Comparison of Pinus taeda L. wood property calibrations based on NIR spectra from the radial-longitudinal and radial-transverse faces of wooden strips

When a radial strip is cut from an increment core it can potentially be cut with two orientations: parallel to longitudinal tracheids, i.e., a radial-longitudinal (RL) strip (the orientation of SilviScan samples), or at an orientation of 90° to the tracheids, i.e., a radial-transverse (RT) strip. Both strips could be used for near-infrared (NIR) analysis, but it is unknown how calibrations based on RT-face NIR spectra compare with those based on RL-face NIR spectra. A total of 20 Pinus taeda L. (loblolly pine) RL strips were characterized in terms of air-dry density, microfibril angle (MFA), stiffness and several tracheid morphological characteristics. NIR spectra were collected in 10-mm increments from the RL and RT faces of matching strips and used to develop calibrations for each property. In general, RL-face NIR spectra gave calibrations that provided stronger relationships. Differences between the two sets of calibrations were small, indicating that either face could be used for NIR analysis.

Meeting visual quality objectives with operational radial-strip partial cutting in coastal British Columbia: A post-harvest assessment

The spectacular aesthetic quality of British Columbia's coastal forests has long been an issue for forest managers who must often meet government-imposed visual quality objectives. The result of such objectives within traditional clearcutting silvicultural systems has often been large reductions in otherwise allowable timber removals. In this document we present the results of a post-harvest analysis of an operational trial using radial-strip partial harvesting in a highly visually sensitive area of coastal British Columbia. The analysis confirmed that this innovative form of partial harvesting successfully met visual quality requirements, while concurrently permitting significantly more timber extraction, in an operationally feasible manner, than would have been available under a traditional clearcutting system. We attribute the visual success of this harvest method in a highly visually sensitive area primarily to: (1) the radial pattern of linear clearings where it is not possible to see more than a few cleared strips from any one vantage point; (2) the avoidance of a regular series of parallel geometric clearings; (3) the narrow clearing width, which maximises bare ground screening; (4) feathered edges, which avoided highly contrasting edges of the strips; and (5) green tree retention across age classes. Faller and management experience with this method is expected to result in higher productivity and lower costs in the future. This harvesting technique appears to present a viable alternative to clearcutting for forest managers working in visually sensitive areas. Future work should focus on understanding and determining impacts on other factors such as ecological values and silvicultural goals. Key words: aesthetics, partial-cutting, simulation, VIA, visual impact assessment, VQO, visual quality objective