Treesearch

Long-term fire history reconstructions enhance our understanding of fire behaviour and associated geomorphic hazards in forested ecosystems. We used 14C ages on charcoal from fire-induced debris-flow deposits to date prehistoric fires on Kendrick Mountain, northern Arizona, USA. Fire-related debris-flow sedimentation dominates Holocene fan deposition in the study area. Radiocarbon ages indicate that stand-replacing fire has been an important phenomenon in late Holocene ponderosa pine (Pinus ponderosa) and ponderosa pine-mixed conifer forests on steep slopes. Fires have occurred on centennia...

Packera franciscana (Greene) W. A. Weber and A. Love is endemic to treeline and alpine habitats of the San Francisco Peaks, Arizona, USA and was listed as a threatened species under the Endangered Species Act in 1983. Species abundance data are limited in scope, yet are critical for recovery of the species, especially in light of predictions of its future extinction due to climate change. This study defined baseline population densities along two transects which will allow the detection of future population trends. Packera franciscana ranged from 3529 to 3722 m elevation along the outer...

Wildland fires and resulting effects have increased in recent years. Efforts are under way nationwide to proactively manage vegetative conditions to reduce the threat of wildland fires. Public support is critical to the successful implementation of fuels reduction programs, particularly at the wildland-urban interface. This study examines public acceptance of fuels treatments and influencing factors in five neighbourhoods in Oregon and Utah located adjacent to public lands. Support for treatment use was high across locations. Findings suggest citizen trust in agency managers to successfully...

An undetermined Armillaria species was collected on Amami-Oshima, a subtropical island of Japan. The phylogenetic position of the Armillaria sp. was determined using sequences of the elongation factor-1a (EF-1a) gene and the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of ribosomal DNA (rDNA). The phylogenetic analyses based on EF-1a and ITS sequences showed that this species differs from known Japanese taxa of Armillaria. The sequences of this species and A. novaezelandiae from Southeast Asia were contained in a strongly supported clade, which was adjacent to a well-supported...

The conservation of wildlife corridors between existing habitat preserves is important for combating the effects of habitat loss and fragmentation facing species of concern. We introduce the Steiner Multigraph Problem to model the problem of minimum-cost wildlife corridor design for multiple species with different landscape requirements. This problem can also model other analogous settings in wireless and social networks. As a generalization of Steiner forest, the goal is to find a minimum-cost subgraph that connects multiple sets of terminals. In contrast to Steiner forest, each set of...

Armillaria isolates were collected from a unique forest ecosystem in the Niobrara Valley Preserve in Nebraska, USA, which comprises a glacial and early postglacial refugium in the central plains of North America. The isolates were collected from diverse forest trees representing a unique mixture of forest types. Combined methods of rDNA sequencing and flow cytometric measurements of nuclear DNA content determined that all Armillaria isolates collected from the site were A. gallica.

Understanding the spatial dimensions of hunting and prey population dynamics is important in order to estimate the sustainability of hunting in tropical forests. We investigated how hunting offtake of vertebrates differed in mixed forest and monodominant forest (composed of Gilbertiodendron dewevrei) and over different spatial extents within the hunting catchment around the logging town of Kabo, Congo. In 9 months of recall surveys with hunters, we gathered information on over 1500 hunting trips in which ungulates were 65% of the species killed and 82% of harvested biomass. Hunters...

Environmental risk assessments characterizing potential environmental impacts of exotic weeds are more abundant and comprehensive for potential or new invaders than for widespread and well-established species such as Dalmatian (Linaria dalmatica [L.] Mill.) and yellow (L. vulgaris Mill.) toadflax. Specific effects evaluated in our assessment of environmental risks posed by yellow and Dalmatian toadflax included competitive displacement of other plant species, reservoirs of plant disease, animal and insect use, animal toxicity, human toxicity and allergenicity, erosion, and wildfire. Effect...

In this paper I describe and compare grassland changes since 1977 at the Central Peloncillo Research Natural Area (CPRNA) with temperature and precipitation data from its nearby weather station. The grama grasslands there have thrived through two distinctive climate periods since 1977. The current period began with warm and dry years beginning around 1993 and continuing to the present. The cover, frequency, and diversity of herbs and shrubs in this grasslands have been precisely measured from permanently marked transects in 1977, 1984, 1996, 2002, and 2007. The grasslands flourish despite...

Seedlings for reforestation and restoration come in many shapes and sizes, i.e., a variety of stocktypes. With so many choices available, land managers commonly ask which stocktype will best meet their management objectives. For years, stocktype studies have been initiated in search of an answer to this question, but few have been done without some degree of confounding. Past studies often confounded seed sources, nurseries, and culturing regimes, and/or failed to address differences in initial seeding quality, which sometimes led to inappropriate conclusions. This article reviews the...