American beech, white birch, pin cherry, red maple, sugar maple, and yellow birch leaves decomposed in litterbags in the Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE). More information on study design can be found in the following file:
Yanai, R.D., M. Fisk, and T.J. Fahey. 2024. Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE): Project description, plot characteristics and design ver 2. Environmental Data Initiative. https://doi.org/10.6073/pasta/6cc8a39d052834c030650fb29937bf4f (Accessed 2024-10-08).
Litter bags (10 x 10 cm) were constructed from nylon mesh and sealed with hot glue. Small mesh bags (63 µm) excluded macrofauna and mesofauna. Large mesh bags allowed detritivores (mesofauna and microfauna) and had a mesh size of 2 mm on the top portion and 63 µm on the bottom portion to minimize loss due to fragmentation. To determine the initial oven-dry weight of the samples, a subsample of bags were reserved and dried at 60°C for 48 hours and then weighed.
The large mesh material was noticeably more rigid than fine mesh material. We assessed the force required to bend 5 bags of each type using a three-point bending test under a constant speed of 10 mm/min (Shimadzu autograph AGS-X series). The large mesh material averaged 3 ± 2 N/mm and the small mesh averaged 0.01 ± 0.001 N/mm.
Both types of litterbags decomposed in plots fertilized with nitrogen, phosphorus, both nitrogen and phosphorus, or an unfertilized control plot within both young and mature stands. Litterbags were deployed on November 17th, 2012. The first collection was on June 12th, 2013. The second collection was on October 25th, 2013. The final collection was on October 31st, 2014. Of the 576 litter bags that were deployed, only 12 were not collected because they were not able to be found.
Extra litter bags were constructed but not taken to the field. Three to four replicates of each combination of nutrient treatments (control, N, P, and N+P) and litter mix (young and old) were analyzed for tissue chemistry (31 samples). Samples were oven-dried at 60°C and ground to pass a 40 mesh screen. For P concentration, 0.25 g of each sample was digested in 10 mL concentrated nitric acid using a MARS 6 microwave digestion system (CEM), diluted to 50 mL with deionized water, and analyzed using ICP-OES. For N concentration, 3.5 - 4.5 mg of each sample was analyzed using a CN analyzer (FlashEA 1112 analyzer, Thermo Fisher Scientific, Inc Waltham, MA, USA).