Canadian Forest Service Publications
Acoustic Velocity Sampling of Western Hemlock on Vancouver Island. March 31, 2009 Final Report. 2009. Sandford, J.S., Mitchell, A. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC.
Issued by: Pacific Forestry Centre
Catalog ID: 34249
CFS Availability: PDF (download)
Phase I Phase I of this project involved record acoustic velocity (AV) data from a variety of mature second growth western hemlock (Hw) stands on Vancouver Island to begin to develop an understanding of the range and variability of western hemlock AV values as they relate to associated stand and site information (site index, stand density, slope, aspect, elevation, etc.) Seventy-two mature second growth western hemlock stands were identified as potential candidates for sampling (twenty-three stands near Campbell River, twenty-two stands near Jordan River, and twenty-seven stands west of Port Alberni). Plots were subsequently established in ten of these stands and AV readings were obtained using the ST300 device for fifty-one trees in each plot. Stand and site characteristics were also recorded for each stand. Vehicular access to the remaining potential sample sites was also determined and is summarized in Appendix 1.
Phase II Phase II of this project involved using the ST300 device to record AV data from a single site immediately prior to harvest and then having staff from FPInnovations sample the same trees (as logs on the ground) using the HM200 AV device. Four plots (fifty-one trees per plot) were established in a cut-block in the Lower Adam operating area of Western Forest Products’ Mid Island forest operation prior to harvesting. Acoustic velocity was measured on 204 standing trees within these plots using the ST300 device. Since then personnel from FPInnovations have measured AV from some of the same trees (logs) after they are cut using the HM200 device. Their ultimate objective is to attempt to determine if relationships exist between AV data obtained by the ST300 and HM200 devices and final characteristics of wood strength and stiffness (MoE, MoR for example). Acoustic velocity and diameter at breast height (DBH) were recorded for each tree sampled in both study phases. Overall descriptive statistics are as follows: AV readings ranged from 3.5 to 5.7 with an average value of 4.6. Tree diameters (DBH) ranged from 13.2 cm to 84.1 cm with an average diameter of 35.8 cm. Further analysis of this data as it relates to stand and site characteristics and strength and stiffness is being performed by staff at the Canadian Wood Fibre Centre (Canadian Forest Service) and FPInnovations respectively.