Wood density and anatomical properties in suppressed-growth trees : comparison of two methods

Abstract

Interest in the commercial value of small-diameter timber has led to testing core samples with SilviScan to characterize density and transverse fiber dimensions. Data showed that latewood density and tracheid diameter in suppressed-growth material can vary spatially on a scale comparable to the 50-_m resolution of the instrument used in our testing. An optical imaging method called Ring Profiler was developed to determine what effect SilviScan’s resolution had on the measurements. A single suppressed-growth specimen of Douglas-fir was used to develop the method. Ring Profiler measurements of the specimen showed that SilviScan overestimated latewood tracheid radial diameters by 59% in growth rings averaging 200-_m width. In those same growth rings, SilviScan latewood density was found to be 19% too low. In all growth rings measured by Ring Profiler, latewood wall thicknesses were anisotropic. Radial and tangential values averaged 13% less than the isotropic wall thickness calculated from SilviScan data. Ring Profiler density measurement from binarized images of wood cross-sections was found to correlate well with SilviScan X-ray density (r-squared _ 0.907); however, better images and an objective method for thresholding are needed for accuracy over a large sample space. With these improvements and automated scanning of samples, Ring Profiler could be an attractive, inexpensive complement to SilviScan.

Citation

Vahey, David W.; Zhu, J. Y.; Scott, C. Tim. 2007. Wood density and anatomical properties in suppressed-growth trees : comparison of two methods. Wood and fiber science. Vol. 39, no. 3 (2007): pages 462-471.