Treesearch

Forest thinning and prescribed fire are expected to improve the climate resilience and water security of forests in the western U.S., but few studies have directly modeled the hydrological effects of multi-decadal landscape-scale forest disturbance. By updating a distributed process-based hydrological model (DHSVM) with vegetation maps from a distributed forest ecosystem model (LANDIS-II), we simulate the water resource impacts of forest management scenarios targeting partial or full restoration of the pre-colonial disturbance return interval in the central Sierra Nevada mountains. In a...

Fog inundation along California's Coast Range creates microclimates that support coast redwood (Sequoia sempervirens(D. Don) Endl.) forests during the summer drought period. With changes in land use and climate, the coast redwood ecosystem is more susceptible to increased drought stress. Thus, understanding the role of fog in relieving drought stress is important to manage the remaining coast redwood forests. Fog presence, other climatic conditions, soil moisture, and sap flow were monitored at the Caspar Creek Experimental Watersheds in northwestern California over the 2020, 2021, and...

This research note describes the development of a pre-assessment survey of urban Black, Indigenous, and People of Color (BIPOC) youth participating in the Outward Bound Adventures (OBA) Environmental Studies Expeditions (ESE) program. The objective of the pre-assessment was to understand their baseline perceptions of nature and their experiences with the outdoors within their cultural context, as well as to inform the pre-and post-surveys that would be used to measure the benefits of OBA’s ESE program by focusing on participants’ understanding of nature, self-improvement, and the effect of...

Advance preparation for wildfire is essential for safe evacuation, and fire weather warnings can alert people to times of high fire danger when additional actions are recommended. However, little is known about the level of preparation of most wildland-urban interface (WUI) community residents, and potential influences on them carrying out preparatory actions. This study assessed the personal preparation undertaken by residents of California, United States, communities, including understanding of and response to fire weather warnings issued by the National Weather Service. We used a...

Mortality risk is a critical and complex component of individual fitness and individual-based ecology, especially when risk-avoidance behaviors are considered. Organisms are subject to multiple kinds of risk that can vary with habitat, time, individual state, individual activity and behavior, and population status. Yet risk is often represented very simply in models and there is little literature on practical ways to model its variation. In our experience, desirable characteristics of risk models include: (a) survival probability can vary with multiple variables of individuals, habitat,...

Stream-dwelling salmonids in the low-latitude and -altitude margins of their range are particularly threatened by climate change. However, they possess a variety of evolutionary, plastic, and behavioural mechanisms that provide resistance against rapid changes in their environment. Behavioural plasticity can be important under rapid environmental change because it is relatively fast and flexible. In particular, salmonids can exhibit flexible diel activity patterns in response to new environmental conditions, but the consequences of this capability for long-term population persistence in...

Wildfire activity in the western U.S. has highlighted the importance of effective management to address this growing threat. The Lookout Mountain Thinning and Fuels Reduction Study (LMS) is an operational-scale, long-term study of the effects of forest restoration and fuel reduction treatments in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and mixed-conifer forests in central Oregon, U.S. The broad objectives of the LMS are to examine the effectiveness and longevity of treatments on wildfire risk and to assess the collateral effects. Treatments include four levels of overstory...

Disturbance plays a critical role in the ecology of forests including influencing the abundance and diversity of fauna. Although numerous studies have focused on forest responses to various disturbance events, less attention has been given to arthropod community responses. California experienced an extreme, multi-year drought from 2012 to 2015 which severely stressed trees and incited epidemics of several bark beetle species (Coleoptera: Curculionidae: Scolytinae). Water stress and bark beetles contributed to a significant mortality event of hundreds of millions of trees in the central and...

Urban populations adjacent to forested areas value water-related ecosystem services and recreational opportunities. However, maintaining these benefits requires active forest management through thinning and prescribed burns, infrastructure development as well as issues of equity. These activities can also lead to public concerns over access fees, smoke emissions, and perceived negative impacts on forest health. This study aims to understand the tradeoffs between public preferences and forest management objectives in Wildland-Urban Interface montane forests. We employed an online survey...

Tropical forests may be nearing critical temperatures, yet tree species may respond differently. Using high-resolution thermal, hyperspectral, and LiDAR imagery, we mapped 652 crowns of four Hawaiian tree species to study the effects of crown traits and abiotic conditions on species’ temperatures at two scales (whole crown vs. sunlit leaves). We show scale-dependent, species-specific relationships with environmental fluctuations. Net radiation was consistently the dominant determinant of crown temperature deviations from air temperature (Tdiff), while vapor pressure deficit, wind speed,...