Application of T-square sampling method in Zagross forests (Case Study: Kermanshah province)

Document Type : Research article

Authors

1 Ph.D. Scholar of Forestry, Faculty of Natural Resources, University of Tehran

2 Professor, Faculty of Natural Resources, University of Tehran.

3 Associate Professor, Faculty of Natural Resources, University of Tehran

Abstract

T-square sampling method is one of the distance sampling methods for estimating the plant density and canopy cover. For plant density measurements, three formulas, of Diggle and Byth have been used. In this study, applicability of these formulas regarding to accuracy of estimate for density and canopy cover of Zagross Oak (Quercus brantii) forests in research and educational Forest of Qasr-e Shirin (Kermanshah province) were examined. At first, 50 hectares of the forest area was selected and the inventory of the population was carried out. Then, 50 systematic random sampling points for T-square sampling method in this area were measured and recorded. The results show that none of the formulas could provide an acceptable estimate based on 10% accepted accuracy; even though, the Byth formula has more accuracy level for density and crown coverage for this kind of forests. 

Keywords


- اسحق نیموری، ج.، 1379. مقایسه روش آماربرداری سیستماتیک با قطعات نمونه دایره ای و روش ترانسکت از نظر دقت و هزینه در جنگل های بلوط غرب. پایان نامه کارشناسی ارشد دانشکده منابع طبیعی دانشگاه تهران. 89 صفحه.
- پوربابایی، ح.، آهنی، ح. و بنیاد، م.ا.، 1383، بررسی الگوی مکانی درختان کرکف درجنگلهای شفارود، رضوانشهر،گیلان. مجله علمی محیط زیست، سال اول:
30-24.
- زبیری، م.،1381. زیست سنجی (بیومتری جنگل). انتشارات دانشگاه تهران، 411 صفحه.
- زبیری، م.، 1384. آماربرداری در جنگل (اندازه‌گیری درخت و جنگل). چاپ سوم، انتشارات دانشگاه تهران، 401 صفحه.
- مقدم، م.ر.،1380. اکولوژی توصیفی و آماری پوشش گیاهی. انتشارات دانشگاه تهران. 285 صفحه.
 -Bonham, C.D., 1989. Measurements for terrestrial vegetation. John Wiley and sons. 338 p.
-Byth, K., 1982. On robust distance-based intensity estimators. Biometrics 38: 127-135.
-Diggle, P.J. 1975. Robust estimation using distance methods. Biometrika, 63:39-48.
-Engeman, R.M., Sugihara, R.T., Pank, L.F. and Dusenberry, W.E., 1994. A comparison of plotless density estimators using Monte Carlo simulation. Ecology 75(6): 1769-1779.
- Krebs, C.J., 1989. Ecological Methodology. Harper Collins, New York. 653 p.
-Krebs, C.J. and Charles J., 2001. Programs for Ecological Methodology, 2nd ed. Dept. of Zoology, University of British Colombia,Vancouver, B.C. Canada V6T 1Z4  (software version 6.0).
-Southwood, T.R.E and Henderson, P.A., 2000. Ecological Methods. Blackwell science. http://www.blackwell science.com/southwood. 575 p.