Treesearch

Whitebark pine will continue to decline over the next several decades, mostly from white pine blister rust, and mountain pine beetle mortality and indirectly by climate change impacts on regeneration and growth. This decline can be reversed or mitigated with proactive restoration actions; whereas if restoration does not take place, whitebark pine forests will continue to decline becoming a minor, if not missing, component on the high elevation landscapes in western North America.

Monitoring records indicate that river temperatures during the summer and early fall months have risen about 1 °C over the past 40 years in the northwestern United States. If river warming continues at rates similar to recent decades, water temperatures are expected to rise another 1 °C by 2050 and by 2-3 °C by the end of the century. In many locations, trout and salmon will have to shift into cooler areas or migrate at different times of the year to avoid thermally stressful conditions.

Recently published research can help land managers to identify important hubs and pathways of genetic connectivity for greater sage-grouse. This knowledge can be used in evaluating proposed development or management actions in terms of how they could disrupt, protect or restore critical places of conservation for greater sage-grouse habitat.

Overall, mulching treatments in three Colorado conifer forest types promoted denser and more diverse native understory plant communities, particularly over the longer-term. The positive effect of mulching on understory plants was largely driven by the response of herbaceous plants; shrubs showed little response to mulching treatments. Exotic plants tended to be more common in mulched stands than in untreated stands. While understory plants in mulched stands could be heavily suppressed in localized areas where mulch contributed to a deep forest floor, these areas were rare.

We performed single-sensillum recordings from male and female antennae of the Asian longhorned beetle, Anoplophora glabripennis, that included as stimuli the two components of this species' aggregation-sex pheromone in addition to various general odorants. We compared the aggregation-sex-pheromone-component responses of olfactory sensory neurons (OSNs) to those of OSNs that responded to a variety of plant-related odorants. In the smooth-tipped, tapered, trichoid sensilla on the most distal antennal flagellomeres nos. 10 or 11 of both males and females, we found OSNs with high-amplitude...

We estimate producers' value of information provided by alternative configurations of a monitoring network for an invasive wind-borne crop disease, soybean rust (Phakopsora pachyrhizi). Soybean producers use monitoring information to inform themselves about their risk of being infected and to make fungicide application decisions. The value of information is the expected gain in producers' profit associated with the use of the monitoring network, and we estimate this with a dynamic model of producer decision-making. We find that the value of the sentinel plot network increases with the...

Mesophication refers to the positive feedback cycle that occurs when fire suppression causes compositional shifts from oak (Quercus spp.) to other, primarily mesophytic, species. Because mesophytic species tend to be associated with relatively high-moisture sites, we sought to understand the extent to which physiographic and edaphic factors influence this process by examining forest successional dynamics over a period of 22 years. In 2016, we resampled a network of permanent plots first sampled in 1994 that were stratified across different landscape positions (e.g., north-facing slopes vs....

Invasive pathogens that cause stem cankers and wilts of trees, and insects that bore into bark and wood have proven extremely destructive to the world’s forests and particularly difficult to manage once established. Such pests are especially devastating when evolutionarily naïve host trees lack adequate natural defenses. Modern tree improvement programs are increasingly capable of restoring such defenses and providing trees for planting that are capable of withstanding alien insects and pathogens. Careful target selection, early implementation and sustained support of these programs are...

The genus Tuber is a lineage of diverse ectomycorrhizal, hypogeous, sequestrate ascomycete fungi that are native to temperate forests in the Northern Hemisphere. Recently, many new species of Tuber have been described in North America and Asia, based on morphological characteristics and molecular data. Here we describe and illustrate a new species, Tuber incognitum, based upon phylogenetic analysis and morphological description. We also present a new record for Tuber anniae in México. These two Tuber species are distributed in the Transmexican Volcanic Belt in the states of México,...

Plants damaged by herbivore feeding can induce defensive responses that reduce herbivore growth. The slowgrowth, high-mortality hypothesis postulates that these non-lethal plant defenses prolong the herbivore's period of susceptibility to natural enemies, such as predators and parasitoids. While many juvenile animals increase their disease resistance as they grow, direct tests of the slow-growth, high-mortality hypothesis in the context of plant–herbivore–pathogen interactions are lacking. Caterpillars increase their resistance to lethal baculoviruses as they develop within and across...