Treesearch

Atmospheric turbulent circulations in the vicinity of wildland fire fronts play an important role in the transfer of momentum into and out of combustion zones, which in turn can potentially affect the behavior and spread of wildland fires. The vertical turbulent transfer of momentum is accomplished via individual sweep, ejection, outward interaction, and inward interaction events, collectively known as sweep-ejection dynamics. This study examined the sweep-ejection dynamics that occurred before, during, and after the passage of a surface fire front during a prescribed fire experiment...

Conservation auctions have been advocated as a way to increase the cost-effectiveness of payment for ecosystem services (PES) programs by reducing the informational rents captured by participating landowners. Most PES programs have continual or periodic (rather than one-time) enrollment. In repeated auctions, it is possible for participants to learn the winning bids from previous auctions and use this information to strategically set their bids, thereby capturing more informational rents. We develop an agent-based model, using data from Costa Rica’s Pago de Servicios Ambientales (PSA)...

The encroachment of pinyon-juniper woodlands into sagebrush habitat in the Great Basin Ecoregion of the western USA, represents a potential source of habitat degradation for sagebrush-associated wildlife species. To restore sagebrush habitat, managers are conducting large-scale conifer removal efforts within the Great Basin, particularly within Greater Sage-Grouse (Centrocercus urophasianus) priority areas for conservation. Such largescale habitat modification efforts may result in unintended ecological trade-offs for wildlife. To investigate these trade-offs, we used community science...

Emulating natural disturbance has become an increasingly important restoration strategy. In the fire-maintained woodlands of the southeastern United States, contemporary restoration efforts have focused on approximating the historical fire regime by burning at short intervals. Due to concerns over escape and damage to mature trees, most prescribed burning has occurred in the dormant season, which is inconsistent with the historical prevalence of lightning-initiated fire in the region. This discordance between contemporary prescribed burning and what is thought to be the historical fire...

Understanding how stand structure responds to stresses such as drought and pollution could aid forest managers in evaluating silvicultural treatment success, predicting treatment durability, and designing adaptive management approaches. The size-growth relationship (SGR), a measure of growth partitioning among different size trees in a stand, may provide a means of linking stresses impacting individual trees to forest stand development and growth. No study to date has tested SGR’s response to drought and pollution, specifically N deposition, across landscapes. We combined Forest Inventory...

Few studies analyze people’s preferences for ecosystem services (ES), disservices (ED) and drivers of change in less populated, tropical municipalities. Understanding such preferences and needs by the community and stakeholder groups before actually assessing, modelling, and measuring the supply of ES is key for decision-making and planning in municipalities, as well as for the conservation of nearby neotropical dry forests. We studied these dynamics in a small rural municipality in Colombia with limited data availability using semi-structured interviews and surveys, as well as ES-proxies...

Tree canopy is critical to urban sustainability. At present, enhancing urban tree canopy in many cities is largely dependent upon plantings on residential and park areas. However, challenges surrounding public engagement in tree planting and stewardship remain. This project engaged visitors to public venues in the City of Los Angeles in a ‘plant your street’ research game. Participants (n = 184) used a gameboard depicting a neighborhood to choose from tree species grouped by a selected prominent ecosystem service - fruit bearing, flowering, climate adaptive, and carbon capture. Of particula...

Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform postfire management in low elevation forests of California, USA, we collected 5-yr postfire recovery data from 1,234 study plots in 19 wildfires that burned from 2004–2012 and 18 yrs of seed...

In natural environments, plants develop adaptive mechanisms at the cellular and molecular levels to cope with many external factors, e.g., insects and soil pathogens. We studied physiological stress induced by different levels of foliage removal (defoliation 30% and 60%) and by infection of root rot pathogen Phytophthora plurivora on the common Polish tree species, Betula pendula, grown in an open greenhouse. This study showed that P. plurivora damaged the root system which negatively impacted all morphological parameters. However the loss of 30% of the leaves had a positive effect on...

Five-needle white pine species provide important ecosystem services throughout the western U.S., and many of these species have become susceptible to stressors including warmer temperatures, insect epidemics, nonnative disease, and altered disturbance regimes. The objective of this study was to characterize recent broad-scale demographic patterns, including species abundance (i.e., numbers of individuals, tree density, size-class distributions, recruitment, growth rates, mortality rates, and causes of mortality, for the six species of five-needle pine that occur in the western US. We used...