Treesearch

This paper explores opportunities for administrative discretion in decision-making for natural resource management. We carried out an exploratory study in the USDA Forest Service to understand factors affecting administrative actions related to recreation use in riparian areas. We conducted semi-structured interviews with 27 resource professionals from a national forest in the northwest region of the United States. Questions focused on professional judgments about recreation in riparian areas, administrative actions related to management of these activities, and the potential for personal...

Physiological adjustments to enhance tolerance or avoidance of summer drought and winter freezing were studied in shallow- to deep-rooted Patagonian cold desert shrubs. We measured leaf water potential, osmotic potential, tissue elasticity, stem hydraulic characteristics, and stomatal conductance across species throughout the year, and assessed tissue damage by subzero temperatures during winter.

The amber-marked birch leafminer has caused severe infestations of birch species in Anchorage, AK, since 2002. Its spatial distribution has been monitored since 2006 and summarized using interpolated surfaces based on simple kriging. In this study, we developed methods of assessing and describing spatial distribution of the leafminer as they vary from year to year, and speculate on potential causes of these trends in landscape patterns.

There is increasing interest in actively managing forests to increase their resilience to climate-related changes. Although forest managers rely heavily on the use of silvicultural treatments that manipulate stand structure and stand dynamics to modify responses to climate change, few studies have directly assessed the effects of stand structure or canopy position on climate-growth relationships, or examined how this relationship may vary among species or across environmental gradients. In this study, we analyzed variability in tree-ring series from 15 low-elevation stands in northeastern...

Conservation in urban areas faces growing financial challenges and inadequate stakeholder involvement. Conservation psychology can mitigate these challenges in many ways. One way is through conservation volunteerism, if we attend to and capitalize on volunteers' motivations. Conservation volunteerism significantly contributes to ecological knowledge acquisition, and public education and awareness of conservation issues. In this study, we explored volunteers' motivations and how those motivations influence frequency of participation in urban conservation activities. We found that volunteers'...

The Forest Inventory and Analysis (FIA) Program's Lichen Communities Indicator is used for tracking epiphytic macrolichen diversity and is applied for monitoring air quality and climate change effects on forest health in the United States. Started in 1994, the Epiphytic Macrolichen Community Composition Database (GIVD ID NA-US-012) now has over 8,000 surveys of lichen community composition, some of which are re-visits that may be used for tracking change over time. Plots are located on the FIA Program's permanent nation-wide Phase 3 grid and are re-visited every 5-10 years (periodicity...

Spatially crown biomass of Pinus pinaster stands and shrubland above-ground biomass (AGB) estimation was carried-out in a region located in Centre-North Portugal, by means of different approaches including forest inventory data, remotely sensed imagery and spatial prediction models. Two cover types (pine stands and shrubland) were inventoried and biomass assessed in a total of 276 sample field plots. We compared AGB spatial predictions derived from Direct Radiometric Relationships (DRR) of remotely sensed data; and the geostatistical method Regression-kriging (RK), using remotely sensed...

Previous studies have debated the flammability of young regenerating stands, especially those in a matrix of mature forest, and no consensus has emerged as to whether young stands are inherently prone to high-severity wildfire. This topic has recently been addressed using spatial imagery, and weak inferences were made given the scale mismatch between the coarse resolution of spatial imagery and the fine resolution of mechanisms driving fire severity. We collected empirical stand and fire-severity data from 44 regenerating stands that are interspersed in mature, mid-elevation forests in the...

The existence of non-serotinous, non-sprouting species in fire regimes where serotiny confers an adaptive advantage is puzzling, particularly when these species recruit poorly from soil seed banks or from burn edges. In this paper, white spruce (Picea glauca (Moench) Voss) was used to show that the timing of fire relative to seed development can control aerial seed bank availability for non-serotinous species. To estimate seed survival in closed cones during crown fires, cone heating was simulated using a one-dimensional conduction model implemented in a computational fluid dynamics...

Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure-without explicitly considering food webs-has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective restoration. We identify three priority food web-related issues that potentially impede successful river restoration: uncertainty about habitat carrying capacity, proliferation of chemicals and contaminan...