Vacuum pressure prewetting - A simple and rapid method to water saturate wood for experimental purposes

Bernd Spänhoff

Limnol. Oceanogr. Methods 5:289-292 (2007) | DOI: 10.4319/lom.2007.5.289

ABSTRACT: A simple and rapid method to prepare water-saturated wood by vacuum-pressure prewetting is presented. Submerged wood pieces can be prepared easily for any experimental purposes without long periods of prewetting and without additional tools for holding the wood under water. The particular wood piece must be submerged in a water filled suction flask that is connected to a diaphragm vacuum pump. Due to the evacuation of the air from the flask the wood rapidly soaks up water until it is saturated. In the experiments, branches displayed a logarithmic water saturation curve soaking up the highest amount of water during the first 10 s of air evacuation. Most branches were water saturated during this time. The method works best for wood pieces with a low or medium density supporting a rapid soaking of water, whereas very dense wood needs much more time to become water saturated. The main problem of the method is the loss of bark material from natural branches and the splitting of larger woods due to the rapid swelling caused by the water uptake. However, this method could be used for any experimental purposes needing standardized submerged wood, like investigations of epixylic biofilm development, colonization of wood by aquatic invertebrates, decomposition of submerged wood, or invertebrate food choice experiments.