Investigation on Four Sampling Methods for Canopy Cover Estimation in Zagros Oak Forests (Case study: Mehrian Forests of Yasuj City)

Document Type : Research article

Authors

1 Associate Professor, Agricultural Sciences and Natural Resources University of Sari

2 Professor, Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran

3 M.Sc. Student in Forestry, Faculty of Agricultural Sciences and Natural Resources, Mazandaran University

4 Ph.D Student in Forestry, Faculty of Natural Resources, Agricultural Sciences and Natural Resources University of Sari

Abstract

In order to investigate and determine an appropriate inventory method for Yasuj Oak forests, considering inventory precision (confidence limit) and accuracy for canopy cover parameter per hectare, four methods consisting of: systematic-random (rectangular plots), transect, strip and stratification were selected and their efficiency in the forest was evaluated. For this purpose, at first 100% inventory was applied in 100 hectare area of Yasuj Mehrian Forests, then geographical characteristics of the total trees were recorded, using GPS apparatus. The geographical data were transmitted to computer and the trees positions were identified on the area’s digital map. The data which had been recorded at 30 replicates by the four inventory methods, were analyzes by AutoCAD, Arc View and Arc Info software's and the outputs were compared with the results of 100% inventory method. The results showed that the real average canopy cover (recorded from 100% inventory) was equal to 2257 m2/ha whereas for the inventory methods of: systematic-random, transect, strip and stratification, was equal to 2390, 2220, 1995 and 2341 m2/ha respectively. The statistical errors for systematic-random, transect and stratification inventory methods were 18, 4 and 14 percent, respectively. Although the strip method is lack of statistical basis, and calculation of sampling error and confidence limit is impossible, but comparing the average canopy cover of this method with the other inventory methods was possible. Overall, the greatest and the lowest accuracy rate belonged to transect and strip methods, respectively. It can be concluded that the transect is the most appropriate inventory method for these forests.

Keywords

References

- Alijanpour, A., 2000. An investigation of the best statistic sampling method in forests of Arasbaran. Thesis submitted for the degree of MSc. in forestry, Faculty of Natural Resources, University of Tehran, 160 p.
- Anonymous, 2003. Manual of forestry plan preparation for out of north forests. 12 p.
- Eshagh Nimvari, J., Zobeiri, M., Sobhani, H. and Zangeneh, H.P., 2003. A Comparison of Randomized-Systematic Sampling with Circle Shape Plot and Transect Method, Based on Precision and Cost, (Case Study in Sorkhedizeh of Kermanshah). Iranian Journal of Natural Resources, 56(4): 383-396.
- Erfanifard, S.Y., Feghhi, J., Zobeyri, M. and Namiranian, M. 2006. Determining suitable area and shape of sample plot for crown cover estimation using forest simulation in Zagros Region. Iranian Journal of Forest and Poplar Research, 14 (4): 360-370.
- Jazirehi, M.H. and Ebrahimi Rostaghi, M., Silviculture in Zagros. University of Tehran Press, 560 p.
- Heidary, R.H., 2006. Study the Different Distance Sampling Methods in the Zagross Forest (Case Study: Sorkhehdizeh at Kermanshah Province), Thesis Submitted For The Degree of MSc. in Forestry, Faculty of Natural Resources, University of Tehran, 116 p.
- Husch, B., Beers, T. and Kershaw, J., 2003. Forest Mensuration. Published by John Wiley and Sons, 443 p.
- Lisa, J.B., 2002. Accuracy and efficiency of methods to sample logs wildlife research and management. USDA forest Gen. Tech., PSW-GTR: 181-185.
- Naghavi, H., 2008. Comparison the Accuracy of Fixed Plot and Transect Sampling Methods in Zagros Forests Inventory (Case study: khoramabad, Kakareza Region Forests), Thesis Submitted for MSc Degree in Forestry, University of Mazandaran, 72 p.
- Naghavi, H., Fallah, A., Jalilvand, H., Soosani, J. and Kooch, Y., 2009. Investigation of Sampling Method Application with Fixed Plot in Sampling of Coppice Forests. Journal of Applied Science, 9 (5): 997-1000.
- Nouki, Y., 2004. Comparison the Precision and Cost Between Line Transect Sampling Method Based on Distance Between Trees and Probability Theory in Khalkhal Forests. Thesis Submitted For MSc Degree in Forestry, University of Tehran, 88 p.
- Paulo, M.J., Tomé, M., Otten, A. and Stein, A., 2005. Comparison of three sampling methods in thecharacterization of cork oak stand for management purposes. Canadian Journal of Forest Research,35 (10): 2295-2303.
- Rudnicki, M., Silins, U. and Lieffers, V., 2004. Crown Cover is Correlated with Relative Density, Tree Slenderness and Tree Height in Logepole Pine. Journal of Forest Science, 50 (3): 356-363.
- Sagheb Talebi, K., Sajedi, T. and Yazdian, F., 2005. Forests of Iran. Research Institute of Forests and Rangelands. 54 p.
- Spark, J. and Masters, R., 2002. Comparative evaluation of accuracy and efficiency of six Forest Sampling Methods. Proc. Okla. Sci., 82: 49-56.
- Southwood, T.R.E. and Henderson, P.A., 2000. Ecological Methods, Blackwell science, 575 p.
- Zobeiri, M., 2002. Forest Biometry. Tehran University Press, 411 p.

Files

Share

How to cite

Statistics