Abstract
Frost damage in trees is caused when bubbles released from thawing ice cavitate due to the low, and often negative, pressure in trees. This thesis presents the development of a method for in situ observations of such nucleation and growth processes in engineered porous media. The experimental results show that freezing in porous media occur in a two-stage process, in which the growth rate is highly dependent on the thermal conduction properties of the system. Observations of gas released on thawing and cavitation are presented, and the implications to natural systems are discussed.