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.)
Read MoreThe 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%.
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.
Material | Ponderosa Pine |
Diameter | 1.3 cm (0.5 in.) |
Length | 50.8 cm (20 in.) |
Weight | 45 g (0.1 lb) |
The 26601 10-hour Fuel Moisture Stick is used with the CS506 Fuel Moisture Sensor. The CS506 fastens onto the 26601 using two stainless-steel strips pressed into groves in the dowel.
The 26601 is not compatible with the retired CS505 Fuel Moisture Sensor.
The CS506/26601 combination is typically measured alongside the CS205/107 combination, which measures the fuel temperature.
The 26817 Mounting Stake is often used to mount the CS506/26601 with the CS205/107. This stake places the probes twelve inches above the forest floor. Because the probes are mounted parallel to each other, shadowing is minimized. Cable ties are included for securing the cables to the side of the stake.