The forests, streams, and meadows of the H.J. Andrews Experimental Forest contain thousands of species of insects, 83 bird species, 19 gymnosperm (conifer) species, 53 mammal species, 9 species of fish, and a host of other taxa (see our species lists). Biodiversity research at the HJA examines the causes and consequences of biological diversity in our landscape. This includes drivers of long-term population dynamics in plants, fish, salamanders, mammals and birds. We seek to understand how land use, natural disturbance, and climate affects these patterns and relationships. Studies range from the genetic to landscape scales, and include field observational studies, experiments, and modeling. 

The ways that carbon and other nutrients move through a forest are influenced by the interaction of many parts of the ecosystem. As such, carbon and nutrients provide a way to examine ecosystem function and response to environmental change. Work in this component seeks to measure rates of production, decomposition, nutrient cycling, and the formation of soil organic matter and to determine the factors controlling spatial and temporal variation in these processes. In addition, the stores of carbon and nutrients involved in these processes and cycles are being measured. Simulation modeling, coupled with remote sensing, are being used to extrapolate results to the Pacific Northwest region.

Natural resource management can be seen as a set of practices, which reflect certain ideas about the world. Ideally management practices will be consistent with our best scientific ideas about the workings of both biophysical and social systems, but management practices also and inevitably manifest our ideas about what is good, what is right, and what is valuable. For example, we manage riparian zones in certain ways because we understand certain relationships between riparian zones and streams and rivers; but also because we believe certain management practices will achieve important goals, or protect important values, related to streams and rivers. In this way, management fuses science and ethics.

Water stores and flows in the HJA are controlled by, and shape, the topography, climate, and vegetation in the landscape, while also affecting human uses of streams, rivers, and water resources. The hydrology of the site is representative of the steep forested ecosystems of much of the Pacific Northwest Cascade mountains. The hydrologic setting of this region includes a mild climate with wet winters and dry summers; massive, conifer, evergreen forests with high leaf area that can intercept, store, and transpire large quantities of water; thin soils on steep, highly weathered hillslopes which facilitate rapid water flux from slopes to channels; and transient snowpacks that can contribute to extreme regional floods. Water flows from the HJA influence downstream communities including the cities of Eugene, Salem, and Portland. Our program has a long history of research using experimental watersheds, tracer and water dating studies, process and ecophysiological studies, analyses of soil hydrologic properties, and other approaches. See our Experimental Watersheds and Gaging Stations page for more information about gages and experimental watersheds.

Science at the H.J. Andrews Experimental Forest has long played an influential role in federal forest management and in public and policymaker perceptions of forest ecosystems, old growth, watershed processes, microclimates, road hydrology, and the role of dead wood in forests and streams. We seek to identify social processes that explain the changing relationship of science to federal forest policymaking, and evaluate the potential for an adaptive governance system characterized by tight connections and feedbacks between scientific discovery and forest management. Past research has included analyses of public perceptions of LTER science, barriers to adaptive management, and the social acceptability of alternative silvicultural practices associated with ecosystem-based management.

The upper canopy of forests is known to experience a very different microclimate than the rest of the forest: it is often simultaneously brighter, hotter, windier, and drier. The upper canopy also contains most of the leaf area; because it absorbs most of the solar radiation, it accounts for the great majority of carbon and water exchanges in most forests. Critically, this is also the zone where most climate variations and stress likely manifest. We seek to understand whether and how the forest canopy and the understory below are affected by broader-scale climate processes such as heat, drought, and wildfires. This research has critical relevance to tree growth and survival as well as wildfire risk. We also aim to understand how canopy microclimate observations can advance fundamental biological understanding of canopy processes and properties and their linkages to atmospheric and sub-canopy dynamics. This includes work on tree physiology (via climbing into the canopy to collect data), to understand how water availability contributes to physiological thermotolerance and post-stress recovery. Our project also utilizes high-resolution dendrometry and canopy microclimate data to understand how climate extremes like the 2021 Heat Dome affect tree stress and growth. This research will help inform predictions of canopy responses to future extreme heat and drought events.

Our long-standing engagement of the arts and humanities does not fit neatly into any one category of activity. It is in part a form of basic inquiry (paralleling basic science), in part science journalism and public outreach, and in part an education effort. In the words of the mission statement of the Spring Creek Project for Ideas, Nature, and the Written Word, our arts/humanities collaborators, we wish to: "bring together the practical wisdom of the environmental sciences, the clarity of philosophical analysis, and the creative, expressive power of the written word, to find new ways to understand and re-imagine our relation to the natural world." Learn more on our Arts and Humanities page.