Forest types of BRT
Not many Tiger Reserves in the country can boast of a range of Forest Types like BRT Tiger Reserve. Located in the crucial link between Eastern and Western Ghat complex. The Tiger Reserve is a mosaic of landscapes within a landscape. From the semi-arid to the evergreen forests the range of forest types seem endless and hard to explain scientifically. Aggregation of species from Wet zones and co-existing with semi-arid ones in a same location is very mystifying indeed. What is a riddle to science is a pleasure to the senses.
The main forest types encountered in BRT are:
WOODLAND TO SAVANNA-WOODLAND
The savanna-woodland vegetation type covers a large part of the western flank and is also found in the shallow valleys along the mid-slope of the eastern side between 900M to 1350M. The woodlands are localised in humid pockets and form a mosaic with Savanna woodlands. Some common canopy species include Anogeisus latifolia, Dalbergia paniculata, Grewia teliafolia. Species in the second story include Buchanania lanzan, Kydia calycina, Schleichera oleosa and in the third strata includes Cassia fistula, Phyllanthus emblica. The under growth consists of shrubs, herbs and grasses especially in savanna woodland.
Tree savannas largely cover the steep eastern slopes and are also sparsely distributed in the northern and western part of the sanctuary between 800M and 1400M. At 800M to 1100M specially on steep slopes tree savannas are characterized by slope loning species such as Baswellia serrata, Commiphora caudate, Givotia rottleriformis, Gsyrocorpus asiatica, Sterculia urens, along with Anogeissus latifolia, Lagerstromia parviflora, Pterocarpus marsupium and Terminalia alata.
SCRUB WOODLAND TO THICKETS
These types occur along the periphery of the sanctuary between 700M to 900M and some times reach upto 1200M especially along eastern slopes and northern parts. Species include Acacia chundra, Diospyros melanoxylon, Diospyrous montana, Ixora pavetta, Limonia accidissima and Rhus mysorensis.
Evergreen forests are mostly confined to streams valleys, glens, hallows and depressions where the soil moisture is relatively high. The evergreen forests can be categorized into two types.RIPARIAN FORESTS
In the midst of deciduous forests, small pockets of evergreen forests occurring along perennial streams is termed “riparian forests”. The typical hygrophylous species are Elaeocarpus tuberculatus, Syzygium malabaricum, Vibernum punctatum. The presence of Cocculus launifolius and Syzygium malabaricum in BR Hills has phytogeographical significance. The former has been recorded only from NE Himalayas and other South Indian hills like Nilgiri and Anamalais, where as the latter is a rare species found in the southern western ghats.
ALTITUDINAL EVERGREEN FORESTS
In the western flank, this kind of forests is particularly distributed between between 1200 and 1400M depending upon the local soil moisture regime. Beyond 1400M, the evergreen forests show over all reduction in density. Physiognomically, they are stunted forests rarely higher than 15M, with short boled trees. The crowns are dense and the leaves are generally large. The branches are twisted and covered with mosses, lichens and other epiphytes. The floristic composition is dominated by members of the Lauraceae family. Schefflera capitata, Meliosma sps. Xantholis tomentosa and Symplocos sp. are characteristic species of these sholas.
SEMI EVER GREEN FORESTS
Semi ever green forests in the sanctuary are either formed due to degradation of original evergreen forests or as transitions to evergreen types. When these forests are disturbed, especially by fire, the openings generally get invaded by deciduous species. Aphanamixis polystachya, Canthium diccocum, Catunaregam torulosa, Meyna laxiflora.
Shrub savannas interspersed amidst sholas dominate the landscape at higher altitudes, particularly on the eastern and the central ridges of hill range. Common species include Artemisia perviflora, Cucurma neilgherrensis, Phoenix humilis and Hypericum mysorensis.