* P [less than or equal to] 0.05 (b) [[alpha].sub.r] = radial shrinkage coefficient; [[alpha].sub.t] = tangential shrinkage
coefficient; [[alpha].sub.v] = volumetric shrinkage coefficient; [s.sub.r] = total radial shrinkage; [s.sub.t] = total tangential shrinkage
; [s.sub.v] = total volumetric shrinkage; GMC = green moisture content [D.sub.o] = ovendry weight density; [D.sub.g] = green weight density.
From these two conditions, the assumption that elliptic changes from the radial to tangential shrinkage
coefficient is enforced according to Figure 4.
The above characteristics of tangential shrinkage
stresses are clearly different from the radial shrinkage stresses, which tend to decrease with increasing RHs (Cheng et al.
Because of the high tangential shrinkage
, this curvature could be a factor for the higher twist.
The variation in longitudinal shrinkage during drying was assumed to be small in relation to radial and tangential shrinkage
. Hence, the longitudinal shrinkage of 0.6 percent (Wagenfuhr 1996) was used for the calculation of volume of dried (MC of 5%) boards.
One explanation for the Ho-ARO configuration could be that the tangential shrinkage
is decreased following a permanent creep deformation taking place at the start of drying because of high tensile stresses at the main drying surface (tangential direction).
Characterize physical and mechanical properties of solid wood for 11 clones of hybrid poplar, including: specific gravity, longitudinal, radial, and tangential shrinkage
, and flexural properties;
Steaming had a slight effect on radial and tangential shrinkage
, and reduced density about 2 percent.