Vegetation and Range Condition Classification, Using Frequency Data

Frequency data in 12 range sites from 3 vegetatign types were used to determine vegetation and range
condition classes. U.S. Forest Service method Was employed for condition classification of the same
sites. Results of this method were considered as control for evaluating the results of frequency method.
To determine vegetation and range condition, percent composition ineach species was calculated from
frequency data. Species were divided into 3 groups of desirable, intermediate and least desirable, and
percent compositions in each group were calculated. Using SPSS 'software, 2 regression models were
constructed. First model with 2 independent variables included percent compositions of desirable and
intermediate range species. In this model, dependent variable was vegetation condition score. The
other model with 3 independent variables included two groups of species percent compositions as
previous model plus soil scores as the third variable. Dependent variable in this modelwas therefore
range condition score. Vegetation and range condition classification of the 12 range sites resulted from
first and second models had 91% and 100%accllfacy respectively, when compared with the results
obtained from U.S. Forest Service method. Qmidrat size (1* l m) proved to be the most appropriate size
for frequency data collection on studied range sites. Frequency datainthese sites were used to create a
condition classification guide. Entering percent composition of desirable and intermediate species in
vertical and horizontal axes of this guide respectively, class of vegetation condition for a given range
site will be determined.