Treesearch

The spatiotemporal dynamics of plant water sources are hidden and poorly understood. We document water source use of Quercus garryanagrowing in Northern California on a profile of approximately 50 cm of soil underlain by 2–4 m of weathered bedrock (sheared shale mélange) that completely saturates in winter, when the oaks lack leaves, and progressively dries over the summer. We determined oak water sources by combining observations of water stable isotope composition, vadose zone moisture and groundwater dynamics, and metrics of tree water status (potential) and use (sapflow). During the...

Over the past several years, plantings of California native plant nursery stock in restoration areas have become recognized as a pathway for invasive species introductions, in particular Phytophthorapathogens, including first in the U.S. detections (Phytophthora tentaculata, Phytophthora quercina), new taxa, new hybrid species, and dozens of other soilborne species. Restoration plantings may be conducted in high-value and limited habitats to sustain or re-establish rare plant populations. Once established, Phytophthorapathogens infest the site and are very difficult to eradicate or...

Exposure to wildfire smoke causes adverse health outcomes, suggesting the importance of accurately estimating smoke concentrations. Geostatistical methods can combine observed, modeled, and satellite-derived concentrations to produce accurate estimates. Here, we estimate daily average ground-level PM2.5 concentrations at a 1 km resolution during the October 2017 California wildfires, using the Constant Air Quality Model Performance (CAMP) and Bayesian Maximum Entropy (BME) methods to bias-correct and fuse three concentration datasets: permanent and temporary monitoring stations, a chemical...

Combining tree-ring data and modern temperature observations with paleoclimate proxies and ecological evidence from other Great Basin ranges provides insights into the environmental context of the alpine villages in the Toquima Range during the three millennia of occupation. Throughout this time, the Mt. Jefferson summit plateau above 3380 m, north and east of Alta Toquima and above Dakabah, appears to have been too cold and too harsh to have supported trees. The current alpine condition of the plateau, therefore, is likely to be similar to that in prior millennia. Alta Toquima is located...

Future estrangement is a profound sense of alienation toward the future. It is the deep-seated feeling that the future is a hostile and bewildering world that we may not have a place in - or may not want to have a place in. This paper outlines numerous impending threats that are the main sources of future estrangement and discusses strategies to overcome this perilous attitude toward the future. Ultimately, reversing the spread of future estrangement will require both addressing its root causes and building resiliency at all levels and in all domains of society.

In North America, the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), continues to spread, and its egg parasitoid, Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae), is being released for emerald ash borer biocontrol well beyond their endemic climatic ranges in China. We developed a multiple cohort rate summation model to simulate O. agrili F0, F1, and F2 generations, and emerald ash borer oviposition for examining host–parasitoid synchrony across a north–south gradient from Duluth, MN (latitude 46.8369, longitude −92.1833) to Shreveport, LA (latitude...