Publication
 

Statistical reliability in SMS's pre-felling inventory: Inferences and implications for sampling tree density, basal area and volume

This study was carried out on a randomly chosen 30-ha (500 × 600 m) forest area within the 50-ha Demography Project of the Forest Research Institute Malaysia (FRIM) in Pasoh Forest Reserve, Negeri Sembilan. A 30-ha study area was used as data set. A higher sampling intensity was needed when sampling tree size classes and species groups that were lower in their frequency of occurrence. Dipterocarp species group (ALL DIPT) needed a higher sampling intensity to detect its occurrence compared to non-dipterocarp species groups (ALL NON-DIPT). A different intensity of sampling was required when considering either diameter classes, species groups, plot sizes or tree parameters separately, and also when different confidence and error levels were used. The implications of attaching confidence and error levels to the intensity of inventory by species group currently used in Selective Management System are also discussed.

Kajianini dijalankan di kawasan seluas 30-ha (500 × 600 m) yang dipilih secara rawak di kawasan Projek Demografi 50-ha Institut Penyelidikan Perhutanan Malaysia (FRIM) di Hutan Simpan Pasoh, Negeri Sembilan. Data dari kawasan 30-ha ini digunakan bagi analisis kajian ini. Keputusan menunjukkan intensiti pensampelan yang lebih tinggi diperlukan apabila pensampelan ke atas kelas saiz pokok dan kumpulan spesies yang kurang bilangannya dijalankan. Kumpulan spesies dipterokarp (ALL DIPT) memerlukan intensiti pensampelan yang lebih tinggi berbanding kumpulan spesies bukan dipterokarp (ALL NON-DIPT). Keputusan juga menunjukkan intensiti pensampelan yang berbeza diperlukan apabila faktor berlainan diambil kira, sama ada kelas diameter, kumpulan spesies, saiz plot atau parameter pokok. Ini juga berlaku apabila tahap keyakinan dan tahap ralat berbeza digunakan. Implikasi hubungan tahap keyakinan dan ralat dengan intensiti pensampelan bagi kumpulan spesies yang sedang digunakan dalam Sistem Pengurusan Memilih juga turut dibincangkan.

Abstract in English and Malay; article in English only.

Authors: 
Wan Mohd Shukri Wan Ahmad & Wan Razali Wan Mohd
Journal: 
Journal of Tropical Forest Science
Year: 
2002
Volume: 
14
Issue: 
1
Pages: 
1-15
Site: 
Pasoh