Planting trees for fuel

I would like to plant some trees with the intention of harvesting for woodgas. Two years ago the wife and I planted 50 trees on the property along the road. They were doug firs and Cedars. Last year we planted Pear, Apple, cherry, Maple and Aspens along the driveway. (I know that doesn’t hold a candle to what Steve U plants in a year)
We have 400’ of creek/border property and we’d like to plant the fastest growing “burner” trees.
Any idea what would be a good choice for the northwet? Poplar seems popular for pulp but I don’t know how well they’d be for woodgas.
Thanks for any ideas!
BBB, Tim J

Hi Tim,

Excellent topic, deserves it’s own thread. Here’s an article I found in MEN when researching the How Much Wood blogpost. On a weight basis, they claim to produce 36 dry tons per acre every 4 years. At 9 tons/acre annually, a 3 acre woodlot could keep 5 drivers supplied with fuel.

I figure if all 33 million acres of ethanol-devoted farmland in this country were planted in “farm trees”, it could fuel up to 55 million drivers, versus the 16 million it does now.

Chris: That sort of freaked me out for a bit there. I was thinking ‘WHERE DOES THIS GUY LIVE?!’
" Purchased Oak 25 cords $1,875 ($75 each)"
It was then that I noticed the article was written in 1980.
Around here, the cheapest green cord of mixed Maple/Fir/Alder is about 140$ and seasoned runs about 225$/cord. One might find a cord of green cottonwood for 90$.

Hi there,

in Germany they use mostly poplar (same as cottonwood?) and willow (same as osier?) for biomass wood production. They plant them in rows and usually harvest every 4 years with a slightly modified forage harvester or a rear-end mounted disk chopper on a tractor.

Best regards,


Chris, thanks for giving this topic it’s own thread! Brian is right about the price of wood around here. We have trees everywhere and the cost of “processed” firewood is pretty steep, just goes to show how lazy people can drive a market!
Sam, I believe you are right about the poplar/ cottonwood being the main fuel source for European biomass, but I believe they pelletize this fuel which is not what we want. I did some research on BTUs and found that specie way down the scale. This is a local guy with tons of experience and a great web page devoted to BTU value of all woods and things I didn’t know were trees.
My quest is to find the best tree for the wet side of the cascades in a moderate climate with little freezing temps. I’m thinking Birch may be the best as they are everywhere ( I think that’s what they are) but specifically Black Birch.
In the meantime I’m gleaning the property where we get our firewood. I feel good about using up what everyone else would leave behind.
Regards, Tim J

In Europe “pellets” or wood chips can mean different than here. Most of the Euro wood processors I’ve seen make good gasifier size chunks, not shreds and dust like we get here. Maybe Sam can confirm what form they use the wood.

Be aware that the fast growing “fuel trees” or “farm trees” will always be light very soft types. Hardwoods take much longer to grow, and produce less over time - they’re making a denser wood. But it grows slowly. Similar concept to fast growing Franken-chicken “sponges” from Tyson, vs hardy backyard hens with some muscle tone. Big difference in the meat. But for gasifiers we don’t need “hi-quality” wood, so farm trees are acceptable.

Pound for pound, all wood has the same BTUs (except some pitch woods). The softwoods will run your gasifier just as well as hardwoods. It just takes up more volume per pound.

Hi Tim,

of course, poplar is not the first choice, when it comes to BTUs. For one’s fireplace, it just does make sense, when the heating period starts and ends - gives you much light and little heat… (same yields for willow, as the chart shows - it is great, by the way! Thanks for sharing!).

And as far as I know, some is pelletized, but most is used as chopped wood for heating in big furnaces and heaters.

I guess there are two important reasons for those being the most popular cultured energy woods (is there a plural for wood?):

  1. You want to have trees that can handle a regular cutting down to the ground and restart growing right away. I know this works great for poplar and willow. And I’m not sure about other species of wood.

  2. It is not so much depending on the BTUs you have in the wood. It is also important how much wood will grow in a year per acre. I.e. BTU per year per acre. And poplar and willow are rather fast-growing. I think that is what makes the difference. You have lower quality wood (better say less BTU per pound) but a higher quantity (more pounds per acre and per year). I believe that is why poplar and willow are chosen so often for growing energy wood.

Best regards,


PS: Willow has one more advantage: You can grow it in really wet spots… as long as you can harvest it at least in the winter.

EDIT: I guess I was late for this party. Chris beat me by two minutes…but I see we mostly have the same idea w.r.t BTU per pound of wood.

Chris and Sam,
Great comments! This is the kind of info I need to make an informed decision/ opinion.
BBB, Tim J

Hey TimJ I am out collecting 8-10 different, three generations of family planted tree pictures. A longer, Cascade wet-side picture set, with explains later.

On the other general factors I will add: LOCATION, LOCATION, LOCATION; overlaying USEAGE, USEAGE, USEAGE.
Gasifier fuel wood I 100% argree the needs are different from what you will find on any woodstoveing info site. Gasifier wood it is not about the BTU’s per pound; long burn time per re-fueling; seasonabilty(how long to get it stove ready, and then how long it can set in a woodpile); flame appeance, noise and and smell, with these; above all else. Gasifier fuel wood by species is about (IMHO) ASH content and cumulitive wood processing PITA’s. “Free” wood fuel stocks can drive you to drinking instead of fun freedom powering.

I much favor selected evolved native species for the area a person actually lives in. I favor dense FOREST planting and growing versus plantation mono-crop growing. Forest planting you can have the trees themselves with just minimal manual or selected animal cultureing do it all. Plantation planting will require either much manual cleaning up culturing or lots of chemical use. Eyeball evidence and more scientific proofs now say that mature trees including Douglas Firs do much soil conditioning and direct nurturing of new tree growth in thier direct genetic offspring.
I personally favor here in a possible to grow year around mild temperate climate conifer evergreens.
Long seasonal frozen, or dry droughted a leaf dropper will probably give better annual yield per area.
Wet footed anywhere will require very specialized trees were thier ability to survive and grow at all will be the Do-All factor. Yep you can gasifiy water suckers like cottonwoods, aspens/poplars. “Sam” is correct you MUST be able to in-the-winter wet sap-down harvest these. Harvested in-leaf, sap-up they will rot before air drying enough to use for anything.
Stump re-sprouting types can yield tremedeous annual weight regrowths not having to regrow a whole new root system. These types cannot thrive everywhere. Relitivly rare here.

TimJ if your growing area is north slope shaded and will stay drought season humid for gasifier fuel wood you would want to 100% culture PNW Red Alder. What I wanted to re-plant! We were too “small” to get any of this years divvy out of limited supply. Wife wanted to wait. NO. The bramble brush will be taking over by then. We put back into Douglas Fir on our river frontage property. Doug Firs will yield the same tons per acre on this property up through about the 15-18 year as the Red Alders then the Alders will pull ahead. Either be good gasifier fuel woods anytime after about 7-10 years and 4 inches plus on the butt. $$$ harvest the Alder would be ready for a Market cutting at 18-25 years and will age out and start dying and falling down from 25 years on. Would have been help for my wife in her retirement when I am done and gone. Doug Fir will need until ~35 years for a Market re-harvest. We had harvest cut at 50-60 years. She will have to sell this property now with the Doug Fir trees planted still growing to see a benefit. We have no children.

Steve Unruh

Hey Sam.
Plural od wood of the same species or even same condition of proceeeong is wood. “That’s a lot of wood!”
Plural of different species of wood types is woods. “That is a lot of woods you have there!” Usually commonly said though, “That is a lot of different kinds of woods!”

Oddly enough there’s not really a singular or plural of wood, because it isn’t a unit of measure. You don’t have one wood or two wood. Like you don’t have one air or two air, just “more air or less air”. Once a unit of measure is applied, that may be pluralized. You can speak of five wood chunks or three wood chips.

Actually I don’t know if Steve’s usage is correct, I’d be more inclined to say “That is a lot of different kinds of wood!” On the other hand, my desk is made from three different woods. That sounds OK.

One usage is somewhat removed from these; “woods” as in forest, many trees close together. “A cabin back in the woods”. etc. This is still not plural though; nor is it a unit (one woods, two woods).

English can be quite contrary!

Something to consider is coppicing which is planting trees that will grow again from the stump. As the root system is already in place it will produce new growth much more rapidly than a new seedling. Also saves you time and money replanting and nurturing a young plant.

I knew I could count on a solid comment from you! Thanks!
I had an idea that “firewood” and gasifier fuel would have different requirements.
My aim is to have fuel and an answer for people regarding sustainability and fuel sourcing in the future.
Thanks again, Tim J

Ha! Ha! Thats fine TimJ
Look on the “Eastern folk” woodstoving fuel sites info and published books and they pity us with our “poor BTU”, popping, snapping, crackling, pitchy, sooty Doug Fir firewoods. Well . . . when that is all you have except for even worse Western Cedar a fellow gets real good at making do, eh? Now anytime I actually get spots of actual rare good stovewood maples, downed apple and cherry woods I moan and complain mightily about having to ax or saw score the radially string cherywood bark, chainsaw down to blocks the maple crotches and burl lumps and having to clean my stove ash out every three days instead of every fir wood every two weeks.
Just don’t go planting entwined, twisted grained Hemlock no matter what others would say unless you want to be sawing down every single piece to a usable size.
If you can use the leaf mulch for your gardening and they will stream side grow for you I’d be very temped with Big Leaf Maples. Fast grow rate. Nice to see the actual stream in off season leaf down. They will shade the stream for fish. And they seem to want to stump coppice regrow well here. Study and ask and be careful about the actual maple species - not all do this here in our climate. And they will make a foot tripping, lawn protruding root, lumpy mowing hazard.
Steve Unruh

Hey guys,

thanks for the grammar discussion - I remembered my old English teacher, who quoted someone whose name I’ve forgotten: “English is an easy language to speak badly.” (EDIT: I think it was George Bernard Shaw, who said that.)

By the way, just this morning our municipality had delivered some wood chips or shreds that are supposed to go on a roadside bed patch in front of our house as mulch. They have lots of it, since they have to maintain all the roadside trees on our roads. So they just put it in a shredder and use it for heating (not our guys, but elsewhere) and mulching. I think they even sell it for cheap. What a bummer, that it is too fine for a gasifier…

Best regards,


I’m looking for some fuel trees now! Red Alder is a first choice (thanks Steve U)
On another note, I plan to use the gasifier to run my 16KW standby genny. It is a propane/natural gas Generac V-Twin.
The scenario goes as such… I drive the Dakota home, a 16 mile commute on woodgas. I park the truck next to the genny and connect the plumbing. (I would add a spigot from one of the hay filter exits)
I would run the genny for 3-4 hours, depending on the tasks.
This engine is about half the size of the 5.2. My concern is fuel size choice for running without the road shake to settle the wood and the dramatically less draw or pull through the gasifier.
I would think smaller size chunks would be mandatory.
A really stupid idea crept into my head the other day.
I have access to some good quality coal,… the underground, mined out type.
Could I crush it up pretty fine and add it as a small percentage of the feedstock? My thought is that it would help create gas better than wood alone at the slower velocity through the gasifier. Or are there too many other nasties released during the pyrolisis to be worthwhile.
Just wanting the most from my WK…without hurting it.
BBB, Tim J

I’d guess that if you were to idle the Dakota with the generator taking the extra gas that it would provide similar suction/draw to the Dakota cruising down the road at moderate speed (somewhere between town and freeway speeds). That is strictly a vaguely educated guess.

I’ve read that even small amounts of dino-coal would probably ruin a wood gasifier. The stuff burns very hot and dirty with lots of sulpheric acid in the gas/smoke, which would end up condensating into liquid in both your hopper and rails. I’d leave the coal out.

“I would think smaller size chunks would be mandatory.”

Good Morning Tim,

The harder I plan on working my truck the smaller the fuel I like to use if I have the choice.

By bringing the gasifier up to normal temperature and having a deep char bed it should run the smaller generator for a while.

+1 to Brian’s comment. Leave the coal out. Also don’t worry about the generator, you’ll be fine running it off the standard unit for a few hours at a time. After a while it would be good to drive around and shake things up.

Actually I’m glad someone’s going to try this so we can see how well it works. Still, Wayne’s already done it with small generators at demonstrations. But you won’t know exactly what happens until you try.

Brian, great insight! I was right, it was a stupid idea :o)
Thanks Wayne and Chris for the tips.
I guess I could hook jumpers up to my battery bank to charge them while the truck is running too.
BBB, Tim J

Hey TimJ
I was involved in woodgas converting a gasoline carburated 17.5 kW version of that Generac setup.
Very easy. Ran sweet with the factory stepper motor electronically controlled trottle/governor.
We did not have on hand enough verifiable load sources to be able to certify the actual woodgassed fueled generator output. Customer/user claimed it was able to handle the loads of a previous 12 kW gasoline unit.

If yours is also electronically stepper motor controlled best you stock a spare controller/motor power supply. Generac has a reputation for changing things and then orphaning now older systems. With a spare you would then be backed up one step deep. Your second step would be having the take out power supply/logic board local GEEK rebuilt.
Steve Unruh