Quantification of the Relationship Between the Height – Diameter of (Pinus brutia Ten), Calabrian Pine Trees in Four Different Microsites in Duhok Governorate. Kurdistan Region, Iraq


  • Tariq K. Salih College of Agricultural Engineering Science, University of Duhok, Duhok, Kurdistan Region, Iraq
  • Hayfaa M. Saaed Abdulaziz Directorate of Forests and Rangelands, Duhok, Kurdistan Region, Iraq




Height – diameter models, height – diameter relationship, Calabrian pine trees, Validation, modeling


A sample of 120 trees was purposely selected from four different microsites (Behere, Swaratoka, Zawita, and Semel), (30 trees from each microsite) in the Duhok governorate. 100 of which were used for model calibration and the rest were used for validation of the selected regression equation. This study consisted of two main parts. In the first part  ,In the beginning, a scatter diagram was conducted for each microsite to detect the type of relationship between height and diameter at breast, which in turn will decrease the number of regression models that will be tested. Accordingly, 4 regression equations were developed for each of the four microsites separately. These models can be used to see how the ratio of height diameter in each of the studied sites is inter-correlated and which of them is the most appropriate for producing Calabrian pine trees.  In the second part, all microsites were then treated as one sample for estimating the parameters of 25 regression models using Excel and Statographic packageThe developed regression models underwent a screening process in order to find the most appropriate one to be used for the prediction of the height of Calabrian pine grown in the four mentioned microsites in Duhok governorate. Many measures of precision among them coefficient of determination, Bias%, Mean absolute error, Ohtomo’s unbiased test, Furnival Index, and AIC criterion were used for testing the performance of the developed equations in the prediction of the height. At last, the equation  was selected, as the best regression model. This equation shows that there is a linear relationship between  and a curvilinear relationship between D and H. The study showed that the height–diameter ratio was highest in Swaratoka and was the most appropriate microsite among the rest, followed by Behere, then Zawita and Semel came in last place.

Author Biographies

Tariq K. Salih, College of Agricultural Engineering Science, University of Duhok, Duhok, Kurdistan Region, Iraq

College of Agricultural Engineering Science, University of Duhok, Duhok, Kurdistan Region, Iraq - (tariq.salih@uod.ac)

Hayfaa M. Saaed Abdulaziz, Directorate of Forests and Rangelands, Duhok, Kurdistan Region, Iraq

Directorate of Forests and Rangelands, Duhok, Kurdistan Region, Iraq - (haifawafa2@gmail.com)


Adame, P., del Río, M., & Cañellas, I. (2008). A mixed nonlinear height–diameter model for pyrenean oak (Quercus pyrenaica Willd.). Forest ecology and management, 256(1-2), 88-98. https://www.sciencedirect.com/science/article/pii/S0378112708003253

Ajit, S. (2010). Estimation and validation methods in tree volume and biomass modelling: statistical concept. National Research Centre for Agroforestry, Jhansi, India 18p.‏

Amaro, A., Reed, D., Tomé, M., & Themido, I. (1998). Modeling dominant height growth: Eucalyptus plantations in Portugal. Forest Science, 44(1), 37-46. https://doi.org/10.1093/forestscience/44.1.37

Amin, H.M. (2016). quantification of diementional properties of Quercus infectoria. Oliv grown naturally in Chamanke area. Duhok. MSc Thesis. College of Agriculture, Duhok University.

Avery, T. E., & Burkhart, H. E. (2015). Forest measurements. Waveland Press. https://books.google.iq/books?id=IWx1CQAAQBAJ

Calama, R., & Montero, G. (2004). Interregional nonlinear height diameter model with random coefficients for stone pine in Spain. Canadian Journal of Forest Research, 34(1), 150-163. https://cdnsciencepub.com/doi/abs/10.1139/x03-199

Carron, L. T. (1968). An outline of forest mensuration with special reference to Australia. Australian National University Press.‏ https://openresearch-repository.anu.edu.au/handle/1885/114864

Chai, Z., Tan, W., Li, Y., Yan, L., Yuan, H., & Li, Z. (2018). Generalized nonlinear height–diameter models for a Cryptomeria fortunei plantation in the Pingba region of Guizhou Province, China. Web Ecology, 18(1), 29-35. https://doi.org/10.5194/we-18-29-2018

Dyer, M. E., & Bailey, R. L. (1987). A test of six methods for estimating true heights from stem analysis data. Forest Science, 33(1), 3-13. https://doi.org/10.1093/forestscience/33.1.3

Durbin, J., & Watson, G. S. (1950). Testing for serial correlation in least squares regression: I. Biometrika, 37(3/4), 409-428. https://www.jstor.org/stable/2332391

Durbin, J. and Watson, G.S. (1951). Testing for serial correlation in least squares regression. II. Biometrika, 38(1/2), pp.159-177.

El Mamoun, H. O., El Zein, A. I., & El Mugira, M. I. (2013). Modelling height-diameter relationships of selected economically important natural forests species. Journal of forest products & industries, 2, 34-42. https://www.researchgate.net/publication/269095707_Modelling_Height-Diameter_Relationships_of_Selected_Economically_Important_Natural_Forests_Species

Furnival, G. M. (1961). An index for comparing equations used in constructing volume tables. Forest Science, 7(4), 337-341. https://doi.org/10.1093/forestscience/7.4.337

Geisser, S. (1975). The predictive sample reuse method with applications. Journal of the American statistical Association, 70(350), 320-328.‏ https://www.tandfonline.com/doi/abs/10.1080/01621459.1975.10479865

Huang, S., Price, D., & Titus, S. J. (2000). Development of ecoregion-based height–diameter models for white spruce in boreal forests. Forest ecology and management, 129(1-3), 125-141.‏ https://doi.org/10.1016/S0378-1127(99)00151-6

Huang, S., Meng, S. X., & Yang, Y. (2009). Using nonlinear mixed model technique to determine the optimal tree height prediction model for black spruce. Modern Applied Science, 3(4), 3-18.‏ https://doi.org/10.5539/mas.v3n4p3

Kariuki, M. (2002). Height estimation in complete stem analysis using annual radial growth measurements. Forestry, 75(1), 63-74. https://doi.org/10.1093/forestry/75.1.63

Kershaw Jr, J. A., Ducey, M. J., Beers, T. W., & Husch, B. (2016). Forest mensuration. John Wiley & Sons. https://books.google.iq/books?id=SGVJDQAAQBAJ

Lappi, J. (1997). A longitudinal analysis of height/diameter curves. Forest science, 43(4), 555-570.https://doi.org/10.1093/forestscience/43.4.555

Larsen, D. R., & Hann, D. W. (1987). Height-diameter equations for seventeen tree species in southwest Oregon. http://hdl.handle.net/1957/8245

Mensah, S., Pienaar, O. L., Kunneke, A., du Toit, B., Seydack, A., Uhl, E., ... & Seifert, T. (2018). Height–Diameter allometry in South Africa’s indigenous high forests: Assessing generic models performance and function forms. Forest Ecology and Management, 410, 1-11. https://doi.org/10.1016/j.foreco.2017.12.030

Neter, J., Kutner, M. H., Nachtsheim, C. J., & Wasserman, W. (1996). Applied linear statistical models.

Ng’andwe, P., Chungu, D., & Tailoka, F. (2021). Stand characteristics and climate modulate height to diameter relationship in Pinus merkusii and P. michoacana in Zambia. Agricultural and Forest Meteorology, 307, 108510. https://doi.org/10.1016/j.agrformet.2021.108510 .

Ohtomo, E. (1956). A Study on Preparation of volume Table. (I). Journal Of the Japanese Forestry Society, 38(5), 165-177. https://www.jstage.jst.go.jp/article/jjfs1953/38/5/38_5_165/_article/-char/en

Philip, M.S., 1994. Measuring trees and forests. CAB international. https://www.cabdirect.org/cabdirect/abstract/19936791705

Pretzsch, H. (2009). Forest dynamics, growth, and yield. Forest dynamics, growth and yield, 1-39.‏ https://doi.org/10.1007/978-3-540-88307-4_1

Salih, T.K., Younis, M.S. and Wali, S.T. (2019). Dendroclimatological Analysis of Pinus brutia Ten. Grown in Swaratoka, Kurdistan Region—Iraq. In Recent Researches in Earth and Environmental Sciences (pp. 9-19). Springer, Cham.

Salih, T.K., Younis, M.S. and Wali, S.T. (2021) Allometric Regression Equations Between Diameter Growth and Age of Valonia Oak Trees Grown in Duhok Province, Iraq. International Hasankefy and Innovation Congress 06 – 07 november 2021 Batman.

Schmidt, M., Kiviste, A., & von Gadow, K. (2011). A spatially explicit height–diameter model for Scots pine in Estonia. European Journal of Forest Research, 130(2), 303-315.‏ https://link.springer.com/article/10.1007/s10342-010-0434-8

Shahbaz, S. E. (2010). Trees and Shrubs, A field guide to the trees and shrubs of Kurdistan region of Iraq. Journal of university of Duhok.

Sharma, M., & Parton, J. (2007). Height–diameter equations for boreal tree species in Ontario using a mixed-effects modeling approach. Forest Ecology and Management, 249(3), 187-198. https://doi.org/10.1016/j.foreco.2007.05.006

Studenmund, A. H., & Johnson, K. B. (2006). Using econometrics: A practical guide 5th edition.

Sumida, A., Miyaura, T., & Torii, H. (2013). Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand. Tree physiology, 33(1), 106-118.‏ https://doi.org/10.1093/treephys/tps127 .

VanderSchaaf, C. (2008). Compatible stem taper and total tree volume equations for loblolly pine plantations in southeastern Arkansas. Journal of the Arkansas Academy of Science, 62(1), 103-106. https://scholarworks.uark.edu/jaas/vol62/iss1/16/

Younis A.J. 2019.Stand volume equations for Quercus aegilops L. and Quercus infectoria Oliv. In Duhok governorate. MSc thesis

Zeide, B., & Vanderschaaf, C. (2002, March). The effect of density on the height-diameter relationship. In Proceedings of the 11th Biennial Southern Silvicultural Research Conference (pp. 463-466). General Technical Report SRS-48. USDA, Forest Service. Southern Research Station, Asheville, NC.‏ https://www.fs.usda.gov/treesearch/pubs/3103




How to Cite

Salih, T. K., & Abdulaziz, H. M. S. (2023). Quantification of the Relationship Between the Height – Diameter of (Pinus brutia Ten), Calabrian Pine Trees in Four Different Microsites in Duhok Governorate. Kurdistan Region, Iraq. Science Journal of University of Zakho, 11(1), 84–90. https://doi.org/10.25271/sjuoz.2023.11.1.1015



Science Journal of University of Zakho