Treesearch

Climate change is not only causing temperatures to rise, it is also altering the amount and type of precipitation that falls across the western United States. Research shows a trend of increasingly dry "dry years," meaning droughts are becoming more severe and streams are flowing lower during these periods.

Blackbrush (Colegyne ramosissima) is a desert shrubland species that is currently dominant on over three million acres of the transition zone between the cold desert of the Great Basin and the warm desert of the southwestern United States. Western landscapes are projected to experience unprecedented changes as the climate warms, and researchers at the Rocky Mountain Research Station have been studying the response of this species to assess whether it can move upward in elevation and latitude. Blackbrush was found to have two distinct populations (in the warmer Mojave Desert and the cooler...

Headwater streams are crucial parts of overall watershed dynamics because they comprise more than 50–80% of stream networks and watershed land areas. This study addressed the influence of headwater areas (ephemeral and intermittent) on stormflow characteristics following harvest within three first–order catchments in the Upper Gulf Coastal Plain of Mississippi. Four treatments including two Best Management Practices (BMPs) were applied: BMP1 – removal of all merchantable stems while leaving understory intact with minimum surface soil disturbance; BMP2 – same as BMP1 with the addition of...

The purpose of this paper is to be an academic inquiry into rating issues confronted by the US Federal Crop Insurance program stemming from changes in participation rates as well as the weighting of data to reflect longer-run weather patterns.

Mortality of retained trees can compromise the ecological objectives of variable-retention harvest. We used a large-scale experiment replicated at six locations in western Washington and Oregon to examine the influences of retention level (40% vs. 15% of original basal area) and its spatial pattern (aggregated vs.dispersed) on the rate and form of tree mortality for 11–12 years following harvest. Cumulative mortality of conifers was greater at lower levels of retention and in dispersed treatments—a result common to most seral groups and canopy strata. The greatest losses, averaging 18% of...

Ongoing forest restoration on public lands in the western US is a concerted effort to counter the growing incidence of uncharacteristic wildfire in fire-adapted ecosystems. Restoration projects cover 725,000 ha annually, and include thinning and underburning to remove ladder and surface fuel, and seeding of fire-adapted native grasses and shrubs. The backlog of areas in need of restoration combined with limited budgets requires that projects are implemented according to a prioritization system. The current system uses a stand-scale metric that measures ecological departure from pre-settleme...

Blow-up fire behaviour can be broadly defined as a rapid escalation in the intensity or forward rate of spread of a wildland fire, and is often accompanied by extreme pyro-convection associated with rapid smoke release and dispersion. Blow-up fire behaviour is difficult to predict and has been linked to firefighter fatalities, making it an important fire management hazard. Byram (1954) compiled the first observational dataset of categorised wind speed and direction profiles associated with blow-up fire behaviour. Low-level jets, varying in height between 30 and 1000 m above ground level...

Bamboo is a potential major bio-energy resource. Tests were carried out to compare and evaluate the property of bamboo and rice straw pellets, rice straw being the other main source of biomass solid fuel in China. All physical properties of untreated bamboo pellets (UBP), untreated rice straw pellets (URP), carbonized bamboo pellets (CBP), and carbonized rice straw pellets (CRP) met the requirements of Pellet Fuels Institute Standard Specification for Residential/Commercial Densified including dimension, density, and strength. The inorganic ash (15.94 %) and gross heat value (15375 J/g) of...

Wood decay fungi are obligate aerobes, deriving nutrients from the biological ‘combustion’ of wood, using molecular oxygen as terminal electron acceptor (Kirk and Farrell 1987; Blanchette 1991). Non-specific extracellular enzymes are generally viewed as key components in lignin depolymerization. The major enzymes implicated in lignin degradation are lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase. All three can act with low molecular weight mediators to bring about oxidation of lignin and various xenobiotics (Cullen 2002).

In forested ecosystems timber harvesting has the potential to emulate natural disturbances, thereby maintaining the natural communities adapted to particular disturbances. We compared the effects of even-aged (clearcut and patch cut) and uneven-aged (group cut, single-tree selection) timber management techniques with natural ice-storm damage and unmanipulated reference forest sites on red-backed salamanders. We used cover boards and litter searches to survey for salamanders in northern hardwood forests in New Hampshire, USA. We estimated abundance while accounting for detection probability...