THE EFFECT OF SOIL-WATER ON GROUND FUEL AVAILABILITY

A determination of ground fuel hydration was carried out in an aspen f orest in Alberta, Canada. The objectives of the study were: (1) to det ermine the relative contribution of precipitation and soil water to th e upper and lower ground fuel layers, (2) to determine if the moisture status of these layers was affected by slope position (bottom, mid, a nd top) or distance to a water body, and (3) to determine the drying r ates for these two fuel layers. Results showed that upper and lower do wned and dead fuels were hydrated by soil water as well as precipitati on and that both sources contributed significantly to fuel moisture. D uring the period May 20 to September 20, 1990, precipitation and soil water contributed about 64% and 36% of the water to fuel moisture cont ents to the upper layer, and 41% and 59% to the lower layer, respectiv ely. Fuel moisture contents varied significantly by slope position. Th e bottom slope position was always the wettest, while the fuel moistur e contents in the other two positions were similar. In the absence of hydration, the upper and lower litter layers reached equilibrium moist ure contents of 15% and almost 22%, respectively, but never dried out completely.