Treesearch

A wealth of evidence links microbial exposure to better human immune function. However, few studies have examined whether exposure to plant diversity is protective of immune diseases, despite the fact that plant leaves support ~1026 bacterial cells. Using the Centers for Disease Control and Prevention’s 500 cities project data, we found that a 1-SD increase in exposure to taxonomic plant diversity is associated with a 5.3 (95% CI: 4.2–6.4; p < 0.001) percentage-point decline in Census-tract level adult-asthma rate. In contrast, A 1-SD increase in overall greenness exposure (measured using...

Collaborative adaptive management (CAM) is hypothesized to benefit management of rangeland ecosystems, but the presumed benefits have seldom been quantified, and never in a multipaddock rotational grazing system. Here, we evaluated average daily weight gain (ADG) of livestock (kg steer−1 d−1) in four grazing management treatments during the summers of 2016−2018 in a semiarid shortgrass steppe. These four treatments had the same stocking rate but differed in stocking densities. The three lowest stocking densities were implemented using nonadaptive grazing management, while the highest...

In western North America beginning in the late 19th century, fire suppression and other factors resulted in dense ponderosa pine (Pinus ponderosa) forests that are now prone to high severity wildfire, insect attack, and root diseases. Thinning and prescribed fire are commonly used to remove small trees, fire-intolerant tree species, and shrubs, and to reduce surface and aerial fuels. These treatments can be effective at lowering future fire severity, but prescribed burns must be periodically repeated to maintain favorable conditions and are feasible only outside the historical summer...

This report highlights key findings from the most recent 10-year survey of Forest Inventory and Analysis (FIA) data collected across southeast and south-central Alaska and represents the first full remeasurement of all forest plots in the coastal Alaska inventory unit. Estimates of forest area, stand age, volume, aboveground biomass, and carbon are provided across ownerships, forest types, and species throughout the region. Of the 54 million ac in the inventory unit, approximately 15 million ac (28 percent) were considered forest land, most of which is managed by Tongass National Forest in...

Field and laboratory emission factors (EFs) of wildland fire emissions for 276 known air pollutants sampled across Canada and the US were compiled. An online database, the Smoke Emissions Repository Application (SERA), was created to enable analysis and summaries of existing EFs to be used in smoke management and emissions inventories. We evaluated how EFs of select pollutants (CO, CO2, CH4, NOx, total particulate matter (PM), PM2.5 and SO2) are influenced by combustion phase, burn type and fuel type. Of the 12 533 records in the database, over a third (n = 5637) are represented by 23 air...

Nearshore ecosystems (e.g., mangrove forests, sea grass beds, coral reefs) are some of the most biologically diverse and ecologically productive on Earth, while providing essential goods and services to human communities. Because these ecosystems are subject to threats from both land and sea, their conservation and management requires a ridge to reef approach. Here, we developed a watershed decision support tool (DST) for Babeldaob Island, Republic of Palau, aimed at prioritizing catchments for reforestation of fire degraded savanna or protection of native forest against conversion to...

Computer models used to predict forest and fuels dynamics and wildfire behavior inform decisionmaking in contexts such as postdisturbance management. It is imperative to understand possible uncertainty in model predictions. We evaluated sensitivity of the Fire and Fuels Extension to the Forest Vegetation Simulator predictions to parameters that determine dynamics of standing dead trees (snags) and surface woody fuels. Predicted peak coarse and fine woody fuels were not sensitive to the decomposition rate of snags but were sensitive to decomposition rate of surface fuels regardless of...

We tested whether post-fire seedling establishment of common boreal tree and expanding shrub species at treeline and in Arctic tundra is facilitated by co-migration of boreal forest mycorrhizal fungi. Wildfires are anticipated to facilitate biome shifts at the forest-tundra ecotone by improving seedbed conditions for recruiting boreal species; at the same time fire alters the composition and availability of mycorrhizal fungi critical to seedling performance. To determine the role of root-associated fungi (RAF) in post-fire seedling recruitment and future biome shifts, we outplanted four...

The Trask River Watershed Study in the northern Oregon Coast Range was designed to examine physical, chemical, and biological effects of contemporary forest management practices on aquatic ecosystems. We measured stream temperature for 11 summers in 15 small watersheds, eight of which were harvested in 2012. Three riparian buffer treatments, which varied by landowner, were implemented. Using half-hourly data, we characterized summer water temperature distributions with five percentiles: 5th, 25th, 50th, 75th, and 95th. Each percentile was analyzed as a separate response variable using a...

Despite a critical need to evaluate effectiveness of forest treatments in improving stand health, practitioners lack quantitative, repeatable metrics to assess tree vigor and stand health. We evaluated canopy and whole tree attributes of ponderosa pine (Pinus ponderosa Dougl. Ex Laws) related to carbon balance, water balance, and susceptibility to insects and pathogens in dry, pine-dominated forest stands during a multi-year drought, an environmental challenge to stand resilience. Metrics of trees in two unmanaged, and seven treated forested stands, in both uplands and lowlands to develop...