TY - JOUR ID - 995 TI - Determining the best form factor formula for Loblolly Pine (Pinus taeda L.) plantations at the age of 18, in Guilan- northern Iran JO - Caspian Journal of Environmental Sciences JA - CJES LA - en SN - 1735-3033 AU - Fadaei, F. AU - Fallah, A. AU - Latifi, H AU - Mohammadi, K. AD - Dept. of Forestry, Faculty of Natural Resources, University of Mazandaran, Sari. Iran. Y1 - 2008 PY - 2008 VL - 6 IS - 1 SP - 19 EP - 24 KW - form factors KW - Loblolly Pine Plantations KW - T KW - test KW - Guilan DO - N2 - In order to determine the best form factor formula for Loblolly Pine (Pinus taeda L.) plantations in Talesh (Western Guilan province-Iran), a number of 110 trees were selected based on their distribution in diameter classes, from 12 to 34 cm (in a two- cm diameter interval). First, several quantitative factors including diameter at breast height, diameter at 0.65 m of height, and diameter at stump were measured using a diameter tape, just before the trees being felled. After cutting the trees, the heights and diameter from breast height up to the height where diameter is 5 cm was measured using a diameter tape in a two meter interval. Finally, diameter at 0.1, 0.3, 0.5, 0.7, and 0.9 meter of the total height was measured respectively. As a consequent, each tree's volume was precisely calculated as the real volume. Next, the real form factor was calculated and its average was statistically compared to the averages of Natural , Artificial , and Hohenadl?s form factors using pair sample T-test. Results showed that there is no significant difference between the averages of real and Hohenadl?s form factors (at = 0.01 level). Furthermore, the averages of real and artificial form factors were not significantly different. Hence, both artificial and Hohenadl?s form factors are capable to replace the real form factor of Loblolly Pine over the study area.   REFERENCES Assman, E. (1970) The Principles of forest yield study. Pergmon Press, Oxford (Translated by S. H. Gardiner), 457 p. Bonyad, A., Rahimnejad, S. (2004) Volume table estimation of loblolly pine in the north of Iran. Pajouhesh-va-sazandegi, 66, 43-47 (In Persian).  Bonyad, A., Rostami shahraji, T. (2005) Study on Slash pine (Pinus elliottii) as a short rotation forestry in the North of Iran. Caspian Journal of Environmental Sciences, 1, 55-58. Bruchwald, A. and Grochowski, J. (1977) Tree Form Factor f1/2 of Scots Pine Stands as a Measure of Stand Taper and as a Basis for Testing the Accuracy of Huber’s Method. SYLWAN. 121, 1-9. Fadaei, F. (2005) Investigating Loblolly Pine Growth in Guilan Plantations Using Stem Analysis (A Case Study of Pilambara Talesh). MSc. Dissertation, University of Mazandaran, Faculty of Natural Resources,  96 p. (In Persian). Girard, J.W. (1933) Volume Tables of Mississippi Bohomland Hardwoods and Southern Pine. Journal of Forestry. 31, 34-41. Heger, L. (1965) A Trial of Hohenadl’s Method of Stem Form and Stem Volume Esimation. Forest Chronology. 41, 466- 475. Hohenadl, W. (1936) Die Bestandesmessung. Forstwiss. Centraldl. 58, 51-61. Mahinpour, M. (2002) Quantitative Investigation and Volume Estimation of Eliotty Pine in Lakan- Guilan. MSc. Dissertation, University of Guilan, Faculty of Natural Resources, Sowmehsara, Iran, 83 p. (In Persian). Philip, M. (1994) Mensuring Trees and Forest. CAB International, p. 310. Rahimnejad, S. (2002) Quantitative Investigation and Volume Estimation of Loblolly Pine in Lakan- Guilan. MSc. Dissertation, University of Guilan, Faculty of Natural Resources, Sowmehsara, Iran,  83 p. (In Persian). Zar, J.H. (1998) Bio statistical Analysis. Prentice Hall Press, NJ, USA, 929 p. Zobeiri, M. (2000) Forest Inventory. University of Tehran Press, Tehran, Iran, p. 401 p. (In Persian). Zobeiri, M. (2002) Forest Biometry. University of Tehran Press, Tehran, Iran, 411 p. (In Persian). Zobeiri, M. and Najjaran, Gh. (1984) Investigation of Beech Form factor in Veisar Forests- Nowshahr. Iranian Journal of Natural Resources, 38, 33-37 (In Persian). UR - https://cjes.guilan.ac.ir/article_995.html L1 - https://cjes.guilan.ac.ir/article_995_6660563b05c441374eef0e6a6a96f4a1.pdf ER -