Adaptive control of bucking on harvesters: Target and timing effects

Optimally bucking individual stems, based on market prices, is unlikely to provide log product yields that meet order book constraints at the harvest unit or forest level. Adaptive control, in conjunction with dynamic programming, has been shown in earlier research to provide superior results from stem and stand log bucking when the stand is subject to order book constraints. Adaptive control can be achieved by adjusting relative prices and small-end diameter specifications as the harvester progresses through the stand. In this paper, the simulated effects on overall apportionment degree of varying 1) target proportions for given log types and 2) update frequencies are examined. The results show that varying the target proportions provided the best overall apportionment degree in only one of four test Pinus radiata stands, compared with holding the target proportions constant. Also, no significant differences in apportionment degree were found when examining update rates from 4 to 512 stems in both of the two test stands. © Forest Products Society 2006.