More than 25 firefighters tackled the blaze in Wimblebury Road and worked for more than three hours to bring the flames under control.
Three warehouse buildings were gutted in the fire last night. It came as rangers on Cannock Chase were left clearing away damage left by grass fires which broke out 24 hours earlier, destroying 160,000 sq ft of shrubland.
Steve Barratt, aged 37, lives just metres from the sawmill and raised the alarm when he saw plumes of black smoke at around 6pm.
"I used to work up there on a Saturday afternoon – I remember putting up all the fencing and doing some of the painting down there when I was around 13 or 14," said the father of two, from Sycamore Road, who now works as a lorry driver. "It's pretty sad to see it all destroyed."
Station manager for the Cannock Chase district, Jim Bywater, said: "It's difficult to say what started the fire at this point but we believe it to be deliberate." Police are investigating.
On Cannock Chase, firefighters battled for more than nine hours to bring two fires under control on Monday. Both are believed to have been started deliberately. It was the biggest blaze at the site since 2010. Rangers are making regular checks to make sure the areas don't re-ignite.
Ranger Scott Dace said: "It is just devastating to see the area damaged again and it is almost certainly arsonists. It is just such a waste."