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Author Topic: Why do some types of wood burn better than others and why do some spit?  (Read 13899 times)

Offline Make it Lady

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Timber!!! My husband has his lumberjack outfit on and is about to embark on some tree felling. We have quite a lot of trees that have become dangerous to know and need to come down. We coppice some of our trees and the wood burns well but we read that the wood from Pine trees spits (not like a hill billy) when burnt. We'd like to know why. So come on all you tree fellers and gals we need to know.


 

Offline JimBob

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It is moisture in the wood. Pine has a lot of sap and therefore moisture. And conifers, unlike deciduous trees, loose more water year-round, thus having to have a higher moisture content in their wood, essentially the wood on the outer part of the tree. But I would suspect this cannot help but be absorbed inward as well.

I do know that conifers have a higher water loss during the winter due to low humidity and not shedding their leaves, but do they store water for these periods of moisture loss and is this store in the inner part of the tree - m ore than a few inches from the bark? Perhaps someone more of a botanist could address that question.
 

Offline Make it Lady

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Thanks JimB, we do dry the logs out by leaving them undercover for a year or so before use though.
 

Offline dentstudent

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This may help...


Beechwood fires are bright and clear
If the logs are kept a year,
Chestnut's only good they say,
If for logs 'tis laid away.
Make a fire of Elder tree,
Death within your house will be;
But ash new or ash old,
Is fit for a queen with crown of gold.

Birch and fir logs burn too fast
Blaze up bright and do not last,
it is by the Irish said
Hawthorn bakes the sweetest bread.
Elm wood burns like churchyard mould,
E'en the very flames are cold
But Ash green or Ash brown
Is fit for a queen with golden crown.

Poplar gives a bitter smoke,
Fills your eyes and makes you choke,
Apple wood will scent your room
Pear wood smells like flowers in bloom
Oaken logs, if dry and old
keep away the winter's cold
But Ash wet or Ash dry
a king shall warm his slippers by.
 

Offline Karen W.

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Timber!!! My husband has his lumberjack outfit on and is about to embark on some tree felling. We have quite a lot of trees that have become dangerous to know and need to come down. We coppice some of our trees and the wood burns well but we read that the wood from Pine trees spits (not like a hill billy) when burnt. We'd like to know why. So come on all you tree fellers and gals we need to know.

denser harder dry woods burn longer and hotter..
pine once dried out for a year burns well, but still pops and crackles because pine is full of pine pitch..or sap like Jim said..Now pine will burn faster then madrone and will produce less heat as far as temperature.....It is a rather soft wood.. not as dense as a hardwood!

Pitch really does crackle pop and spit as does any wood that is not dried properly!
 

Offline dentstudent

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*looks for his post about conifers and deciduous trees....*
 

Offline dentstudent

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Here is an updated post from a while back in answering a slightly different question, but should help...

So - there are evergreen (coniferous) and broadleaved (deciduous) trees:

Coniferous = cone bearing
Deciduous = leaf dropping

The leaves of a deciduous tree are generally broad and flat. The leaves of a conifer are generally needles, and are thin and pointy. The leaf area is the primary area of photosynthesis in any tree.

Deciduous trees tend to drop their leaves annually at the end of the growing season during Autumn, whilst conifers retain theirs all through the winter. Conifers keep their needles for several years, though this changes with species and with a trees position in the forest.

There is a strong habitat difference between the two tree types deciduous trees tend to be at lower altitudes or in latitudes of shorter day maximum day length, but where the sun reaches a higher elevation. Conifers are found more commonly in more harsh environments, where the growing season is somewhat shorter, where there is an acutely angled solar radiation and water is potentially scarce due to soil depth, freezing conditions and so on. This is perhaps the key driver of the differences in the leaf morphology.

Deciduous trees require large quantities of water in order to grow, which in winter is less dependable.  They have become highly adapted to making use of spring and summer water, and putting on their growth during this period. As they grow, waste products are stored back in the leaves, which are then removed during leaf fall. You can see these products (tannins and so on) in some of the oranges and reds in the leaves as the green pigmented chlorophyll dissipates - some of these colours are also accessory pigemnts that help the tree photosynthesis more efficiently through using other light wavelengths. Broadleaves also have a large storage system within the trunk for carbohydrates, ready for the following years new growth. So the leaves become filled with waste products, and also the pores (stomata) within the leaves become blocked by dust and so reduce the trees growing capacity through reducing its water and gas exchange processes. It is more efficient for the tree to grow new leaves and then have a strong growth capacity than it is to retain the leaves and have a resultant reduction in growth.

Conifers do not have the same level of carbohydrate storage capacity as boadleaved trees, and so need to make use of this "evergreen" system. Because the needles of coniferous trees are continuously available to the tree, the tree can take advantage of short growing periods without having to firstly grow its leaves. Therefore, the conifers can strongly out-compete broadleaves in the harsher terrains. Their needles also have a waxy coating, which helps their adaptability with reducing water-loss.

There are other reasons as to why there is a generalisation of broadleaves at lower altitudes and conifers at higher elevations.  For example, conifers can easily become water-stressed in hot temperatures due to their smaller root system. Deciduous trees can become frozen at higher elevations due to the internal cell structures of the wood. But, hopefully this answer sheds light (rather than leaves) as to why there are leaf differences between the two tree types.
 

Offline dentstudent

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We have quite a lot of trees that have become dangerous to know and need to come down. We coppice some of our trees and the wood burns well.

MiL - Do you know which species you have? If you are coppicing, then they are probably deciduous (there are, I think, only 3 species of conifer that coppice).
 

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