The litter is the organic layer on the forest ground and has a variety of ecological functions. The litterfall is the main source of litter. The structure of forest canopy affects most ecologic processes such as the net primary production and litterfall in forest ecosystems. This research study focused on the exploration of the changes of litterfall based upon canopy closure of Uludag fir forests. The study area was selected from Bolu Aladag forests. Ten litterfall traps were systematically emplaced under the stand. The litterfall accumulated in each trap was collected monthly. The hemisphere photographs of the canopy closures above the stands were analysed with Gap Light Analyzer (GLA) software. The canopy closures were calculated separately for each hemisphere photographs with angles expanded in the multiples of 10 degrees angle of view. The highest correlation coefficient (r = 0.359) was found between the amount of total litterfall (333.5 g.m(-2).y(-1)) and the canopy closure at 20 degrees angle of view. The canopy closure values observed at 20 degrees angle of view varied between 6.4% and 83.3%. Different mathematical models were developed to estimate the amount of litterfall fractions based on the canopy closure values at 20 degrees angle of view. The coefficients of determination (R-2) for the models developed as part of this study are 0.93 for foliar, 0.82 for seed and 0.83 for wood fraction. Practitioners can estimate the amounts of litterfall components, spreading distances and the accumulating amounts based on the distance by using the mathematical models developed in this study.