Geospatial and within tree variation of wood density and spiral grain in Douglas-fir

In many parts of the world, log markets are becoming increasingly competitive and complex. Buyers are demanding, and suppliers are offering, logs that have been Cut for very specific end-uses and which may be specified in terms of internal as well as external properties. Optimally matching logs to markets requires good measurements and/or predictions of the wood properties in each stern. This information could be used either at the planning stage or in on-board computers installed in harvesters to enhance bucking and sorting. To assess the geospatial and within-tree variation in wood density and spiral grain in Douglas-fir sterns, over 400 wood disks were collected from 17 sites in the Cascade and Coastal Ranges of Oregon. Sites were selected from a range of elevations and aspects. Trees selected at each of the sites were of a similar age (28 to 57 yr) and average size (20 cm to 54 cm diameter at breast height). Disks came from different vertical positions in each tree. No statistically significant relationship between wood density and either elevation or aspect was found. There was evidence of a weak negative association between wood density and the height in the tree where the samples were removed. No statistically significant relationship between height, elevation, or aspect was observed for spiral grain.