Update on burning that punky wood: I tried to burn a stack of that punky wood today. I doused it with diesel/gas mixture and let it soak in for a while. Then about half an hour later, I lit the fire. Unfortunately, the wood did not burn good at all.
It only slowly smoldered with no real flames to speak of. No way am I going to waste all my time and effort trying to burn that rotted wood. I thought my stack of wood on top of the stump would burn out in maybe half an hour, but after 3 hours not much was burned and I had to leave it for the night.
I'll check tomorrow to see if it finished burning down to the stump. But it sure would take a long time to burn the rest of the tree that way. My new plan is to load up that punky wood and toss it in a big wood pile I have in the tall grass and let nature break it down over years.
Instead of burning out the stump, I might have to chop it up with an axe and use a shovel and/or landscaping bar to remove the stump. The stump is all rotted, so it should be easier to chop out than a normal stump from a healthy tree.

FWIW, I did a little research online to find out why the punky wood would not burn - only smolder slowly in the fire ring. I don't normally burn rotted wood, so I had no idea why it was only smoldering. Keep in mind our humidity level this past week has been over 75%, very high. Here is the response I got...
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That smoldering, low-flame behavior is
very typical of rotted wood, and it’s rooted in both
moisture content and
structural degradation. Birch, especially when punky or decayed, becomes a sponge for ambient moisture—even if it feels light or dry to the touch.
Why Rotted Wood Smolders Instead of Burns
1. High Moisture Content
- Rotted wood often holds 50–70% moisture, even if it feels dry on the surface.
- Fungi and bacteria break down the wood’s structure, leaving behind a spongy matrix that traps water.
- When burned, most of the energy goes into evaporating moisture, not producing heat.
2. Low Density = Low BTU Output
- As decay progresses, the wood loses its lignin and cellulose, which are the fuel-rich components.
- Less density means fewer British Thermal Units (BTUs)—so even if it ignites, it won’t sustain a flame.
3. Poor Combustion = Smoke and Creosote
- Incomplete combustion leads to smoke, smoldering, and creosote buildup in your chimney or flue.
- This not only reduces heat output but can also pose a fire hazard over time.
4. Health Risks
- Burning rotted wood can release fungal spores, mildew, and bacteria into the air, which may irritate your respiratory system.
- It’s especially risky indoors or for people with asthma or allergies.
What You Can Do
- Use it as kindling only if it’s dry enough and mixed with solid hardwood.
- Avoid burning it indoors, especially in stoves or fireplaces.
- Check with a moisture meter—ideal firewood should be below 20% moisture.
- If you’re burning outdoors, make sure there’s good airflow and dry fuel to support combustion.
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