The terrain in that area is very steep and there are many old shafts covered by thick undergrowth, thats what worries me most.
The last time i was in the area, up around Barry's Reef, i was surprised at how much i really needed to take care in watching my forward path and step. Some of these shafts are virtually invisible due to the thick growth and you wouldnt even know they were even there unless you were watching closely, or new how to spot the tell tales.
There are some deep boggy track crossing close to the Lerderberg river as well, so lets hope he just got stuck and stays with his vehicle because that is what they will find first.
The Wombat State forest is quite a vast area and one of the largest state forests in Vic.
Its rather concerning so lets hope he is ok and found safe and well.
Regards