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Burn time by species

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Joful, Feb 5, 2013.

  1. tsquini

    tsquini Minister of Fire

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    Are you talking 3/4 of a face cord or a full cord 128 sq ft.?

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  2. Joful

    Joful Minister of Fire

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    Why not? As I showed above, that's only three loads of 2.0 cubic feet per day per stove. Hardly pushing it for two 3.0 cubic foot stoves, although in reality, I was running two larger loads and one smaller load each day, as my schedule dictates.

    Heh... that was with part of the house closed off! We closed off one of the three bedrooms on the second floor (the one with no storm windows at the moment), and the entire third floor (guest suite with bedroom, kitchenette, bathroom). We also always keep the basement closed off, although we do keep some heat on down there (finished rec. room).

    I'm running out of poplar now, so I'm getting into more and more oak. A standing dead Pin Oak that I CSS'd last spring is actually burning quite well. The live red oak from the same time period is much more difficult. In any case, this stuff burns WAY longer than the poplar, so I think I can chalk that record usage up to what I was burning at the time.

    3/4 of a full cord = 96 cubic feet, over 8 days. Again, not hard to do when feeding two 3.0 cubic foot stoves three times per day. 3.0 cu.ft. * 3 loads * 2 stoves * 8 days = 144 cu.ft.
  3. corey21

    corey21 Minister of Fire

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    Around here we have yellow poplar i had to cut a lot for next year.
  4. begreen

    begreen Mooderator Staff Member

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    I think that's where the confusion is. The 11.5hrs between loading is not your normal loading pattern. That made it seem like they were only getting filled twice a day. It sounds like they are getting reloaded every 8 hrs. which is the same cycle we get on when it's cold. Fortunately that is not for weeks at a time!

    I'll bet you will really welcome warmer weather. Running multiple stoves regularly gets pretty old by late winter. Do you have next years firewood split and stacked already?
  5. tfdchief

    tfdchief Minister of Fire

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    Unless you are a wood burning psycho like me :mad:
    Joful and corey21 like this.
  6. StihlHead

    StihlHead Guest

    Those are OWB cordwood numbers there.

    I would bet on the 35% oak myself (comparing the poplar to oak by volume). True poplars/cottonwoods have about half the heat value of white oaks around here, and at 35% by weight moisture, the oak will have more heat even with the higher moisture content. It will also burn less efficiently and put out more smoke and creosote though. By most moisture graphs, the energy beakeven for wet oak vs. dry poplar would be between 40-50% for the oak.
    Joful likes this.
  7. Backwoods Savage

    Backwoods Savage Minister of Fire

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    Nope. Two different birds there. Poplar and cottonwood may be in the same families but they are very different.
  8. StihlHead

    StihlHead Guest

    I would counter to the contrary, at least with poplar and cottonwoods around here. Cottonwood, aspen and true poplars are all in the Poplar genus, and very similar. They all have low heat values as firewood.
    Joful likes this.
  9. Backwoods Savage

    Backwoods Savage Minister of Fire

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    Well, that doesn't sound like much of a counter to me. Said pretty much the same thing; same family but still different trees. And yes, we have poplar and cottonwood here and like where you are, they are still different trees.
  10. rideau

    rideau Minister of Fire

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    Joful,
    the math makes sense. But I don't burn anywhere near that much wood, so obviously don't put anywhere near 2 cu ft of wood in my stove per load.
    When I think about it, I put way less than 2 cu ft in my stove at a time. I just loaded up about two hours ago, for instance. Put in a 16 inch maple split, 1/2 of a 6 inch log, but not really quite half, because it was hollow in the very middle. 6 inch beech log, about 18 inches long. And a bunch of Ironwood kindling, just to burn it, because I am cutting up an ironwood at the moment and the branches are long dead and very dry. Small though they are, they put out a ton of heat. And that is my load. It is burning very actively now, good constant secondaries, stovetop temp about 440. It's about 22 out, going down to 5. The house is about 70.
    I'll probably put about the same amount of wood in around 11 PM, on a good bed of coals, and it will burn until morning. So, for 14 or 15 hours, I'll have used about 1.7 cu ft plus ironwood kindling.
    I've got about 5 more pieces of maple in this stack, then it it birch, ironwood and beech. I think I'm going to put the Beech aside for next year.
    I started this stack, which is between 16 feet x 5 feet x 16-18 inches, about four weeks ago. Have a couple of days worth of wood in the house, and nearly 1/3 of the stack left.
  11. Joful

    Joful Minister of Fire

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    They're getting loaded three times per day, but not in equal 8 hour increments. Reload times are approximately 6:30am, 6pm (hence 11.5 hours), and 9:30pm. The 6pm load is smaller, and is burned hot and fast, so I can be ready for the bed-time reload by 9:30 - 10pm. The other two loads are burned with the air shut down for max burn time. This smaller 6pm load is why I "only" went thru ~100 cu.ft. of wood, and not the 144 cu.ft. these stoves should be cable of gobbling in that time.

    I have about 9 cords cut and stacked now, and anticipate I'll be going thru another 2 before this year is out, leaving me 7 cords for next year. I also have 3 cords of ash rounds sitting in my driveway (which would've been CSS'd in November, had my helper not cut off his finger!), and about 5 - 6 cords of fresh cut logs sitting on my wood lot, all of which will be processed in March, and stacked for the 2014 - 2015 burn season. So... I'm getting ahead, very slowly.

    My first-hand experience would agree. I only regret I didn't start burning some of this oak back when it was bitter cold. I'm getting equal or greater burn times and the same stove-top temps with much less wood in the stove (maybe 60% of what I was using before), using the partially-seasoned oak versus well-seasoned poplar.

    Yep... my comment was based on the well-known table at Sweep's Library, in which he has listed: Cottonwood (Balsam Poplar): Populus trichocarpa. I won't even pretend I know the difference, but I do know the poplar I was burning was not tulip poplar. We do have a very large tulip poplar blown down at the place where I do all my cutting, though.
  12. tfdchief

    tfdchief Minister of Fire

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    I think where the confusion comes is from the fact that there are at least 35 different species of "Poplar", genus Populus, Willow Family. So, What one person in a particular area thinks of as Poplar, may be very different from what someone else, 100s miles away, in a different area, with different species thinks of as Poplar.
  13. StihlHead

    StihlHead Guest

    OK, if you need a more detailed explanation: what I am saying is that not only are they all in the same poplar family, but that in most cases (at least with western species), they have wood that has low heat value. Some species (like the aspens) have slightly better heat value. Also as said above, there are issues with what people consider as poplars. Cottonwoods and poplars are in fact common names given for the exact same species. For example, what we call black cottonwood here in the PNW is also called western balsam poplar or California poplar. So is it a cottonwood or a poplar? Its scientific name is Populus trichocarpa. It grows from California to Alaska and east to the Rockies. It does not split well when dry, it is hard on chainsaw chains, it smells like cat pee when burned (I am burning some right now, actually), it has really low heat value, and it is all around crappy firewood. The flip side to that is what is commonly called Tulip poplar (aka yellow poplar) which is not a true poplar at all. It is a type of magnolia that grows mainly east of the Mississippi.

    So when I say poplar I am referring to any number of trees in the genus Populus, that may or may not be called poplar or cottonwood or aspens here, there or elsewhere. To me a poplar is typically a more narrow form of the genus, and a cottonwood is more spreading. Aspens are also narrow in growth habit though, so it is hard to make a fine line distinction. They are all related to the willows, and like willows, they tend to make for low quality firewood and tend to smell badly when they are burned.

    Clear as mud? It seems that we in the PNW and in NE are on the same page when we refer to poplar, and in the South and Midwest you have a somewhat different idea of what they are.
    Joful likes this.
  14. Joful

    Joful Minister of Fire

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    All I know, is when I burn that crap (poplar), it takes me twice as long and much higher stove-top temperatures to get the cat to light off. Burning my 10-months CSS'd hardwoods (three different types of oak, dogwood, and some maple), I'm watching all of my former frustrations melt away. My cat's are lighting off much quicker, at lower stove top temps, and are cruising much, much, much longer. My only (apparent) trouble with the oak is that it's leaving a lot more chunks in the ash bed than the poplar ever did.
    rideau likes this.
  15. rideau

    rideau Minister of Fire

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    It's midnight, I'm down to a good bed of coals and stovetop temp of 250, from the two splits I loaded over 7 hours ago. I think there was about 4/10 of a cubic foot of wood in there. It put out a lot of heat for about 4 hours, and has been coasting along burning coals since, with me gradually opening the air, and the stovetop temp gradually falling...was 350 about an hour ago. House temp has now dropped a few degrees, which is fine with me in the late evening.
  16. madison

    madison Minister of Fire

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    At the 3/4 cord per week rate, I think your 2 cords for the rest of the yr maybe an underestimate
  17. ddahlgren

    ddahlgren Feeling the Heat

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    3/4 cord a week sounds like a full time job..LOL.. I am wondering about going to coal if i can fins a good used coal /wood stove or at least have the option for very cold weather and burn wood on the warmer parts of the year. I am just not sure if there is a place to buy coal in SE CT.. I know this is probably the wrong forum to talk about it but suspect the accumulated knowledge here has had experience with a lot of different fuels.
  18. Joful

    Joful Minister of Fire

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    Read again! The week in which I went thru 3/4 cord was exceptionally cold / not our normal weather. I have been thru only 3/4 cord since 1/27/13, so my normal usage is roughly half of that. I anticipate I'll need another 2 - 3 cords (maximum), to get thru the rest of the year.
  19. clemsonfor

    clemsonfor Minister of Fire

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    We must have different cottomwoods because ours here is an eastern cottonwood and its sientific name is Populos deltoides?
  20. madison

    madison Minister of Fire

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    Sure I'll reread it again..... Since the 27th of January, Philly has been quite warm,
    Sun
    1/27/2013
    36° 17°
    Mon
    1/28/2013
    38° 27°
    Tue
    1/29/2013
    54° 35°
    Wed
    1/30/2013
    68° 38°
    Thu
    1/31/2013
    62° 30°

    Fri
    2/1/2013
    32° 23°
    Sat
    2/2/2013
    30° 18°
    Sun
    2/3/2013
    33° 26°
    Mon
    2/4/2013
    32° 23°
    Tue
    2/5/2013
    35° 29°
    Wed
    2/6/2013
    42° 26°
    Thu
    2/7/2013
    37° 25°
  21. Joful

    Joful Minister of Fire

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    Well, I live a few miles north of the city, and our average lows have been 8 degrees (20F vs. 28F) lower than Philly this month.

    I'm sorry to bore everyone else with this, but since you're pressing the issue, here's how I came up with my 2 cord estimate for the remainder of this heating season:

    I filled my wood crib on 1/27/13, and by this Sunday (an even two weeks), I'll have used 3/4 of a cord from that load. The heating degree day count in that time has been 403 for the 11 days following Jan.27, so we'll just scale to 513 HDD's per 3/4 cord. Averaging data for the last three years, we see an average of 1877 HDD's from today thru July 4, meaning I'm going to need 2.74 cord, if I continue heating with wood on every day with a mean temperature below 65F.

    Knowing that I'll likely switch over to oil any time the outside temp peak into the 50's, I anticipate I'll use less than the 2.74 cords... or closer to my originally suggested 2 cords.

    If you know a more accurate way to predict usage, I'm all ears. This is a crude snapshot of how your oil and propane companies predict when you need your tanks filled, and is accepted to be the best practical method.
  22. topoftheriver

    topoftheriver Member

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    I think I remember you mentioning that you have a drafty old farm house. That could be some part of the problem. Your wood comsumption seems heavy. Either you like to keep burning or take a analytical look at your home and what you could possibly do reasonably.
  23. Joful

    Joful Minister of Fire

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    yep... all in time. We just moved in last year, but there are some projects in our future, which will make a marked improvement!
  24. topoftheriver

    topoftheriver Member

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    My home in Mass is fairly tight enough to hold the heat per se, but the cabin in Maine is another story. We leak every where. But there are hundreds of acres of woods to draw fuel from. Biggest problem; too much work but what are you supposed to do? Freeze???? Think not! However, I have been in many old farm houses. From the 19th century to the early, or even later, 20th century, plenty of leaks, drafts, and you name it. That is why they have "This Old House:. What were they thinking. But good tech you must admit when they tackle a problem. I guess just stay warm for now. Spring is coming.
    Joful likes this.
  25. StihlHead

    StihlHead Guest

    Yes, a lot of the cottonwood/poplar that we have here is Populus trichocarpa which grows mainly west of the Rockies. Populus deltoids is commonly called Eastern Cottonwood, and/or Eastern Poplar. It grows mainly east of the Rockies. There are several subspecies of Populus deltoids though, and some of them grow as far west as California.

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