It later came under the control of the Kannan Devan Hills Produce Corporation to be managed as a private hunting preserve, having proved to be unsuitable for plantation work. Hills generally rise up to 500m above the plateau. Mean annual rainfall is 4050mm, three quarters of which falls during the monsoon months of June, July and August. Strong westerly winds up to gale force are common during this period. The north-east monsoon lasts from September to December during which rainfall is greatly reduced, with a monthly mean of 250mm, and winds are moderate to variable.
Mists commonly shroud the hills during the monsoons.
The principal vegetation types are grassland, shrubland and forest. Terrain over 2,000m is covered mainly by grassland as is characteristic of the Western Ghats. Numerous small patches of forests, known locally as sholas, occur in hollows and gullies. Predominant species include Eulalia phaeothrix , Ischaemum indicum , Arundinella fuscata , Tripogon bromoides , Tripogon ananthaswamianus and Sehima nervosum . There is thick cover of the shrub Strobilanthes kunthianus in some areas.