## 4 Discussion  
Vegetation is a group of plants growing together in a particular locality [43], and it may also be defined as a unit that retains its unique structure and physiognomic characteristics in an adequately great and sufficient way to permit their distinction from other units [46]. The understory plant species in the oak-dominated forests consist of 58 species belonging to 32 families at 30 different locations in the Hindukush ranges of Swat. The physiognomy of the studied area was dominated by herbaceous growth form with 47 plant species (81%), followed by shrubs with 10 plant species (17%), and trees with individual plant species (2%). Herbaceous dominancy and less tree percentage might be due to altitudinal and geographical variations, which indicates that the climatic factors favor the herbaceous flora. Our findings are associated with researchers in allied, neighboring, and national regions in which the species reported were mostly herbaceous [47, 48]. Among all families, Fabaceae was recorded as the leading family with eight plant species, followed by Asteraceae and Lamiaceae with seven species each. For instance, several researchers [5, 32, 33, 34, 38, 46], for instance [31], have documented Asteraceae and Fabaceae as the two most important families. While other researchers [38] cited Lamiaceae and Rosaceae, and [48] cited Lamiaceae, Moraceae, and Asteraceae, as dominant plant families from Darra Adam Khel, KP, Pakistan. Figure 5: RDA ordination of physiographic and graphic variables concerning stands and the understory vegetation. **Note:** Blue square represent the species point in the ordination biplot; St (Stand number). Plant life-forms and vegetation are indicators of the climate [6]. According to [PERSON] [49], life-forms are reflective of the bioclimates of an area. [PERSON] [6] designed three major phytoclimates based on life-form spectra on the earth. It includes planerophytic climate for the tropics, therophytic for the xeric environments, and hemicrypophytic for the cold temperate region. The present study identified seven different life-form classes in the study area. The most dominant life-form was hemicryptophytes with 19 species (33%), followed by nanophanerophytes with 15 species (26%) and therophytes with 13 species (22%). Hemicryptophytes usually prevail in open physiognomies, while planerophytes are mainly in closed ones [50; 51]. Biological spectra are important in comparing geography and habitats and might change due to biotic influences, viz., grazing, human activities, and climatic changes [52; 53; 54]. Hemicryptophytes lose their aboveground parts during most summer and winter months while therophytes remain seeded to avoid summer, drought, and cold winter stresses. Furthermore, the flora of the study area is under anthropogenic pressure in the form of overgrazing and deforestation by nomadic and native people. [PERSON] and [PERSON] [55] reported a similar finding from District Chakwal, where therophytes were the dominant biological spectra. A community that therophytes dominate can be a characteristic feature of a highly disturbed area under anthropogenic pressure [48; 54]. In addition, [56] reported therophytes as the dominant plant species of the rangeland, district Tank, Pakistan, and [57] assessed that therophytes is the leading life-form of Lahor, District Swabi, Pakistan, showing that the results of the current study are in compliance with the findings of several other studies. Results of leaf size spectra trait revealed that species with microphyllous leaves dominated the area (with 24 species, 41%), followed by nanophylls (17 species, 29%), leptophylls (11 species, 19%), and mesophyll (5 species, 9%). Nonetheless, 2% with meagophyllous leaf size was also recorded. Microphyllous leaf size class is normally the characteristic feature of meadow plant species, while leptophylls and nanophylls are illustrative of hot deserts [7; 54].