N-Tree Distance Sampling vs. Fixed-Radius Plots methods for tree density estimation in central Zagros forests

Document Type : Research article

Authors

1 M. Sc. Forestry, Department of Forestry, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, I.R. Iran.

2 M. Sc. Student, Department of Forestry, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, I.R. Iran

3 M. Sc. Forestry, Department of Forestry, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, I.R. Iran

Abstract

N-tree Distance Sampling (NTDS) is a well-known distance sampling method which is considered as cost-and time effective compared to fixed-Radius Plots. This study was conducted across an area of 36.40 ha in Helen forest reserve in Chaharmahal and Bakhtiari Province. The study area mostly comprises of natural, old-growth Brant`s oak (Quercus brantii) stands. Here, the stands were first fully callipered. Two estimators of Moore and Kleinn-Vilcko sample plot methods were applied to derive the diagnostic measures of relative bias (RB) and relative root mean square error (RRMSE) for a number of 2 to 12 trees. For each estimator, 30 repeats with each encompassing 50 Sample points were selected. The results showed the fixed plot sampling (FPS) to be of higher performance in the clumpy-distributed trees within stands with 154.25 trees per ha. In addition, the Kleinn-Vilcko estimator was shown to be most efficient for N ≥ 5 trees. Due to its high error rate, the Moore estimator yet returned poor performances in density estimation across the study area.

Keywords


- Arman, Z. 2013. Developing a conceptual model for ecological monitoring in central Zagros landscape (Case study: Helen forest protected area). M. Sc. thesis, Shahrekord University, 123p (In Persian).
- Askari, Y., Zobeiri, M. and Sohrabi, H. 2013, Comparison of five distance sampling methods for estimating quantitative characteristics of Zagros Forests. Iranian Journal of Forest and Poplar Research, 21(2): 316-328 (In Persian).
- Bauersachs, E. 1942. Bestandesmassenaufnahme nach dem Mittelstammverfah ren des zweitkleinsten Stammabstandes. Forstwiss, Centralbl, 64: 182-186.
- Beasom, S.L. and Hauck, H.H. 1975. A comparsion of four distance sampling techniques in south texas live oak Mottes. Journal of Range Management, 28(2): 142-144.
- Cottam, G. and Curtis, J.T. 1949. A method for making rapid surveys of woodlands by means of pairs of randomly selected trees. Ecology, 30: 101-104.
- Eberhardt, L.L. 1967. Some developments in distance sampling. Biometrics, 23:207-216.
- Erfanifard, Y., Mahdian, F., Shamsi, R.F. and Bordbar, K. 2012. Comparative investigation on the methods of true spatial pattern analysis of trees in forests (Case study: Wild pistachio research forest, Fars province, Iran). Iranian Journal of Forest and Poplar Research, 20(1): 73-62 (In Persian).
- Essed, D. 1957. Estimation of standing timber. Ph. D. thesis, Wageningen, 60p.
- Foshat, M., Hosseini, S.M., Fallah, A. and  Fakhari, M.A. 2011. Determination of suitable N-tree sampling method in Populus deltoeides plantations. Research Journal of Forest Science and Engineering, 1(3): 65-76.
- Heidari, R.H., Zobeiri, M., Namiranian, M., Sohrabi, H. and Safari, A. 2010. Study of accuracy of nearest individual sampling method in Zagross forests. Iranian Journal of Forest, 2(4): 323-330 (In Persian).
- Haxtema, Z., Temesgen, H. and Marquardt, T. 2012. Evaluation of n-tree distance sampling for inventory of headwater riparian forests of western Oregon. Western Journal of Applied Forestry, 27(3): 109-117.
- Karamshahi, A., Zobeiri, M., Namiranian, M. and Feghhi, J. 2011. Investigation on application of k-nn (k- nearest neighbor) sampling method in Zagros forests (Case study: Karzan forest, Ilam). Iranian Journal of Forest and Poplar Research, 19(4):  453-463 (In Persian).
- Kleinn, C. and Vilčko, F. 2006a. A new empirical approach for estimation in k-tree sampling. Forest Ecology and Management, 237(1-3): 522-533.
- Kleinn, C. and Vilčko, F. 2006b. Design-unbiased estimation for point-to-tree distance sampling. Canadian Journal of Forest Researches, 36(6):1407-1414.
- Köhler, A. 1952. Vorratsermittlung in Buchenbesta¨nden nach Stammdurch- messer und Stammabstand. Allgemeine Forst Jagdzeitung, 123: 69-74.
- König, G. 1835. Die Forstmathematik mit Anweisung zur Forstvermessung Holzscha¨tzung und Waldwertrechnung, nebst Hu¨lfstafeln fu¨r Forstscha¨tzer. Gotha, in Commission der Becker’schen Buchhandlung, 436p.
- Krebs, C.J. 1989. Ecological  Methodology. Harper Collins: New York, 653p.
- Krebs, C.J. 1999. Ecological Methodology. 2nd ed., Addison-Wesley Educational and P. Pub. Inc: California, 620p.
- Lessard, V., Reed, D.D. and Monkevich, N. 1994. Comparing n-tree distance sampling with point and plot sampling in northern Michigan forest types.  Northern Journal of Applied Forestry, 11(1): 12-16.
- Lessard, V.C., Drummer, T.D. and Reed, D.D. 2002. Precision of density estimates from fixed-radius plots compared to n-tree distance sampling. Forest Science, 48(1): 1-6.
- Lo, C.P. and Yeung, A.K.W. 2007. Concepts and Techniques in eographicInformation System. Pearson Education, Inc., USA, 544p.
- Moeur, M. 1993. Characterizing spatial patterns of trees using stem- mapped data. Forest Science, 39(4): 756-775.
- Moore, P.G. 1954. Spacing in plant populations. Ecology, 35(2): 222-227.
- Payandeh, B. and Ek, A.R. 1986. Distance methods and density estimators. Canadian Journal of Forest Researches, 16: 918-924.
- Pielou, E.C. 1959. The use of point-to-plant distances in the study of pattern of plant population. Journal of Ecology, 47: 603-613.
- Prodan, M. 1968. Punktstichprobe für die Forsteinrichtung (A point sample for forest management planning). Forst Holzwirt , 23(11): 225-226.
- Schöpfer, W. 1969a. Die 6-Baum-Stichprobe in der Forsteinrichtung. Teil 1 (6- tree sampling for forest management planning, part 1). Allgemeine Forst Zeitung, 25: 533-536.
- Schöpfer, W. 1969b. Die 6-Baum-Stichprobe in der Forsteinrichtung. Teil 2. (6-tree sampling for forest management planning, part 2). Allgemeine Forst zeitung, 26:588-591.
- Stoffels, A. 1955. Die Genauigkeit der Bestimmung der Stammzahl pro Hektar durch  Messung von Stammabsta¨nden (The  accuracy  of estimation of number of stems per hectare  with distance measurements). Forstwiss. Centralbl, 74: 211-218.
- Soltani, A., Zobeiri, M. and Namiranian, M. 2007. Optimization of Proden’s six tree sampling method. Journal of Natural Research, 60(4): 1291-1307.
- Wang, J., Sharma, B.D., Li, Y. and Miller, G.W. 2009. Modeling and validating spatial patterns of a 3D stand generator for central Appalachian hardwood forests. Journal of Computers and Electronics in Agriculture, 68: 141-149.
- Weck, J. 1953. Untersuchung über die Brauchbarkeit und Genauigkeit eines Verfahrens der Bestandesmessung unter Verwendung von Stammabsta¨nden (A study on usefulness and accuracy of stand estimations with distance measurements). Forstarchiv, 24: 257-260.
- Zobeiri, M. 1978. Tree sampling in natural forest of Northern Iran. Forestry Chronicle, 54(3): 171-172.
- Zobeiri, M. 2005. Forest Inventory (Measurement of Tree and Forest). University of Tehran Press, 401p (In Persian).