Brooding and primeval, the forests of Udzungwa seem positively enchanted:
a verdant refuge of sunshine-dappled glades enclosed by 30-metre high trees, their buttresses layered with fungi, lichens, mosses and ferns.
Udzungwa is the largest and most biodiverse of a chain of a dozen large forest-swathed mountains that rise majestically from the flat coastal scrub of eastern Tanzania. Known collectively as the Eastern Arc Mountains, this archipelago of isolated massifs has also been dubbed the African Galapagos for its treasure-trove of endemic plants and animals, most familiarly the delicate African violet.
Udzungwa alone among the ancient ranges of the Eastern Arc has been accorded national park status. It is also unique within Tanzania in that its closed-canopy forest spans altitudes of 250 metres to above 2,000 metres without interruption.
Not a conventional game viewing destination, Udzungwa is a magnet for hikers. An excellent network of forest trails includes the popular half-day ramble to Sanje Waterfall, which plunges 170 metres through a misty spray into the forested valley below.

Animals and Birds
Four bird species are peculiar to Udzungwa, including a forest partridge first discovered in 1991 and more closely related to an Asian genus than to any other African fowl.
Of six primate species recorded, the Iringa red colobus and Sanje Crested Mangabey both occur nowhere else in the world – the latter, remarkably, remained undetected by biologists prior to 1979.
Undoubtedly, this great forest has yet to reveal all its treasures: ongoing scientific exploration will surely add to its diverse catalogue of endemics.

What to do
.) two-hour hike to the waterfall to camping safaris
.) combine with nearby Mikumi or en route to Ruaha

Seasons
It is possible all the year round although it's very slippery in the rain season.
The dry season is from June to October before the short rains. But be prepared for rain anytime.