[Strawbale] Sustainability of wood heat.

[Sherwood Botsford]

Speireag Alden wrote:
>
>   
>      No.  Burning wood produces particulates and ashes, and most of  
> the time the wood is not harvested sustainably, though in theory it  
> can be.  I would not use wood in an application where you will lose  
> 70-80% of your input.
>   
>
Oh come now.

Particulates depend on how well you run the stove.  Poison and pollution 
are matters of concentration.  I have 12 neighbors within a 4 mile 
radius.  That's 1 neighbor per 900 acres roughly.

Ashes are fertilizer. (Potassium and phosphorus) One of my spring chores 
is to take the ashes out to the wood lot ans spread them around.

70-80% is a bit harsh.  Even crummy wood stoves can manage about 60% if 
they have a reasonable tight door.

 Harvesting sustainable is not rocket science. 
Here's how I figured it:  By looking at stumps the mature black poplar 
on my land are between 80 and 120 years old when they start to die off.  
Often the time after age about 60 is pretty slow growth.  Ok.  We'll 
assume 100 years for a mature tree.   On that basis I can harvest about 
1% of the tree biomass per year.  This ignores the much faster growth 
while young, the biomass in the understory.  With much thought and 
study, I could remove 3-4% of the biomass per year.



So that means I can harvest about 1% of each class of tree.  In practice 
I ignore the stuff under 4"  And I ignore the patriarchs (too hard to 
split) unless they look like they are going to hit the house.  the best 
size for my time are about 16" at the butt, and 60 feet high.

A cord is about 300 chunks, where ia chunk is 16" long by about 7" in 
diameter.  60 feet of tree makes 45 lenghts, averaging 3 chunks per 
length.  135 chunks per trunk.
I can get a few more from the bigger branches.  So two trees per cord.  
20 trees per year of heat. That's probably an over estimate.  This year 
looks like it's going to be a 6 cord year.  And I think it only takes 
1.5 trees to make a cord.  Carry on!

My woodlot is about 12 acres.  So I have to cut not quite two trees per 
acre on the average to get 10 cords. Or ten 8" poplar per acre.   At 10 
foot spacing there are over 400 trees per acre.  (And yes 10 is more 
than 1% of 400, but it was 1% of all age classes.  I usually end up with 
a mix of sizes.)

More concern:  What will removing the dying trees do to the ecology -- 
I'm inserting myself in the place of 'peckers, bugs, and 'shrooms.  
Well, I'm still leaving the patriarch trees.  I average at least one of 
those per acre.  They stay until they fall over.
Sometimes they are fine for firewood. Sometimes they are punky and I 
leave them be, or turn the hollow ones into petunia planters for a few 
years.

And the branches are too much work to cut up and transport.  They feed 
the mushrooms and bugs. 

As a mark of our success:  Our pair of piliated wood peckers have 
successfully raised a brood each year. (5 of them on the platform feeder 
at once!)  Both kinds of nuthatches fledged their flocks, and the downy 
and hairy also succeeded.

My conclusion:  Do I have an impact? In the long term, yes.  Is it 
sustainable?  In the long term, yes.  Does it have less impact that 
heating with gas.  Definitely.  Do I have much of an alternative in this 
climate?  Not really.  Two nights ago it was -44.  We get less than 10 
hours of daylight at this time of year.  The sun is still low enough 
that we have to use a visor driving south at noon.  Sunlight at this 
time of year is not very nourishing.  (It does make a difference 
however.)  To heat entirely with solar heat I have to store 3000 degree 
days worth of heat.  (Annually we have about 10,000)
Wind power also feeble in winter here.  I have a windmill to aerate the 
pond.  It doesn't spin much in the winter.   Hydro is not an option.  My 
creek drops 10 feet as it crosses my property.  It flows for 3 days a year.

If I rebuilt my house, I could probably heat it with 1/5 the wood.  If I 
work hard on retrofitting the present house, I can probably heat it with 
1/3 the wood.  It's not clear to me that the environmental cost of the 
full retrofit is worth it, although the first half certainly is.