Treesearch

California’s high density, fire-excluded forests experienced an extreme drought accompanied by warmer than normal temperatures from 2012 to 2015, resulting in the deaths of millions of trees. We examined tree mortality and growth of mixed-conifer stands that had been experimentally treated between 2011 and 2013 with two different thinning treatments, one with more structural variability (HighV) and one with less structural variability (LowV), applied alone or in combination with prescribed burning. Tree mortality between 2014 and 2018 varied by species ranging from 42% of white fir (Abies...

Legacy effects from one disturbance may influence successional pathways by amplifying or buffering forest regeneration after the next disturbance. We assessed vegetation and tree regeneration in non-serotinous Sierra lodgepole pine (Pinus contortavar. murrayana) stands after a 1984 wildfire which burned with variable severity and again after a high-severity subsequent fire in 2012. The legacy effects of the 1984 fire were amplified; seedlings and saplings were abundant in areas initially burned at low severity (1267 stems ha−1) despite high reburn severity, but regeneration was low in...

Although the effects of shifting fire regimes on bird populations have been recognized as important to ecology and conservation, the consequences of fire for trophic interactions of avian species – and raptors in particular – remain relatively unknown. Here, we found that within national parks with long‐standing (40+ years) fire management programmes, California Spotted Owls Strix occidentalis occidentalisconsumed predominantly Woodrats Neotomaspp. and Pocket Gophers Thomomysspp.; however, in contrast to our predictions, when their territories experienced more extensive and frequent fire,...

On 14 November 2018, a symposium Managing bark and ambrosia beetles with semiochemicals was held in Vancouver, British Columbia, Canada, at the Joint Meeting of the Entomological Society of America, the Entomological Society of Canada, and the Entomological Society of British Columbia. The focus was on the application of behavioural chemicals for management of bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) in conifers and hardwoods in North America and Europe. Contributors included nine invited speakers from Canada, Slovakia, and the United States of America who summarise...

Insects are essential components of forest ecosystems, representing most of the biological diversity and affecting virtually all ecological processes (Schowalter 1994). Most species are beneficial (Coulson and Witter 1984, Haack and Byler 1993), yet others periodically become so abundant that they threaten ecological, economic, social or aesthetic values at local to regional scales (tables 6.1 through 6.3). Insects influence forest ecosystem structure and function in complex and dynamic ways, for example, by regulating certain aspects of primary production; nutrient cycling; ecological...

This report provides detailed protocols for urban tree monitoring data collection. Specifically, we discuss the core variables necessary for field-based monitoring projects, including field crew identification, field crew experience level, tree record identifier, location, site type, land use, species, mortality status, crown vigor, and trunk diameter. The intent of this Field Guide is to serve urban forest managers and researchers who collect longitudinal field data on urban trees, as well as interns and citizen scientists. This report is a companion document to Urban Tree Monitoring: A...

The guidelines proposed in Urban Tree Monitoring: A Resource Guide (hereafter referred to as the Resource Guide) were developed and refined over many years to address the need for standardized urban tree monitoring protocols. The Resource Guide provides in-depth guidance for urban forest managers and researchers who want to design and implement a tree monitoring project. This Resource Guide is a companion to Urban Tree Monitoring: A Field Guide; however, the Resource Guide can also be used on its own. The Resource Guide is divided into three parts. In Part I, we discuss (1) the varied...

Over the past six years, inadvertent plant pathogen introductions into restorations plantings have stunned and frustrated vegetation ecologists. Sticky monkeyflower (Diplacus aurantiacus), toyon (Heteromeles arbutifolia), sages (Salvia spp.), and other common restoration plants have been found to harbor soilborne Phytophthora species, relatives of the sudden oak death pathogen (Phytophthora ramorum). Detections in native plant nurseries and restoration sites include new to the US Phytophthora species (Phytophthora tentaculata, P. quercina), new species (P. taxon agrifolia), and new...

Concentration-discharge (C-Q) relations can provide insight into the dynamic behavior of the Critical Zone (CZ), as C-Q relations integrate the spatial distribution and timing of watershed hydrogeochemical processes. This study blends geomorphologic analysis, C-Q relations and reactive-transport modeling using a rich dataset from an elevation gradient of eight watersheds in the Southern Sierra Nevada, California. We found that the CZ structure exerts a strong control on the C-Q relations, and on the hydrogeochemical behavior of headwater watersheds. Watersheds with thin regolith, a large...

This regional summary addresses the effects of climate change on soils of seven of the eight main Hawaiian islands (Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Kaho‘olawe, Maui, and Hawai‘i), the territories of Guam and American Samoa, the Commonwealth of the Northern Mariana Islands, and the freely associated Republic of Palau, Federated States of Micronesia, and Republic of the Marshall Islands. The distribution of soil types in Hawai‘i and the US Affliated Pacifc Islands (USAPI), and their sensitivity to climate change, is determined as elsewhere by soil-forming factors and their interactions...