A user's guide for estimating allowable use of tracked vehicles on nonwooded military training lands

Abstract

ABSTRACT: To avoid excessive soil erosion and insure the continued availability of US. military training lands, there must be a bask for estimating allowable levels of sustained tracked vehicle use. The allowable use management objective can be attained by establishing permanent line transects in areas representative of each ecological response unit. The point-intercept method is employed along each line transect to determine botanical composition, amounts of ground and campy cover for untracked and tracked points, and percent of the surface tracked and untracked. Soil samples are collected to determine soil erodibility. Slope lengths and gradients are measured. For each vehicle type, estimates are made of the average cross-country distance traveled per day (surface wverage is computed by adding the width of the tracks timas distance traveled). Estimates are made of the average number of years for tracked areas to regrow vegetation cover equivalent in C-valuefor the universal soil loss equation to untracked areas and the average number of years that a track mark remains visible. With this information and using the USLE, maximum allowable use can be estimated for each ecological response unit. Allowable use is calculated in tracked vehicle days per year (TVD8/year) for militay trainers and percent surface disturbance for land managers. Land managers verify that allowable use is not exceeded by measuring the percentage of the surface that appears tracked. Adjustments in allowable use are based on trends in the amount of ground cover (detected by short-term monitoring) and by observing changes in botanical composition (detected by long-term monitoring).