Abstract

Successful management of natural forests depends on good natural regeneration of valuable species. The present investigation was conducted in the Kerala part of Western Ghats from Northern to Southern Forest Circles representing all the Ranges belonging to each Forest Division. The study envisaged to assess demographic details of Terminalia crenulata, T. paniculata, T. travnacorensis and their regeneration status in natural populations. T. crenulata and T. paniculata are mainly confined to moist deciduous forests. T. travacorensis, a large tree endemic to the Western Ghats, occurs in lowlevel evergreen forests of Kerala. These species are important components of our natural forest ecosystems. A total of 218 plots were enumerated (51.7 ha) throughout Kerala. Seeds of T. crenulata, T. paniculata and T. travancorensis were subjected to viability test and presowing treatments to enhance germination under laboratory condition. A trial for vegetative propagation of the species was also carried out. Trees of T. paniculata were observed in 168 plots, T. crenulata in 101 plots and T. travancorensis in 5 plots with a density (trees ha1) of 67.14, 19.01 and 0.46. Frequency, basal area and importance value index (IVI) of the species were 0.78, 0.47, 0.02; 497.1 m2, 179.9 m2, 13.1 m2; 54.118, 19.031, 0.996 respectively. About 250 species were enumerated from the study sites and X. xylocarpa was the major associate species with a density, frequency, basal area and IVI of 28.94, 0.43, 158.6 m2, and 21.001, respectively. Overall species richnes (R=26.93) and diversity (H=3.71) of the study sites showed a high value. Generally, density of T. paniculata was higher than that for T. crenulata with a significant difference between Forest Circles (P=0.01 for T. paniculata and P=0.05 for T. crenulata).

The study indicated that T. paniculata is more or less stable compared to T. crenulata. However, occurrence of T. travancorensis is limited to the few localities in Kerala.

Regeneration enumeration was carried out from all the temprory plots established in each Forest Division. Generally, regeneration of T. paniculata was more when compared to T. crenulata. Regeneration in the study sites had a density of 73.58 for T. paniculata, 18.47 for T. crenulata and 0.019 for T. travancorensis. Of the total regeneration of T. paniculata, 46% comprised unestablished seedlings (<3 cm collar girth), 24% established saplings (39.9 cm Gbh) and 30% advanced (poles) category (1030 cm Gbh). Fiftysix per cent of the regeneration of T. crenulata comprised seedlings, 26% saplings and 18% poles. However, the regeneration of T. travancorensis was negligible, i.e., only a single pole of T. travancorensis was found from the study sites. Regeneration of T. paniculata and T. crenulata between Forest Divisions was significantly different (P=0.01). However, it was not in par with mature trees. The study revealed that germination of T. paniculata was very low due to infertility and heavy pest infestation. With respect to T. travancorensis, weathering treatment of seeds was needed to get a better germination. Juvenile shoots from the established seedlings responded to rooting hormones. Optimum combination for better rooting was IBA+Kinetin at 6000 ppm.