GIRDLING EASTERN BLACK WALNUT TO INCREASE HEARTWOOD WIDTH

Eastern black walnut (Juglans nigra L.) has often been planted at spacings that require pre-commercial thinning. These thinnings are deemed pre-commercial due to the small diameter of the trees and the low ratio of dark wood to light wood. As a consequence of size and wood quality, these thinnings are often an expense rather than a source of revenue. In an effort to increase the value of these thinnings it would be beneficial to increase the ratio of dark wood to light wood. One way to increase the amount of dark wood is through costly processing using steam. However, several non-scientific studies have reported that dark wood can be increased by girdling small trees and allowing them to remain on the stump for a certain period of time. This study was designed to test this idea. In a black walnut plantation scheduled for thinning, 10 trees were randomly selected and double-girdled. At that time, increment cores were taken 30.48 cm above the top girdle. These trees were allowed to remain on the stump for 21 months before they were harvested. Results of this study will describe changes in dark wood content following the girdling treatment. The results will compare light to dark wood ratios of the initial increment cores to the boards sawn from the harvested logs.