Red alder soil-site study

There were several data sets collected in 25- to 50-year-old, well stocked, natural red alder stands in western Washington and northwestern Oregon between April and December of 1982. These were designed to develop relationships between red alder site index and soil site properties, and to evaluate height growth patterns from stem analysis data as well as to collect additional data on tree and stand characteristics in natural stands. This data publication contains the data from this study. The site data included elevation, slope, precipitation, and physiographic position. The soil data included soil texture, organic matter, pH, internal drainage, soil depth, rock and gravel content, depth to summer water table, parent material, and bulk density. In addition, a subset of stands had dominant and codominant trees felled and stem sections aged and measured for diameter.
This project was part of short-rotation research on biomass production of Populus and Alnus funded by the U.S. Department of Energy. Funding agency was interested in predicting where alder would grow best and how to quantify it. In addition, planned future work related to shorter rotations seemed more appropriate with site index curves based on a younger base age so trees were felled and analyzed to develop height growth and site index curves for base age 20 (older curves used base age 50).
Additional red alder soil-site data collected by Crown Zellerbach, the USDA Soil Conservation Service, and the British Columbia Ministry of Forests were collected, evaluated, and then used for some analyses; those data are included in these files as appropriate. Previously published height-over-age data was also included as that data source was not available online (Johnson and Worthington 1963).