All about a Chimney
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A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator or fireplace from human living areas.
Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney effect.
The higher you can make the chimney the better the draw of air through the shelter. If your shelter has a roof of branches or leaves you may not need a chimney, but you will still want to have a section of roof that is higher than the rest, so most of the smoke will rise higher than your head.
Industrial chimney use dates to the Romans, who drew smoke from their bakeries with tubes embedded in the walls.
However, domestic chimneys first appeared in large dwellings in northern Europe in the 12th century.
Just a point of history.. we are talking about neither of these chimneys.
A little Science thrown in
The most important mechanical function of a fireplace is to generate a draft. If you think of a hot air balloon, you know that a mass of heated air rises. A fireplace creates a column of heated gas inside the chimney. As that air rises, more heated air from the fire is pulled after it. The result is a draft -- a steady flow of smoke and hot gases -- up the chimney.
The draft serves another purpose, too. Any fire needs a steady flow of oxygen to keep burning. As the hot gas rises, it pulls fresh air into the pile of burning fuel.
You might remember from physics class that there are three methods by which heat moves:
Conduction -- a hot object touches a cooler one
Convection -- a movable substance, such as hot air or liquid, circulates into cooler areas
Radiation -- warm electromagnetic waves, such as rays from the sun or a heat lamp, carry heat to cooler objects and warm them by making their molecules move faster
In Our Story
Coming to the realization that his tree will be freezing inside without heat, Sam sets about figuring out how to heat it. Off on his raft fishing one afternoon he comes across a bank covered in clay. Using the clay, he decides that he can build a fireplace. The process of building the fireplace is a great example of how persistent and resourceful Sam is.
He begins by dragging all of the needed clay from the river bank to his tree. Next, he goes through many trial and error designs before he finds a way for the clay to hold its own weight up and not be too heavy. Now think of the fireplace in a house... you know that the chimney's purpose is to allow the smoke to filter out of the house through the roof instead of filling the living area with smoke. Sam needs the same system: How does he modify his fireplace so he does not fill the inside of the tree with smoke? Finally after finding a flat narrow stone to place on top of his fireplace, Sam is able to have a ledge hold up the funnel, moving the smoke outside of the tree.
Feeling satisfied with his finished fireplace and makeshift chimney, Sam closes the flap of deerskin over the cave's opening, lights his fire and begins to relax comfortably in the warmth he has created until all of a sudden he sees that his falcon, Frightful, is toppling off her perch and her eyes are glassy! He quickly opens the flap and they breathe in the fresh air. Oxygen! The fireplace had used all the oxygen in the tree and was sucking the air from the small space. This event leads Sam to his final alteration: creating knotholes to let in fresh air.
Some things to know about wood
There are two basic kinds of wood:
Hardwood – comes from deciduous trees, which are trees that have leaves that fall off. Typically, you can think of these as any tree that has leaves. They are known to have broad flat leaves and will shed their leaves each fall. There are many different species of hardwood trees, but the most common types are Birch, Cherry, Maple, Oak and Walnut.
Softwood – comes from evergreen trees; these are trees with needles, conifers or evergreen trees are recognized by their sharp needles and the cones that they produce. They typically shed their needles once every 2 to 4 years. Cedar, Pine, Fir, Spruce and Juniper are all well-known types of softwood.
Where
Where to Find Dry wood
Where to Find Dry wood
As trees grow, they pull water up through their roots, and it spreads through all of their cells. That’s why you can’t burn wood as soon as you cut it off the tree. It has to dry out.
Finding wood that is already dry is the best option for starting a fire quickly. Otherwise, you would have to dry it yourself. To find dry wood on a dry day, you can typically just gather branches that have fallen off of trees.
Be sure to gather dry leaves and dry grass to start the fire. Then, pick up dry twigs and progressively larger branches.
But what should you do if it’s been raining? Look up in the tree branches themselves. As branches die out, they fall but sometimes get caught in other branches. Since they’ll be held off the ground, they’ll stay dry even when it rains.
Also, look for branches that are sheltered from the rain under rock outcroppings or thick trees. You can still gather a lot of wet wood because layering them on an already hot fire will dry them out.
Again.. In Our Story..
In Chapter 17, Sam determines to stockpile as much wood as he can. He makes two large piles within arm's distance of his tree because he wants to have wood within reach should the snow become too deep to go out into. After these two piles, he has the idea to make a line of other chopped wood piles so that if he uses up one, he can tunnel to the next. He realizes he is scared waiting for the coming storms, and because he is scared, he keeps ''cutting wood and piling it like a nervous child biting his nails.''
Stacking wood
Techniques for stacking firewood varies around the world. The way it is stacked and stored depends upon the quantity needed.
Norwegian Round
This way of stacking firewood has become very popular due to the book by Lars Mytting called “Norwegian Wood: Chopping, Stacking, and Drying Wood the Scandinavian Way”. This method builds large rounds of wood formations with barked firewood covering the top of the round pile to protect the underlying firewood from the elements. It sits on pallets to keep the pile off the ground, and is started by building the pile around while standing inside the wood pile. Once the circumference is complete, the pile is filled with uneven/smaller pieces of firewood making up the interior while the exterior is built while standing outside the structure.
Amish Stack
The Shaker or Amish method stacks firewood in the round, but without the central stake as a reference point.
Not only are these round wood files aesthetically pleasing, the wood enthusiasts that utilize them feel they are better than the traditional rectangular shaped wood pile because they :
Take less time to stack
Shed water better, than a pile with a tarp cover which can trap moisture
Are more stable due to the wider width
Or also seen with a tree as the centre... and the wood stacked at an angle.
German or Holzhaufen
The German method of stacking firewood, known as the holzhaufen (woodpile) or holz hausen (wood house). This intentional design is used to allow air to flow from the outside of the stack into the center to keep all pieces dry. The wood pile dimensions are 6 ft around by 7 ft height. To make them as uniform as possible, the firewood must be 12 to 24 inches in length and similar in width. A stake is used in the center to ensure the pile is 7 ft high. The firewood is then laid down with one end pointing to the center stake and the other pointing to the outside which creates the circumference. This method is repeated in a circular fashion until the pile reaches around 7 ft high. To finish the German wood pile, pieces with bark are placed on top (just like the Norwegian Round method) to protect the pile from the elements.
US Traditional
In America we stick to a rectangular method often changing the direction of the wood for each layer for optimal air flow. These wood piles are often narrow and long creating easy access to individual pieces while blending into the background of a backyard, porch or deck. Typically anchor pieces are established vertically of either end of the pile while pallets or some other type of material is utilized on the bottom of the pile to keep the firewood off the ground surface.
Between two trees seems to be an old New England standard which works quite well and has stood the test of time.
Or you can get really fancy...
Woodpile mosaics you say? They may look like they’re more suited to an art gallery than a shed, but anyone with enough patience (and the right wood) can create their own work of woodpile art.
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