The utility of a high-resolution snow-hydrologic model to derive climatological indices that describe the variability in radial growth of four conifer species in two Sierra Nevada sites is presented herein. Nine annual indices associated with radial growth were developed to represent the winter dormancy, characteristics of the snowpack and soil water content, and the duration of the seasons. Site chronologies of earlywood (EW) and latewood (LW) ring widths were developed for mountain hemlock (Tsuga mertensiana), red fir (Abies magnifica), white fir (Abies concolor), and ponderosa pine (Pinus ponderosa) at two sites on leeward and windward slopes. The signal strength for annual climatological indices derived from model output was tested with correlation and regression, in combination with principal components analysis. Results show significant snow-related climate signal in the tree-ring data, with substantial differences between species and between EW and LW. Dependence on previous year's snow and soil moisture (a lagged response) were found for EW of hemlock and red fir. The primary EW-LW signal contrast for those species is a shift toward dependence on current-year moisture conditions for LW, especially for red fir. Lagged climate response was less evident for white fir and ponderosa pine. Regression of tree-ring series on principal components of climatological indices showed a stronger average signal in EW (R 2 = 0.48) than in LW (R 2 = 0.35). Differences in tree-ring hydrologic signal at the two sites are attributed to microclimate and contrasts in snow regime. Results attest to the hydrologic model usefulness for investigating temporal relationships between tree rings and local climate.
Snowpack in the Sierra Nevada Mountains accounts for around one-third of California’s water supply. Melting snow provides water into dry summer months characteristic of the region’s Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response is critical in this region of agricultural, recreational, and ecological value. Here we investigated the relationships between tree rings of montane conifer trees ( Tsuga mertensiana, Abies magnifica, Abies concolor, Calocedrus decurrens, Juniperus occidentalis, and Pinus ponderosa) and regional climate indices with the goal of reconstructing April 1 snow-water equivalent (SWE) in the North Fork American River watershed of the Sierra Nevada. Chronologies were positively correlated with April 1 SWE of the year prior to ring formation. Temporal trends in correlation between tree-ring chronologies and climate indices indicate strengthening tree growth response to climate over time. We developed a skillful, nested reconstruction for April 1 SWE, 1661–2013. Variability of the reconstruction is within the envelope of 20th and 21st-century variability; however, the 2015 record low snowpack is unprecedented in the tree-ring record, as in results from previous studies. Future research should focus on integrating modern snow sensor data into paleoclimate research and understanding mechanistic linkages between snow and tree growth response.
<p>We have significant vulnerabilities across our food, water, and energy systems &#8211; any of which could undermine societal resilience in light of growing populations and climatic change. Rising average temperatures, extremes in precipitation, and more severe storms present increasing agricultural production risks &#8211; particularly across dryland regions. Land managers across the southwestern United States are already feeling the pressures of a changing climate. Between 11&#8211;21% of the total irrigated acreage experienced yield declines over the past 40 years due to irrigation interruptions &#8212; despite increased water usage. Food producers are experiencing increased uncertainties around production security from severe weather, interest rates to invest in climate adaptations, income support payments or incentives, and climate-related risks to pollinator abundance that affect crop yields and labor conditions and availability. Combined with trends towards increases in retirements from farming, these risks are leading to more land moving out of food production &#8212; often shifting to energy production. A growing demand for photovoltaic (PV) solar energy from ground-mounted systems, projected to require ~8,000 km2 by 2030, is resulting in an increase of land-use conflicts for these two primary needs &#8212; food and energy. Is it possible to improve both food and renewable energy production security sustainably? An &#8216;either-or&#8217; discourse between food and PV solar energy production unnecessarily compounds issues related to allocating space, water, and capital for development of sustainable strategies.</p><p>We believe that a hybrid agricultural-PV solar &#8216;agrivoltaics&#8217; can increase resilience in food and renewable energy production, water and soil conservation, and rural prosperity and economic development&#8212;critical sustainability metrics. However, successful adoption of this technology requires research from a socio-environmental systems perspective to optimize bio-technical trade-offs at the field scale, while also rigorously assessing the sociopolitical barriers and how to overcome them at both individual and societal levels. Our research design is centered on stakeholder engagement approaches with impactful, associated outreach activities to communicate and enhance the reach of potential benefits of agrivoltaics. An emerging trend in sustainability research has been to recognize that resource challenges need to be addressed as integrated and interconnected sets of issues, where outcomes result from interacting social (S), ecological (E), and technological (T) subsystems (SETS). Often, sustainability transitions are seen more as a governance challenge than an infrastructure or technological challenge. That is, while technological solutions such as agrivoltaics can be developed, the adoption and spread of innovations takes place through a myriad of social, political, and economic processes. This is further complicated across food and energy systems, where multiple stakeholders present different backgrounds, cultures, demographics, and decision making processes. We describe an evaluation of agrivoltaic systems from a holistic SETS perspective in order to develop implementation pathways for widespread adoption of agrivoltaics across the US.</p>
This study reports two multi-century regional reconstructions of annual precipitation based on Pinus ponderosa and P. edulis from four sites in central northern Arizona. It compares standard regional and time-nested methods to generate reconstructions from 1581-2016 C.E and 1529-2016 C.E respectively. The strongest climate relationship is a positive correlation between total ring width and 12-month total precipitation ending in July of the growth year. The chronologies account for 50% of the variance of observed annual precipitation in the regional model and 59%, 60%, and 47% and 35% in the nested models. The two reconstructions are highly correlated (Pearson's correlation: >0.97, p <0.001) demonstrating that the reconstructions are highly similar over the period common to both reconstructions, with the nested-models' advantage of extending the range of the reconstruction. The precipitation reconstructions explain ~66% of variation for this region in the North American Drought Atlas (NADA).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.