A forensic anthropologist has been helping police since the remains were found at Pentrellyncymer near Cerrigydrudion in November.
His body is believed to have been in the forest for several years.
Police said the man is believed to be aged over 54 and between 5ft 8in (172cm) and 5ft 10in (177cm) tall.
Further forensic tests by experts continue to enable police to establish the circumstances of the death, said Det Supt John Hanson, of North Wales Police, the senior investigating officer.
Mr Hanson said: "The meticulous examination and recovery phase of this operation at the scene at Pentrellyncymer is now complete and the forensic anthropologist continues to examine all the remains.
"The, as yet unidentified, man sustained serious head trauma and whilst the circumstances of his death are unknown at this time the injuries indicate the death is suspicious so detectives will continue to work alongside forensic experts to establish the man's identity and circumstances and cause of his death.
"I am conscious at this stage the description of the man is very limited, and initial indications suggest his remains have been in the forest at Pentrellyncymer for several years.
"However I would still ask if anyone in the community can help me identify this man and offer any information which would progress this investigation to please contact North Wales Police."

Police have just released pictures of the stolen items in an attempt to trace them.
The jewellery was stolen from Stanley Hunt Jewellers in Marshalls Yard, Gainsborough, on 18 November, between about 19:30 and 20:00.
The Lincolnshire force is asking anyone who is offered one of the items to get in touch.
One person was arrested and is currently on police bail.
Police also want to hear from people who may have been in the shop at the time.
More on this and other local stories from across Lincolnshire

Hasbro, the maker of My Little Pony, approached Mattel about a deal late last year, according to Bloomberg news.
The combination of the two toy-makers would produce a company with a $20bn market capitalization as of Wednesday.
In 1996, Mattel made a $5.2bn (Â£3.5bn) offer to buy Hasbro, but the two sides failed to reach a final agreement.
Over the last few years, Mattel has lost market share to Hasbro and Denmark's Lego. Lego overtook Mattel as the world's largest toy-marker in 2014.
In its most recent quarter, Mattel reported a 4% drop in worldwide sales and expects sales to decline this year.
That is partly because Hasbro has taken over the contract to produce toys based on the Disney movie Frozen, and toys sold under the Princess brand.
Mattel estimated in 2014 that the Princess brand brought in $300m.
In an effort to boost sales of its Barbie line, Mattel introduced three new body types and seven new skin tones in January. Sales of Barbie dolls fell 10% globally in 2015.
Neither company has commented on the rumoured deal.
Hasbro's share price rose 1.5%. In afternoon trading, Mattel shares fell back and were trading up 1.6% on the day.
Hasbro reports its full-year earnings report on 8 February.
Tests on the remains of a man found in a Conwy county forestry have shown he suffered serious head trauma and died in suspicious circumstances.
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Jewellery worth £35,000 was stolen from a shop during a Christmas lights switch-on event in Lincolnshire.
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Shares in Mattel, the maker of Barbie dolls, jumped 8% on Thursday following a report it had discussed a merger with rival Hasbro.