Efficiency of C-nn distance sampling method in comparison to sampling with fixed area plot for estimation of forest stem basal area in Kheyroud forests of northern Iran

Document Type : Research Paper

Authors

1 Associate Prof., Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran

2 Research expert, Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran

Abstract

Plotless or distance sampling methods, also known as k- tree sampling, are practical field sampling methods for forest inventories and ecological surveys. In this research, in order to test the efficiency of Continues Nearest Neighbor (C-nn) distance sampling method a 220 ha forest area was selected in Kheyroud forests of northern Iran. Then field sampling was performed using: 1- circular sample plots of 1000 m2 which is conventional in these forests and 2- C-nn samples with k = 15 trees, both based on a 150 m×200 m systematic grid. In total, we measured 77 circular sample plots and 77 C-nn samples in the study area. Results showed that there was no significant difference between estimation of forest stem basal area using the two methods and even among different values of k (6 to 15). However, sampling precision decreased significantly by decreasing the amount of k from 7 to 6 trees. Furthermore, time cost in the C-nn method was significantly lower than the other one. Therefore, regarding to the ease of implementation and the statistical precision of the C-nn sampling method, we concluded when sampling using plotless methods is needed to apply in these kind of forest, the C-nn sampling method can be implemented with k =7 trees based on cost and precision of inventory. 

Keywords

Main Subjects

Iranian Journal of Forest
Volume 10, Issue 1
June 2018
Pages 111-122

Files

History

  • Receive Date: 22 October 2017
  • Revise Date: 14 August 2017
  • Accept Date: 13 November 2017

Share

How to cite

Statistics