Good day at the firewood symposium

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Poindexter

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Went to the symposium today co-sponsored by the University of Alaska at Fairbanks and the Yukon Valley chapter of the Society of American Foresters.

One thing I finally understand is the difference between expressing the moisture content of wood on a wet basis versus dry basis. I just couldn't quite really get my head around it. One speaker explained with a piece of wood that weighs five pounds right now. Its four pounds of cellulose and one pound of water. Compared to the wet weight of the wood - five pounds - the one pound of water is 20% of the weight of the wood piece, this is wet basis. Dry basis, compared to the dry four pound weight of the wood in the piece the one pound of water represents 25% of the weight of the dry wood.

All the electronic moisture meters they know of calculate on dry basis, so when I stick my probes in a split and it reads "25%" (dry basis), I now know the same piece of wood is at 20% (wet basis) and therefore seasoned enough to go in my EPA cert stove- because the stove manufacturers are looking for 16-20% moisture content wet basis.

That was cool to learn.

The whole shindig was aimed at folks new to or thinking about wood burning, so some review for me. A lot of time talking about your homes "HHI" or Home heating Index. I was thinking about all y'all down south getting hammered with cold weather this season and tried to pay attention. Really HHI boils down to how good your air seals are and how thick your insulation is. A super tight house with really thick insulation has a low HHI - takes fewer BTUs to maintain a given temperature, a leaky house with thin insulation takes more BTUs to maintain the same temperature. Intuitively obvious, but they got right down into the math. My personal HHI is about a six, moderate for Alaska, excellent for the lower 48.

I finally got a grip on HDD, or heating degree days too. If your average temp in a 24 hour period is +65dF, then you accumulated zero heating degree days that day. If the average temperature in 24 hours is zero degrees Farenheit, you accumulated 65 HDDs that day.

Thirty year trailing average for Fairbanks is 13,666 HDDs annually. We are averaging 1872HDDs in November, 2141 in December, 2260 in January and 1858 in February.

For comparison, Minneapolis in January 2013 had 1482 HDDs, for January 2014 I'm finding 1762HDDs, typical numbers for Fairbanks average October and November. I did find a HHI estimator online here: http://www.nhsaves.com/homeheating/ , but it errored on my not valid NH zipcode.

A bunch of time on firewood seasoning too. Local we get little rain but have damp earth, our two prime directives are get it off the ground and get it covered on top- with math and pictures with circles and arrows and all the rest at this one.

All in all a good day. I did win a fuel value calculator as a doorprize. I spun the wheel to $5.03/ gallon for propane. Assuming 95% propane efficiency an air dried cord of firewood in a 70% efficient wood stove is worth $700. Break even price for coal in a 50% efficient coal stove is $911/ ton. Or you could break even on natural gas at $57.40 for 1000cf. Jeeeeezz that's a lot of money. Felling my own on state land a cord runs me about $80 c/s/s/c at the house, allowing for truck fuel, saw maintenance, splitter fuel, the whole nine yards.

FWIW I last paid $3.86/ gallon for #2 heating oil, my break even price for a cord of air dried wood is $511.60, so every cord I burn is $431.60 for my time.
 
Thanks for sharing. There are too many numbers for me to crunch at this time but I will look back at the info later.

You may have overlooked something. Your labor is not taxed when you are cutting your own firewood so depending on your tax burden your number of $400 for your labor may be low. You may be saving as much as $600 or more.

I truly love being able to use my labor to be self sufficient when ever possible. If you can grow your own food that also really reduces your tax burden on your income as well as all sells taxes.

Keep on cutting.
 
That sounds like a great event. Your numbers sound about right until you get to the part about how much money you save by cutting your own firewood. You should be comparing your cost of $80 per cord to the next best alternative, which isn't heating oil. In your case the cheapest alternative to cutting firewood yourself is buying firewood from someone else. For example, if you can buy a cord for $200 then your cash savings are $120 per cord, not $431.60. As jwp notes, this should then be adjusted upward for tax savings (including both payroll taxes and income taxes). Whether this a good deal financially depends on how long it to takes you to gather and process a cord and the value of your time.

Extending the analysis, it's possible that the exercise you obtain from cutting, hauling, splitting and stacking means that you will not have to join a gym to stay in shape. You could then add in the money you save on gym membership, amortized on a per-cord basis. In addition, if you get a lot of enjoyment from the process (as I do) you could add in the entertainment value of cutting your own wood. How much would you have to spend on other entertainment to obtain the same level of enjoyment (per cord)?

It's not easy to calculate the monetary value of gathering and processing your own firewood, but as an economist I am convinced that it is a great deal for those who enjoy the activity. If you don't enjoy it then it may make more sense to pay someone else to do it, unless you are very fast or the value of your time is very low.

Doug
 
That sounds like a great event. Your numbers sound about right until you get to the part about how much money you save by cutting your own firewood. You should be comparing your cost of $80 per cord to the next best alternative, which isn't heating oil. In your case the cheapest alternative to cutting firewood yourself is buying firewood from someone else. For example, if you can buy a cord for $200 then your cash savings are $120 per cord, not $431.60. As jwp notes, this should then be adjusted upward for tax savings (including both payroll taxes and income taxes). Whether this a good deal financially depends on how long it to takes you to gather and process a cord and the value of your time.

Extending the analysis, it's possible that the exercise you obtain from cutting, hauling, splitting and stacking means that you will not have to join a gym to stay in shape. You could then add in the money you save on gym membership, amortized on a per-cord basis. In addition, if you get a lot of enjoyment from the process (as I do) you could add in the entertainment value of cutting your own wood. How much would you have to spend on other entertainment to obtain the same level of enjoyment (per cord)?

It's not easy to calculate the monetary value of gathering and processing your own firewood, but as an economist I am convinced that it is a great deal for those who enjoy the activity. If you don't enjoy it then it may make more sense to pay someone else to do it, unless you are very fast or the value of your time is very low.

Doug
Dang, all that cipherin' so early in the mornin' gave me a headache. I popped a couple pills to make it go away and now I gotta do more cipherin' to see if I can claim the pills as a tax deduction...
 
Good points jwp and Doug Fir.

As an example, we had a pretty severe forest fire down the road a piece last summer, standing dead spruce outta there is $250/cord delivered, there is more than 10,000 acres of it. With oil at $3.86 per gallon (I have an oil furnace) I can have some of that delivered and and still heat with wood at half the price of oil.

Another thing that came up is "how much wood is in a cord?" I think we can all agree that a cord is a stack 4x4x8 feet, but how much of that volume is air and how much is wood? The commercial cutter at the symposium goes with 70-75cf of wood in a cord. The engineer had tables from a couple engineering sources that work with 80-85cf of wood in a cord. The way the foresters stack their wood - between uprights with no criss-cross pieces- they are fitting 90-95cf of wood in the same 128cf volume. So you could buy three cords of wood stacked by a forester, restack it and have four cords of wood to sell...
 
...
Another thing that came up is "how much wood is in a cord?" I think we can all agree that a cord is a stack 4x4x8 feet, but how much of that volume is air and how much is wood? The commercial cutter at the symposium goes with 70-75cf of wood in a cord. The engineer had tables from a couple engineering sources that work with 80-85cf of wood in a cord. The way the foresters stack their wood - between uprights with no criss-cross pieces- they are fitting 90-95cf of wood in the same 128cf volume. So you could buy three cords of wood stacked by a forester, restack it and have four cords of wood to sell...

That's very interesting! I have always used 85cf when estimating the BTU content of a cord. That number is based on an Oregon study from the 70s. I think that the last cord of firewood I purchased contained about 65cf. I guess the seller was stacking it for optimal drying, which is a good thing since that cord of "seasoned" wood was close to 40 percent moisture content. :laugh: As I learned form your first post, that's measured on a "dry" basis, and so it's not as bad when you convert to a "wet" basis, but it was still too wet to burn effectively. :cry:

Doug
 
Thanks for sharing that information. You do know you have provided yet another excuse for a CAD sufferer to buy a new saw.LOL
 
One thing I finally understand is the difference between expressing the moisture content of wood on a wet basis versus dry basis. I just couldn't quite really get my head around it. One speaker explained with a piece of wood that weighs five pounds right now. Its four pounds of cellulose and one pound of water. Compared to the wet weight of the wood - five pounds - the one pound of water is 20% of the weight of the wood piece, this is wet basis. Dry basis, compared to the dry four pound weight of the wood in the piece the one pound of water represents 25% of the weight of the dry wood.

All the electronic moisture meters they know of calculate on dry basis, so when I stick my probes in a split and it reads "25%" (dry basis), I now know the same piece of wood is at 20% (wet basis) and therefore seasoned enough to go in my EPA cert stove- because the stove manufacturers are looking for 16-20% moisture content wet basis.


No offense but I think they smoked some wood before this portion of the presentation. 25% reading on a moisture meter is really 20%...ok, if they say so. They are saying a moisture meter calculates the weight of the wood (4lbs) and the weight of the water (1lb) and spits out 25% weight according to "dry basis", which is really 20% moisture content on a wet basis. Doesn't make sense to me but I am not the one with the high $ education....
 
Thanks for the info. As they used to say on the foundry working floor, "That's why they get paid the big bucks"!!!! (the high $ educated)
 

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