Abstract:
Maximizing the profits obtained in the conversion of wood logs into lumber is a primary
interest of forest product processing companies and a concern of forest managers. Log
conversion efficiency in the sawmilling industry is commonly expressed as the yield or
recovery of sawn wood from a given log. The aim of this study was to estimate the lumber
recovery of Cupressus lusitanica logs under different log length, log taper and sawing
techniques at Injibara wood sawmill, run by Amhara Forest Enterprise. A total of 240 sample
logs were selected from Injibara sawmill log desk. From the total sample, 180 sample logs
were used to compare the lumber volume recover of three log length levels (3m, 3.5m and
4m), each length levels had 60 sample logs. The 60 sample logs under each length class were
re-grouped into three taper classes (small with ≤ 0.35, medium with 0.35-0.75cm/m, and high
with >0.75cm/m), i.e. each taper class had 20 sample logs. Two sawing techniques (live and
plain sawing) were also evaluated for their lumber volume recovery efficiency using 120
sample logs (60 logs for each sawing technique). The collected data were analyzed by using
Microsoft excel and R-software. The results revealed that there were significant (P<0.05)
differences between log taper on lumber recovery percentage with small taper having higher
recovery percentage (48.31%) than medium (46.40%) and large taper (44.61%) logs. This
result also revealed that there were not statistically significant variations between two sawing
methods. But, live sawing method produced higher lumber recovery (45.463 %) than plain
sawing method (44.08%). Logs having shorter length produced highest lumber volume
recovery (47.68%) than logs having a longer length (45.46%). Based on these findings
Sawmills would be recommended to use live sawing method, logs having lower taper and
shorter length depending on the situation to generate higher yield of lumber
