. Bulletin. Natural history; Natural history. Pig. 5.—Fluxing through branch crotches is common in elms affected with wetwood. The flux on this tree, invaded by air-borne organ- isms, has coated the bark below the crotch with slime. In most elms, wetwood is confined to the inner sapwood and heartwood, and there is very little or no streaking in the outer sapwood and no discoloration in the cambial region or phloem. However, in those affected elms that exhibit wilting of twigs and branches, grayish brown dis- coloration can be found in the outer sapwood and occasionally in the cambial region an
. Bulletin. Natural history; Natural history. Pig. 5.—Fluxing through branch crotches is common in elms affected with wetwood. The flux on this tree, invaded by air-borne organ- isms, has coated the bark below the crotch with slime. In most elms, wetwood is confined to the inner sapwood and heartwood, and there is very little or no streaking in the outer sapwood and no discoloration in the cambial region or phloem. However, in those affected elms that exhibit wilting of twigs and branches, grayish brown dis- coloration can be found in the outer sapwood and occasionally in the cambial region and phloem as well* as in older wood. Gas.—In wetwood-affected tissues, gas is produced in large amounts by the action of the fermenting bacteria on carbohy- drates and other materials in the trunk. This gas, confined in the trunk, causes abnormally high sap pressures to develop. Pressures up to 60 pounds per square inch have been recorded. Sap.—Sap accumulates in abnormally large amounts in affected wood. Because of the abnormally high pressure caused by the gas produced by fermentation, sap frequently is forced out of the trunk. Fig. 6.—This elm is fluxing through a crack in the trunk, which originated as a frost crack during the preceding winter. Fluxing through the crack in the bark became apparent by Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
