26601

The 26601 is a ponderosa-pine dowel that emulates the moisture content of similarly sized twigs on the forest floor. Our CS506 fuel moisture sensor fastens onto the 26601 and measures its moisture content. The CS506/26601 combination is used to assess forest fire fuel and is often incorporated in our prewired or custom fire-weather stations. (The image shows the CS506 fuel-moisture sensor attached to the 26601 fuel-moisture stick.)

The 26601 10-hour Fuel Moisture Stick is constructed from the same carefully selected USFS-standard ponderosa dowel as the traditional weighing fuel-moisture rack. No artificial materials (e.g., epoxy sealant) are added to the dowel that would adversely influence the natural behavior characteristics of it. Because the complete dowel surface is accessible for moisture exchange, the response of the CS506 is similar to that of the traditional weighing racks.

To optimize probe-to-probe repeatability and to allow probe interchangeability without individual calibration, two additional sorts are performed on the dowels before they are selected to be used as a sensor. First, the dowels are sorted dry by density to improve accuracy in the dry range of 0 to 15%. Second, the dowels are sorted after a 50-minute soak by weight to reduce probe-to-probe time response variation and minimize variability in the wet range of 20 to 50%.

Replacement Dowels

The 26601 is easily replaced in the field using a Phillips screwdriver and an adjustable wrench. Customers should replace the 26601 each spring; more frequent replacements may be required in some environments. The more wet/dry cycles the 26601 experiences the more frequently it will need to be replaced.