ADVANCED MULTIVARIATE TECHNIQUES TO INVESTIGATE VEGETATION-ENVIRONMENTAL COMPLEX OF PINE FORESTS OF MOIST TEMPERATE AREAS OF PAKISTAN

Forty one stands of conifer forests of moist temperate areas, covering the natural limits of this forest type, in northern Pakistan were investigated. Multivariate techniques including cluster analysis (Ward's agglomerative method and TWINSPAN a divisive method) as well as ordination (DECORANA) were used to explore vegetation composition and structure of canopy trees and understorey (shrubs and herbs) vegetation and their relationship with the associated environmental factors. Classification of overstorey trees derived by TWINSPAN and Ward's methods showed some similarities in groups. Among the topographic variables, only elevation was found to be significant (P < 0.01) while edaphic variables showed no significant difference in group means. For understorey vegetation some similarities were also recorded between TWINSPAN and Ward's method. Among environmental variables elevation (P < 0.001), aspect (P < 0.05), canopy cover (P < 0.001) and soil pH (P < 0.01) were found to be significant. In many cases relationship of axes in DCA stand ordination and environmental variables were also significantly correlated, however axis two of understorey ordination did not show any significant correlation with any environmental variables. Present study showed similarities between Ward's cluster analysis of tree vegetation and understorey vegetation data, despite a long history of anthropogenic disturbance in these areas.