Master’s Thesis Abstract by Susan Prichard (1996)

Estimates of carbon (C) storage in northern latitudes and high elevation systems are critical for quantifying terrestrial C cycling and predicting how C cycling may change with global warming. In this study I quantified C storage in high elevation ecosystems of the Olympic Mountains. A sharp precipitation gradient created by the Olympic Mountain range allows for comparison of C storage in different climate regimes (dry northeast vs. wet southwest). I examined C and soil chemical properties potentially associated with C in subalpine forest and meadow soils of the NE and SW Olympics. In addition, I quantified ecosystem C pools in soils, vegetation, and woody debris in subalpine forest and meadow sites.

Mineral soil C concentrations are high in all soil profiles, even within deeper horizons. Soil C concentrations are most strongly and consistently correlated with N, but correlations with other soil properties vary and depend somewhat on site type. Total soil C is significantly higher in meadows than forests in the dry NE (P = 0.009) and higher in forests than meadows in the wet SW (P = 0.038). Soil C is greater in SW forests than NE forests (P = 0.056), while soil C storage in NE meadows was not significantly greater than SW meadows (P = 0.137). Ecosystem C storage is far greater in forests than meadows, and SW forests store greater ecosystem C than NE forests (P = 0.018).

Under warmer climatic scenarios with drier summers and wetter winters, subalpine carbon storage may generally decrease in the NE and increase in the SW. Changes in C storage will be closely related to vegetation distribution, ecosystem productivity, rates of organic matter decomposition, and local disturbance regimes. Because ecosystem processes and associated C storage can differ between high and low elevation sites, it is important that high elevation C stores are included in storage estimates for terrestrial ecosystems.