Influence of Bravo fungicide applications on wood density and moisture content of Swiss needle cast affected Douglas-fir trees.

Abstract

Wood density, moisture content, tracheld width and cell wall size were examined in trees from plots that were sprayed for 5 years with chlorothalonil (Bravo ®) fungicide to reduce the impact of Swiss needle-cast (SNC) and from trees in adjacent unsprayed plots. The unsprayed (more heavily diseased) trees had significantly narrower sapwood, narrower growth tings, lower sapwood moisture content, and narrower tracheid cell wall thickness than did the sprayed (less heavily diseased) trees. Moreover, unsprayed trees had altered earlywood denslty—earlywood width, relationshlps, higher latewood proportion, and higher overall wood density than the sprayed trees. We hypothesize: (1) that the decreased moisture content of diseased trees results from their poor carbon economy resulting in insufficient energy (photosynthate) to reverse sapwood embolisms, and (2) SNC decreases wood density relative to growth rate.

Citation

Johnson, G.R.; Gartner, Barbara L.; Maguire, Doug; Kanaskie, Alan. 2003. Influence of Bravo fungicide applications on wood density and moisture content of Swiss needle cast affected Douglas-fir trees. Forest Ecology and Management. 186: 339-348