Cedar burns with an aromatic glow, but doesn't burn for long.
In-game description

Cedar firewood is a material in The Long Dark.

It is a fuel source for a fire and increases the probability of lighting a fire by 15%.

Cedar firewood has an estimated fire duration of 1 hour. With 120 min/kg it has a better burning time per weight than fir firewood, which gives 90 min/kg.

Cedar firewood can be harvested from cedar tree limbs, using a hatchet or hacksaw. A small limb will give 3 pieces of firewood, while a large limb gives 5. Cedar firewood can also be found inside some building, such as fishing huts as loot.

Fire Starting
Starters Cardboard matchesFirestrikerMagnifying lensWood matches
Tinder Birch barkCat tail headTinder plugCashNewsprintNewsprint rollStack of papers
Fuel BookCedar firewoodCoalFir firewoodFirelogReclaimed woodStick
Accelerant AccelerantLantern fuel
Hides Black bearDeerMooseRabbitWolf
Other Crow featherCured leatherGut
Medicinal Old man's beard lichenRose hipReishi mushroom
Sapling Birch saplingMaple sapling
Wood Reclaimed woodStick
Miscellaneous Arrow shaftArrowheadClothScrap metal