Treesearch

Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed fire, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface fire regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an information-theoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling...

The Lake Tahoe basin is in environmenal distress. The lake is still one of the world’s most transparent bodies of water, but its fabled clarity has declined by half since discovery of the high-mountain lake basin by explorers a century and a half ago. At that time, incredibly, objects could be observed on the lake’s bottom a hundred feet down. Two-thirds of the lake’s transparency has been lost in just the past 30 years. The forests that surround 200-square mile Lake Tahoe were ravaged more than a century ago to feed expanding mining efforts in adjacent Nevada. Stands of yellow pines, once...

Post-fire seeding is used to stabilize burned slopes by increasing plant cover, prevent invasion of burned areas by noxious weeds, replace weedy annual grasses on burned rangelands, and reestablish desirable vegetation including tree species. Fast-growing pasture grasses and forbs have been most widely applied for post-fire stabilization and rehabilitation, but use of native species is increasing. Successful ground cover enhancement with seeded species depends on protection of the seed from predators and desiccation, the amount and timing of growing-season rainfall, and resting the area...

Emergency rehabilitation to mitigate the effects of flooding, accelerated erosion, and sedimentation that inevitably follows wildfire has been practiced in California, USA for nearly a century. However, California is a physically and culturally diverse area, and rehabilitation measures that work in one part of the state may not be appropriate in other regions. Rehabilitation philosophy can vary with different land management or hazard protection agencies, and may often reflect socio-political considerations as much as the resources or values at risk. Initial rehabilitation efforts in...

Fuel reduction in the wildland–urban interface is a widely used international strategy for assisting human communities regarding wildfire threats, but very little research has examined whether certain fuel reduction methods and their seasonal timing promote nonnative invasion. To address this issue, we evaluated nonnative and native plant response to five of the most commonly-practiced shrubland fuel reduction methods in Mediterranean climates, including (a) fall prescribed fire, (b) winter prescribed fire, (c) spring prescribed fire, (d) fall mastication (slashing) and (e) spring masticati...

Non-market valuation methods and geographic information systems are useful planning and management tools for public land managers. Recent attention has been given to investigation and demonstration of methods for combining these tools to provide spatially-explicit representations of non-market value. Most of these efforts have focused on spatial allocation of ecosystem service values based on land cover types, but recreation value has yet to be considered. This article presents an objective method for spatially allocating forest recreation value that is based on readily available data,...

This research uses the Contingent Valuation Method to test whether willingness to pay increases for larger reductions in acres of forests burned by wildfires across the states of California. Florida and Montana. This is known as a test of scope, a measure of internal validity of the contingent valuation method (CVM). The scope test is conducted separately for White households and Hispanic households to determine if cultural differences influences whether the scope test is passed. The public program to reduce acres burned involved prescribed burning and a mechanical fuel reduction program....

We investigated mean residence time (MRT) for soil organic carbon (SOC) sampled from paired hardwood and pine forests located along a 22 °C mean annual temperature (MAT) gradient in North America. We used acid hydrolysis fractionation, radiocarbon analyses, long-term laboratory incubations (525-d), and a three-pool model to describe the size and kinetics of the acid insoluble C (AIC), active and slow SOC fractions in soil.

Depending on management, forests can be an important sink or source of carbon that if released as CO2 could contribute to global warming. Many forests in the western United States are being treated to reduce fuels, yet the effects of these treatments on forest carbon are not well understood. We compared the immediate effects of fuels treatments on carbon stocks and releases in replicated plots before and after treatment, and against a reconstruction of active-fire stand conditions for the same forest in 1865. Total live-tree carbon was substantially lower in modern fire-suppressed condition...

Restoring Sierra Nevada mixed-conifer forests after a century of fire suppression has become an important management priority as fuel reduction thinning has been mandated by the Healthy Forests Restoration Act. However, in mechanically thinned stands there is little information on the effects of different patterns and densities of live-tree retention on forest canopy microclimate. This study compared gradients of air temperature and vapor pressure deficit (VPD) through the vertical forest profile among an overstory-thin, an understory-thin, an un-thinned control, and a riparian environment...