Studies on the effect of forest and agricultural land uses and fire on tree flora conservation in and around Tain 11 forest reserve

Effect of forest and agricultural landuses and fire on tree floral conservation was studied in Tain II forest reserves in the Brong Ahafo Region of Ghana. The general objective was to examine the influences of forest and agricultural landuses and fire on flora and their implications on floral conservation. Six landuse categories were selected in and around the reserve, namely Taungya (Agroforestry) farm, Maize/Cassava farm, Natural forest, Cocoa farm, Teak plantation and Yam farm. These selected land use categories were placed under two major study zones (fire prone and less fire prone). Eighteen (18) plots of size 30metre x 30metre were randomly laid within each zone, making a total of thirty six (36) plots in all. Data on tree heights, diameter and numbers were collected on trees that had diameters 5cm and above dbh. Tree seedlings were also enumerated and data was analyzed for comparison. In terms of tree population density, with respect to trees of diameter 5cm to 35cm, taungya farm had the highest number of trees per ha (459.26/ha) and maize farm recorded the least population (29.63/ha) (P =0.001). Similar result was obtained from the diameter class of 36cm to 66cm where teak plantation recorded the highest tree density. However, the high population densities in Taungya and Teak plantations compared to natural forest for the diameter-size class of 5-35cm and 36-66cm did not correspond to the diameter-size class at 67cm and above dbh. The natural forest had the higher density of trees per ha (88.89) at this diameter class (67 and above dbh) (P = 0.009). It is therefore important to note that, low tree population density recorded by maize/cassava farm in the study area, could be as a result of logging and conversion of forest to farmland. In case of tree species richness and tree diversity cocoa farm and natural forest had the highest results of 30.40 and 2.28 respectively in the less fire prone zone whiles teak plantation recorded the lowest value of 6.82 and 0.39 in the less fire and fire prone zone respectively. The lowest tree species richness recorded by teak plantation could be attributed to the practice of growing teak as monoculture plantation. Natural forest exhibited highest basal area of trees (222.33), whiles maize/cassava farm recorded the lowest basal area (BA) of 2.92. The higher basal area of the natural forest per ha confirmed the fact that natural forest had a greater number of larger trees as result of less farming activities as the reserve is being regulated by the Forestry Commission. There were no significant effects of tree density between fire prone and less fire vi prone zones as far as fire regime is concerned. However, tree species richness, tree diversity and tree basal area were significantly different between fire prone and less fire prone zones suggesting that fire can cause deforestation and deterioration of ecological systems. Natural forest again had the highest relative abundance of scarlet star and pink star rated species whiles teak plantation had the lowest. This least figure recorded in teak plantation partly implies that these star rated species were heavily exploited in the past by legal and illegal logging. The interaction between landuses and the fire regimes showed significant similarities. Finally the land use categories and wild fires in Tain II forest reserve has not only transformed the physical landscape but also impacted negatively on the biological community of trees in the area. The impact of landuse, particularly maize and cassava farm had been very severe on tree resources thereby reducing significantly tree population density. And in the fire prone zone there is preponderant occurrence and vigorous growth of savanna grasses as well as many noxious farm weeds. The most relative abundant trees encountered during the study include Tectona grandis (Teak), this obviously for the teak plantation area, Blighia sapida (Akye), Sterculia tragacantha (Osofo), Spathodea campanulata (Kokonisue), Anogeissus leiocarpus (Kane), Holorrhena floribunda (Sese), Lonchoocarpus sericeus (Sante) and Ficus exasperate (Nyankyerene).

Source: KNUST