Past research at the H. J. Andrews Experimental Forest has often occurred at different study locations at different times making comparisons between sites difficult. The small watersheds at the Andrews Forest have been the most extensively studied areas at this research forest and this database is intended to provide comparable nutrient information for these watersheds. The samples collected for these nutrient analysis used a uniform method during the summers of 2005 and 2006. Samples were collected throughout each watershed for the following pools; major tree species foliage, major tree species bark, major tree species wood, high shrubs, low shrubs, herbs. These nutrient analysis will compliment the quantification of biomass measurements made over the years in these watersheds.
Becky Fasth, Jay M. Sexton, Mark E. Harmon, Steven S. Perakis
The net uptake and storage of nutrients such as N and P in live and dead vegetation can be calculated from the concentration of these elements and the amount of organic matter in these pools. In most of the small watersheds there are estimates of live and dead plant biomass, and for some net changes in these pools. Unfortunately there is no comparable set of data on nutrient concentrations to make estimates of nutrient pool sizes or net changes in these pools. The only dataset available for small watersheds is for WS10 when it was in an old-growth condition. There are no concentration data for other old-growth watersheds or for other age-classes.
We sampled 7 of the small watersheds at Andrews Forest (WS01, WS02, WS06, WS07, WS08, WS09, and WS10) to determine the concentration of major elements within dead and live vegetation. We conducted this sampling so that it can be repeated in time to determine if concentrations are changing. The data is stored online and can become a general resource for investigators at the site. Specifically, concentration data was determined for: 1) the forest floor, 2) fine woody detritus, 3) trees, 4) shrubs, and 5) herbs. Concentrations in coarse woody detritus and soil were not determined, although rough values for the former have been published. Samples were taken systematically throughout each watershed so that a watershed average can be determined. The intent is therefore not to collect data that shows seasonal trends, only to provide reasonable bulk concentration data for general estimates of long-term stores and fluxes of these elements. Nitrogen and carbon were determined on a C/N analyzer. Cations and P were determined using ICAP.