Moisture Content in Forest Residues: an Insight on Sampling Methods and Procedures

Purpose of Review: Taking moisture content samples from forest residue stack piles has been a challenge due to numerous factors such as varying shapes of piles, difference in material types, and financial constraint of the research. Additionally, there has been no standard sampling procedure set for the task encompassing the various constraints, especially in-wood conditions. For these reasons, samples taken from forest residue piles may not accurately represent the average moisture content of the population. This study attempts to classify the sampling methods commonly used for measuring moisture contents of forest residue piles for scientific research. Recent Finding: We reviewed over 28 studies focusing on moisture content in forest residues to develop four general sampling methods, namely weighing stack piles, weight from scale ticket, fixed location sampling, and transect sampling. Advantages and limitations for each sampling method along with the type of data generated from each were described in detail. For example, weighing stack piles provided the most accurate form of continuous data, but could not be used for in-wood conditions and was usually limited to small pile structures. On the other hand, fixed location sampling and transect sampling would be preferred in field experiments and could detect moisture content variation within layers of the pile. Attempts were also made to determine the situations in which each of these sampling methods could be adopted. Summary: This study could assist researchers set up their experimental designs and provide insight for handling potential challenges during data collection.