Treesearch

To determine the current range of water temperatures in streams inhabited by California Golden Trout Oncorhynchus mykiss aguabonita, we deployed and monitored water temperature recording probes from 2008-2013 in three meadows in the Golden Trout Wilderness in the southern Sierra Nevada, California. Ninety probes were placed in three meadow streams: Mulkey Creek in Mulkey Meadow (2,838 m), South Fork Kern River in Ramshaw Meadows (2,640 m) and Golden Trout Creek in Big Whitney Meadow (2,963 m). Year-round water temperatures were successfully downloaded from seventy-nine probes along with...

Wildland firefighting is an inherently dangerous activity, and aviation-related accidents in particular comprise a large share of firefighter fatalities. Due to limited understanding of operational factors that lead to aviation accidents, it is unclear how local decisionmakers, responsible for requesting aviation support, can mitigate the risk of an aviation accident once resources are requested. This research expands the knowledge base regarding the quantification and analysis of aerial firefighting exposure by developing methods to evaluate expected aviation accident rates at the...

Wood growth in trees depends on the acquisition of resources, and can vary with tree size leading to a variety of stand dynamics. Typically, larger trees obtain more resources and grow faster than smaller trees, but while light has been addressed more often, few case studies have investigated the contributions of water use and water use efficiency (WUE) within stands to isolate the tree-size dominance effect. Our sites were located near the cities of Aracruz and Eunapolis in Northeastern Brazil. We measured tree biomass growth, water use and WUE to explore patterns of growth among dominant...

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is a pest of eastern and Carolina hemlocks (Tsuga canadensis (L.) Carriere and Tsuga caroliniana Engelmann, respectively) in the eastern United States and has already caused catastrophic changes to eastern forests. As one of the significant exotic forest pests, it is imperative that the basic biology of hemlock woolly adelgid be understood for use in novel and improved management techniques. Scanning and transmission electron microscopy and enzyme assays were used to elucidate the feeding biology of hemlock woolly...

Tree species distributions and diversity could be explained by rank changes in performance over multiple spatiotemporal resource gradients, i.e., resource partitioning. For 14 species planted in 45 harvest gap and closed canopy locations in a mesic northern hardwood forest community, Michigan, USA, we asked the following questions: (i) are species growth responses to light, nitrogen (N), or N form (ammonium vs. nitrate) related to their ecological distributions and phylogenies? and (ii) is there evidence of growth-based resource partitioning over measured resource gradients? Growth...

The ability of forest resource managers to understand and anticipate landscape-scale change in composition and structure relies upon an adequate characterization of the current forest composition and structure of various patches (or stands), along with the capacity of forest landscape models (FLMs) to predict patterns of growth, succession, and disturbance at multiple scales over time. Comprehensive vegetation maps, which classify patch polygons or raster cells into forest cover types, can be developed from available inventory data (e.g., FIA Grid) in combination with remotely sensed data,...

The northern long-eared bat (Myotis septentrionalis) has been a common insectivorous bat in much of eastern North America, including Arkansas, which is located near the southwestern edge of its range. While this species is expected to occur throughout the Ozarks and Ouachita Mountains, it has only been previously documented in 19 of 75 Arkansas counties (Harvey and McDaniel 1983, Saugey et al. 1989, Sealander and Heidt 1990, Saugey et al. 1993, Wilhide et al. 1998a, Tumlison et al. 2002, Sasse and Saugey 2008).

Effective population size (Ne) is an important parameter in conservation genetics because it quantifies a population's capacity to resist loss of genetic diversity due to inbreeding and drift. The classical approach to estimate Ne from genetic data involves grouping sampled individuals into discretely defined subpopulations assumed to be panmictic. Importantly, this assumption does not capture the continuous nature of populations genetically isolated by distance. Alternative approaches based on Wright's genetic neighborhood concept quantify the local number of breeding individuals (NS) in...

Using mature hypocotyls as the initial explants, an Agrobacterium tumefaciens-mediated genetic transformation system was successfully developed for pumpkin ash (Fraxinus profunda). This transformation protocol is an invaluable tool to combat the highly aggressive, non-native emerald ash borer (EAB), which has the potential to eliminate native Fraxinus spp. from the natural landscape. Hypocotyls were successfully transformed with Agrobacterium strain EHA105 harboring the pq35GR vector, containing an enhanced green fluorescent protein (EGFP) as well as a fusion gene between neomycin phosphotr...

An improved protocol for Agrobacterium-mediated transformation of an elite, mature black cherry genotype was developed. To increase transformation efficiency, vacuum infiltration, sonication, and a combination of the two treatments were applied during the cocultivation of leaf explants with Agrobacterium tumefaciens strain EHA105 harboring a PsAGAMOUS RNAi plasmid (pART27-PsAGRNAi). The effects of Agrobacterium culture density and cocultivation duration on transformation efficiency were examined using EHA105 harboring either pBI121-MDL4 or pBI121-PsTFL1. In addition, the effect of the...