Firewood in Southern Oregon: Madrone, Oak, Fir or Pine, and What It Does to Your Chimney

What a Cord of Each Local Wood Gives You

These are the only per-cord figures we could read in a source from this state. They come from OSU Extension publication EC 1628, which says they are "approximate values" for a cord taken as 85 cubic feet of solid wood at 20 percent moisture. Other sources assume different amounts of solid wood in a cord, which is why published tables disagree. The Forest Service's own Northwest fuelwood report gives ponderosa pine at 22.1 million BTU per cord on a 90 cubic foot basis, against 17 million here.

We did not find figures we could read for California black oak, incense-cedar, white fir or bigleaf maple on a per-cord basis, so none are given. The reason for the gap between species is density, not chemistry. The Forest Service report says heating value per oven-dry pound is nearly the same across species, "9,000 Btu/OD lb ± 10 percent," and that "the higher the density... the more Btus per cubic foot of wood are available." EC 1628 draws the practical conclusion: denser hardwoods give longer burning fires and the most heat per unit of volume, while softwoods burn faster. It also notes that well-seasoned oak and madrone are cost-competitive with alternative fuels, as are larch and Douglas-fir.

Moisture Beats Species for Creosote

Creosote forms when smoke cools and condenses inside the flue. CSIA lists the conditions that speed it: "Restricted air supply, unseasoned wood and, cooler than normal chimney temperatures," and explains that burning unseasoned wood keeps the smoke cooler because so much energy goes into driving off the water in the logs. OSU's older burn-dry bulletin says the smoke from a low-temperature fire contains gases and acids that condense in the chimney, and that green firewood, which is more than 50 percent moisture, means more frequent cleaning. EC 1628 adds that drier wood produces less creosote and that a chimney should be cleaned at least once a year.

Sources do not agree on whether the species itself matters. Penn State Extension says conifers like pine and fir should be limited because their secondary compounds can coat a chimney with tar, soot and creosote, and Utah State says conifers spark and pop more because of their resin. None of the sources we read is a controlled test of creosote by species, and we found no creosote study of Southern Oregon woods at all. Our advice is the part every source shares: dry wood, a hot clean fire and a yearly inspection. If you burn fir or pine, the most we can say is to expect more sparks and to keep an eye on the flue.

How Dry Is Dry Enough

EPA's Burn Wise guidance, now an archived program page, says to "season wood for at least six months," stored outdoors off the ground with only the top covered, and that wood "burns best at a moisture content of less than 20 percent." It recommends testing with a moisture meter. EPA's brochure on wet wood gives about six months for softwoods and about 12 months for hardwoods, which puts oak and madrone at the long end. OSU's EC 1628 says air-dried wood protected from rain should settle below 25 percent in western Oregon after a dry summer of stacking, and that "seasoning over two summers is even better." OSU's older bulletin warns not to count on Oregon's cool, humid fall to dry firewood.

Buying Firewood in Oregon

The Oregon Department of Agriculture's method-of-sale rule says firewood is to be advertised and sold only by the cord, a fraction of a cord, or the cubic meter (with separate rules for packaged wood, manufactured logs and pellets), and defines a cord as wood in a space of 128 cubic feet, ranked and well stowed. It bars "face cord," "rack," "pile," "truckload" and similar terms. For wood that is not packaged, the buyer must be given a delivery ticket or sales invoice showing the vendor and purchaser names and addresses, the date delivered, the quantity, the price, and a description of the wood, including any quality claim made in the sale.

The ODA document is dated 2009, so confirm with the Department of Agriculture if a dispute turns on its exact wording. That is why the OSU table above counts a smaller volume: a cord is 128 cubic feet of stack, and OSU says a tightly stacked cord holds about 80 to 85 cubic feet of solid wood.

Moving Firewood: What Oregon Law Says

• ORS 570.720 bars transporting firewood into or within Oregon, or selling it here, unless it was harvested in Oregon, Idaho or Washington or has been treated as the Department of Agriculture prescribes.
• OAR 603-052-1080 exempts people who cut and burn their own firewood in Oregon from the documentation, treatment and labeling rules, and says firewood harvested and sold within the Pacific Northwest does not need to be treated or labeled. Firewood from outside the region must be heat treated, and the rule says air drying is not enough.
• Sudden oak death is under quarantine in part of Curry County, west of the Rogue Valley. Under OAR 603-052-1230, tanoak logs and firewood harvested inside the "generally-infested area" may not be moved outside the quarantine area. The Oregon Department of Forestry reported in its December 31, 2025 update that the quarantine boundary had been expanded, so check the Department of Agriculture's current boundary before moving tanoak firewood.
• EPA's advice is to buy and burn locally cut firewood to reduce the risk of spreading forest pests.

What Never to Burn

DEQ's rule OAR 340-262-0900 bars burning garbage, treated wood, plastic, rubber, animal carcasses, asphalt products, waste petroleum, paint, chemicals, products containing lead, mercury or other heavy metals, asbestos materials and particleboard in a wood stove or fireplace. Paper may be used to kindle a fire.

What This Means for Cleaning

No local study tells us how fast creosote builds from madrone versus fir, so base the schedule on the flue, not the species. CSIA's rule is to sweep a masonry fireplace at 1/8 inch of sooty buildup, sooner if there is any glaze. A $99 inspection in Southern Oregon shows how much has built up and what kind it is, before you have to guess. Burn dry wood and keep the stove hot, and the schedule gets longer.

What We Could Not Confirm

• The state rules above were read on a public mirror of the Oregon Revised Statutes and Administrative Rules, not the Legislature's or Secretary of State's own pages, which did not load for us. Check the official text before relying on a penalty or a deadline.
• Jackson and Josephine County rules on open burning and firewood. Those county sites block our machine. For burn days, see our burn day guide.
• Per-cord heat values for California black oak, incense-cedar and bigleaf maple.

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