Bacterial WetwoodLarge elm and poplar trees with vertical stripes of bleached bark are a common sight in many parts of the U.S. The disease, bacterial wetwood, and the slime flux associated with it cause the bark disc
http://nu-distance.unl.edu/homer/disease/hort/Tree...
Wetwood (Corynebacterium)Importance- Poplars commonly develop wetwood, a water-soaked condition accompanied by a darkening of the wood. Premature death of poplars, especially of Lombardy poplar, has been associated with wetwo
http://www.forestpests.org/poplar/wetwood.html