Green lumber waiting for kiln

[kristosig]

I came by something just now, while reading page 26 in Drying hardwood lumber. They are talking about how air velocity changes when changing sticker size and the size of the actual area the air goes through.

When calculating the air velocity in my chamber, I forgot to account for the lumber! As about half the volume of the chamber will be lumber, the average air speed in the chamber, if I use my 1677 CFM box fan, will actually be about double my original calculations, so 256 fpm. And the air velocity inside the stack will be higher, as there is just as much air volume that must flow, but through much narrower openings. So, as long as the fan is strong enough to overcome the associated friction, the air velocity inside the stack should be in the range you are recommending, that is 500-600 fpm.

So, I think I'll just close the chamber. Put the fan in the hole where the WDU will sit, blowing out. Open the hole on the left side, where the outflow vent will be, and just turn on the fan. The air velocity will benefit from the small stickers, as long as the fan can overcome the friction. As it is slabs I'm drying, not dimensional lumber, there will be significant lateral (horizontal) gaps between the slabs, which also permit airflow and decrease the risk for stale pockets of air.

I will have to measure the in- or outflow (doesn't matter which) to know, but I'm guessing I will have quite adequate air velocity. My biggest concern now is how to make sure it won't become too much. I'm worried that my lumber will start cracking and deforming. The anchor seal on the butts of the slabs will help. Maybe I can control the air flow by adjusting the vent (which in this scenario temporarily serves as an inflow vent, rather than outflow as it will do when the WDU arrives).

I'll continue reading the book (great source of info, by the way, thanks heaps for pointing me into that direction) and see what more I can find out. I'm guessing I should be able to estimate the speed of drying from the air flow. Let's say for arguments sake I have 800 board feet of European ash, 8/4, it's MC is about 50 procent, the average temperature of the air is 9.4°C (49°F) and the humidity around 90 percent. With an air velocity of 500 fpm, it should lose...X percent points of humidity per day...I'll read on.

Apart from the math problem above, what is really interesting to me is what I should be aiming for. Ash is supposed to be very forgiving, so losing 3 percent points in moisture per day may be OK. This would mean my lumber would reach EMC (about 19%) in ten days. That actually frightens me. I envision a heap of cracked propeller blades when I come home from my trip and open the chamber.

We will mill the lumber 4th of October. I will leave for my next business trip 10th or the 11th and come back home on the 31st. Logosol will deliver the WDU the Friday before I come home. I guess I could turn on the fan directly after stacking the lumber on the 4th and measure the MC every day during that week. Then I will know the drying rate. If it as fast as I suspect, I may turn off the fan during the night. And maybe just turn the fan off, period, when I leave. If I'm down to about 35% MC by then, I can just open the chamber and let it stand. The risk for fungi is not that high in lumber with MC 35% in an average temperature of 49°F.

[doc henderson]

well you will learn a lot from this first go round.  glad you are reading, and it puts us all on the same page.  the air needs to come from the side and move parallel to the stickers, and i would measure air flow on the out side, since normally you have a baffle to force the air through the stack,  and air going 1000 ft/second over the top does not help.  air flow is most important at high MC.  good luck.

[GeneWengert-WoodDoc]

The temperature, relative humidity and velocity determine the drying rate.  To get even drying, we need close to the same co dictions throughout the kiln.

Evaporating moisture takes energy.  You can use various sources for energy...solar, wood, gas, etc.  you can use these sources and make electricity, hot air, or steam or other heat source.  The lumber does not care the basic heat source...it cares about having enuf energy to evaporate water.  In some cases like air drying, the air temperature provides the energy, but using hotter air in a kiln means much faster drying.  Using fans can also speed air drying.

So, then we have to consider what gives us quality drying.  For example, faster drying gives us whiter color, faster drying creates shrinkage stress and checking.  Slow drying encourages mold and mildew, as well as blue stain.  Some species, like pine, can take a lot of abuse and still turn out well.  Other species, like oak, needs slow, careful drying.  Drying time is determined by the wood quality desired and not the kiln's drying speed ability.  (Analogy:  if driving a car that can safely go 200 km or 120 miles per hour, up a curved mountain road at 30 kilo per hour is reasonable do be safe.  The road conditions and safety determine the speed.)

Steaming lumber prior to drying is covered in the US by patents from Danny Elder.  Steaming for color like walnut is not included.  Steaming does "discolor" the white woods, like ash, beech, maple, etc.

[YellowHammer]

As pointed out, "drying wood" and "drying wood for quality" are two different things.  

Typically, the last thing I would want to do is rewet a load of partially air dried wood in a steam chamber without a lot of background information.  An initial high kiln moisture level can cause a mostly air dried board's case to swell and expand, which can cause voids in the core (honeycomb), if done incorrectly.  For example, in a conventional kiln, the machine should be set as to an initial point of wet bulb and dry bulb so the the kiln conditions match the current moisture content of the wood, to avoid rewetting the surface.

Drying too fast causes all kinds of damage.    

Also, the industry standard thickness for stickers is 3/4" or so, and that because it is a good balance of airflow on the the lumber stack to get even airflow without requiring excessive velocity.  Too much or too little air velocity can really dictate the quality of a load being dried.  Most kiln are designed for a median airflow velocity using standard sticker thickness so changing from the manufacturers recommendations could be problematic.

One issue I see is that the thinner stickers the kiln calls for would be much too thin for me to use for quality air drying.  Air drying is a necessity simply because for no other reason it allows time for the fresh sawmill cut wood to be "staged" while waiting its time in the kiln.  So that leads to a problem of the stacks having to be "restickered" from the air drying yard to be used in the kiln.    

Certainly, there are different drying procedures for "white wood" to reduce enzymatic sticker stain caused in part by too much heat during the wrong part of the drying cycle, where some other woods are more prone to fungal sticker stain, which requires a different procedure.  Some woods should be dried cool, some should be dried hot.

Does the "App" take these factors into account?  Does it have a different procedure for white oak, which is very finicky vs pine which is very forgiving?

[kristosig]

The temperature, relative humidity and velocity determine the drying rate.  To get even drying, we need close to the same co dictions throughout the kiln.

Evaporating moisture takes energy.  You can use various sources for energy...solar, wood, gas, etc.  you can use these sources and make electricity, hot air, or steam or other heat source.  The lumber does not care the basic heat source...it cares about having enuf energy to evaporate water.  In some cases like air drying, the air temperature provides the energy, but using hotter air in a kiln means much faster drying.  Using fans can also speed air drying.

So, then we have to consider what gives us quality drying.  For example, faster drying gives us whiter color, faster drying creates shrinkage stress and checking.  Slow drying encourages mold and mildew, as well as blue stain.  Some species, like pine, can take a lot of abuse and still turn out well.  Other species, like oak, needs slow, careful drying.  Drying time is determined by the wood quality desired and not the kiln's drying speed ability.  (Analogy:  if driving a car that can safely go 200 km or 120 miles per hour, up a curved mountain road at 30 kilo per hour is reasonable do be safe.  The road conditions and safety determine the speed.)

Steaming lumber prior to drying is covered in the US by patents from Danny Elder.  Steaming for color like walnut is not included.  Steaming does "discolor" the white woods, like ash, beech, maple, etc.

Hello Dr Wengert. I must say I am honoured that you take the time to share your insights in my thread. I am currently listening to your webinars (half-way through the four-part "Kiln drying hardwood lumber") and I am reading your book "Drying hardwood lumber". Excellent sources of information and fantastic that they are available free of charge.
I will obviously take in as much of the available material first, before asking questions that I may find have already been covered. I do wonder, however, if it were OK that I ask a few questions in case I do not fully understand after reviewing the material? What I am mostly wondering right now is what I can get away with in storing green lumber and trying to maintain its high MC to the extent possible while avoiding mould, staining, insects and other quality degrading factors until my kiln is delivered and I can make my first attempt at properly drying the lumber.
I will be sure to include environmental factors such as humidity, dew point, temperature etc if and when I ask my questions.

[kristosig]

As pointed out, "drying wood" and "drying wood for quality" are two different things.  

Granted. Incidentally, my ambition is to do the latter. However, given my complete lack of experience, I will be lucky if I only achieve the former.

Typically, the last thing I would want to do is rewet a load of partially air dried wood in a steam chamber without a lot of background information.  An initial high kiln moisture level can cause a mostly air dried board's case to swell and expand, which can cause voids in the core (honeycomb), if done incorrectly.  For example, in a conventional kiln, the machine should be set as to an initial point of wet bulb and dry bulb so the the kiln conditions match the current moisture content of the wood, to avoid rewetting the surface.

I certainly see your point. I believe the manufacturer (and therefore I) uses the term steaming somewhat loosely. The procedure seems to be turning the equipments thermostat to 50°C (122°F). 

The actual temperature achieved will depend on the environmental conditions. They say it can heat air going through the equipment by 25 degrees centigrade (45°F), so the maximum temperature allowed by setting the thermostat to this setting will be achieved on the first pass only if the outside temperature is 25°C (77°F) or more. Otherwise, the temperature gain rate and end point achieved will depend on the outside climate and the kilns insulation. It is, of course, conceivable that a poorly insulated kiln in a cold climate will never achieve this temperature. For practical purposes, I will assume my kiln is insulated enough (built out of a double layer of overlapping 2 inch XPS boards (total thickness 4 inches), screwed and glued together with PU glue).

For green lumber, no water is added. Otherwise, the app suggests a certain volume of water to be added (simply poured on the chamber floor) depending on the MC of the lumber.

Then the chamber is closed. The vent is completely closed as well. As I understand it, the air is heated to 50°C (122°F). If not on the first pass through the equipment, then in subsequent passes, as the air is circulated within the chamber. The water will vaporise. This will create a very warm, humid environment in the chamber. The general advice from the manufacturer is to maintain this environment for 2-4 days. The app makes more specific suggestions based on the values one inputs.

I do wonder if this temperature (50°C/122°F) is enough to effectively kill insects and fungi. According to dr Wengerts lecture, the "magic number" is 133°F (dr Wengert does present this a little tongue in cheek, I believe, notes that this is the "magic number" the US authorities claim). I would be inclined to believe that although this temperature lies under the typical temperature used to safely eradicate the common insects/fungi, this may be compensated by the time factor. Meaning that although they may be able to survive a couple of hours or maybe a day in this environment, two to four days will still kill them. This however is a mere guess on my part.

After this procedure, one is to adjust the thermostat. For soft woods, continue on 50°C (122°F). For harder wood and species that require more special care, lower settings are recommended, down to 30°C (86°F). The vent is opened a bit to let humid air out. The general advice is to just have it open enough that the air coming out is very humid. The app suggests an air flow defined in m3/h (I think the app can also be configured to display values in CFM). The app will also make a suggestion as to the exact temperature to which to set the thermostat.

Also, the industry standard thickness for stickers is 3/4" or so, and that because it is a good balance of airflow on the the lumber stack to get even airflow without requiring excessive velocity.  Too much or too little air velocity can really dictate the quality of a load being dried.  Most kiln are designed for a median airflow velocity using standard sticker thickness so changing from the manufacturers recommendations could be problematic.

One issue I see is that the thinner stickers the kiln calls for would be much too thin for me to use for quality air drying.  Air drying is a necessity simply because for no other reason it allows time for the fresh sawmill cut wood to be "staged" while waiting its time in the kiln.  So that leads to a problem of the stacks having to be "restickered" from the air drying yard to be used in the kiln. 

I am quite ambivalent on this point. Everything I read suggests this standard thickness (or more). However, the manufacturers instructions say minimum 5 mm (13/64"). Unfortunately, the logistics of using taller stickers than 12 mm (15/32") would be problematic for me. It would require me to create some kind of storage area for milled planks that do not fit into the kiln. Obviously not impossible, but quite impractical as I am starting this operation outside my home in a normal suburb. Just having a kiln outside my house is a stretch. I am considering renting better facilities, but before doing that, I would like to run this process at least one time to get some hands-on experience and insight into the requirements.

Stacking the lumber once after milling and again when the kiln arrives (ie the actual WDU; the kiln chamber I will build myself) is an option. A somewhat cumbersome option, as I would need a great many stickers that are too tall to be re-used after the kiln equipment arrives, but an option.

The actual trees will stand, still living, in the forest, until I get them. So storage is really only a problem after I actually fell a tree.

I am quite inclined to rely on the manufacturers instructions for this first go-around, that is in what I do after I receive the WDU. Especially at my level of experience and expertise (nill), this would seem to be the safest initial approach. The question that remains, however, is how I treat the lumber prior to receiving the WDU.

I do plan to follow dr. Wengerts recommended procedure on oven-drying a sample and following the weight of sample bits in the kiln to familiarise myself with the progress.

Certainly, there are different drying procedures for "white wood" to reduce enzymatic sticker stain caused in part by too much heat during the wrong part of the drying cycle, where some other woods are more prone to fungal sticker stain, which requires a different procedure.  Some woods should be dried cool, some should be dried hot.

Does the "App" take these factors into account?  Does it have a different procedure for white oak, which is very finicky vs pine which is very forgiving?

I believe so, for the most part. The app has a basic and advanced mode. In basic mode, one just inputs the species, amount of lumber, its MC, climate conditions, equipment and chamber type (the commercially available chambers), target MC and a choice of fast, normal or high quality drying.
In the advanced mode, one can input a custom-built chamber in great detail. Density of the material in the chamber, thickness, custom species of wood (density), initial temperature in the chamber/wood, and many other variables. Right now, the apps login doesn't work (this is early beta, they are working on it), so I am unable to post a screenshot.
Whether the app takes into account other properties of the species of wood than the density, I am not sure.
The app uses a step-wise approach. It does project the total time for the process, but it would seem that it does not give exact instructions for more than a few days at a time. I haven't gone through the process, but what I have tested just gives me the initial step and then initiates a countdown timer. After that, one is supposed to indicate this initial step is done. Supposedly, further instructions are provided after this. Probably one is asked to input some more variables at this point, which will mould the instructions provided.
According to Logosol, they actively collect the data one inputs into the app to refine it's suggestions. So I imagine it must require objective information from the various stages of the drying process.

[kristosig]

I actually believe the following merits its own post, as it is the core of my perceived predicament.

There is a lot of good information in this thread and in various other places, especially in dr Wengerts amazing material, about how to dry lumber. I believe I have gathered a rudimentary outline of how I would best dry my lumber before the kiln equipment is delivered. I should, in that scenerio, stack it with wide stickers (I have a stack of roughly cut 2x4s, about 12 feet long, that I could use). Place it in a height of about 40 cm (1.3 feet) above ground. I should make a roof over the stack to shield it from rain and sun, and I should place it somewhere with adequate air flow (not too much, not too little). One example would be my carport, maybe with a fan blowing.

However, I am concerned that this approach would mean my lumber going through the most dangerous stages of drying without taking advantage of the equipment I am explicitly buying for the purpose of reducing the risk for degradation of the quality of the lumber in exactly those beginning stages. If we refer to dr Wegnerts terminology, I am referring to the first two stages of drying here, when the problems arise and when they become bigger.

So I come to the preliminary conclusion that my best bet is to try to maintain the high MC in the lumber while waiting for the kiln equipment to be delivered. Realising that this puts the lumber at risk for fungi and insect infestations, as well as staining, I am quite ambivalent as to whether my conclusion is correct.

The mere fact that I do not find that much information on how to safely store green lumber after milling it, while preserving its green state, may suggest that this is simply a bad idea on my part.

I have read about two methods. Storing the logs unmilled and to store the lumber in water. The former option is available to me. However, it would mean losing an opportunity where I have a group of guys helping me, where we were planning to go through all the stages of logging/milling to get some hands-on experience. The latter option is not available to me, as I do not have access to a body of water where I can keep 800 board feet of lumber.

I do believe that after this initial test; dress rehearsal if you like; I may streamline the process by actually felling all the trees, cutting away branches/twigs etc, cutting them to length and transporting the logs to a storage area. Then just milling out planks as kiln space becomes available. I am allowed to store the logs temporarily near the forest, the landowner will pick a spot I can use. This area is about two hours from my home, so I may, depending on how this goes, choose to rent facilities closer to home where I can store unmilled logs, saw them, kiln-dry them, and store the kiln-dried lumber.

[doc henderson]

If you store the logs, seal the ends.  you can mill and stack under the carport.  that sounds perfect as many if not most people stage stacks to get started air drying to decrease time in the kiln.  what is you average RH this time of year where you are.  I think you mentioned 49 ° F temps.  thanks for reading the available material, and now we are all speaking the same language, so to speak.

[YellowHammer]

However, I am concerned that this approach would mean my lumber going through the most dangerous stages of drying without taking advantage of the equipment I am explicitly buying for the purpose of reducing the risk for degradation of the quality of the lumber in exactly those beginning stages.

Oddly, I have found it very beneficial and safe to pre air dry very high grade lumber (thats only what we sell) before it goes into a kiln.  Other than very occasional sticker stain in white wood, caused by summer time high outdoor ambient temperature and humidities, using a suitable end sealer, and stacking high, I believe many good things happen to outweigh the negative with correct air drying, and it allows the wood to get down to a relatively low MC with very little risk.  As a general rule, I won't put a load in a DH kiln until it has been in our air drying yard at least 6 weeks, and some of the local smaller producers who have had historic kiln drying problems are adopting that policy, even though it adds to their timeline.  At that point, setting the initial points on the kiln are based on the moisture content of the wood.  I just follow the convention of the big local producers.  This is a manufacturer of predominantly white oak, and at any given point they have 2 million bdft on the air drying yard at one time.

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This will create a very warm, humid environment in the chamber. The general advice from the manufacturer is to maintain this environment for 2-4 days. The app makes more specific suggestions based on the values one inputs.

For certain North American species, such as poplar and maple, the ones I am familiar with, this would cause alarm bells to go off in my head and I would be very concerned about sticker stain and discoloration of the wood, most likely the sapwood would streak.  For the "whitewood classification" such as these species, there are very specific kiln schedules in which the temperatures are kept relatively cool during the drying cycle to maintain bright colors and quality.
 
For a species such as pine, which dries extremely fast, I wouldn't see the reason for this part of the cycle, I would go straight to drying the wood, and save the 4 days of kiln time and electricity.
 
There are several data points for killing mold but it is generally accepted to be above 120F, although there are some FDA publications that list the minimum as 140F.  However, the 133F point is the generally referenced point for acceptable lumber drying and safety.  There are quite a few very interesting publications on the subject, and even more interesting is that not only are they a function of time, but much is based on wet bulb temperature vs time, not necessarily dry bulb temperature.
   
I personally like to go to a minimum of 145F or 150F and hold for 24 hours.  We have a very heat resistant "canary" insect here, its called a black carpenter ant, and I have seen them alive, although very damaged, when wood has only been to 120F.  They are tough little critters.  I have never seen anything survive 133F and l inspect every load.  So to be safe, I like to get to even the higher 145-150F values to make sure everything is dead.

This is what I like to see: dead bugs such as this one that tried to get out of the board and got cooked before it had a chance to leave.  The results of sterilization are easily apparent.


The oven dry method is the gold standard and very effective and easy.  I've done it for many years.

I would highly recommend the installation of a wet bulb and dry build sensor, if one is not supplied by the manufacturer.  These are simply two temperature sensors that are exactly the same, except one has a moist sock or "shoe lace" over the probe.  The other end of the sock is inserted in a water bottle next to it which keeps the wick moist.  The numerical display is mounted outside the chamber.  WB and DB are invaluable for understanding what is going on inside the kiln.

I'm very interested to follow your progress.  

[K-Guy]

Even though I work for a kiln manufacturer, there is nothing wrong with air drying , as long as it is done properly! 

I have seen good results too many of you here to ever argue that point but you need a kiln to get low (7-9%) moisture content in most areas and too sterilize.

[GeneWengert-WoodDoc]

One issue with thinner stickers as that they would break easily, especially when there is a gap between two adjacent pieces of lumber that are different lengths.

Air drying relies on the weather being acceptable for drying,  but, sometimes here in GA, we see 80 F, 36% RH and 400 rpm or higher air flow.  So, air drying is ok if done properly which may mean using a roof and may plastic burlap or even a shed with a slight reduction in air flow.

[kristosig]

OK, I've been reading Drying Hardwood Lumber, all the helpful comments here and listening to some of the webinars.

I have some organising to do, actually for two different scenarios:

I What to do after I get my kiln up and running.

Should I air dry first or should I just end-coat the logs and mill them as kiln space becomes available? Air-dry first is much easier, I guess. Shortens kiln-time. My kilns maximum capacity is 800-1000 bdf, I have six trees to mill/process and I only have about 30 weeks to do this. On the other hand, I would get much more quality out of milling and kiln-drying directly.

One approach would be to fell all the trees, cut to length, end-seal. Mill and air-dry the ash. We're approaching winter now, so I really doubt it will over-dry (that is become dryer than 25-30 percent). Mill the cherry as needed to load the kiln, but keep it in end-sealed logs until I've got space in the kiln. When I'm done with the 3-4 cherry trees I have, start kiln-drying the ash.

II How to treat the first lumber I get, about 1,7 m3 (800 board feet) of ash and, the next day, a minor amount of cherry. At this point, my kiln equipment is 26 days from being delivered.

After reviewing all of your comments, reading the book and listening to the webinars, I have slowly been more and more inclined to accept that I have to dry the lumber while waiting for the kiln. Otherwise, I risk getting insects and fungi which will damage my lumber. This means accepting that the first and critical stage of drying will be more or less uncontrolled. This may lead to internal/external/end checking and warping. My reasoning here is that ash is a brightly coloured wood that should be dried fast. It is not at all prone to checking or warping, according to Drying Hardwood Lumber, it can safely be dried at a whopping 4.1% per day (8/4). Also, ash is known to be very sensitive to fungi and insects. My safest course of action is thus to dry it fast, while still doing what I can to reduce degradation. End-sealing. Properly stacking. Protecting from rain.

I have made a little sketch of a temporary solution, a stand of sorts, where I will put the lumber while waiting for my kiln. For your convenience, I have added the dimensions in inches. As I designed this in millimetres, the numbers are not even when converted to inches. I also indicate north/south, as I will be discussing prevailing winds later in this post.



 

The studs I will use are some roughly cut spruce I have laying around. Bought it from a nearby farmer who has an ancient tractor-driven sawmill. It's 52x105 mm I believe (roughly 2x4 inches, but not nominal, but actual dimensions).

A very basic design. Three gavels made of two vertical studs each. For each of the two resulting rows of vertical studs, I will put two horizontal studs, one on each side of the studs, for a total of four horizontal studs. The "roof" extrudes 250 mm (9.8 inches) to the front and back of the stand. I think I'll just put a tarp there.

I have space for two stacks, as I would like to keep the cherry separate from the ash. I make the stand much taller than the expected height of a stack, because if I choose to air-dry the future lumber-loads before kiln-drying them, I would like to be able to add a second layer of horizontal studs and thus increase the stands capacity to four stacks.

From my reading, I understand the stacks should be oriented perpendicular to the prevailing winds. From weather data, one can see that the wind will be perpendicular to the stack about 40% of the time. But as there are more things blocking the wind in the other directions (that is the directions that would go right through the stack from one long side to the other), I believe that at this particular place, a much higher percentage of the wind will go perpendicular to the stack.

The bolsters, as you may note, are placed face-up rather than edge-up. This is just for my convenience. If I place them on edge, they will constantly be falling down when stacking the lumber. They will thus be 52 mm (2") tall and 105 mm (4") wide. On top of every bolster, there will be a 25x25 mm (1x1") sticker to minimise the surface area where the lowest layer of lumber will be in direct contact.

The bolsters will not be fixed to the horizontal studs. My thinking is that I will arrange them to fit the lumber I am drying. Make sure the very ends are supported and then a column of bolster->stickers every 300 mm (12").

The space between the gavels (which I forgot to write into the picture, sorry) is about 116 inches. The maximum length of planks I can mill is 106 inches.

Obviously, I was a bit skeptical that this would hold. But I "did the math" (ehh, used the Sagulator). I assumed that I would be stacking a maximum of 1.7 m3 (800 board feet) in each of the two parts of the stand. I assumed a weight of 1 metric ton per cubic metre (approx 5000 pounds per 1000 board feet). Thus, a total weight of 1.7 metric tons per stack (3748 pounds). Those four horizontal studs will share this load equally and it will be spread evenly on those 116 inches (practical shortcuts for my calculations).

The sag will be right there dancing around 0.02" per foot, which is the maximum I can accept. But I was quite generous with the max weight (it probably won't weigh this much) and it will decrease in weight quite quickly.

The stickers are 25x25 mm (1x1") and are placed with 300 mm (12") intervals. Made out of the same air-dry spruce.

The place I will be placing the stand will probably be an extra parking place I have in the far end of my property, facing a (very) low traffic road. It's paved, so no growth under the stack. The short ends of the stack face the road on one side and my garden on the other. One long side faces a low, sparse hedge. The other one faces the side of the parking space and on the other side of that, a rather dense hedge.

Here is a little historic weather data:

First of all: In the month of October, we typically have an average temperature of 9.4°C (49°F) and average relative humidity of 80 percent. This is based on hourly measurements 24 hours/day.

Here are some more details:


 


 

 

 

 

 

 

[doc henderson]

well my first comment (now that you have been studying) is you can screw it up just as easy with a kiln.  you have to set it up so you get air through the stack,  you blunt it for oak and such.  air goes perpendicular to the stack, but also parallel with the stickers.  Out of all the data, we need you average RH to figure the end point EMC for the wood.  end coat your logs.  better to saw hardwood sooner usually.  get it stacked and airdrying.  your shed looks good.  if it will be tall, may need longer overhand, and or protective side covers.

[doc henderson]

with a high relative humidity, your evaporative drying will be slow.  you will want good air flow so the air in contact with the wood surface will not reach 100 %.  your kiln will work by raising the temp, and thus dropping the RH in the kiln.  you are not going to over (air) dry your lumber.  @GeneWengert-WoodDoc

[K-Guy]

I don't know you plan on drying oak but be aware that oak in the US is different from Europe. You will probably have Sessile oak and that is different from American white oak.

[kristosig]

I don't know you plan on drying oak but be aware that oak in the US is different from Europe. You will probably have Sessile oak and that is different from American white oak.

Thanks for the tip. I won't be drying any oak in the near future. A little too risky for me. I'd be running the risk of damaging my kiln (the tannins; according to the kiln manufacturer, oak should be air dried for 6-12 months before being put into the kiln too avoid corrosion). I would also be likely to damage the lumber. I am a beginner and oak does not exactly have a reputation for being kind on beginners.
Right now I'm focusing on the trees I have. Three large ash trees and three cherry trees (large for cherry trees, obviously not as large as the ash trees). Additionally, I will be getting one small cherry tree from a friends garden. He has already felled it, so I'm just going to saw it to planks and take it home with me next week, rid him of it.

[kristosig]

well my first comment (now that you have been studying) is you can screw it up just as easy with a kiln.  you have to set it up so you get air through the stack,  you blunt it for oak and such.  air goes perpendicular to the stack, but also parallel with the stickers.  Out of all the data, we need you average RH to figure the end point EMC for the wood.  end coat your logs.  better to saw hardwood sooner usually.  get it stacked and airdrying.  your shed looks good.  if it will be tall, may need longer overhand, and or protective side covers.

I see you found the chart with the average humidity. In October, the average temperature is 9.4°C (49°F) and RH 80 percent, EMC 16.4 percent.
But you mean I also should saw the cherry soon and air dry it? Even if its maximum safe drying rate is only 2.3% per day? Sounds a bit risky? Of course, I could start with the ashes. Then it'll be winter when I get to the cherry trees and then the drying will be slower.

Obviously, I am studying and learning a lot right now. There is still a lot I do not yet know. Both on the theoretical side and in pure logistics. For example, I do not know how long it will take me to mill a tree. Maybe a whole day. Maybe two hours. Next Sunday will give a lot of information. That's when we (five friends and I) will go and fell the first tree, saw it to planks, take it to my house and stack it. Then I will know how much work it is, what parts are the hardest, which challenges we face, etc.

As for the logistics, if I could just cut all the trees down and mill them, that might make for the easiest logistics. 

I won't be planning future logistics until after next Sunday, of course. But I have some preliminary thoughts.

One would be to fell all the trees, store them on site in logs cut to length but not in planks. Then going there every time the kiln is ready for a new load, saw a proper amount of planks, and drive them home. This would mean renting a large van (like a U-haul van, $55 USD per day) and driving to the site, two hours away (total four hours driving plus getting and returning the van).

If I could get all five trees milled fast, I could have all the lumber transported to my house by a truck with a crane. It costs $300 USD, but that way I would have all the lumber air drying at home, just waiting for the kiln. Each load taking less kiln time than the previous, as it will have air dried longer.

Maybe I can fell all five trees in one day, gather all five logs in the second day and mill them all in two days. So two weekends?

[doc henderson]

yes, I think so.  at your temp and RH you will have a final emc of about 18 percent.  I assume your homes (interior wood use) are heated/conditioned and result in a lower emc inside.  so your kiln will help you get there.  In the states in the summer we can air dry down to 12% most places, and covered in plastic, I have gotten air dry with a little solar to 7%.  so you will air dry slow, whether you like it or not!  your high RH will keep things slow, so I think you are safe.  You choose and do what makes you most comfortable.  only you know your space available and wood volume you can handle.  If you are less worried about the ash, and many say it is easier to dry, go for that first.

[kristosig]

I have now (as promised) started a separate thread to document this process.

https://forestryforum.com/board/index.php?topic=112349.0