Contact-free digital image analysis was performed of the radial shrinkage of fresh, fully saturated small spruce wood beams. An experimental test set-up was developed to ensure constant distance from the charge-coupled device camera to the sample surface as well as constant climate and light conditions during the whole experiment. Dimensional changes were observed immediately after the drying process began. An unexpected distinct effect could be observed which could not be explained by drying surface layers only. After a fast initial radial shrinkage a slowing down of the dimensional changes occurred at high mean moisture contents. A complete interruption of any dimensional changes followed. Finally, a recovery from shrinkage was even observed. It is assumed that strong negative pressure occurred in the fully saturated capillaries owing to dehydration which led to additional dimensional changes. As a consequence, the break of the water column and aeration in these capillaries finally resulted in a recovery period in the shrinkage rate due to the pressure release. After this effect, the dehydration was characterized by a phase of fast and almost linear shrinkage due to drying surface layers. Finally, the shrinkage slowed down to zero when reaching equilibrium moisture content.

对新鲜、完全饱和的小云杉木梁的径向收缩进行了非接触式数字图像分析。开发了一种实验测试装置，以确保电荷耦合器件相机到样品表面的距离恒定，以及整个实验过程中的气候和光照条件恒定。干燥过程开始后立即观察到尺寸变化。可以观察到出乎意料的明显效果，这不能仅通过干燥表层来解释。在快速的初始径向收缩之后，在高平均水分含量下尺寸变化会减慢。随之而来的是任何尺寸变化的完全中断。最后，甚至观察到从收缩中恢复。假设由于脱水导致额外的尺寸变化，在完全饱和的毛细管中出现强负压。结果，由于压力释放，这些毛细管中的水柱破裂和曝气最终导致收缩率的恢复期。在此作用之后，脱水的特征在于由于干燥表层而出现快速且几乎线性收缩的阶段。最后，当达到平衡含水量时，收缩减慢至零。由于干燥表层，脱水的特征是快速且几乎线性的收缩阶段。最后，当达到平衡含水量时，收缩减慢至零。由于干燥表层，脱水的特征是快速且几乎线性的收缩阶段。最后，当达到平衡含水量时，收缩减慢至零。