Treesearch

Climate change is altering legacies of native insect-caused disturbances and contributing to non-native invasions globally. Many insect fitness traits are temperature dependent and projected climatic changes are expected to cause continued alterations in insect-caused tree mortality, with uncertain consequences for forest ecosystems and their management. Dendroctonus ponderosae in Pinus habitats of western North America and Ips typographus in European Picea are among the most significant tree mortality agents on each continent. Changing climate is influencing both species in their native...

Mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is a significant forest disturbance agent with a widespread distribution in western North America. Population success is influenced by temperatures that drive phenology and ultimately the adult emergence synchrony required to mass attack and kill host trees during outbreaks. In addition to lifestage-specific developmental rates and thresholds, oviposition timing can be a source of variance in adult emergence synchrony, and is a critical aspect of mountain pine beetle phenology. Adaptation to...

Seed predation by rodents presents a significant barrier to native plant recruitment and can impede restoration seeding efforts. In nature, some plants contain secondary defense compounds that deter seed predators. If these natural defense compounds can be applied to unprotected seeds to inhibit rodent granivores, this approach could improve restoration seeding. Capsaicin is the active ingredient in chili pepper (Capsicum spp.) seeds that creates the burning sensation associated with human consumption of hot peppers. This compound has a similar effect on other mammals and is believed to...

Erosion of soil carbon (C) and nitrogen (N) following severe wildfire may have deleterious effects on downstream resources and ecosystem recovery. Although C and N losses in combustion and runoff have been studied extensively, soil C and N transported by post-fire erosion has rarely been quantified in burned landscapes. To better understand the magnitude and temporal pattern of these losses, we analysed the C and N content of sediment collected in severely burned hillslopes and catchments across the western USA over the first 4 post-fire years. We also compared soil C and N losses from...

Stem-maps, maps of tree locations with optional associated measurements, are increasingly being used for ecological study in forest and plant sciences. Analyses of stem-map data have led to greater scientific understanding and improved forest management. However, availability of these data for reuse remains limited. We present a description of eight 4-ha stem-maps used in four prior research studies. These stem-maps contain locations and associated measurements of residual trees and stumps measured after forest restoration cuttings in Colorado, Arizona, and New Mexico. Data are published...

Background: In the Inland Pacific Northwest of the United States, fire is a dominant driver of ecological change. Within wildfire perimeters, fire effects often vary considerably and typically include remnant patches of unburned islands. As fires reburn the landscape, some unburned islands remain persistently unburned. These persistent unburned islands can serve an important ecological function as fire refugia; however, their characteristics have not been quantified. The objective of this study was to assess the characteristics of persistent unburned islands and compare them to the burned...

Consistent with a ubiquitous life history trade-off, trees exhibit a negative relationship between growth and longevity both among and within species. However, the mechanistic basis of this life history trade-off is not well understood. In addition to resource allocation conflicts among multiple traits, functional conflicts arising from individual morphological traits may also contribute to life history trade-offs. We hypothesized that conflicting functional effects of xylem structural traits contribute to the growth-longevity trade-off in trees. We tested this hypothesis by examining the...

Wildfires can drastically alter belowground processes such as organic matter (OM) decomposition. We used wood stakes of two different tree species, trembling aspen (Populus tremuloides Michx.) and loblolly pine (Pinus taeda L.), placed at three soil locations (soil surface, forest floor-mineral soil interface, mineral soil), as an index of the long-term (5-year) effects of wildfire on OM decomposition in two forest stands after high-severity wildfire and in an unburned control. Wood stake mass loss was generally higher for aspen, especially in the mineral soil of burned plots, than in...

New technologies may enhance management by enabling quantitative testing of assumptions of vegetation response to climate and management. State-and-transition simulation models can keep track of interactions that are too complicated for us to comprehend using only conceptual models. This tool takes conceptual state-and-transition models to the next level, fostering greater communication and dialogue with stakeholders. Based on the models and climate data used here, increased drought may enhance transitions between vegetative states. It is important to be as explicit and quantitative as...