As part of the International Crown Fire Modeling Experiment (ICFME), destructive sampling was carried out over two seasons (1999-2000) to evaluate trends in diurnal fine fuel moisture content and fine fuel moisture code (FFMC) characteristics at northern latitudes. The moisture content of various fuels, including black spruce (Picea mariana) bark flakes, feather moss (Pleurozium schreberi) tips, jack pine (Pinus banksiana) needles, twigs (< 0.5 cm and 0.5-1 cm diameter classes), litter (0-2 cm), and the forest floor profile, was sampled on an hourly basis at 2 sites, one with and one without a significant understory of black spruce. Automatic weather stations and 10-hour fuel moisture sticks were established within stand at each of the 2 sampling areas, as well as in the open, and hourly or better values of rainfall, wind speed, wind direction, temperature, and RH were recorded. The effects of the presence or absence of an understory (2,350 stems/ha) on microscale weather and fuel moisture characteristics were evaluated. Temperature and RH values were greater at the site with an understory than at that with no understory. Within-stand wind speeds at the site with no understory were significantly higher than those measured at the site with and understory. Despite temperature, RH, and wind speed differences, discernible site differences in moisture content were only significant for duff (0-2 cm) and bark flake fuels. The moisture content data for feathermoss and needle litter were used to assess the performance of the diurnal and hourly FFMC models, and notable differences between the FFMCs computed are reported. For dry days, the diurnal model best described the amplitude of the moisture content of feathermoss fuels throughout the day, whereas the amplitude of jack pine needle moisture content was better described by the hourly FFMC. Both the hourly and diurnal models overestimated the minimum moisture content of needles and feathermoss on dry days, and both models overestimated needle moisture content and underestimated feathermoss moisture content following rain.