(11) Long term Leaf Litter Mass in the Split Creek Watershed and its impacts on Forest Productivity

The purpose of this study is to analyze long term leaf litter mass patterns in the Split Creek Watershed, and relate that to forest productivity and litter residence time. Split Creek is an upland, oak-hickory dominated... [ view full abstract ]

The purpose of this study is to analyze long term leaf litter mass patterns in the Split Creek Watershed, and relate that to forest productivity and litter residence time. Split Creek is an upland, oak-hickory dominated watershed in Sewanee, Tennessee. The study began in 2002, when five leaf litter baskets (0.76 m2 total area) were installed at each of 13 locations in the watershed to collect leaf litter biomass. Leaf litter biomass was recorded from 2002 through 2005, 2007 through 2014, and 2017-2018. In summer 2017, new baskets were constructed using a new design, and 4 baskets (1.0 m2 total area) were installed in each of the original 13 locations. Leaf litter was collected multiple times this fall (2017) and again at the beginning of February 2018. The leaf litter was dried to 35°C, and was then sorted into oak, non-oak, bark and wood, and fines. Samples were weighed in grams and converted to kg ha-1  for each sample. Total leaf biomass prior to 2017, ranged from 3001 to 4639 kg ha-1, and averaged 3858 kg ha-1.The biomass for 2017-18 averaged 3254 kg ha-1, which is within the range of previous years, but below average. Oak leaves comprised 76% of the overall leaf mass, which is slightly higher than the 72% average of previous sample years. Litter contained an additional 630 kg ha-1 of bark and small wood (less than 1 cm in diameter) and 648 kg ha-1 of fruit, the majority of which consisted of acorns. Total forest floor leaf litter biomass was measured by pooling three samples at three of the 13 litter collection sites, and the number of years it takes leaf litter to decompose, is being estimated by comparing the average litter production per year to the amount of litter measured in the forest floor.