Treesearch

The presence of fire in Hawai'i has increased with introduction of nonnative grasses. Fire danger estimation using the National Fire Danger Rating System (NFDRS) typically requires 5 to 10 yr of data to determine percentile weather values and fire activity. The U.S. Army Pōhakuloa Training Area in Hawai‘i is located in the interface zone between windward and leeward weather conditions and needed to develop fire danger values but did not have sufficient weather or fire occurrence data. Use of simulation to estimate fire danger (expressed as fire risk) for areas with limited weather data was...

Many US forest managers have used historical ecology information to assist in the development of desired conditions. While there are many important lessons to learn from the past, we believe that we cannot rely on past forest conditions to provide us with blueprints for future management. To respond to this uncertainty, managers will be challenged to integrate adaptation strategies into plans in response to changing climates. Adaptive strategies include resistance options, resilience options, response options, and realignment options. Our objectives are to present ideas that could be...

Wildfires are a societal problem that threatens many ecosystems, affects millions of people worldwide, and causes major ecosystem and economic impacts at local regional, national and global scales. In Europe, and especially in the Mediterranean countries (France, Greece, Italy, Portugal and Spain), wildfires continue to be a major environmental threat (Requardt et al. 2007) where, an average 500 000 ha of forests are burned annually (San-Miguel and Camia 2009). Wildfires affect the forests and other wooded land, and neighbouring systems such as urban areas, infrastructure networks (i.e....

Despite a strong anthropogenic fingerprint on 20th Century wildland fire activity in the American West, climate remains a main driver. A better understanding of the spatiotemporal variability in fire‐climate interactions is therefore crucial for fire management. Here, we present annually resolved, tree‐ring based fire records for four regions in the American West that extend back to 1400 CE. In all regions, years with high fire activity were characterized by widespread yet regionally distinct summer droughts. Overall fire activity was high in late Medieval times, when much of the American...

Bacterial communities are known to play important roles in insect life histories, yet their consistency or variation across populations is poorly understood. Bacteria associated with the bark beetle Dendroctonus valens LeConte from eight populations, ranging from Wisconsin to Oregon, were evaluated and compared. We used the culture-independent technique of denaturing gradient gel electrophoresis to visualize bacterial diversity, or individual operational taxonomic units (OTUs), from individual beetles. One-way analysis of similarities was used to test for differences of bacterial communitie...

Recent studies have investigated the relationships between pairs or groups of exotic species to illustrate invasive mechanisms, but most have focused on interactions at a single trophic level. Here, we conducted pathogenicity tests, analyses of host volatiles and fungal growth tests to elucidate an intricate network of interactions between the host tree, the invasive red turpentine beetle and its fungal associates. Seedlings inoculated with two strains of Leptographium procerum isolated from Dendroctonus valens in China had significantly longer lesions and higher mortality rates than...

In the Karuk Tribe’s worldview, planetary stewardship is maintained through the place-based spiritual and cultural philosophy of World Renewal. A philosophy of Renewal reaffirms the responsibility of humans as stewards as well as a critical ecosystem component. The Tribe believes in renewal of the human-environment relationship that is compatible with ecological processes, promotes a sustainable economy, and increases ecosystem resilience.

Pest Risk Analysis (PRA) is an internationally recognized, structured process of determining whether plant pests and pathogens that are absent from a country or area could enter, establish, and cause an economic or environmental risk that is deemed unacceptable. PRA is also used to help identify phytosanitary measures to reduce risks to an acceptable level. United Kingdom (U.K.) PRAs for Phytophthora ramorum have been produced and developed since 2000, starting with the unknown Phytophthora causing sudden oak death in California, United States (U.S.). Other European Union (EU) Member...

Sudden oak death (SOD), caused by the non-indigenous forest pathogen Phytophthora ramorum, causes substantial mortality in coast live oak (Quercus agrifolia) and several other oak species on the Pacific Coast of the United States. Quasi-experimental hedonic models examine the effect of SOD on property values with a dataset that spans more than two decades including a decade of transactions before and after the invasion. The long study period allows for a unique contribution to the hedonic literature on natural hazards by studying the dynamic response of property values to an invasive...