Boreal Forest Transect Case Study with a natural climate gradient resulting from latitudinal variation provides a spatial proxy for expected climate change, and can help to understand its impact on different ecosystem processes and how the forest species are adapting to these changes. We investigated year to year variation in aboveground litter production for 2001–2010 in 13 different mature jack pine (JP) and black spruce (BS) stands in relationship to climatic variables. Simple linear and step-wise regression analysis showed that tree species interacted differently with climate and stand variables affecting litterfall. Annual total and woody litterfall varied from 57 to 164 g·m^-2·y^-1 in JP and 18 to 63 g·m^-2·y^-1 in BS. Needle litterfall accounted for about 70% of the total litter production in JP and BS and about 80% in mixed wood stands, and explained significant variation in total litter production. On regional scale, needle litter production was strongly influenced by growing degree days (R² = 0.96). Woody litterfall decreased with winter precipitation (R² = 0.95) in JP, and increased with productivity (R² = 0.88) in BS. Regression models developed here are useful tools in carbon budget models.