GROUND FLORA DIVERSITY UNDER MAN-MADE FORESTS OF DIFFERENT SPACINGS IN STRESS SITE

摘要

Plantation ecosystem, partiularly in stress site, provides unique condition and changing environment. The modified environment gives ever-changing pattern of competition. Invasion of newer and more aggressive species also takes place all the time. Competition leads to elimination of weaker elements on the one hand and increases in population of better adjusted ones on the other hand. The present investigation deals with the assessment of floral diversity in open stress sites and under plantation of Dalbergia sissoo and to identify new introductions and elimination of species in plantations of different spacing.A comparison of ground flora species occurring in 2mx2m and 4mx4m plantation of Dalbergia sissoo and open land revealed that all together 32 species were eliminated in 2mx2m spacing and 11 species were eliminated in 4mx4m spacing with reference to the open land. The new introduction included 8 species in 2mx2m spacing and 22 in 4mx4m spacing. The highest number of new introduction in 2mx2m spacing consisted of 2 species each in Poaceae and Amranthaceae families and one each in Euphorbiaceae, Convolvulaceae, Solanaceae and Malvaceae family. It was important to note that 7,11 and 12 species in 2mx2m, 4mx4m and open land respectively were of medicinal value.Elimination of species was found maximum in Poaceae (4) followed by Papilionaceae (3), Convolvulaceae (2), Cesalpiniaceae (2), Nyctaginaceae (1), Cyperaceae (1) and Malvaceae (1). With respect to new introduction, 5 species were introduced in Poaceae family followed by one each in Convolvulaceae, Euphorbiaceae, Sterculiaceae and Papilionaceae.