Predicting forest floor moisture for burned and unburned Pinus banksiana forests in the Canadian Northwest Territories

Abstract

We assessed how well the fuel moisture codes of the Canadian Forest Fire Weather Index System can be used to predict forest floor moisture in burned and in mature, unburned jack pine (Pinus banksiana Lamb.) stands in Canada’s Northwest Territories. Moisture content sampled at varying depths in the forest floor profile was compared with hourly variations in the Fine Fuel Moisture Code and daily variations in the Duff Moisture Code and Drought Code. Fuel moisture samples were collected in June 2000 and August 2002 from one mature forest stand and four experimental plots that were burned between 1997 and 2000. Forest floor moisture, drying rate, and water-holding capacity varied between the mature, unburned forest and burned plot areas, as well as between surface and subsurface fuel layers within the mature forest. The Duff Moisture Code was the best predictor of forest floor moisture for all the fuel components examined, based on the coefficient of determination (r2 = 0.81–0.90) and because its relationship with forest floor moisture more closely resembled relationships observed in previous studies.