When compiling the Algonquin Backcountry LNT booklet, the commentary was developed that "Under no circumstances should any live vegetation, or dead branches from live trees, be used for firewood. Ideally the gathering of firewood should be limited to fallen branches and twigs from the forest floor." That was based on the regulated prohibition against the cutting of any live growth .. along with the sensibilities of not damaging living trees by possibly encouraging disease to spread into 'good wood' and not degrading the natural visual environment around established campsites.
While leaving standing dead wood to serve as part of the natural habitat of insects and birds is particularly commendable around established campsites, it appears that the park recognizes that 'ground litter firewood' will be inaccessibly covered by snow during the winter. Accordingly, the park allows the cutting of standing deadwood during the winter. This shouldn't negatively impact established campsites because winter camping is not allowed at established campsites.
Reg. 347/07, s. 21 (2).
From April 1 to Thanksgiving, no person shall possess a chain saw, power saw, power ice auger, gasoline generator or similar device in an area operated for interior camping in Algonquin Provincial Park.
http://www.ontario.ca/laws/regulation/070347