Today most sawmills use optimization techniques to maximize yields from logs. If open market conditions are assumed when maximizing volume or value yields, overproduction of some products and underproduction of others may result. In this study, a system is described that links production with log sawing optimization while also addressing demands for timber products of differing qualities. The system is based on an optimization framework that is implemented in a log sawing simulator, AUTOSAW. Unlike other optimization systems that use static product ''values'' such as board volume or timber price, dynamic values are used that are updated regularly according to previous timber production. The efficiency of the system was tested with three orderbooks via comparisons with volume- and value-optimized solutions obtained from sawing pruned Pinus radiata D. Don logs. In each case, product optimization required fewer logs to satisfy all demands than did either volume or value optimization. Furthermore, underproduction was eliminated and overproduction reduced.

Shrubland biomass is important for fire management programmes and for carbon estimates. Aboveground biomass and the combustible portion of biomass, the fuel load, in the past have been measured using destructive techniques. These techniques are detailed, highly labour intensive, and costly; hence, an alternative approach was sought. The new approach used linear mixed-effects models to estimate biomass and fuel loads from easily measured field variables: shrub overstorey height and cover, and understorey height and cover. Site was regarded as a random effect. Sampling sites were located throughout New Zealand and included a range of shrubland vegetation types: manuka ( Leptospermum scoparium J.R. Forst. et G. Forst.) and kanuka ( Kunzea ericoides (A. Rich.) J. Thomps.) scrub and heath, pakihi (mixed low heath, fern, and rushes), and gorse ( Ulex europaeus L.). The approach was extended and confidence intervals were constructed for the regression models. Statistical analysis showed that understorey height and overstorey cover were significant (at the 5% level) in some cases. Overstorey height was highly significant in all cases (p < 0.0001), allowing development of models useful to the operational user. The models allow rapid estimation of average fuel loads or biomass on new sites, and double sampling theory can be applied to calculate the error in the resultant biomass estimate.

Journal of the Operational Research Society (JORS) is the world's longest established OR journal and an official journal of The OR Society. It is the aim of the Journal to present papers which are relevant to practitioners, researchers, teachers, students and consumers of operational research, and which cover the theory, practice, history or methodology of OR.

Exposure to carbon monoxide (CO) emitted by chainsaws can negatively impact health in forestry workers. This exploratory study measures CO concentration within the breathing zone of chainsaw operators during motor-manual operations, and discusses the potential influences on CO exposure levels. A CO monitoring instrument was paired with a concurrent video recording of task activities to enable correlation of exact working operations to critical exposure levels. Multiple streams of meteorological data were also collected from sensors worn by the eight professional tree fellers/log makers. Time-weighted averages were applied to investigate levels of CO exposure during a nominal 1-hr monitoring period. The differing task demands and environment were found to influence worker exposure to CO, supporting previous research. Pending further investigation, a number of possible actions are recommended to reduce observed high exposure levels and/or emission concentration.

To understand the effects of silvicultural treatments on tree and product modulus of elasticity (MOE), an intensive study along the stand-tree-product value chain was conducted. Acoustic tests were performed on 460 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from two sites in the US Pacific Northwest.