U., Anta, M.B., Rodríguez, M.S., and von Gadow, K. (2006). A generalized height–diameter model including random components for radiata pine plantations in northwestern Spain. Forest Ecology and Management, 229(1-3): 202-213.
[7]. Curtis, R.O. (1967). Height-diameter and height-diameter-age equations for second-growth Douglas-fir. Forest Science, 13(4): 365-375.
[8]. Mehtätalo, L., de-Miguel, S., and Gregoire, T.G. (2015). Modeling height-diameter curves for prediction. Canadian Journal of Forest Research, 45(7): 826-837.
[9]. Trincado, G., VanderSchaaf, C.L., and Burkhart, H.E. (2007). Regional mixed-effects height–diameter models for loblolly pine (Pinus taeda L.) plantations. European Journal of Forest Research, 126(2): 253-262.
[10]. Adame, P., del Río, M., and Canellas, I. (2008). A mixed nonlinear height–diameter model for pyrenean oak (Quercus pyrenaica Willd). Forest Ecology and Management, 256(1-2): 88-98.
[11]. Özçelik, R., Cao, Q.V., Trincado, G., and Göçer, N. (2018). Predicting tree height from tree diameter and dominant height using mixed-effects and quantile regression models for two species in Turkey. Forest Ecology and Management, 419: 240-248.
[12]. Temesgen, H., Zhang, C.H., and Zhao, X.H. (2014). Modelling tree height–diameter relationships in multi-species and multi-layered forests: a large observational study from Northeast China. Forest Ecology and Management, 316: 78-89.
[13]. Bronisz, K., and Mehtätalo, L. (2020). Mixed-effects generalized height–diameter model for young silver birch stands on post-agricultural lands. Forest Ecology and Management, 460: 117901.
[14]. Ahmadi, K., and Alavi, S.J.  (2016). Generalized height-diameter models for Fagus orientalis Lipsky in Hyrcanian forest, Iran. Journal of forest science, 62(9): 413-421.
[15]. Kalbi, S., Fallah, A., Bettinger, P., Shataee, S., and Yousefpour, R. (2018). Mixed-effects modeling for tree height prediction models of Oriental beech in the Hyrcanian forests. Journal of Forestry Research, 29(5): 1195-1204.
[16]. Abedi, R., and Abedi, T. (2020). Some non-linear height-diameter models performance for mixed stand in forests in Northwest Iran. Journal of Mountain Science, 17(5): 1084-1095.
[17]. Doctor Bahramnia Forestry Plan district one. (2008). Forest Science Faculty, Gorgan university of Agricultural Sciences and Natural Recourses, 478p.
[18]. Mohammadi, J., and Shataee, S. (2017). Study of different height-diameter models for hornbeam (Carpinus betulus L.) in uneven-aged stands of Shastkalateh forest of Gorgan. Iranian Journal of Forest and Poplar Research, 24(4): 700-712
[19]. Sharma, R.P., Vacek, Z., and Vacek, S. (2016). Nonlinear mixed effect height-diameter model for mixed species forests in the central part of the Czech Republic. Journal of Forest Science, 62(10): 470-484.