We are examining the growth, growth history and climate sensitivity of white and black spruce trees on the floodplains of the major rivers fed by glacial meltwater in Interior Alaska. To date we have sampled 624 trees on 41 sites distributed across 1,783 km of the Yukon River, 375 km of the Tanana River, and 370 km of the Kuskokwim River, for a total of 2,528 km of river length.

We are beginning new studies of phenology at the Andrews Forest to better understand influences of existing complex climatic gradients on timing of springtime life history events for multiple trophic levels. Phenological events are highly sensitive to temperature and climatic variations and are some of the most responsive indicators to climate change. By studying timing of events at multiple sites in a very heterogeneous climatic landscape, we expect to learn much about plant, insect and bird responses to current abiotic variability (i.e.

Alliaria petiolata (garlic mustard) is an herbaceous biennial herb that has been present in the New England landscape for over a century. We investigated the ecological and historical factors affecting A. petiolata's invasion pattern across the New England landscape, including forest community structure, geophysical attributes, and habitat fragmentation. One-hundred-and-seventy-five 25× 100 m roadside, forested plots across two ecoregions were visited in the summers of 2006 and 2007. A. petiolata presence and cover, dominant canopy species, slope, and soil moisture were recorded.

The Warra Long-Term Ecological Research site in southern Tasmania was created to reflect the commitment of eight site partners to understanding the ecology of wet eucalypt forests as a necessary part of their management. The 15,900-ha site is adjacent to a major tourist facility (the Tahune airwalk) and contains both State Forest, managed for multiple use including timber production, and relatively inaccessible World Heritage Area.

The Luquillo Forest Dynamics Plot (LFDP) is a 16-ha long-term study plot in subtropical wet forest in the Luquillo Mountains of Puerto Rico. It is part of the Luquillo LTER and the Center for Tropical Science (CTFS) network of large tropical forest plots. Forests are often subject to multiple, compounded disturbances, representing both natural and human-induced processes. Our goal is to understand forest structure, diversity and dynamics, and to predict long-term changes resulting from interactions of past human land use and intermittent hurricane damage.

Relatively little attention has been given to the processes that control the production and subsequent availability of amino acids in temperate forest soils. We examined how differences in soil organic matter chemistry and mycorrhizal association between temperate forest tree species of the Northeastern US lead to variation in amino acid cycling. We measured amino acid cycling throughout the growing season in soils from single tree species plots located in both the Harvard Forest, MA and the Pisgah State Forest, NH.

The temperate forests of eastern North America support high biodiversity and critical ecosystem functions while providing natural resources and cultural benefits to an expanding human population. The region is shaped by a legacy of landscape change: major shifts in climate, vegetation and disturbance at millennial time scales; extensive deforestation for agriculture in the 17th – 19th centuries; and abandonment of farmlands, natural reforestation and increasing urbanization through the mid-21st century.

Tropical environments are changing fast due to deforestation and regrowth, urbanization, climate change, and other forces. The consequences are immense for the whole array of ecosystem services people require. The Luquillo Long-Term Ecological Research Program (LUQ) is tackling these issues in Puerto Rico. LUQ began in 1988 and focused on natural disturbances (hurricanes, landslides, droughts, floods) and ecosystem response. That work revealed patterns of resistance and resilience to cycles of natural disturbance.

The National Ecological Observatory Network (NEON) is a national-scale research platform for assessing the impacts of climate change, land-use change, and invasive species on ecosystem structure and function.

This session is intended both for social and biophysical scientists who want to help develop a proposal for the kind of “multi-site, highly collaborative and integrated research initiative” envisioned by the LTER planning group. The focus will be on what the LTER planning process calls the “centerpiece” of the group's conceptual framework, as well as one of “Grand Challenges” to be addressed at the network level – “the dynamics of coupled human-natural ecosystems.”