Treesearch

Logging debris remaining after timber harvest can modify the microclimate and growing conditions for forest regeneration. Debris also can influence tree seedlings indirectly through its effects on development of competing vegetation, although the mechanisms are poorly understood. At two sites in Washington and Oregon (USA) that differed in availability of soil water and nutrients, mechanisms were studied by which logging debris and competing vegetation interacted to influence performance of planted Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) seedlings. In a split-plot...

Basin wildrye [Leymus cinereus (Scribn. & Merr.) Á. Löve] and creeping wildrye [Leymus triticoides (Buckley) Pilg.] are outcrossing perennial grasses native to western North America. These divergent species are generally adapted to different habitats but can form fertile hybrids. Cultivars of both species are used in agriculture and conservation, but little is known about genetic diversity and gene flow among these species. Therefore, multilocus amplified fragment length polymorphism (AFLP) genotypes and chloroplast DNA sequences were evaluated from 536 L. cinereus and 43 L. triticoides...

Coarse woody debris (CWD) has been identified as an important component in many forest ecosystem processes. Perpendicular distance sampling (PDS) is one of the several efficient new methods that have been proposed for CWD inventory. One drawback of PDS is that the maximum search distance can be very large, especially if CWD diameters are large or the volume factor chosen is small. Here, we propose a modified method, which we call distance-limited PDS, that addresses this limitation. We describe the field procedures, develop new a new estimator, and provide a proof of unbiasedness of that...

The first full annual inventory of Illinois' forests was completed in 2005. This report contains 1) descriptive information on methods, statistics, and quality assurance of data collection, 2) a glossary of terms, 3) tables that summarize quality assurance, and 4) a core set of tabular estimates for a variety of forest resources. A detailed analysis of inventory data is presented in a separate publication. (Crocker et al. 2009) https://www.nrs.fs.usda.gov/pubs/7094/

Sunflower family (Asteraceae). Bigflower agoseris is a short lived perennial forb from a simple or branched taproot. The stems and leaves contain a white milky juice. The leaves are all basal with the flower heads solitary on a naked scape. Leaves are 8 to 25 cm (3 to 10 in) long and 1 to 3 cm (0.4 to 1.2 in) wide, oblanceolate pinnatifid to nearly entire. The flowering stems are 15 to 45 cm (6 to 18 in) tall (Welsh et al. 2003). The floral heads are made of numerous yellow ray flowers (similar to a dandelion). Flowering occurs in spring. The fruit is an achene with a 4 to 7 mm (0.16 to...

Elevated suspended solids are a widespread stressor of aquatic ecosystems, but their effects on growth and reproduction in freshwater mussels are largely unknown. We fertilized experimental ponds to create a gradient in total suspended solids (TSS) and examined the effects of TSS on growth, nutritional status, reproduction, and clearance rate in Ligumia subrostrata. The number of females that became gravid declined sharply with increasing TSS, and no gravid females were found in the highest TSS treatments. The proportion of gravid females was not related to the TSS organic:inorganic ratio....

ASTM(1) G198, Standard test method for determining the relative corrosion performance of driven fasteners in contact with treated wood, was accepted by consensus and published in 2011. The method has two different exposure conditions for determining fastener corrosion performance in treated wood. The first method places the wood and embedded fasteners in a chamber at 95% relative humidity (RH), 32 °C for 120 days. The second method involves a cyclic fog, with 48 hours of fog followed by 72 h of dry for 120 days. The corrosion rate of embedded metals is an extremely sensitive function of...

The early detection of wood decays in high-value standing trees is very important in urban areas because mitigating control measures must be implemented long before tree failures result in property damage or injuries to citizens. Adverse urban environments increase physiological stresses in trees, causing greater susceptibility to attacks by pathogenic decay fungi. The detection of fungal root rots in urban trees is particularly difficult because conventional detection tools, currently used for diagnosis of wood decays, are not feasible below ground level. Portable electronic olfactory...

Two new species of Cerambycidae, Tessaropa elizabeth Bezark, sp. nov. (subfamily Cerambycinae, tribe Methiini ) and Anelaphus cordiforme Tyson, sp. nov. (subfamily Cerambycinae, tribe Elaphidiini), are described from the western part of the Darien, Panama. Nine new country records for Panama are reported for the following species: Adetus linsleyi Martins & Galileo, Estola strandiella Breuning, Nubosoplatus inbio Swift, Paranisopodus heterotarsus Monné & Martins, Pempteurys sericans Bates, Rosalba costaricensis (Melzer), Tomopterus brevicornis Giesbert, Psapharochrus nigricans (Lameere),...

Due in large part to fire exclusion, many oak-dominated (Quercus spp.) forests, woodlands, and savannas throughout eastern North America are being replaced by less diverse forest ecosystems. In the interior coastal plain of the southern United States, these forests are dominated in the mid- and understory by mesophytic species such as Acer rubrum L. and Liquidambar styraciflua L., which may eventually displace overstory oaks. Oak regeneration has been shown to respond positively to open canopies and prescribed burning. In 2008, a severe tornado damaged previously established study plots in...