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Thanks for all the great advice. While I am waiting for the world to end: The wood is freshly cut and at the moment in my "office" where the temperature changes between 10 to 19C. Is it important for the wood to season outside in a covered area? I can probably arrange a covered area, but fear that sooner or later bugs attack the wood. Is seasoning really important or is air drying inside enough?

Hi,

"Seasoning" is an English word; in the timber trade it means exposing the wood to the changing temperatures of the seasons. That is what the old timers did. If you have time and the right place; protected from rain, letting in some daylight and plenty of air circulation, give your wood a chance. The wood should be stacked as far away from the ground as possible, as some moisture always rises from the ground. Woodworm gets into the wood if it gets damp and is stored in the dark.

Merry Christmas!

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From what I've read (again), leaves fall due to a hormone release by the plant, mostly in response to available daylight. Reduced light causes the plant to grow an interface between the leaf stem and the branch, which shuts off fluid and nutrient transfer, and also pushes the leaf off of the branch.

Here's one short and very readable reference on why leaves fall:

http://www.npr.org/t...oryId=114288700

Hi David Burgess,

I've just got round to reading the quaint write-up in the link. Professor Raven knows his stuff, however even scientists make mistakes sometimes!

ere is a quote from the little story:

Around this time of year in the Northern Hemisphere, as the days grow shorter and colder, those changes trigger a hormone in leaf-dropping trees that sends a chemical message to every leaf that says, in essence, "Time to go! Let's part company!"

The stalk of the leaf is very thin and is attached to the branch only in a small area. After an automn frost and the general drop in temperature the leaf and the branch both contract in opposit direction and break the bond. The leaf gets less and less sap and changes color. It is interesting to watch a walnut or an ash tree after a sharp autumn frost in crisp windless morning. The leaves are perfectly still, when the sun comes up, they start to fall. I seen a wallnut tree strip before 12 noon.

Perhaps the botanist have not heard of the Laws of Thermo-Dynamics? :)

Merry Christmas and a Happy New Year

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Sadly, I cannot contribute anything to the debate about cutting seasons and sap flow. Cutting grape vine in our garden and knowing grape vine since my childhood, I tend to agree with Melvin. But I wouldn't know whether this would apply to maple, other woods or sap flow in general. Nevertheless, the few pieces of maple I have, were cut two months ago and are quite fresh. We stack a lot of firewood in the garden and have been doing so for the past few years. No matter what we do, when we bring in the wood for the stove, most logs are covered with bug and all sorts of fungi that grows on them. I wouldn't feel safe to stack the wood outside, even though I know that seasoning would make a lot of sense.

Merry Christmas and a happy new year to you all.

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Perhaps the botanist have not heard of the Laws of Thermo-Dynamics? :)

I wouldn't know, but based on the number of sources, there seems to be good agreement among botanists that hormones trigger the growing of a weak cork-like interface between the leaf stem and the branch, which progressively cuts off nutrient flow and weakens the attachment. It also serves to seal and protect the spot on the branch where the leaf was once attached. I suppose it would be a waste of nutrients if sap was oozing out of every spot where there was once a leaf attached, like one gets when tapping a tree for maple syrup. ;)

Theories on how the dropping of leaves benefits the tree, include that this type of leaf is fragile enough to be heavily damaged during the winter, so it's more efficient to grow new ones in the spring, and not have the old damaged ones still around interfering with the sunlight the new ones get.

Dropping the leaves in the fall may also give the tree better resistance to strong winds, and snow and ice loading.

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Hi,

Theories on how the dropping of leaves benefits the tree, include that this type of leaf is fragile enough to be heavily damaged during the winter, so it's more efficient to grow new ones in the spring, and not have the old ones still around interfering with the sunlight the new ones get.

I would not argue with the botanists as I'm just an idle observer nature; watching the world go by!:) Trees and other living things adapt to the conditions and genetics have a big part to play. Some trees can keep their leaves some shed them. However all matter living or inert must obay the laws of the universe. It is the little electrons on strings that make the world go round! not money!When the sun shines they speed up and the matter expands and when it gets colder they slow down. When it gets warmer the small branches on the top of the tree get warm first, they expand and draw the sap up, when it gets colder they contract and push the sap dow towards the roots. It is all according to the Law.

The botanists are putting the chicken before the egg! :)

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Nevertheless, the few pieces of male I have, were cut just two months ago and are quite fresh.

If you are only trying to dry a few violin backs there will be no problem with storing it indoors. A coolish room would be best rather than next to a radiator! Expect it to warp quite a bit as it dries, as others have mentioned this is no bad thing. It will take several years for it to be dry enough to use. Slab sawn wood can benefit from being left a bit longer, it tends to move around more.

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It is all according to the Law.

The botanists are putting the chicken before the egg! :)

Who's law?

I think any good scientist now understands that the egg is in fact the chicken.DNA and all.

The problem with simple casual observance is that it is oft times wrong,

The scenario you describe is as a bulb syringe filled with water, and having the open end immersed in water. a hot cold/expansion contraction cycle does not affect the amount of water in the tube,or trunk in this case.We do know thru casual observance that water goes up & out of a tree , ....but what of water traveling down?

I have seen,in a single day, up to ten gallons of sap come from one small tap,indicating pressure/flow changes but not necessarily moisture levels,as in flowing water thru a sponge. oddly enough I never see sap flow on the cooling cycle,just a tapering off to nothing. If in fact, the material were being pushed back I would expect to see sap flowing out , come to think of it I would also expect the converse true ...that is during a warming/pulling we might expect to observe a sucking action and flow ceasing around the cut fibers of the wood. could there be a pressure from below pushing the sap up ????? something to do with ground frost and snow cover?

before seasoning REMOVE ALL BARK.

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When it gets warmer the small branches on the top of the tree get warm first, they expand and draw the sap up, when it gets colder they contract and push the sap dow towards the roots

Try to stop the mercury rising when it is warm, or from falling when it is cold an you'll find out!

So it's your belief that the mercury in a thermometer rises because the internal diameter of the glass tube expands at the top, pulling the mercury up? Hmmm.....

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So it's your belief that the mercury in a thermometer rises because the internal diameter of the glass tube expands at the top, pulling the mercury up? Hmmm.....

I dont know if the glass expands, but if you look at some threads on this forum, heads difinitely do! :)

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One thing that has been glossed over here is that sugar sap flows only in winter, while the tree is dormant. Once a maple is actively growing again a wound bleeds minimally, if at all.

I also have seen the sudden drop of walnut and butternut leaves, in my front yard. Still completely green and completely fallen in a few hours. Not enough time for any significant hormonal effect. And there are oaks and chestnuts that hold brown leaves for months. I don't think the leaf-shedding thing has much to do with sap flow/loss or even the moisture content of the tree.

But I could be wrong.

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Ok, there's a lot of botony questions and statements here. I pulled out the quotes mostly as subject headers, so if I seem to be taking your quote out of context I opologize.

Hi David Burgess,

I've just got round to reading the quaint write-up in the link. Professor Raven knows his stuff, however even scientists make mistakes sometimes!

ere is a quote from the little story:

The stalk of the leaf is very thin and is attached to the branch only in a small area. After an automn frost and the general drop in temperature the leaf and the branch both contract in opposit direction and break the bond. The leaf gets less and less sap and changes color. It is interesting to watch a walnut or an ash tree after a sharp autumn frost in crisp windless morning. The leaves are perfectly still, when the sun comes up, they start to fall. I seen a wallnut tree strip before 12 noon.

Perhaps the botanist have not heard of the Laws of Thermo-Dynamics? :)

Merry Christmas and a Happy New Year

David was on target with his readings. Photo period (hours of daylight) triggers the hormone release that results in leaf senescence. Deciduous trees grown in a green house will still loose there leaves in the fall. The leaves are not precisely changing colors. As photosythesis production is shutting down chlorophyll, the green pigment, begins to break down. Carotenes and xanthophyll, yellow to orange pigments, hang around a bit longer. So the aren't really changing into yellows, oranges, and reds, rather these colors are being revealed in the absence of green. Yes, we know all about the laws of thermo-dynamics (just poking fun back). :) For full disclosure I'm an Ecologist not a Botonist, but that close enough for what we're talking about here.

I wouldn't know, but based on the number of sources, there seems to be good agreement among botanists that hormones trigger the growing of a weak cork-like interface between the leaf stem and the branch, which progressively cuts off nutrient flow and weakens the attachment. It also serves to seal and protect the spot on the branch where the leaf was once attached. I suppose it would be a waste of nutrients if sap was oozing out of every spot where there was once a leaf attached, like one gets when tapping a tree for maple syrup. ;)

Most of the nutrients in the leaves (~75%) are drawn back into the tree leaving the rest, mostly carbon, in the leaf. This is a good reason by the way to mulch your fall leaves into your lawn instead of picking them up.

Hi,

I would not argue with the botanists as I'm just an idle observer nature; watching the world go by! :) Trees and other living things adapt to the conditions and genetics have a big part to play. Some trees can keep their leaves some shed them. However all matter living or inert must obay the laws of the universe. It is the little electrons on strings that make the world go round! not money!When the sun shines they speed up and the matter expands and when it gets colder they slow down. When it gets warmer the small branches on the top of the tree get warm first, they expand and draw the sap up, when it gets colder they contract and push the sap dow towards the roots. It is all according to the Law.

The botanists are putting the chicken before the egg! :)

The spring rush of sap is caused by the negative pressure that occurs in the tree when the temperature drops below zero causing CO2 contract (and other things) resulting in a suction and that draws water and nutrients into the roots and sap wood. When the temperature warms in the day the pressure allows the sap to flow when the tree is tapped.

Who's law?

I think any good scientist now understands that the egg is in fact the chicken.DNA and all.

The problem with simple casual observance is that it is oft times wrong,

The scenario you describe is as a bulb syringe filled with water, and having the open end immersed in water. a hot cold/expansion contraction cycle does not affect the amount of water in the tube,or trunk in this case.We do know thru casual observance that water goes up & out of a tree , ....but what of water traveling down?

I have seen,in a single day, up to ten gallons of sap come from one small tap,indicating pressure/flow changes but not necessarily moisture levels,as in flowing water thru a sponge. oddly enough I never see sap flow on the cooling cycle,just a tapering off to nothing. If in fact, the material were being pushed back I would expect to see sap flowing out , come to think of it I would also expect the converse true ...that is during a warming/pulling we might expect to observe a sucking action and flow ceasing around the cut fibers of the wood. could there be a pressure from below pushing the sap up ????? something to do with ground frost and snow cover?

before seasoning REMOVE ALL BARK.

Your observations are right as long as it freezes at night and warms during the day. But if you get a wierd weather pattern where it gets warmer towards the evening and stays above freezing at night the sap will flow at night.

Aside from making syrup, water and nutrients are drawn up from the roots by capillary action when the stomatal pores in the leaves open to allow CO2 in for photosynthesis. When the stomatal pores open water is released (transpiration) which creates a suction to draw water and nutrients up from the roots.

Cheers,

Jim

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" When the stomatal pores open water is released (transpiration) which creates a suction to draw water and nutrients up from the roots."

If it were that simple trees could grow to only about 32 feet tall at sea level.

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" When the stomatal pores open water is released (transpiration) which creates a suction to draw water and nutrients up from the roots."

If it were that simple trees could grow to only about 32 feet tall at sea level.

Correct if the water transport was like a really long soda straw, but its not. First the water travels through cells (xylem) that are like chambers with one way check valves. The diameter is also small so it is easier for surface tension to pull the water up. Root pressure also helps, but this is minor compared to the capillary action. If a tree is experiencing water stress (not enough) water then cavitation can occur. The cavitation results in an air embolism and everything above that point will die. Mostly the xylem takes water and nutrients from roots to shoots like a one way street. Of course there are exceptions just to keep life interesting. :)

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There are two types of water trapped in the wood. Free water and bound water.

This conversation has been a discussion of the free water ie. the water which travels up through the tree transporting nutrients to the crown. This water is relatively easy to get rid of. It happens quickly and well within the first year after cutting....if the wood is stored properly. It is also the moisture which promotes the fungal growth we know as "sticker stain"...the result of improper circulation and surface contact. This suggests that vertical storage early after cutting and spliting and having no contact on the surface of the block is a good idea.

Then there is bound water. This is water which is part of the structure of the cell walls. This is more difficult to get rid of...but necessary for dimensional stability. Kiln drying removes this water, but results in a [sometimes too] rapid collapse of the cell wall structure. Properly air dried wood will reach an equilibrium moisture content, which is the sign of stability, at different rates depending on the climate and thickness of the wood. Around here...NE USA....equilibrium moisture content is between 12% and 16% for maple and 11% and 14% for spruce. This process takes about 2 years per inch of thickness for winter cut wood. As wedges are not of uniform thickness they need an environment which will let them dry slowly.

on we go,

Joe

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Joe,

Some of my experimentation has involved soaking wood in various things, and I found that standing the wedges on end allowed some the liquid to drain out by gravity. Yes, there was still a lot of free water that had to evaporate out over time, but the vertical hanging helped. Quite a lot of water drained out.

Time for free water to evaporate was surprisingly quick, less than a month. Below is the weight vs. time chart for two sets of top wood, initially starting soaking wet. I don't dispute the wisdom of "2 years per inch" drying, but from my data, it would have something to do either with the bound water, or some of the non-water components in the wood.

post-25192-0-11341800-1356363819_thumb.jpg

Also, my experience was that cell collapse only happened when there was free water and elevated temperature, suggesting that surface tension was a key player. I'm thinking that kiln drying failures of this type may be due to rushing the process, before the free water is all out. I have never had any cell collapse once the free water is gone, and I've been doing some pretty extreme things... a few days' process ending up with 0% moisture.

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Hi,

This is also a quote from Melvins post:

Don't take my word for it. You can try it for yourself next summer.

Perhaps it is too obvious for an academic to mention in a book?

I live in New England and spent my childhood hauling sap buckets. Anything that runs out of a tree late spring and throughout the summer is water, not sap in the same context as what produces syrup. The sap starts to form in the fall when the tree stops absorbing water (hence, no water flowing from the cut branch) Actually the highest sap content is late winter-early spring. Anything cut in the summer would be wetter but would not have sap in it, but anything cut during the winter will. I do have to add my personal opinion here, if there is "sap" in the wood how can it matter? if you take all of the sap from one billet and boil it down you may have enough to put a glob on the head of pin so I do not see how that much sugar could be a concern.

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Dan,

Are you suggesting there is a confusion between sap and water in the discussion? What you describe makes sense to me: Higher amount of sap in winter but lower water content.

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Sap bleeds from the tapping wound when internal tree pressure is higher than atmospheric pressure. The internal tree pressure can be up around 30 psi under good tapping conditions (instrumented and measured), but lack of a natural pressure differential due to less than ideal weather conditions can be gotten around by applying vacuum.

Some sources say that sugar concentration is highest in the winter, in preparation for the energy required to re-foliate the tree. After that, reserves are somewhat depleted, and build up again throughout the summer.

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Joe,

Time for free water to evaporate was surprisingly quick, less than a month. . I don't dispute the wisdom of "2 years per inch" drying, but from my data, it would have something to do either with the bound water,

Also, my experience was that cell collapse only happened when there was free water and elevated temperature,

Don,

My experience with free water released in less than a month agrees with yours. The "2 years per inch" is release time for the bound water resulting in equilibrium moisture content....where I live.

Cell wall collapse is definitely related to raising the temperature too fast when the wood is too fresh. My best luck has been in the controlled environment of a dehumidification kiln.

Joe

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Hi,

So what's happening in winter that makes the sap so sweet?

A maple tree looks bare during winter but if you look under the roots as soon as the leaves fall root fibres start growing. There may be as much woody material under ground as above it.

It is very obvious that the material for the white, newly formed root fibres were at least partly made in tle leaves by photosynthesis. It is also obvious that the water and the chemical elements came from the ground. There is a top to bottom circulation inside the tree, but how maple syrrup is made remains the mystery!

Dons post and experiment supports the advantage of end reared seasoning, however everybody whorks with freshly cut timber can see with a naked eye the sap flowing infront of a blade.

Regardin wood cut during sommer, there is more sap and mere extractives inside the cells so the specific weight of the wood will be more that some cut during winter.

Here are some exposed roots of a small maple tree:

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post-5577-0-97174500-1356384454_thumb.jpg

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Hi,

So what's happening in winter that makes the sap so sweet?

Sugar (carbohydrate) storage to be used for re-foliation in the spring, from what I have read.

Regardin wood cut during sommer, there is more sap and mere extractives inside the cells so the specific weight of the wood will be more that some cut during winter.

Perhaps so, but I haven't been able to find any scientific evidence for it so far. Just the usual lore, and handed-down beliefs. It's looking more like winter is the time of higher nutrient storage.

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"Some people have speculated that wood cut in the fall and winter should weigh less, since the “sap is in the ground.” However, the water content of wood is roughly the same year-round."...University of Tennessee, College of Agriculture and Natural Resources

The reason we always did winter cut wood is because it hangs on to the bark better....we were mostly cutting boule for cabinetwork. This plus the temperature does not promote fungal growth.

Joe

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I had a very interesting conversation with the late Koen Padding re tree felling. From what I remember he had found an !8th C Dutch naval treatise complaining about reduced timber quality resulting from the abandoning of traditional tree felling methods. The abandoned method involved ring barking the tree when in full leaf and felling later ( I understood it to be winter). This was thought to yield superior timber but keep in mind that it might be oak for ship building rather than spruce or maple which are more vulnerable to fungal attack.

I mentioned this to two trained foresters who supply spruce and maple for the violin trade and they both said that maple or spruce cut in this way would be damaged by insect and fungal attack. However a year or so later one of these guys, Andreas Pahler was rather excited to show me a cello front he had cut from a tree that had recently died standing. He said...' I cut this tree 3 months ago but I think you can make a cello from it now'...I agreed and used it a few months later with happy results. There is also the case of the engleman that Simeon Chambers harvested from long dead ghost pines which had some very nice qualities.

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Melvin - ring-barking is still standard practice for Japanese temple builders!

I sometimes wonder if forestry traditions aren't quite pragmatic - at a time when all timber had to be dragged by humans or horses, it was handy to lose some weight by getting a lot of the drying done before you felled the tree. Then if you brought it out it when there was snow on the ground, it was so much easier to haul.

On Stobo Estate (where I used to have a small sawmill), there were various remnants of old horse-drawn sleds which were used for timber extraction until about 30 years ago.

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