The impact of log-end splits and spring on sawn recovery of 32-year-old plantation Eucalyptus globulus Labill.

Thirty dominant or co-dominant, straight trees were selected from a 32-year-old thinned plantation of Eucalyptus globulus Labill. Growth strain at tree surface at breast height was estimated using a CIRAD-foret method. Log-end splits in the butt logs were measured. The butt logs were quarter-sawn following a pre-determined sawing pattern. The most common dimensions of sawn boards were 28 x 105 x 3000 and 28 x 77 x 3000 mm. The volume of the curved-edge off-cuts was estimated for each butt log. The end splits in the dried sawn boards were measured and the volume of the wood containing the splits in the boards calculated. The estimated reduction in sawn recovery due to removing the curved edges in the slabs was equivalent to 6% of the log volume. The estimated reduction in recovery due to end-docking log-end splits was equivalent to 1% of the log volume, or approximately 4% of the dried board volume. For a sawmill processing 40 000 m(3) of logs per annum, this could translate into an annual loss of $758 000 (log volume) and $385 000 (board volume). These numbers are high in the context that end splits in these logs overall were quite mild and the estimated strain at tree surface was moderate.