H.J. Andrews LTER Site

On September 14, 1988, the 40th anniversary of the H.J. Andrews Experimental Forest was celebrated with a ceremony lead by officials from Oregon State University, US Forest Service research and land management, and National Science Foundation who are all involved in the partnership that has fostered the productive Andrews research program. In the course of these 40 years the research program has evolved through a series of stages of emphasis: systems for harvest and regeneration of old- growth Douglas fir forest (1950s); watershed research on effects of forest cutting on water, sediment, and nutrient budgets (1960s); basic forest and stream ecosystem research as part of the International Biological Program (1970s); and a mixture of basic and applied studies (1980s).

The cornerstone of the basic research program of the 1980’s has been LTER, which has 6 major components:

1. Structural and compositional change of forest vegetation sampled in permanent plots in stands of varying age since disturbance by clearcutting (up to age 26 yrs) and wildfire (80 to 1000 yrs).
2. Higher trophic level studies, emphasizing taxonomic and successional studies of invertebrates in habitats ranging from soil to the tops of 90 m tall trees. Over 3500 species have been listed in the process of successional and ecological studies such as community variation of needle-damaging invertebrates and their predators in young and old-growth stands.
3. Effects of nutrient levels and stand density on production and mortality in young Douglas-fir forests.
4. Positive and negative effects of varying density of Ceanothusvelutinus, a nitrogen-fixing shrub, on the long- term patterns of growth of Douglas-fir and stand productivity.
5. Decomposition of logs examined by periodic destructive sampling of subsets of 570 logs 6-m long, 0.5-m diameter logs of four species. Entomological, nutrient cycling, mycological, and physical factors are tracked with LTER and other NSF support.
6. Forest-stream interactions, including long-term patterns of input and redistribution of large woody debris and effects of riparian forest succession on aquatic biota in streams.

An LTER study concerning long-term site productivity is now in the early stage of pretreatment site characterization. In 1991, treatments will be established following clearcutting about 40 ha of natural forest at low and high elevation sites and applying different levels of wood residue removal and burn or no burn on 0.4 ha plots. A variety of carbon and nitrogen manipulations and vegetation exclusion practices will be carried out on subplots. We will then investigate how various levels of key ecosystem “legacies” (e.g., propagules, wood structures, soil properties) carried over from the pre-disturbance system influence the pathways and rates of post-treatment forest development. We invite other investigators to capitalize on this experimental manipulation through cooperative studies.

Under the leadership of Mark Harmon and Tim Schowalter the log decomposition study, now in its third year (only 197 years to go), has yielded a variety of interesting results. Over 100 species of invertebrates and over 50 microbial taxa are involved in the initial breakdown of logs. Leaching loss of nutrients by water flowing through the logs has been greater than expected.

Comparable aspects of the log decomposition study have been set up at 3 other LTER sites and at the Changbai Shan MAB Bio-sphere Reserve which will be part of the LTER system in the Peoples Republic of China.

The Andrews LTER program and our Quantitative Sciences Group are in the process of gearing up with GIS on a Sun system through support from NSF (Susan Stafford, P1), NASA (Bill Ripple, Dept. of Forest Management, Oregon State Univ. and Tom Spies, Forest Service, PIs), and the Forest Service (Tom Spies and George Lienkaemper, coordinators). Within 6 to 9 months we expect to be operational with ARC/INFO, MOSS, AND ERDAS on-line. Initial studies will focus on change of forest landscape patterns through time as a result of logging and wildfire, and some of the ecological consequences of those landscape dynamics.

For additional information contact Fred Swanson, Forestry Sciences Lab, 3200 Jefferson Way, Corvallis, OR 97331 or Art Mckee, Forest Science Dept., Oregon State University, Corvallis, OR 97331.