Aspen Bibliography

Wet Wood, Bacteria, and Increased pH in Trees

Document Type



USDA Forest Service


No. 2215

Publication Date



The knowledge of the differences between sapwood and heartwood and the transition from one to the other leaves much to be desired. The common assumption has been that heartwood formation coincides with the natural death of the parenchyma due to its age, or as in oak to its distance from the cambium. In the pines, Douglas-fir, oaks, and some other common trees, heartwood is more acid than sapwood, and in the pines and Douglas-fir, it is lower in moisture. Both heartwood and sapwood of healthy trees are thought of as ordinarily free from micro-organisms except for the heart-rotting Hymenomycetes or local infections near wounds. For the most important commercial genera, there is little reason to challenge this view.