WATER CHEMISTRY OF A HEMLOCK FOREST IN THE ROBERT V. RIDDELL STATE PARK OF NEW YORK

Invasive insects continue to impact forest ecosystems. The hemlock woolly adelgid (HWA) is one of the species that is spreading into the hemlock forests of the south-central area of New York State. Chemical and biological treatments have been utilized to combat the spreading and allow the infested areas to recover. However, the applied methods have not stopped the spreading of HWA. Hemlock die-offs not only affect ecosystem composition and function but can also modify the physical and chemical properties of the soil, soil water, and streams. Robert V. Riddell State Park lies on the boundary of Otsego and Delaware counties of New York State and has not been infested with HWA. Thus, a long-term monitoring site was established in 2014 to allow monitoring chemical and physical properties of soil, soil water, and streams in an HWA free hemlock forest to determine a baseline, pre-infestation, conditions. In this presentation, we report on four years of water data collected from soil water samplers that were installed to depths of 25 to 65 cm, and from a second order stream running through the study area. Field parameters such as pH, temperature, and electrical conductivity were measured onsite. Dissolved oxygen and turbidity was also measured for the stream samples. Major cation and anion concentrations were quantified using atomic absorption spectrometry and ion chromatography, respectively. Bicarbonate ion concentrations were determined by titration. The average pH of the soil water (7.50) is about one unit higher than the stream water. Soil waters contain 6-7 times more total dissolved solids than the stream waters. The water chemistry is dominated by calcium, bicarbonate, and sulfate, but measurable concentrations of magnesium, sodium, and chloride are also detected in each sample. Potassium, nitrate, and phosphate are below the detection limit of the instrumentation. Overall, the water composition shows calcium-bicarbonate and magnesium-sulfate waters in the studied forest with similar yearly distribution. These results can provide information about the state of water in a healthy hemlock forest and be used as a baseline to detect changes when HWA infest this area.