This project uses a temperature gradient spanning 5 degrees Celsius to perform studies on responses to warming in a tropical system, including: soil carbon response, soil microbial community response, and carbon stock and flux responses for above and below ground carbon pools and fluxes. These studies take place in the Hawaii Experimental Tropical Forest and Hakalau Forest National Wildlife Refuge, across an area where canopy vegetation, soil type, soil moisture, and successional history are all relatively constant.
Water stress represents a common mechanism for many of the primary disturbances affecting forests, and forest management needs to explicitly address the very large physiological demands that vegetation has for water. This study demonstrates how state-of-science ecohydrologic models can be used to explore how different management strategies might improve forest health.
Widespread threats to forests due to drought stress prompt re-thinking of priorities for water management on forest lands. In contrast to the widely held view that forest management should emphasize providing water for downstream uses, we argue that maintaining forest health in the face of environmental change may require focusing on the forests themselves and strategies to reduce their vulnerability to increasing water stress in the context of a changing climate. Management strategies would need to be tailored to specific landscapes but could include: a) thinning; 2) encouraging drought-tolerant species; 3) irrigation; and 4) strategies that make more water available to plants for transpiration. Hydrologic modeling reveals that specific management actions could reduce tree mortality due to drought stress. Adopting water conservation for vegetation as a priority for managing water on forest lands would represent a fundamental change in perspective and potentially involve tradeoffs with other downstream uses of water.
The Water Erosion Prediction Project (WEPP), is a physically-based soil erosion prediction technology. WEPP has a number of customized interfaces developed for common applications such as roads, managed forests, forests following wildfire, and rangelands. It also has a large database of cropland soils and vegetation scenarios. The WEPP model is a distributed parameter, continuous simulation model, and is able to describe a given erosion concern in great detail for an experienced user.
The WEPP model consists of multiple applications that can estimate erosion and sediment processes on hillslopes and small watersheds, taking into account climate, land use, site disturbances, vegetation, and soil properties.
Peatland ecosystems represent 3-5% of earth's land surface, but store 12-30% of soil organic carbon. However, this very large pool of carbon is vulnerable to loss to the atmosphere as CO2 because of climate change. Lowered water tables caused by climate change or human-caused drainage can shift peatlands from being net carbon sinks to net carbon sources. The PEATcosm experiment was initiated to study the relationships between water tables, plant communities, and carbon and nutrient cycling in peatlands in a controlled setting. Read more on the experiment here [pdf].
The largest terrestrial carbon pool is contained in soils. Carbon stored in soils plays a number of important roles, including keeping carbon out of the atmosphere and improving moisture and nutrient retention.