Age of tree

[Richie]

Does the age of a tree affect potential BTU's. For instance, does a 15 year red oak throw the same heat as a 90 year old red oak. Just took down a red oak that was maybe 25 ft tall and 8" diameter. The wood looked different to me than that of a more mature tree.

 

[JOHN BOY]

Oak is Oak , i really dont think diameter will directly effect BTU'S . Maybe others can chime in .

 

[Jon1270]

The wood looked different to me than that of a more mature tree.

Different how?

 

[bmblank]

I could see a difference in slow growth vs. quick growth, but that's a flat out density issue.

 

[Paulywalnut]

I see a difference in Pin oak branches and the straight run of the tree. I don't see how age could effect BTU's.

 

[Woody Stover]

The bigger the trunk, the more heartwood vs. sapwood....

 

[Jon1270]

I could see a difference in slow growth vs. quick growth, but that's a flat out density issue.

Speed of growth doesn't necessarily affect density. In deciduous / hardwood species, slower growth often means wood is less dense, not more. Slow-grown wood *looks* denser because the rings are closer together, but that doesn't mean there's more material packed into a smaller space; it's just less new wood per year. Discussion on another forum:

From Gene Wengert, forum technical advisor:
Slow grown softwoods are indeed denser. But slow grown hardwoods can be the same (maple, birch, etc.) or lower in density for ring porous (oak, ash, etc.). They would not be denser.

Wikipedia:

In the case of the ring-porous hardwoods there seems to exist a pretty definite relation between the rate of growth of timber and its properties. This may be briefly summed up in the general statement that the more rapid the growth or the wider the rings of growth, the heavier, harder, stronger, and stiffer the wood. This, it must be remembered, applies only to ring-porous woods such as oak, ash, hickory, and others of the same group, and is, of course, subject to some exceptions and limitations.

 

[ScotO]

I can tell ya for a fact that woods such as pine, poplar, and even maple are denser if grown in a forest vs. grown in an open field or yard. Old growth poplar and oak (virgin timber) grown in dense forests had much denser/harder properties.

The 9'x9"x9" hand-hewn pine beam from an 1860's barn I tore down is proof of that.....sucker weighs over 300lbs., and in the 9"x9" end there is over 170 annual rings if I'm not mistaken......I'll have to get a pic of it later when I get home.....

 

[Hickorynut]

In my opinion, woody stover nailed it. The bigger the trunk, the more heartwood, which is denser. The caveat to this would be the rot you might find in older trees especially near the bottom.

 

[Richie]

In my opinion, woody stover nailed it. The bigger the trunk, the more heartwood, which is denser. The caveat to this would be the rot you might find in older trees especially near the bottom.

Yeah that is interesting. When you look at the endgrain of a locust log, it appears to be 99% heartwood with about an 1/8" of sapwood where cherry and oak may have an 1" to 2" of sap wood. Heartwood does not decay as fast.

 

[ScotO]

Yeah that is interesting. When you look at the endgrain of a locust log, it appears to be 99% heartwood with about an 1/8" of sapwood where cherry and oak may have an 1" to 2" of sap wood. Heartwood does not decay as fast.

That's not always the case.....I've cut many, MANY trees down over the past 10 years and I can tell you a tree that has a limb lost (lightning strike, wind or ice damage, etc) doesn't always heal well, and that wound allows water, bugs and other critters to take residence, leading to very fast heartwood decay on some instances. Also, borer worms in some species (oak for example) that can come up from the taproot can eventually ruin the core of the tree, which eventually leads to ants or termites, and can literally eat the tree from the inside out.

Some species.of tree also have much more sapwood than others (walnut, cherry etc.). Much of how a tree decays or lives healthy depends on many combined factors....

 

[hobbyheater]

This is a large piece of petrified wood, very old, very solid, but NO BTU value!




This was found on the side of a freshly constructed logging road; just a piece of road ballast.



It really is solid rock.

 

[hobbyheater]

Does the age of a tree affect potential BTU's. For instance, does a 15 year red oak throw the same heat as a 90 year old red oak. Just took down a red oak that was maybe 25 ft tall and 8" diameter. The wood looked different to me than that of a more mature tree.

I've seen a few posts on this subject over in the "Boiler Room" and the general consensus is that once a type of wood is dry, the BTU output per lb is constant.

 

[Applesister]

A pound of feathers vs a pound of lead? lol