Firewood: Oak vs. mixed hardwood?
ab
"deciduous." You can have some soft hardwoods...Aspen comes to mind.
If the hardwoods in the mix are about as heavy as oak, then they are
ok. Maple, Walnut, and other nut/fruit trees can make a good fire, with
different colors of flame, even. It can be very nice.
I wouldn't and don't store wood next to my house due to the potential
problems with termites.
ab
Igor wrote:
>
> I have a woodburning stove and am looking to buy one or two face cords
> of firewood. A face cord is 4x8ft x 18in of firewood. Even though my
> stove is an energy efficient machine, it has glass windows so it also
> is like a little bit of a fireplace.
>
> The best quotes I have seen so far are:
>
> Mixed hardwood: $70 delivered and stacked
> Oak: $95 delivered (stacking extra).
>
> My understanding is that oak is a lot better with respect to energy
> yield and burns longer.
>
> Is it "worth it" to get the more expensive oak? Any thoughts on this?
>
> Also, how much harder is it to ignite oak compared to mixed hardwood?
>
> Also, can I stack the wood right by my house ir it is a bad idea
> due to various wood-eating insects?
>
> Thanks
>
> ----------------------------------------------------------------------------
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>
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> \______(_______;;; __;;;
Jerbear
http://www.ext.vt.edu/pubs/forestry/420-003/420-003.html#L5
Wood & water
Keep in mind that when firewood is cut, it contains a large amount of water.
In fact, one fresh-cut cord of oak can have enough water to nearly fill six,
55 gal. drums. When put in a wood-burning stove or fireplace, that wood has
to dry out before it will burn. Boiling off the water steals a lot of heat
away from the house.
The critical word when buying firewood, is seasoned. In general, seasoned
means the wood has been dried to a level that will allow it to burn easily,
and to give up a high proportion of its heat value. Well-seasoned firewood
will have dried until less than 20% of its weight is water, whereas when
first cut, water makes up 40 - 50% of its weight.
Wood & heat
For producing heat during burning, all wood is about the same when dry ---
pound for pound. Actually, because of natural resins in the wood, pine
produces slightly more heat per pound than hardwoods. However the biggest
difference comes from differences in weight or density among different
woods.
Dry oak and hickory logs weigh more than sweetgum or pine logs of the same
size. That means a greater number of pine or sweetgum logs have to be lugged
in from the wood pile to produce the same amount of heat when burned, than
oak or hickory.
"Creosote"
The sticky gum-like resins in pine wood have given some people the
impression that pine produces more residue or buildup, called creosote, than
hardwood. Research has found this is not true. The buildup on fireplace or
wood heater walls, chimneys and flue pipes, seems to be more a result of
burning wood at relatively low temperatures. When wood is heated, some of
its chemical ingredients are first changed to a gas and then ignited if
temperatures are high enough. However, at temperatures too low for them to
burn, they become part of the smoke, and if they contact a cool enough
surface, they will condense back to a liquid or a solid there. Over time,
these condensed materials form a thick layer of creosote that a hot fire can
ignite in place, causing a dangerous chimney fire.
Filling a wood stove at night and closing the damper to reduce airflow, can
keep a fire burning slowly until morning with no additional wood. However,
this practice favors formation of creosote. Burning wood which has not been
seasoned long enough also favors creosote buildup, because evaporating water
cools the burning process. Burning small amounts of wood at high
temperatures is one solution to the problem, but doing that by hand makes
for busy and sleepless nights. The best solution I know of is automatic-feed
wood-pellet stoves.
Determining seasoning success
How can you tell if firewood is dry enough to burn well? Although moisture
content is not always readily apparent, there are some indications of very
wet wood. Split a fireplace log and look at the split surfaces. Recently-cut
wood will have a darker-colored (wet-looking) center with lighter
(drier-looking) wood near edges or ends which have been exposed since
cutting. Wet wood will be easier to split than dry wood too. When firewood
is very fresh, the bark will be tightly attached. Bark on very dry logs
usually can be pulled off easily. The real indication is weight. Because of
the water in it, unseasoned wood is heavier than dry wood. Comparing weight
(using a bathroom scale) of a fixed volume (such as a cardboard boxful) of
dry firewood to the weight of wood of unknown moisture content, will tell
something about the degree of seasoning.
APPROXIMATE WEIGHT OF FIREWOOD
lbs./
cu. ft.
lbs./
cord
Oak
fresh
seasoned
64
45
5440
3825
Hickory
fresh
seasoned
64
48
5440
4080
Sweetgum
fresh
seasoned
63
36
5355
3060
Poplar (yellow or tulip)
fresh
seasoned
49
31
4165
2635
Pine (Southern hard)
fresh
seasoned
59
37
4930
3145
Other "quality" considerations
What else should be considered when buying firewood? If it is to be burned
in a wood stove, nearly any kind of wood will do. As discussed before, logs
of heavier woods like oak, hickory and ash will burn longer than gum, poplar
or pine. Split pieces catch quicker and burn easier than round logs.
Tendencies to smoke, pop or smell do not matter much in a stove, but for
open fireplaces, woods which look nice, smell good and dont pop or spark
much are desirable. Round logs or bark-edged split logs seem to provide the
greatest ambiance. Woods from fruit trees are said to produce pleasant odors
when burned, and pines, hickory and poplar are said to be most likely to
produce popping sparks.
Firewood volume measure
A final thought concerns the way firewood is advertised and sold. The
Georgia Department of Agriculture regulates firewood sales, and they require
that the volume of firewood advertised or sold in bulk be expressed only in
cords or fraction of a cord. A full cord is a volume of wood equivalent to a
stack of logs four-feet high, four-feet wide and eight-feet long. This
equals 128 cubic feet of wood, bark and air-space. No volume units such as
face cord, rack, pile or truckload are legal descriptions of a quantity of
firewood being advertised, sold or bought. However, small bundles of
firewood such as those sold at grocery and convenience stores, can be marked
as containing a certain weight and number of sticks and/or by the fraction
of a cord.
Species Btu/Cord
black locust 26,500,000
hickory 25,400,000
hophornbeam 24,700,000
beech 21,800,000
hard maple 21,800,000
red oak 21,700,000
yellow birch 21,300,000
yellow pine 20,500,000
white ash 20,000,000
white oak 19,200,000
soft maple 19,100,000
black cherry 18,500,000
white birch 18,200,000
sweetgum 18,100,000
elm 17,700,000
yellow poplar 15,900,000
hemlock 15,000,000
red spruce 15,000,000
fir 13,500,000
white pine 13,300,000
basswood 12,600,000
Species, Relative Amount of Heat, Ease of Burning, Ease of Splitting,
Production of Heavy Smoke, Production of Sparks, General Rating
ash, red oak, white oak, beech, birch, hickory, hard maple
high high high low low excellent
soft maple, black cherry
medium high high low low good
elm, sweetgum
medium medium low medium low fair
basswood, yellow poplar
low high high medium low fair
yellow pine
high high high high low good
white pine
medium high high medium high fair
spruce low high high medium high poor
anthracite type of coal with highest carbon content (86% to 98%) and thus
highest heat value (nearly 15,000 BTUs-per-pound); found mostly in 11
northeastern counties in Pennsylvania
bituminous type of coal with carbon content from 45% to 86% and heat value
of 10,500 to 15,500 BTUs-per-pound; most plentiful form of coal in U.S.
lignite type of coal with lowest carbon content (25% to 35%) and a heat
value of only 4,000 to 8,300 BTUs-per-pound; called "brown coal"
subbituminous type of coal with 35% to 45% carbon content and heat value of
8,300 to 13,000 BTUs-per-pound; generally has lower sulfur content than
other types, and so is cleaner-burning; found mainly in Western states and
Alaska
Heating Oil contains 138,690 BTUs per gallon.
Natural Gas has 100,000 BTUs per therm. It takes 1.4 therms to equal the
heat content of one gallon of heating oil.
Kerosene has 131,890 BTUs per gallon; 1.05 gallons equals the heat content
of one gallon of heating oil.
Propane has 91,500 BTUs per gallon; 1.52 gallons equals the heat of one
gallon of heating oil.
Electricity has 3,413 BTUs per kilowatt hour (kwh); 40.6 kwh equals the heat
content of a gallon of heating oil.
Type Value (BTU/lb)
urban brush 4000 - 5000
mill residue 4000 - 5000
secondary manufactured wood 7000 - 8000
urban wood waste (non-brush) 7000 - 8000
coal blend 10000
tire rubber 15000
rubber manufacturing plant waste 15000
waste plastics 14000 - 17000
paper & composites from mfg. plants 8000 - 10000
auto shredder fluff 9000 - 11000
There's nothing cozier than a flickering fire on a cold winter night.
But there's no easy way to figure out if you're getting a fair deal when
buying wood to fuel the flame -- in terms of amount, type and quality.
Even the so-called "lumber experts" can't tell.
"If someone comes with a truckload of firewood and says it's cured, buyer
beware," said Phil Grimm, staff forester with the state Department of
Forestry. "There's no way of proving it, and it's very difficult to know by
looking."
"Seasoned" or "cured" are the buzzwords relating to quality. Wood that is
ideal for stoking the fire has been stacked for at least six months,
allowing air to circulate so the water and sap can dry out.
The weight of the log can lend some insight. Common sense dictates the
lighter the better. Radial cracks as well splitting bark at the end of the
logs also suggest curing.
If burned unseasoned, wood will smoke before catching fire. A lot of heat is
lost in drying wood as it burns, which can lead to creosote buildup in your
chimney, said Eldridge Collins, Virginia Tech extension agricultural
engineer. The creosote buildup is a fire hazard.
The best woods to burn for heating are hardwoods such as oak, hickory, apple
or locust. They are denser and offer more heat per cubic foot than softwoods
such as pine.
However, wood is generally sold as mixed hardwood only, and it is not
possible to request a particular species, according to Firewood for Home
Heating, a Virginia Cooperative Extension publication.
"The more dense woods are going to have a lot more heat value," Collins
said. "By the same token, they will be slower to dry and cure."
Most complaints about firewood sales relate to quantity. Wood is measured by
the cord, which equates to 128 cubic feet. When stacked, a cord typically
measures 4 feet high by 4 feet wide by 8 feet long. A face cord, by
comparison, measures about half that.
"When you buy wood, it's usually thrown in the back of a pickup truck," said
James Johnson, Virginia Tech extension specialist in forestry. "The only way
to know what you're getting is to stack it up and measure it, and nobody
really does that. You just have to guesstimate."
Or you can request that the wood be stacked upon delivery and measured
before paying.
Many vendors claim to sell a cord when they are selling less. Even how much
a typical pickup truck can hold appears to be a matter of opinion. The
Virginia Department of Agriculture and Consumer Services maintains that a
standard pickup usually holds about two-thirds of a cord, while literature
from the Department of Forestry says it's only a fourth to a half of a
standard cord.
Regardless, Tim Tucker of Amelia, who sells firewood, said he makes his
deliveries in a one-ton dump truck so he can sell a full cord.
When balmy temperatures bathed Virginia earlier this winter, Tucker said, he
couldn't give a truckload of wood away. But more recent frigid temperatures
and icy precipitation prompted a flurry of sales, which depleted much of his
supply.
While many firewood vendors jacked up prices during the holiday ice storm,
Tucker said he kept his price constant at $110 to $120 a cord, the going
rate in this part of Virginia.
In the past three years, seven complaints in the Richmond and Hampton areas
have been filed with the Department of Agriculture and Consumer Services.
All alleged short measure of the firewood delivered.
The department warns that unscrupulous sellers often unload wood after dark
and demand cash payment, or they make deliveries while the resident is away
and return at night for payment. For big orders, rip-off vendors may deliver
one cord neatly stacked and then demand payment for the full order before
delivering the remainder in a pile so that it is difficult to determine the
amount sold.
Virginia law prohibits using the words "face cord," "rack" or "pile" when
advertising or selling wood to burn as fuel. It also requires the seller to
write a ticket or invoice that includes the purchaser's name and address,
delivery date, quantity and price.
INSECTS AND FIREWOOD, SOME FACTS...
With the increased interest in the use of wood as a home-
heating fuel, many people are beginning to notice the insects
that periodically emerge from firewood.
DO THE INSECTS CAUSE ANY DAMAGE TO THE FIREWOOD - We do not
feel there is any real damage associated with insects in fire-
wood. If the seasoning (drying) operation is done properly, the
wood will dry before the insects complete development, and they
will not survive. Although one may observe small piles of
sawdust on or near the woodpile which indicate insect activity,
most of the wood used for fuel in the northeast are hardwoods,
and little real damage occurs.
WILL FIREWOOD INSECTS ATTACK WOOD IN THE HOUSE - For the
most parts insects are only nuisance pests in the house.
However, if the house has the correct conditions for an insect
infestation, firewood could be the source of damaging insects.
One example might be carpenter ants. If one brings in wood
infested with carpenter ants, and stores it in a basement or
garage containing some wet structural wood, perhaps already
starting to decay, carpenter ants might move into it as the logs
dry out and establish a nest. This is the exceptional case,
rather than the rule.
SHOULD I SPRAY LOGS TO AVOID INSECT PESTS - We do not
recommend spraying firewood for any reason. Insect pests can be
reduced by proper cutting and storage.
WHAT INSECTS ATTACK FIREWOOD (or any type of wood) - There
are three main groups of insects that can damage wood. They are
bark beetles, ambrosia beetles and wood borers. The bark beetles
burrow between the bark and sapwood, ambrosia beetles bore
through the bark and into the sapwood and/or heartwood, while
wood borers can be found either between the wood and the bark,or
in the heartwood or sapwood.
WHEN ARE INSECTS ACTIVE - Most insect activity occurs during
the growing season - in New York State from April to October.
During this time adult beetles are actively looking and
then learn the activity cycles of the various insect pests.
WHAT CAN I DO TO AVOID LARGE NUMBERS OF INSECTS - Cutting
firewood at the right time of the year (during the dormant
season) will help avoid some pests. Pile the logs soon after
they are cut, either off the ground or under cover so that the
inner bark dries rapidly and thoroughly before the beetles begin
to fly in the spring. If logs are cut during the growing season,
remove them from the forest as soon as possible. Even a ng and
then learn the activity cycles of the various insect pests.
WHAT CAN I DO TO AVOID LARGE NUMBERS OF INSECTS - Cutting
firewood at the right time of the year (during the dormant
season) will help avoid some pests. Pile the logs soon after
they are cut, either off the ground or under cover so that the
inner bark dries rapidly and thoroughly before the beetles begin
to fly in the spring. If logs are cut during the growing season,
remove them from the forest as soon as possible. Even a few days
exposure when insects are active may be enough time for an
infestation to begin.
HOW SHOULD I STORE FIREWOOD - Firewood should be stored
out-of-doors, under cover and near the house so that valuable
space in the house is not used, but the wood is still nearby.
Insects are kept outside this way and the dirt problem is
reduced.
Store wood under cover to keep it dry - storage places might
be a woodshed, uneated garage or utility building, or under a
sheet of plastic or sheet metal roofing. Be certain to keep an
air space between the wood and any covering.
If wood is dried quickly, few insects are likely to
survive. The greater the surface area of the wood exposed to
air, the more rapid the drying. Stacking wood in loose piles
raised off the ground as well as splitting or sawing will
accelerate drying. This is especially needed with logs greater
than eight inches in diameter or longer than four feet.
Firewood placed in an open area will dry rapidly and
deterioration will be prevented. Put a cover over the top tier
of wood - clear plastic sheeting can be used. Temperatures under
the plastic covering will rise higher than outside, warming the
wood and evaporating the contained moisture. Water vapor either
escapes or is condensed on the plastic, therefore some arrange-
ment for ventilation is necessary.
FOR FURTHER INFORMATION on firewood, see: "Burning Wood",
NE Publication 191 available from your Cooperative Extension
Office or from Distribution Center, Building 7, Research Park,
Cornell University, Ithaca, NY 14853, $1.00 per copy.
Igor <ig...@Algebra.Com> wrote in message
news:slrn7c8pr...@manifold.algebra.com...
sherwind
Jerbear wrote in message <7a2511$6g7$1...@winter.news.rcn.net>...
>
<snip>
>Characteristics of Firewood
>There are many different species of firewood available to Virginia
>homeowners. Different types of wood have different properties in terms of
>heat value, ease of burning, ease of splitting, etc. The information in
>Table 1and Table 2 should prove useful in comparing some of the more
>common species in Virginia.
<snip>
>
Mary Conner
Igor <ig...@Algebra.Com> wrote:
>I have a woodburning stove and am looking to buy one or two face cords
>of firewood. A face cord is 4x8ft x 18in of firewood.
On a side note, is the term "face cord" standardized and regulated in
your state? Here it is not, and firewood sellers can use the term "face
cord" to mean just about anything, so price comparisons for "face cords"
are worthless.
Donald Phillipson
Igor (ig...@Algebra.Com) writes:
> I have a woodburning stove and am looking to buy one or two face cords
> of firewood. A face cord is 4x8ft x 18in of firewood. . . .
Usually 1/3 a lumberjack's cord i.e. 4x8 ft x 16 inches (instead of
4 ft.)
> My understanding is that oak is a lot better with respect to energy
> yield and burns longer.
Prices depend on local supply and competition. The main considerations
ought to be dryness and thermal energy. All fuel woods should be
air-dried for at least two years.
Weight (of dried wood) is the most useful guide. The heaviest
wood has the most thermal energy. Long-term fires are built up
slowly (for an hour or two) until the stove will maintain
high temperature when you load in a couple of really thick and
long-burning logs.
> Also, how much harder is it to ignite oak compared to mixed hardwood?
Ignition is no problem when kindling is used appropriately. (The
only N.American woods I know seriously difficult to burn are
tamarack and elm.)
The best guide I know is: Soderstrom, Neil
Heating Your Home with Wood
Harper & Row/Times Mirror (1979)
which discusses all these topics.
--
| Donald Phillipson, 4180 Boundary Road, Carlsbad Springs, |
| Ontario, Canada, K0A 1K0, tel. 613 822 0734 |
Steve Rehrauer
> Ignition is no problem when kindling is used appropriately. (The
> only N.American woods I know seriously difficult to burn are
> tamarack and elm.)
Might depend upon the elm species. I don't know what kind we burned in
the 1970s, after Dutch elm disease killed most of the elms on the family
farm. I don't know that we ever tried to _start_ a fire with it, but I
can attest that it burned _quite_ well when added to a fire. (It _is_ a
bear of a wood to split, though. Nightmare cross-locked grain.)
As for the poster's original question, why not ask the seller if they can
say what species might be found in a "mixed" load? Maybe they know, maybe
not. Here in central Massachusetts, I've gotten a lot of birch (burns
quickly), red & white oaks, a little of what looked to be apple (old orchards
being cleared for development, sigh), etc. I wouldn't be surprised to get
(but don't know if I could identify) black locust (watch that it doesn't crack
a cast-iron stove! :-), cottonwood (junk), ash (similar to oak), maple (superb
if sugar maple) and lesser-known species like hackberry (no idea how well this
burns).
I'd expect a "mixed load" of hardwoods in the poster's area would have
different species, but perhaps a similar distribution of junk/fast/slow
burners. If you can figure out which is which, it's kinda nice to start
a fire with the faster-burning birch etc, then load up the slower-burning
oaks etc. --Steve
ab
>
>
> while termites could be a problem, I've always believed that the
> reason that you wouldn't store wood near the house is because of the
> vermin that are attracted to the wood pile.
>
I guess it depends upon geography. There are several houses in my
neighborhood that have had termite damage attributable to using pine
bark for flower bed mulch. I won't do that, and I won't put my wood
next to the house.
Of course, I would consider termites vermin. But I'm sure you mean the
occasional copperhead, right? I don't want them in my house either.
But there are a lot fewer of them than there are termites. :)
If I had a concrete and steel construction house, I would probably use
that as a reason not to store wood against the house.
AB
Chris Matthaei
>On Fri, 12 Feb 1999 14:28:20 -0600, ab <n...@spamthis.com> wrote:
>
>>It depends upon what other hardwoods are in the mix. "Hardwood" means
>>"deciduous." You can have some soft hardwoods...Aspen comes to mind.
>>If the hardwoods in the mix are about as heavy as oak, then they are
>>ok. Maple, Walnut, and other nut/fruit trees can make a good fire, with
>>different colors of flame, even. It can be very nice.
>>
>>I wouldn't and don't store wood next to my house due to the potential
>>problems with termites.
>>
>reason that you wouldn't store wood near the house is because of the
>vermin that are attracted to the wood pile.
Are termites a problem in northern climates? I live in a Chicago suburb,
and have never heard of anyone having termites. I kinda figured they just
weren't a problem up here, but I don't know for sure. I was planning on
getting a wood rack for my garage, and storing some wood in there (maybe a
pile 3 feet by 3 feet). The garage is insulated and usually stays above
freezing, so I figured the wood would get nice and dry in there. Is this a
bad idea?
Chris
Nick Hull
> If you are only storing a small amount of wood for short periods of
> time, it shouldn't be too much of a problem. Long term storage is
> something that I wouldn't recommend because the wood becomes a home
> for vermin. Do you want to provide a mouse condo in your garage?
>
>
A cat can keep the mice in check
--
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