Biological-drying of Pinus radiata and Eucalyptus cladocalyx trees

Abstract

In studies in South Africa, 19-yr-old P. radiata were sour-felled each month for a year and left in the shadow of the plantation or in direct sun. A third group of trees were felled, branches were removed and stems were cross-cut before storage in direct sun. Mass losses were determined for 55 days. A similar, but smaller, study was done on E. cladocalyx. Mass losses were significantly greater in sour-felled trees than in logs dried for the same period. Drying of pines was most effective during Oct.-Feb., with mass losses in sour-felled trees and logs of 37 and 12%, respectively. Corresponding losses in Mar.-Sep. were 19 and 3%. There was n.s.d. between drying in shadow or direct sun. Greatest mass loss in eucalypt was from barked sour-felled trees and least from logs with bark. Greatest differences between sour-felling and log drying occurred after 55 days in pine and during the first 8-10 days in eucalypt. Sour felling resulted in more uniform radial distribution of m.c. Planks from sour felled pines had less warp after kiln-drying than planks from logs. Blue stain was less in sour-felled pines during Dec-Mar., but not during Oct.-Dec. No blue stain occurred during Apr.-Sep.