. [Bulletins on forest pathology : from Bulletin , Washington, , 1913-1925]. Trees; Plant diseases. CONTROL OF DECAY IN PULP AND PULP WOOD 15 both runs. The temperature of grinding varied between 120 and 180° F. (49 to 82° C). After the separated screenings were weighed the pulp was run over the wet machine and the dry weight calculated. The essential data obtained from these tests are shown in Table 1. Table 1.—Data on the grinding of sound and decayed spruce Decayed wood, sample 2546 Quantity of wood -- - Weight of rough wood Weight of rough wood, oven-dry3 do—
. [Bulletins on forest pathology : from Bulletin , Washington, , 1913-1925]. Trees; Plant diseases. CONTROL OF DECAY IN PULP AND PULP WOOD 15 both runs. The temperature of grinding varied between 120 and 180° F. (49 to 82° C). After the separated screenings were weighed the pulp was run over the wet machine and the dry weight calculated. The essential data obtained from these tests are shown in Table 1. Table 1.—Data on the grinding of sound and decayed spruce Decayed wood, sample 2546 Quantity of wood -- - Weight of rough wood Weight of rough wood, oven-dry3 do— Loss in barking, based on oven-dry wood Weight of barked wood, oven-dry Yield of pulp, oven-dry weight do— Yield of oven-dry pulp, based on oven-dry barked wood per Yield of oven-dry pulp, based on oven-dry rough wood do—. 2 250 18,839 12, 600 8,650 6,783 12-foot lengths. -foot lengths. Computed from moisture samples. YIELD AND QUALITY OF PULP The results of this particular trial indicate a yield of per cent in the case of the sound and of per cent in the case of the decayed wood, on the basis of oven-dry weights in each case. Decay thus accounts for a loss of per cent. A sample of the pulp from each grinder run was shipped to the Forest Products Laboratory for physical and microscopic examina- tion and for paper-making trials. Samples were also placed in moist storage for further observation, as described later. Sedimentation tests indicated that the pulp made from decayed wood was slightly freer than that made from sound wood, although the difference was not marked. Microscopic examination of the average length of fiber particles showed millimeters for the sound in comparison with millimeters for the decayed material. The decayed pulp contained about twice as much debris, in the form of very small particles evidently produced by pulverizing the infected wood in the grinding. A large percentage of this
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