Ethanol and Water in Pseudotsuga menziesii and Pinus ponderosa Stumps

Abstract

Douglas fir (Pseudotsuga menziesii), west of the Oregon Cascades, and ponderosa pine (Pinus ponderosa), east of the Cascades, were cut during the fall in conjunction with various forest management practices. Trees cut varied in size and age, and the stumps were exposed to disparate winter temperatures and precipitation patterns. Nevertheless, the stumps showed similar responses in their synthesis and accumulation of ethanol. The following spring, ethanol concentrations in above-ground tissues of both species ranged from 3 to 116 times higher than in their corresponding root tissues. We suggest that this difference results from the above-ground tissues being more hypoxic than roots because they were exposed to more water from precipitation and warmer temperatures. Ethanol concentrations in the above-ground tissues of ponderosa pine stumps were about two to six times higher than in Douglas fir, and root tissues from pine stumps usually contained more ethanol after anaerobic incubation than roots from Douglas fir. Ethanol and volatile terpenes released from stumps can attract various beetle species that not only vector root diseases, but can also damage or kill seedlings and saplings. Understanding the dynamics of ethanol synthesis and accumulation in stumps and slash might contribute to new alternatives for managing these insects.