What tree species gives the most BTUs per acre per year?

[wolfram]

Thank you again for the help.  The initial question came up here in the context of farming sustainably for firewood to heat individual homes and businesses, within a small community.  However, I was trying to extend the thinking to cover a potential future case of the addition of a few small centralized facilities in town for power generation and heat.  Like most things, the best solution depends on a proper statement of the problem.  Sounds like those are two different problems to solve.  That's ok, since solving the first one would not preclude future action on the second.

Regarding logistics, the thinking was to have one set of fixed expenses for fuel production on a controllable nearby site.  Farm labor would come from members, with proper incentives and a component of charity in place.  It would have people problems for sure.  And we have a good share of those already!

[Ron Wenrich]

That context takes on a whole different set of parameters.  If you're looking at producing power, you have a variety of fuels you can use.  I helped to place one of those a few decades ago, and we used a lot of wood waste.  Things have come a long way since then. 

But, the thinking is you need a use for your trash steam.  That's the co-generation part.  On my project, we used the trash steam for cooking tomatoes in a factory setting.  There are other settings you can use such as heat for schools, hospitals, community buildings, and anything else that would use steam for heating or cooking.  You also need a source of water.

Our project used a combination of sawdust and wood chips.  If you are looking at growing biomass for fuel, then you want the fastest growing material, not necessarily the densest wood. 

Other fuel inputs could include construction waste, garbage, and other burnable by products.  For waste material, you often can charge a tipping fee. 

If you are generating power, you should be able to make it a money making project and the need for volunteers would be minimal.

[Phorester]

My personal experience and observation with volunteer groups, homeowner associations, and the like is that the initlal enthusiasum and desire to do the work fades away over a few years as the first bunch of people gets older, moves away, gets tired of the extra effort they need to make, looses interest in it, etc.  Then the next wave of people feels that it is a burden and not a labor of love.  Then that community demands that the local government take it over, which they do, with an increase in everybody's taxes, of course.

So I'd suggest setting it up initially to have it a money making proposition as Ron suggests, or at lease break-even, with a core of hired people to do the majority of work, and volunteers as an additional but not necessary source of labor. 

[SwampDonkey]

People being as they are, I would have to agree with Ron and Phorester. You'll never maintain the harmony unless there is a lot of ignorance, innocence and isolation. And I can quote two well known instances. ;)

[nb_foresttech]

Thought I might throw this one into the mix. So many variables with site and genetic stock that there probably isn't a right answer. In the right site Tamarack might offer an alternative. It's best traditional growth is in the Great lake states. It certainly isn't at the bottom of the BTU list and grows fast. Easy to manage and has few pests. The following is a highlight from
http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/larix/laricina.htm

Growth rate (particularly diameter) declines after 12 to 15 years if tamarack is planted at close spacings such as 1.5 by 1.5 m (5 by 5 ft), but it should be unimpeded for the first 25 years at wider spacings up to 2.4 by 2.4 m (8 by 8 ft). In a good plantation in eastern Ontario, height at 25 years averaged 14.9 m (49 ft), d.b.h. 17.3 cm (6.8 in), and volume 202 m³/ha (32 cords/acre). Depending on site, final harvests of 189 to 252 m³/ha (30 to 40 cords/acre) are possible at 25 years in well-managed tamarack plantations (27). Intensively cultured plantations can produce two to three times more biomass than conventionally tended stands (51).

[ihookem]

I wanted to plant trees for my future firewood supply and ended up with hybrid poplars. They have been growing 3 summers now. I went with hybrid poplars for a few reasons, it grows fast(not as fast as they  said but fast)  they are real nice lookng trees, I got the "cuttings for 15 cents each, I can most likely sell the twigs or cuttings for some money,  it grows very straight planted close together and splits easy and when I cut them down you end up with sucker shoots from the trunk. The down side is of coarse it lacks the btu's of maple and it does not do well with weeds or grass. They love tons of water too. I planted mine on high ground and they only grew an avr. of 2 ft. per year. We have had three dry years in a row to make matters worse. If taken care of they will grow 4' the 1st yr. and 5' the 2nd year and about 6 ft per year after that. They also grow quite tall when close together. I have about 350 on 1/3 of an acre with ash, maple and some elm growing with them and another 1/2 acre growing naturally with ash, hickory, elm,and white pine for good looks. I did this cause I've always said "someday opec is gunna turn off the spicket" and at least I have poplar to burn. I figure in 7 years I can thin them some and hope to get  a cord or so. Then let the best sucker shoot grow, and the ash, cut the other sucker shoots into cuttings and sell them or replant or just let them all grow.  If I had to do it all over I think I would have tried finding elm trees, but have no idea where to find them. Silver maple might have been better too.

[woodtroll]

That leads back to Black Locust. It grows well in moist and dry conditions. Grows straight, sprouts from stump, likely could plant cuttings, splits well, burns very hot. May be a nitrogen fixer. Some of these good traits are the same as why it can be a weed.

[Magicman]

Back in the "wood stove days", my Dad told me that the only wood that they used was Black Locust.

[Phorester]

WOODTROLL, black locust is a legume so it indeed fixes nitrogen in the soil.  In the South decades ago before lawn fertlizers were common, black locust was  planted as a yard tree because the nitrogen fixing qualities of its roots made the grass greener in the yard.

[SwampDonkey]

Just plant alders, it's been known to warp a stove and fixes nitrogen to. ;D

[Twig farmer]

Apple. Grows pretty fast, produces fruit, gives great heat.

[SwampDonkey]

 :D :D :D

I'm not in the apple wood camp like some folks. I tried some one winter as I cleared out an old orchard. All I can tell ya's is I was some glad to get into the hard maple pile to keep my butt warm. :D

[Twig farmer]

:D :D :D

I'm not in the apple wood camp like some folks. I tried some one winter as I cleared out an old orchard. All I can tell ya's is I was some glad to get into the hard maple pile to keep my butt warm. :D

This link says Apple has more BTUs per cord than Maple..if "other" is hard maple..silver can't even compare...

http://extension.usu.edu/forestry/HomeTown/General_HeatingWithWood.htm

Personally, I found the white oak to be just as the link said. It does the best job. I had about 3 cord of it this year, and next I'll have 6.

[SwampDonkey]

I don't believe it from my experience with it. Apple wood I mean. In fact they don't even have the right weight per cord for hard maple. A cord is 100 ft³ of solid wood on average, which is 5600 lbs green, 4400 lbs @12%. Any apple wood I've handled would compare between black ash and red maple, which matches their figures pretty much bang on. Their white ash is way off to.

[downeast]

By far one of the most interesting threads in any forum !  8)

The "best" species does depend on soil quality, Ph, micro climate, and again, the density/BTU of the species. Also, as said, the "pioneer" growth of any tree, or how fast it will grow to harvestable size for firewood after a harvest.  These downeast Maine coastal woodlands are in bad shape due to lack of proper forestry since WWII. The iconic Maine 'look' of spruce/fir is only because of neglect, associated disease, and the so-called environmentalist Bambi attitude towards ANY cutting, sustainable or not. Forestry be damned. :

What do we have here for firewood ? In the Deer Isle/Blue Hill penninsula mostly Red/Soft Maple, Paper/White Birch for firewood, and a scattering of Red Oak, Green Ash, small Beech (diseased > 12" DBH ), some Yellow Locust, little White Ash, a lot of abandoned Apples. Most of our 5-7 cords/year is White Birch and Red Maple.

Thanks for an informative, intelligent thread guys.  8)

[woodtroll]

Osage orange easy to split? Never in my experience. Of course compared to straight ash or white oak for splitting...

[SwampDonkey]

Same with the birch, and it can't be yellow birch they have there, it's weight is way off. White birch is easy to split even air dried, yellow is medium though. Just the weight of the axe will practically bust white apart. Their figures on weight are about 1000 lbs off on hardwood like beech, hard maple, and yellow birch.  White ash, beech, yellow birch, hard maple are all right there together as far as density. Not a lot different in 12 % dry weight either, right around 4400 lbs average. And most folks will have their firewood around 16-20%, so it's even heavier.

[downeast]

Same with the birch, and it can't be yellow birch they have there, it's weight is way off. White birch is easy to split even air dried,

Wish it were so "easy".  :( Paper/White Birch in many cases is a $#%&* to split, dry or green. Depends on the growth- whether it heliotropes ( follows the sun, or grows as a pioneer in the open for straight grain growth). Paper Birch "pooches" or rots quickly if not split along the bark. We usually score the bark before bucking. It rots fast unfortunately in spite of bark splitting, so it's a bad storer for firewood. A year at most, then it starts to do the carbon thing====ashes to ashes.

[SwampDonkey]

You sure your not into that cursed gray birch being down east an all? My uncle split cords and cords and I helped in my younger years, and it was a joy. I don't use any here just yellow birch. But, as to it's spoiling that can be true, but we never left his wood outside to spoil, it went under cover before the warm season. There were cords and cords of white birch laying to waste on crown lands, 18-24" blocks of it. We used to load (grandfather and I) the half ton full after returning from fishing trips.

[downeast]

You sure your not into that cursed gray birch being down east an all? My uncle split cords and cords and I helped in my younger years, and it was a joy. I don't use any here just yellow birch. But, as to it's spoiling that can be true, but we never left his wood outside to spoil, it went under cover before the warm season. There were cords and cords of white birch laying to waste on crown lands, 18-24" blocks of it. We used to load (grandfather and I) the half ton full after returning from fishing trips.

No, it's Paper Birch, common pioneer species here that gets crowded by spruce and fir. It rots fast even under cover and scored in a year, maybe two at most.
Yellow Birch isn't common here, though it ranks up with the oaks for BTUs. You are spoil't.  ;D
BTW: what are "crown lands" ? Something the Queen owns ? ;D

[SwampDonkey]

what are "crown lands" ? Something the Queen owns ? ;D

:D :D like that.

Well if I didn't know better I'd say the forest companies owned them. But, no they are suppose to be public owned land like your state forests. ;)

Yellow birch isn't my main firewood, hard maple is. But, yellow birch and beech in lesser quantities. Getting hard to get good beech, it's half dead and rotten.

Gray birch has waxy triangle leaves with a solitary male catkin on worty branch tips. Just in case. ;D

[jim king]

Physical properties of burning wood fire wood BTUs


Physical Properties of Firewood by Tree Species
Chart of Common Firewood Heating Potential
By Steve Nix, About.com Guide
See More About:
•   firewood
•   best firewood trees
•   firewood fuel value
Firewood performance can differ from species to species. The type of tree you use for burning can vary widely in heat content, burning characteristics, and overall quality. I have created a table that presents several important burning characteristics for most species used in North America.
Definitions of Chart Terms
•   Density - wood's dry weight per volume. Denser or heavier wood contains more heat per volume.
•   Green Weight - the weight in pounds of a cord of freshly cut wood before drying.
•   mmBTUs - million British Thermal Units. Wood's actual available heat measured in BTUs.
•   Coaling - wood that forms long-lasting coals are good to use in wood stoves because they allow a fire to be carried overnight effectively.
Wood Heating Values
Common Name   Density-lbs/cu.ft.   Pounds/cd. (green)   Million BTUs/cd.   Coaling
Hickory                50   4,327   27.7   good
Osage-orange   50   5,120   32.9   excellent
Black locust   44   4,616   27.9   excellent
White oak   44   5,573   29.1   excellent
Red oak   4                        4,888   27.4   excellent
White ash   40   3,952   24.2   good
Sugar maple   42   4,685   25.5   excellent
Elm                35   4,456   20.0   excellent
Beech                41      27.5   excellent
Yellow birch   42   4,312   20.8   good
Black walnut   35   4,584   22.2   good
Sycamore   34   5,096   19.5   good
Silver maple   32   3,904   19.0   excellent
Hemlock   27      19.3   poor
Cherry                33   3,696   20.4   excellent
Cottonwood   27   4,640   15.8   good
Willow                35   4,320   17.6   poor
Aspen      18.2                             good
Basswood                4,404   13.8   poor
White pine   23      15.9   poor
Ponderosa Pine      3600   16.2   fair
Eastern Red Ced  31   2,950   18.2   poor
Sponsored Links
Physical properties of burning wood fire wood BTUs


Physical Properties of Firewood by Tree Species
Chart of Common Firewood Heating Potential
By Steve Nix, About.com Guide
See More About:
•   firewood
•   best firewood trees
•   firewood fuel value
Firewood performance can differ from species to species. The type of tree you use for burning can vary widely in heat content, burning characteristics, and overall quality. I have created a table that presents several important burning characteristics for most species used in North America.
Definitions of Chart Terms
•   Density - wood's dry weight per volume. Denser or heavier wood contains more heat per volume.
•   Green Weight - the weight in pounds of a cord of freshly cut wood before drying.
•   mmBTUs - million British Thermal Units. Wood's actual available heat measured in BTUs.
•   Coaling - wood that forms long-lasting coals are good to use in wood stoves because they allow a fire to be carried overnight effectively.
Wood Heating Values
Common Name   Density-lbs/cu.ft.   Pounds/cd. (green)   Million BTUs/cd.   Coaling
Hickory                50   4,327   27.7   good
Osage-orange   50   5,120   32.9   excellent
Black locust   44   4,616   27.9   excellent
White oak   44   5,573   29.1   excellent
Red oak   41                4,888   24.6   excellent
White ash   40   3,952   24.2   good
Sugar maple   42   4,685   25.5   excellent
Elm                35   4,456   20.0   excellent
Beech                41      27.5   excellent
Yellow birch   42   4,312   20.8   good
Black walnut   35   4,584   22.2   good
Sycamore   34   5,096   19.5   good
Silver maple   32   3,904   19.0   excellent
Hemlock   27      19.3   poor
Cherry                33   3,696   20.4   excellent
Cottonwood   27   4,640   15.8   good
Willow                35   4,320   17.6   poor
Aspen   


   18.2   good

[SwampDonkey]

Now I see where the figures are based on: "Weight and Heat content figures are based on seasoned wood at 20% moisture content, and 85 cu ft of wood per cord."

No wonder I can't believe them, the cordage of solid green wood is way too low. Split firewood stacks a lot tighter than round wood. I know it to be true because of thousands of scale slips processed by marketing boards from mills. Always been 2.5 metric tonne in hardwood which is averaged 5600 lbs green (beech, maple, yellow birch) with 100 ft³ of solid wood.

[downeast]

Boy, Steve Nix's chart missed some species: White/Paper Birch, and Red/Soft Maple. Fast pioneer growers here Downeast Maine. 

That 20% moisture content is interesting...just "interesting" maybe academically. We don't have the time, interest, or luxury to run around checking moisture in firewood. Those M²(moisture meter) things only check the surface anyways. Good for milling.

We heat 100% with wood ( well, 99% with a propane space heater for those winter days away) with  two EPA wood stoves.  For too too long the trees are cut in winter ( no bugs, hard ground, soft landing in snow, easier bucking over snow, no water under foot, less sweat ), stacked crudely in the open in butt stove length, then split and stored later in the summer and early fall. It has worked well for years even with the- rare for us - dreaded Red Oak. The secret ?  Stack the +/- 18" butts in rows separated by a foot or so. They dry some in winter and spring.  After splitting and stacked in the wood shed they are ready by November. 8)

[SwampDonkey]

Most well seasoned firewood is going to be 16-20%. You have to have a baseline, in this case 20 % and not green, because trees between species can have moisture content of 30 - 267% of their weight.

For academic purposes the Wood Handbook uses a formula to figure the Max moisture content of a species based on specific gravity of green wood and wood cell walls. Maximum moisture content Mmax for any specific gravity can be calculated from Mmax=100(1.54-G_g)/1.54G_g where G_g is basic specific gravity (based on ovendry weight and green volume) and 1.54 is specific gravity of wood cell walls. Maximum possible moisture content varies from 267% at specific gravity of 0.30 to 44% at specific gravity 0.90.

Conceptually, the moisture content at which only the cell walls are completely saturated (all bound water) but no water exists in cell lumens is called the fiber saturation point.The fiber saturation point of wood averages about 30% moisture content, but in individual species and individual pieces of wood it can vary by several percentage points from that value. The fiber saturation point also is often considered as that moisture content below which the physical and mechanical properties of wood begin to change as a function of moisture content.

From what I can gather green weight for each species listed in the Wood Handbook is taken at MC 30%. That is the baseline used for the FSP of wood. At or above this MC wood is considered green. Of course this varies from sample to sample in a species and across species. But you have to have a baseline of some kind. ;) Without having the "Standard Method of Testing Small Clear Specimens of Timber"  from the American Society for Testing and Materials, I can only make that assumption. ;D