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Milling trees cut in summer vs. winter, green wood, drying etc.

Started by OcoeeG, January 30, 2012, 10:12:29 AM

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OcoeeG

I am in the preliminary stages of planning for a timber frame build starting this summer.  I have been doing lots of research about building with green timbers (going to try to use oak), cutting/raising green, drying in place etc.  I would love to start milling in the summer and have timbers ready to cut by say mid-October.  I found some info regarding the fact that trees cut in the winter dry faster and are potentially more stable than trees cut in the summer.  How much truth is there to this?   And if anyone knows of any good posts about this topic and cutting/drying green timbers please let me know.  I have done a search and came up with some information but not a ton.  Thanks in advance.

Jim_Rogers

Welcome to the forum.

I don't have any experience cutting an oak frame.

I have milled oak timbers and lumber before.

I can't say that I have actually noticed any difference in winter cut and summer cut timbers

I would believe that winter cut would have less water in them, but I don't have any evidence as to whether or not this is true.

Welcome to the forum.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

WDH

The moisture content of the wood is stable throughout the year, so that will not matter.  What might matter with thick timbers is that the drying conditions in the winter in many areas of the Country are milder with lower temp and higher humidity versus the summer.  When it is hot and dry, thick timbers can dry too fast and split and check from the stress.  However, given a thick timber to begin with, one winter or one summer will not be even close to enough time to dry anyway, so like Jim, I suspect that it does not practically matter a whole lot.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

shinnlinger

I have done some work on oak frames and let me tell you it its way easier when they are green regardless of time of year.  Old timers talk of firewood being dryer if you cut out after it has lost leaves but I think it is a negligible difference
Shinnlinger
Woodshop teacher, pasture raised chicken farmer
34 horse kubota L-2850, Turner Band Mill, '84 F-600,
living in self-built/milled timberframe home

Hilltop366

Some guys around here drop there firewood trees in the summer when the leaves are on, then go back in the to limb them up and haul out to be blocked and split. They say the leaves will get rid of a lot of water before they dry up and shorten drying time. Not sure how true this is,

beenthere

Won't get rid of a "lot" of water. Somewhat of an old wive's tale but one which persists to be passed around.  At least the leaves will lose their water. ;)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Brucer

From first hand sawing experience (not joinery experience) ...

Around here the winters are long and cold, with plenty of snowpack. As near as I can tell, the moisture content of the heartwood stays the same year round. Sapwood is driest in the winter, wettest in the spring, and dry again in the summer.

That kind of figures. There's a reason they collect maple syrup in the spring. In the winter the sapwood would freeze and rupture if it had too much moisture. In the summer when it's hot, there isn't as much moisture in the ground (usually). In the spring there is plenty of moisture available and the temperatures are above freezing.

I read a report recently on experiments with Western softwoods. It appears that leaving the needles on the fallen trees through the spring does help dry them out -- but only at the surface. Once again, it's the sapwood that's affected.

This isn't necessarily going to apply in every climate.


Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

Thehardway

OK, I'm going to be the rebel here and go "against the grain" ha, ha.   First of all I never discount the wisdom of our ancient ancestors.  They were much more in tune with the rhythms and cycles of nature.  Doing things without mechanization requires this type of wisdom to survive.  That said, I like to try and substantiate the oral traditions with modern day scientific research.  OK, enough rambling.

When harvesting a tree for lumber with low moisture content:

1. You cannot lump all trees into one group
2. You cannot use Annual averages
3. You cannot use seasonal averages
4. You cannot use daily averages
5. You cannot use the average content of the trunk

OK, here is the why part.

Trees are much like people.  They don't just stand there, they are alive and working.  Their work is to grow, produce roots, branches, leaves, resist pests and disease, droughts, wind, solar radiation, and utimately, if all goes well and they are lucky, they have children!

Much like people, this is a routine which begins every morning at the crack of dawn.  As the sun begins to rise, water has to be transported up the stem of the tree to the branches and out into the leaves.  The leaves use this moisture for several purposes, they perspire to stay cool in the sun, they combine it with light, carbon dioxide and nutrients to produce food (sugar) for the tree and promote growth. They store some moisture in their cells just to stay hydrated and keep from dying out just like we do.

Because of this process, the water content of a tree trunk (where we obtain the majority of our lumber from), varies and is cyclical on a diurnal basis. It also varies somewhat by season although averages may not accurately reflect this.

Just like people, the hotter it gets outside, the more water we must take in in order to stay hydrated.  During the summer, large amounts of free water are transported through the sap wood and up to the branches for transpiration, this continues until early afternoon at which point the tree is growing "dehydrated".  You may notice some wilt or curling of the leaves.  It then begins the process of trying to rehydrate for the next day utilizing the onset of falling temperatures, dew and its root system to store up water for the next days work.  Mich like at 4 o'clock you are relatively dehydrated from the days work and you sit down and consume a fair amount of your favorite beverage.  Because of this daily process, the water content of the sapwood can vary greatly throughout the course of the day while the heartwood remains somewhat stable.  This is important to note for harvesting lumber.  We do not cut a tree down little by little over the course of a day so as to obtain a daily average.  Most trees are felled at a specific point in time.  Once they are felled they may or may not be immediately processed.  If left to lay with the branches and leaves on, they will deplete much of their moisture through the leaves as they dry up and fall off.  The remaining moisture will seek to reach an equilibrium across the full tree.  This is why time of day and speed of processing can cause as more variation in MC of sawn lumber than time of year.

Most of you have cut wood and have had trees which when you drive a felling wedge into them, the water gushes out visibly around it and your saw dust is wet and clumpy. Other times you may have cut trees and the sawdust is dry and has almost no moisture.  From this you know that water content is not the same all the time. 

So what about winter vs. summer?

In late summer, early fall, sugar concentrations in tree cells begins to rise.  This sugar was produced by the leaves during the summer and will support the cells resuming life in the spring.  Much like when you are in the hospital and not taking in regular food through oral feeding, they will place you on a sugar drip IV.  Just enough water is in this solution to keep the cells hydrated and transport the sugar so as to sustain your life.  This sugar concentration also help to keep the cells from freezing as sugar changes the freezing point of water.

In general, trees have less moisture variation during the winter. This does not mean the heartwood has a lower MC than it does in the summer. The MC of the heartwood is relatively stable.  Most deciduous trees are dormant or semi-dormant in the winter.  Their leaves are usually gone and therefore they do not have to transport water to the leaves for cooling, food production, or for the support of fruit production.  They maintain just enough moisture in the sapwood to support early bud formation and general hydration.  Think about it.  When you are asleep, you usually perspire at a somewhat stable rate, unlike during the time you are working where it can vary greatly.  Your internal MC stays constant but the MC of your skin and outer layer varies.  Do you get chapped hands and lips in the winter?

In the spring, water levels can rise rapidly as the tree emerges from dormancy and tries to begin using up sugar stores for bud production and new leaf formation, much like when you arise in the morning you usually excrete your waste water and then take a fresh drink of water or juice as one of your first functions.

As mentioned before, not all trees are the same, conifers differ from deciduous and temperate, species can vary based on exposure and a variety of other factors.


So when is it best to harvest a tree?

What kind of tree is it

What part of the tree do you wish to use?

Are you going to cut it into logs on the day it is felled?

Are you going to leave the logs stacked for drying or process immediately?

Are you going to soak them in a log pond?

Are you concerned about sugar content and bugs?

Are you more concerned about stability?

All of these questions have to be asked in order to determine the best answer and only you can answer them.  This is a good reason why cutting your own trees and milling your own lumber is superior to buying it.  You can control all of the factors based on your intended end use.  This is why there is a great difference in commercially harvested lumber and selective lumber production.  This is the wisdom our ancient ancestors had, knowing when and how to harvest and only harvesting what was needed for the task at hand. 

I'm not saying anyone here is right or wrong, just at any given time they may be either ;D

For reference you may wish to review;
Vascular transport in plants By Noel Michele Holbrook, Maciej A.


Norwood LM2000 24HP w/28' bed, Hudson Oscar 18" 32' bed, Woodmaster 718 planer,  Kubota L185D, Stihl 029, Husqvarna 550XP

WDH

I do not agree that trees are like people at all.  I believe that they are very different, and trees do not have children in the same sense that people do.  Human tissue and skin is not at all like bark and wood.  The comparison is misleading.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

Thehardway

WDH,

You must not have seen Avatar! LOL.

Would you agree that the bark of a tree is its protective covering? When a tree is injured we say it is a "wound" and it may "bleed" and then "scab" over?  The outer layer of bark is dead much as the surface layer of skin cells is dead and are shed or sloughed off.  This sounds much like skin. No it is not the same but it seems to have more likenesses than differences.  Please expound on some of the differences.

Like humans, trees can get diseases.  I agree that the biological system of a tree is nothing like the biological system of a human in the sense of having a heart, blood, specific internal organs etc.  It is much simplified and quite basic compared to the complexity of the human body.  It is however still quite complex in that it has an immune system and is able to sustain growth in some of the most unlikely situations.

If you look at the breeding programs for fruit trees you will find very little difference in human offspring and that of trees.  Genetic traits of the parents are passed to the offspring and they can be good or bad.  They have a literal family tree which can be traced over several generations.  Although trees do not have offspring as the result of an intimate relation like humans and specifically egg and sperm, they are still sexual in nature requiring pollenation which results in seeds and replication.

My objective was not so much to attribute human qualities to a tree as it was to get people thinking of trees as living, breathing organisms that are in a constant state of change and performing daily functions of life.   We tend to think of trees more as an elemental material like iron, magnesium or aluminum which has a constant and specific weight, strength and molecular structure.  Trees and the wood they yield is anything but static. 

Some would argue that trees have personality and some may even argue a spiritual dimension to trees.  I think this is a little over the top but who am I?  A team of scientists at the University of Washington in Seattle, led by Professor David F. Rhoades, claim to have evidence that proves that trees really do "talk.'' Humans cannot hear their conversations, but one can be understood by another. Supposedly this communication took place over a distance of 100 yards or more. This claim is disputed by others but I still find it interesting.  Trees communicate in many ways with humans.  They let us know when a storm is on the way, how windy it is, where water can be obtained, when seasons begin and end etc. 

Shakespeare said ""Stones have been known to move and trees to speak," Is this purely superstition?

I am sure as a forester you know much more about the biological properties of trees than I do and I will not claim to be any kind of authority,  I've just read a few books and been in the woods all my life as an observer and many times things are not what we think we see. I have no formal education in forestry or wood science.

As I stated I was going against the grain in an effort to stimulate thought outside the proverbial box.  I do know from experience in the woods that the amount of free water and cellular water in a living, standing tree varies greatly and is not the same all the time as we would be led to believe in earlier posts.

Please take no offense.
Norwood LM2000 24HP w/28' bed, Hudson Oscar 18" 32' bed, Woodmaster 718 planer,  Kubota L185D, Stihl 029, Husqvarna 550XP

matt eddy

My experience in working with oak is cut your joinery when its green and try to get it up before it drys.  I cut a oak frame, let it sit 6 months or so and it twisted and moved so much the raising was very difficult.  I have used dry oak and was very happy with the end result but not happy with joinery process.  spent alot of time sharpening.  What did help was keeping a water bottle on hand to wet down places that required hand tools.  My best oak frame result was one I cut in winter and raised it while the timber was still frozen.  Went up slick and joinery was easily done.  When it dried joints stayed tight, with help from draw-boring.  Good luck with your frame and I hope you have fork truck cause oak is heavy!
Matt

WDH

Quote from: Thehardway on February 15, 2012, 09:45:41 AM
My objective was not so much to attribute human qualities to a tree as it was to get people thinking of trees as living, breathing organisms that are in a constant state of change and performing daily functions of life.   We tend to think of trees more as an elemental material like iron, magnesium or aluminum which has a constant and specific weight, strength and molecular structure.  Trees and the wood they yield is anything but static. 

Shakespeare said ""Stones have been known to move and trees to speak," Is this purely superstition?

I see where you are coming from, and I agree with and respect your position on trees.  I especially like the Ents in the Lord of the Rings!  I also thought Avatar was great.

The moisture content of trees may vary diurnally or over a period of time, but as a living system, these changes are not large in magnitude and do not have a significant effect on their use.  If you boiled down people, their moisture content would vary person to person and probably from the morning to the night, but the differences would not affect the soup much.

However, I appreciate discourse about moving stones and trees that talk  ;D.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

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