Treesearch

Terrestrial gross primary productivity (GPP) and evapotranspiration (ET) are two key ecosystem fluxesin the global carbon and water cycles. As carbon and water fluxes are inherently linked, knowing oneprovides information for the other. However, tightly coupled and easy to use ecosystem models arerare and there are still large uncertainties in global carbon and water flux estimates. In this study, wedeveloped a new monthly coupled carbon and water (CCW) model. GPP was estimated based on thelight-use efficiency (LUE) theory that considered the effect of diffuse radiation, while ET was...

Reliable and accurate monitoring of soil water content (θ) across the landscape is indispensable for many water resources applications. Capacitance-based in situ soil water content measuring devices are extensively used despite their sensitivity to soil properties besides water content, e.g., temperature and organic matter content. The main goals of this study were to: (i) examine the effects of temperature, hysteresis of the temperature response, and probe-to-probe variability on the performance of three (5TE, EC-5, and EC-TM) single capacitance sensors (SCS) in a Hawaiian Oxisol; and...

In areas where fire regimes and forest structure have been dramatically altered, there is increasing concern that contemporary fires have the potential to set forests on a positive feedback trajectory with successive reburns, one in which extensive stand‐replacing fire could promote more stand‐replacing fire. Our study utilized an extensive set of field plots established following four fires that occurred between 2000 and 2010 in the northern Sierra Nevada, California, USA that were subsequently reburned in 2012. The information obtained from these field plots allowed for a unique set of...

Forest ecosystems can act as sinks of carbon and thus mitigate anthropogenic carbon emissions. When forests are actively managed, treatments can alter forests carbon dynamics, reducing their sink strength and switching them from sinks to sources of carbon. These effects are generally characterized by fast temporal dynamics. Hence this study monitored for over a decade the impacts of management practices commonly used to reduce fire hazards on the carbon dynamics of mixed-conifer forests in the Sierra Nevada, California, USA. Soil CO2efflux, carbon pools (i.e. soil carbon, litter, fine...

Understanding how alternative vegetation types co-exist in a landscape is important in managing for biodiversity within an ecosystem. In California, mixed conifer forest is often interrupted by stands of shrubs known as montane chaparral. The development of chaparral stands following recent high severity or stand-replacing wildfires in mixed conifer forests has been well documented. Fire has been excluded from mixed conifer forests for over a century, and fuel loads are at historically high levels across much of this landscape. Despite contemporary post-fire research on mixed conifer...

Large wildfires in California cause significant socioecological impacts, and half of the federal funds for fire suppression are spent each year in California. Future fire activity is projected to increase with climate change, but predictions are uncertain because humans can modulate or even override climatic effects on fire activity. Here we test the hypothesis that changes in socioecological systems from the Native American to the current period drove shifts in fire activity and modulated fire–climate relationships in the Sierra Nevada. We developed a 415-y record (1600–2015 CE) of fire...

Epigenetic modifications of chromatin structure are extremely important in mediating stress responses in plants. Epigenetic modifications are especially important in perennial species such as trees, where they contribute to phenotypic plasticity and adaptation to unfavourable environments. Populusis a model for physiological studies of trees, and is suitable for phytoremediation of Zn-contaminated soils. Currently, epigenetic modifications involved in Zn stress response are poorly characterized for Populus. Here, we compared changes in epigenetic modifications under excess Zn using...

Wind predictions in complex terrain are important for a number of applications. Dynamic downscaling of numerical weather prediction (NWP) model winds with a high-resolution wind model is one way to obtain a wind forecast that accounts for local terrain effects, such as wind speedup over ridges, flow channeling in valleys, flow separation around terrain obstacles, and flows induced by local surface heating and cooling. In this paper we investigate the ability of a mass-consistent wind model for downscaling near-surface wind predictions from four NWP models in complex terrain. Model predictio...

Climatic conditions, particularly extreme rainfall, snowmelt, and flooding, pose substantial risks to the infrastructure on and near the National Forests and Grasslands of the Rocky Mountain Region. Essentially all infrastructure is vulnerable to some degree, but risks and vulnerability differ greatly from place to place. Useful distinctions can be made that can inform environmental assessments, land-use planning, and priorities for climate adaptation.

Concealment behavior by stream salmonids can benefit individuals and populations, but the availability of concealment habitat may be limited in many streams. Quantification of concealment habitat is likely to be a valuable process in the management of stream salmonids; it is a necessary step in the application of spatially explicit, individual‐based models that incorporate concealment behavior. We conducted a series of laboratory experiments with Rainbow Trout Oncorhynchus mykissto aid in the identification and quantification of concealment habitat. Overall, individual Rainbow Trout about...