Green needles were collected from wind-blown limbs on May 26, 1986 and allowed to air dry at room temperature for approximately 1 month at room temperature. Polyester litterbags with 1 mm mesh and measuring 14 x 14 cm were used. Subsamples were taken to determine moisture and initial chemical constituents. Litterbags were transported to the laboratory and needles were dried as soon as possible at 75° C to a constant weight. Ash free dry weights were determined using samples ignited in a muffle furnace at 550° C. Decomposition constants (k values) were calculated using the negative exponential model of Olson (1963). Microclimate Daily maximum, minimum and average forest floor temperatures were obtained from July 1986 to October 1988 using thermistors and a battery operated NEC data logger located in the upper (at 730 m elevation) and lower watershed (at 260 m elevation).
Chemical analyses
Initial litter samples and litter in three randomly selected litterbags collected at 12, 37 and 61 months were used for chemical analyses. Litter was ground to pass through a No. 20 stainless steel screen. Ground liter was digested using the wet oxidation procedure of Parkinson and Allen (1975). Nitrogen and P concentrations were determined using a Technicon autoanalyzer II. Concentrations of K, Ca, Mg, Mn and Na were determined using a Jarrel Ash ICP (Model 61e). Carbon was determined using a Leco carbon analyzer. Lignin concentrations were determined using a modification of the 72% sulfuric acid extraction method of Van Soest (1963). Sintered glass funnels were used without the asbestos mat.