Treesearch

This report is aimed toward improving general awareness of various types of Armillaria samples and recommended survey practices to obtain collections for isolation/culture, DNA-based identification, and/or future studies. High-quality samples yield a higher success rate for DNA-based identification and allow isolation in the laboratory to obtain pure, living Armillaria cultures that can be archived for long-term storage for use in future research projects. In root disease surveys, samples of pathogenic Armillaria are frequently obtained from trees showing symptoms of disease, such as...

Although Armillaria has been previously surveyed in several western states of the USA, little definitive information on Armillaria species distribution in California has been provided in the last 20 years (e.g., Baumgartner and Rizzo 2001). Furthermore, it is well established that climate and climate change influence the distribution of Armillaria species that cause Armillaria root disease, which is a major cause of losses in forest growth and productivity (e.g., Lockman and Kearns 2016; Kim et al. 2021, 2022). This paper details recent progress towards identifying Armillaria for subsequent...

Altered fire regimes and post‐fire tree regeneration failures have the potential to drive forest cover losses throughout western North America, but management practices such as active reforestation may help address these challenges. Planting of nursery‐grown tree seedlings currently accounts for the majority of active reforestation in the western United States. Direct tree seeding—an alternative approach that involves dispersing seeds into a project site—is rare but has the potential to supplement planting and increase the pace and scale of reforestation activities, particularly where...

Rapid human modification of landscapes around the world has made understanding how humans affect the genetic connectivity of wildlife populations urgent. The consistency of anthropogenic impact on genetic connectivity across taxa is unclear, in part because it is rare to have data representing functional connectivity for multiple taxa on the same landscape. We use microsatellite data for 10 mammalian species in New Jersey, USA, to assess cross‐taxonomic patterns in the impact of urbanization on genetic connectivity. In doing so, we also evaluate the efficacy of species‐specific and...

During wildland fire spread both slope and wind act together to modify fire dynamics, commonly accelerating the rate of fire spread. To investigate this coupling effect, flow field measurements were conducted on stationary gaseous fires produced over a tilt table in a wind tunnel, with fireline intensities ranging from 41 to 123 kW/m. The angle of inclination (θ) and the wind speed (V) were varied from 0 to 30° and 0.30 to 1.27 m/s, respectively. The surface gas velocity of the fire at various downstream locations was measured using temperature-correlation velocimetry (TCV), which was...

Oak powdery mildew, caused by Erysiphe alphitoides, is a widespread disease that affects oaks. We aimed to understand the complex interactions between extrinsic (environmental) and intrinsic (provenance) factors that influence the infection rate of E. alphitoides on Quercus robur seedlings. In a common garden controlled water experiment, we investigated the natural infection rate of E. alphitoides considering factors such as oak provenance, soil moisture availability, and the seedlings’ location in the microenvironment. We examined infection rates on first- and second-flush leaves,...

Increased frequency, severity, and duration of droughts and increased wildfire severity are impacting many conifer forests globally. Reforestation in these changing disturbance regimes requires tree seedlings capable of establishing in hotter and drier climates. We evaluated the morphological and physiological effects of drought conditioning on second-year ponderosa pine (Pinus ponderosa), western white pine (Pinus monticola), and western larch (Larix occidentalis) seedlings. Treatments included a well-watered control (75% of container capacity) and a water-limited (40% of container...

WEPPcloud - European Union (EU) is an online interface of the Water Erosion Prediction Project (WEPP) model designed to predict streamflow and sediments in European forested watersheds. Although designed to be run in any location in Europe, its performance has not yet been evaluated against observed data. This study evaluates WEPPcloud - EU's performance in simulating streamflow and suspended sediment yield for two burned catchments, Ermida and Serra de Cima, in continental Portugal during the first year after the fire. The default parameters significantly underestimated streamflow and...

Wildfires accelerate soil erosion. Preventive fuel management and post-fire control measures are two distinct strategies that can be used to mitigate wildfire-induced soil loss with varying effectiveness and costs. Here, we quantified the impacts and effectiveness of pre- versus post-fire treatment strategies on soil loss mitigation. We coupled fire simulations with soil erosion modelling to estimate annual wildfire-induced soil loss for two watersheds in Portugal. We identified optimal treatment locations with the aim of maximizing the reduction in soil loss, and estimated treatment...

Forests are changing rapidly due to drought, disease, wildfire, and forest management, with unknown impacts on snowmelt resources. While hyper-resolution forest hydrology models capture the effects of canopy cover amount and arrangement on snowpack, they are too complex for landscape-scale assessments. Here, we evaluated two statistical approaches to emulate high-resolution (1 m) mechanistic model maps of snow variables for future application in forest management and drew inferences about topographic vs. forest canopy controls. We tested a simple landscape classification using one or more...