Geology topics

J.M. Benedict

Publications and source records attributed to J.M. Benedict.

5 recordsLinked to original sources

USGS2018

Travel time variation on backcountry trails

Numerous interrelated factors influence the travel times of hikers and riders on backcountry trails. This study sought to quantify those factors which were thought to be most important in affecting trail speeds. The travel times of 897 backpacking parties, 634 day hiking parties, and 111 riding parties were obtained from gentle (0.75%), moderate (5.0%), and steep (12.5%) trail segments one mile in length. The significance of party size, direction of travel, and slope class were tested for each type of party. It took an average of 34.8 minutes for backpacking parties, 36.4 minutes for day hiking parties, and 27.3 minutes for horse parties to travel all of the sample trail segments. Party size was not significant for all three types of parties, and slope-direction class was significant for only backpacking parties. For these parties, average times for uphill travel were greater than downhill travel and time increased as the slope increased. Regression equations were developed for backpacker travel times as a function of direction of travel and slope. The application of these data are discussed in relation to a wilderness use simulation model developed by the Forest Service and Resources for the Future.

Journal of Leisure Research↗

USGS1998

Heat content variation of Sierra Nevada conifers

A study of fuels of Siena Nevada conifer species showed that percent ash content, heat content with ash, and heat content without ash of needle and duff fuels significantly varied by species, fuel component, and developmental stage of the overstory. Ash and heat contents of woody fuels varied by species and fuel component but not by developmental stage. Bark fuels significantly differed by species, while no factor significantly affected cone fuels. Regional variation in ash and heat content was evident but small. However, the values reported here for heat content with ash for fine fuels averaged 2.50 MJ kg -1 higher than the standard values used in fire behavior prediction systems. Using standard values can result in significant under predictions of fireline intensity of an average of 16 percent for all species of up to 47 percent for Pinus albicaulis .

International Journal of Wildland Fire↗

USGS1998

Fuel bed characteristics of Sierra Nevada conifers

A study of fuels in Sierra Nevada conifer forests showed that fuel bed depth and fuel bed weight significantly varied by tree species and developmental stage of the overstory. Specific values for depth and weight of woody, litter, and duff fuels are reported. There was a significant positive relationship between fuel bed depth and weight. Estimates of woody fuel weight using the planar intercept method were significantly related to sampled values. These relationships can be used to estimate fuel weights in the field.

California↗

USGS1996

Physical properties of woody fuel particles of Sierra Nevada conifers

A study of the physical properties of Sierra Nevada conifer fuel particles showed that average diameter, squared quadratic mean diameter, surface-area-to-volume ratio, and specific gravity varied significantly by species for all four timelag fuel diameter size classes. The nonhorizontal angle was not significantly affected by size class, and the developmental stage of the overstory did not affect any of the properties. These values are used to calculate fuel weight and predict fire behavior. Regional variation in physical properties can result in fuel weight estimates for the Sierra Nevada that differ from under 40.8 percent to over 8.3 percent from those calculated from Rocky Mountain values. These differences made small changes in predicted fire behavior.

International Journal of Wildland Fire↗

USGS1980

Wilderness permit compliance and validity

In Yosemite National Park, 92 percent of the parties using back country areas had permits. Parties without permits were smaller in size and stayed for shorter periods of time. For all parties with permits, 62 percent made changes to their trips. Parties changing their trips in both time and space accounted for 27 percent of the total, while 14 percent made temporal changes only, and 21 percent made spatial changes only. Use estimates can be adjusted by multiplying by 1 + C + Δ where C is the noncompliance factor and Δ is the change factor for compliers. While the combined effect of these factors on total visitor nights for the Yosemite backcountry was an overestimation of 12.5 percent, areas near trailheads received heavier use and outlying areas received lighter use than permits indicated.

Journal of Forestry↗