Student:	Oytun Emre SAKICI
Supervisor:	Prof. Dr. Hakkı YAVUZ
Department:	Orman Mühendisliği
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University, Turkey

Title of the Thesis:	Comparing Various Sampling Methods Used in Timber Inventory
Level:	Ph.D.
Acceptance Date:	30/1/2009
Number of Pages:	219
Registration Number:	Di672

Summary:

This research aimed to compare various sampling methods used in forest inventory

for estimation of success and cost. The data were collected from even-aged Pinus brutia -

Pinus nigra stands in Burhaniye and from uneven-aged Abies nordmanniana subsp.

bornmulleriana - Pinus sylvestris stands in Ayancık.

Simple Random, Systematic, Stratified, Cluster, Angle Count and Six Tree

sampling methods were used. Three sample sizes (400, 600 and 800 m2) for fixed plot size

sampling methods and five coefficient of variations for varying plot size sampling methods

were took into account. Four sampling errors (5, 10, 15 and 20%) which are commonly

used in forest inventory were also considered. Totally 435 sampling designs were

developed by using various sampling methods, different sample plot sizes (or coefficient of

variations) and different sampling errors. These designs were compared for power of basal

area estimation by using absolute percent bias and compared for cost by using total

sampling costs. Two optimization models, one of which minimizes the sampling cost for a

given sampling error and the other minimizes sampling error for fixed budget, were also

solved for various strategies.

According to the research results, Angle Count Sampling for even-aged stands and

Two-Stage Cluster Sampling for uneven-aged stands were efficient methods. In terms of

sampling cost it was the sample plot size of 600 m2 or 800 m2 were efficient for even-aged

stands, while the sample plot size of 600 m2 was effective for uneven-aged stands.

According to the validity check of the results by using the records of General Directorate

of Forestry, the results are favorable. The study also generated some equations for

calculating the time required to measure the diameter.

Key Words: Timber Inventory, Sampling Methods, Sampling Cost, Sampling Efficiency