Treesearch

Large trees (≥76.2 cm/≥30″ DBH) and especially very large trees (≥101.6 cm/≥40″ DBH) are key structures of Sierra Nevada forests for their ecological function, habitat, and carbon storage. Many of these trees have been lost to historic harvest and more recently to drought and wildfires. Understanding the current frequency and distribution of these large trees is essential to understanding their ecological contribution and management needs. We used airborne lidar to census large trees across three Sierra Nevada landscapes (cumulatively 396 K ha) in lower (dominated by ponderosa pine and...

Given increasing forest disturbances, novel solutions are needed to rapidly recover ecosystem services such as carbon storage, while bolstering climate change adaptation. Reforestation with single-species mixed-provenance plantings is an emerging strategy that may enhance stand productivity and disturbance resistance, while assisted gene flow is a potentially powerful tool for matching seed-source with future planting-site climate. We investigated the potential of mixed-provenance plantings and assisted gene flow for maximizing early growth using a historical dataset for knobcone-Monterey...

The Tahoe-Central Sierra Initiative (TCSI) Blueprint for Resilience (hereafter TCSI Blueprint) is a set of strategy maps that identify opportunities for forest protection and adaptation across a 978 381-ha (2.4 million-ac) region of the central Sierra Nevada. The TCSI partners, along with scientists and forest managers versed in the concept of resilience, defined resilience based on 10 ecological and social pillars. The TCSI Blueprint includes evaluations of 30 unique metrics, such as large tree density and probability of high-severity fire, that describe conditions across five of the...

Background In California’s mixed-conifer forests, fuel reduction treatments can successfully reduce fire severity, bolster forest resilience, and make lasting changes in forest structure. However, current understanding of the duration of treatment effectiveness is lacking robust empirical evidence. We leveraged data collected from 20-year-old forest monitoring plots within fuel treatments that captured a range of wildfire occurrence (i.e., not burned, burned once, or burned twice) following initial plot establishment and overstory thinning and prescribed fire treatments. Results Initial...

The North Bay area of California is a populous and ecologically diverse area that has experienced significant changes in the past century, as well as a series of recent wildfires, after over a century of fire suppression practices. While much research has been conducted quantifying drivers and patterns of vegetation change in conifer-dominated ecosystems, and how such changes have influenced current trends in fire behavior, studies of similar focus and scale are rarer in non-conifer ecosystems, including mixed-hardwood forests or shrub-dominated ecosystems in central and coastal Northern...

Geovisualization tools can supplement the statistical analyses of landscape-level wildfire behavior by enabling the discovery of nuanced information regarding the relationships between fire spread, topography, fuels, and weather. The objectives of this study were to develop and evaluate the effectiveness of geovisualization tools for analyzing wildfire behavior and specifically to apply those tools to study portions of the Thomas and Detwiler wildfire events that occurred in California in 2017. Fire features such as active fire fronts and rate of spread (ROS) vectors derived from repetitive...

While climate change will have significant impacts on terrestrial organisms, microclimates offer potential refugia for vulnerable species when regional conditions become unsuitable and temperatures exceed physiological limits. The efficacy of microclimates as buffers to extreme events is determined not only by their availability, but also by the behavioral flexibility of individuals to access these unique environments during stressful periods. We characterized (i) how forest structure and topography shaped microclimates at roost sites used by California spotted owls (Strix occidentalis...

White-nose syndrome (WNS) has notably affected the abundance of Myotis lucifugus(little brown myotis) in North America. Thus far, substantial mortality has been restricted to the eastern part of the continent where the cause of WNS, the invasive fungus Pseudogymnoascus destructans, has infected bats since 2006. To date, the state of Washington is the only area in the Western US or Canada (the Rocky Mountains and further west in North America) with confirmed cases of WNS in bats, and there the disease has spread more slowly than it did in Eastern North America. Here, we review differences...

High-resolution microscopy of deep tissue with large field-of-view (FOV) is critical for elucidating organization of cellular structures in plant biology. Microscopy with an implanted probe offers an effective solution. However, there exists a fundamental trade-off between the FOV and probe diameter arising from aberrations inherent in conventional imaging optics (typically, FOV < 30% of diameter). Here, we demonstrate the use of microfabricated non-imaging probes (optrodes) that when combined with a trained machine-learning algorithm is able to achieve FOV of 1x to 5x the probe diameter....

Objective The literature on thermal refuges has focused on when fish use what kinds of refuge, but we address how refuge availability and characteristics affect population abundance and persistence under warming. Methods Population benefits of thermal refuges are very difficult to assess empirically, so we used InSTREAM, an individual-based trout population model. InSTREAM represents several ways temperature affects survival and growth, as mediated by behaviors such as deciding when and where to feed. The model’s credibility was established by showing that it closely reproduced 10 observed...