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Ventilation and the TBH There have been many questions and as many opinions on ventilation in bee hives. Two different environments need to be examined, hot and cold.
And
The fact that the bees are trying to maintain a temperature around 92 degrees F.
In a Hot Environment The TBH main concern is comb failure. Many beekeepers get hung up on the idea and forget that TBH hives are actually the opposite of the traditional Langstroth style hives. In a TBH you will not find the "chimney effect" you get with stacked supers, length vs. height. Many beekeepers are concerned that the bees are devoting way to much time fanning at the entrance or bringing in water to cool it down.
An interesting point is bar length. When given free roam by means of a long bar like my first ones 24 inches, it was observed that the bees stuck to one side of the hive and curved the ends of the comb, which would cause it to cross to the adjacent bars. Why the curve which is not observed by TBH keepers with smaller bars 15 inches or less. It can only be speculated that this is done for either stability or ventilation.
I had two hives of this dimension one in the shade and the other in full sun, neither of which was ventilated. The one in the sun was fine, but the one in the shade had 3 bars collapse. The only noticeable differences in the two was the one in the sun had 22.5 degree sloped sides and was older and stronger than the one in the shade which was made from a old military foot locker and had straight sides and new comb.
Both of these hives were made with 30 bars and in both the bees never built past the tenth bar. They were content with a large brood nest with the honey and pollen stored on the fringes of all the combs. The hive in full sun made it thru the previous winter with NO follower board I just left the empty space. Both hives were elevated a full bubble on one side. The idea here was to prevent the moisture from dripping on the cluster. I was hoping if there was a moisture problem it would run off to one side. I will touch on this in more depth later.
This led to a few conclusions, which I want to stress are for my geographic location only!
1. My hive volume is too large.
2. Strong colonies will control the temperature on their own
3. Weaker colonies may need some help getting started, but should be left on thier own ASAP.
Michael Bush from Bush Bees has discussed in detail the position of the entrance. He leaves the 3/8ths inch bee space in front of the first bar open to be used as the entrance. Common sense would tell you heat rises so this would be a great place for it to escape. This is what I would recommend for a hive which would need a little help.
An experiment I intend to run takes this one step further by raising the front of the hive a degree or two higher. To see the effects on the comb.
Dennis Murrell writes:
“Visited my bee yard yesterday and the difference between TBH and lang ventilation was obvious. The bees were hanging out on all the lang and my combo hives. The langs are equivalent to 5 deeps and the combo has the equivalent of 5 deeps above the hive. Yet, these bees were hot and were hanging outside to reduce temps inside the hive. The TBHs were not bothered by the heat. Bee activity was normal at the entrance with a half dozen bees fanning. I lifted the cover which is blocked up above the top bars. The top bars were cool to the touch. I had commented on this difference last year but I've lost the thread. The difference between the two types of hives, those using frames and those with natural comb is very obvious. The combo (long) hive with frames had the same problem as the Lang hives with frames. The TBH with their natural comb attachments and very little 'free' space surrounding them are much more efficient at controlling the ventilation and temperature. The extra 'gaps' in Lang equipment must hinder the bees somehow. “
Regards Dennis
“Evaporative cooling is what the bees do to cool it and that requires careful, controlled ventilation to get that temperature. The bees do it all the time in natural hives with very small openings”.
- Michael Bush The above observations are a testament to the fact that Mother Nature knows what she is doing and does not need our help.
See this study published March 2006. Do honeybees, Apis mellifera scutellata, regulate humidity in their nest?
In a Cold Environment The main concern is moisture dripping on the cluster also mold and disease associated with the wet humid environment. Many beekeepers thought that SBB’s were the answer. Screened bottom boards= the bottom of the hive cut out and a piece of #8 hardware wire stapled in place. Here are some comments on the use of SBB’s for winter ventilation:
“I have been thinking of ventilation though, and the best thing I can think of is to drill holes in the back end, maybe one to three one inch holes. I am not sure though yet, just something I am thinking about. In the winter, the ventilation is actually beneficial, not harmful. Ventilation helps disperse winter moisture which is on the list of #1 things that kill bees in winter. Your bees will keep plenty warm in the winter with the ventilation and you do not need to close it off for winter.” -quote from Bee Source
Just a note here: remember COLD is TOP on the list!!! Below is an example of why the above statment is not true everywhere and of what differences in bees, regions and unpredictable weather can do!
“One of the older, most experienced beekeepers in my acquaintance lives several counties farther west than I do, so his USDA climate zone up there on the Alleghany Front is identical to your town. He had told me that he left the SBB's open all winter there on his mountaintop bee yard, and the bees all came through more vigorous than before!!! One of our master beekeepers has been preaching for years that moisture build-up in winter is a bad thing. So, considering that the older gentleman I referred is TWO full climate zones colder than Harpers Ferry, I figured I might see more vigorous colonies as well, and I divided my bee yard in half -- 50% I covered the SBB's, and 50% I left uncovered. Sure enough, the uncovered hives in my yard (all Langs, as I have said in other posts, I am just now discovering and thinking about TBH) DID -- for that winter of 2002-03 -- come out better. I thought to myself ' This is amazing.'
So for the winter of 2003-04 I went whole hog and left ALL the SBB's open. But January & February 2004 around here were record-breakers, and all my colonies perished, with plenty of stores on the frames left and right of the clusters, much to my shame.
So I won't go down that road again, personally. TBH or Langstroth, I will close the bottoms in future winters."
"Another factor to consider when using SBBs is upward ventilation. The amount of draft through the hive is determined by how the hive is set up on the bottom and top of the chimney.”
-quote from Bee Source Some beekeepers believe that cold is never an issue just moisture. Every living thing on the planet has its thresholds of hot and cold, nothing is immune!
Who said moisture was a winter bee killer and where is the evidence to support the theory? I cannot find any! I can offer you evidence that moisture in the hive is a valuable winter resource. A study conducted by Dennis Murrell using a Plexiglas inner cover showed that moisture did not form above the cluster but in a ring around it. It also showed that when the bees were able to break cluster they quickly consumed the moisture. See http://bees.farvista.net/gwin.htm for the full text.
A Possible Solution
Combining hive styles to solve a common problem
So what is the answer to the ventilation problem, after all bees survive in the wild with no help from man! Well let’s examine that statement. If we want to know how bees survive with no help where better to observe then a wild colony? What is the preferred choice of nesting site for a wild swarm? Hands down the first answer that should come to mind is a cavity in a tree. If you reached into a cavity in a tree and scooped out a handful of whatever was on the bottom what would you come out with? You would probably find rotting wood, insects and all kinds of unidentifiable organic debris. If you did the same to the inside walls and top of the cavity what would you feel? You would probably feel dry spongy wood, pieces of which would probably show signs of wood boring insects. This is the ceiling of our wild hive; it has a capillary like moisture absorbing effect which can be duplicated.
Abby Warre’ designed a hive with a cover that mimics the ceiling of a tree cavity. Warre’ made a cover system for his hive which consisted of a cloth laid on the top bars to prevent propolizing of the actual lid. On this was placed a ten cm deep box filled with saw dust. On one side a wood cover was secured and on the other a piece of cloth was secured to hold in the saw dust. The completed lid, called a quilt, was placed cloth side down on top of the cloth already laid on the top bars. Moisture rises and is absorbed by the saw dust the same way it is absorbed in a tree cavity. The saw dust should be changed out every season prior to the formation of the winter cluster. This type of cover should be incorporated onto every hive with moisture problems at least as an experiment. You may be asking how this cover can be used with a TBH. It would work very well with a TBH which uses spacers or has some bars removed.
Warre’ Hives
A Warré hive is a tiered top-bar fixed-comb hive comprising a stack of boxes each with internal dimensions of 300 x 300 x 210 (deep) mm with 8 top-bars in each box at 36 mm centers and 12 mm spaces between each bar and between outside bar and the walls.
Warre’ Hive Links
http://www.mygarden.me.uk/ModifiedAbbeWarreHive.htm
Download the book Beekeeping For All by Abbé Warré. English version
Warré beekeeping links
http://ruche-warre.levillage.org -- includes links to sites of many Warré beekeepers
Bernhard Heuvel's sustainable beekeeping based on Warré hives:
http://www.selbstversorgerforum.de/bienen/sustainable_beekeeping.pdf
Warré's book 'L' apiculture pour tous' that describes his method
In French
http://lo.gui.free.fr/apiculture/apiculture.php/200-apiculture.html
In German
http://www.selbstversorgerforum.de/bienen/bienenindex.html
French language site for Warré beekeeping
http://www.ruche-ecologique.org/
Ian Rumsey's hive idea, similar to Warré's
http://www.beesource.com/bee-l/biobeefiles/ian/beekeepingpure_simple.htm
René Gaillet's 'Modulor' hive home page
http://pagesperso.aol.fr/rgaillet/modulor/index.html?f=fs
La Ruche Francaise
http://laruchefrancaise.canalblog.com/
A blog of a Roger Delon version -- good pictures
Illustrations of construction of Warré hives
http://lesruchesdebrunehaut.multiply.com/photos/album/1
Condensation in buildings
Condensation is the most common form of dampness encountered in buildings. In buildings the internal air can have a high level of relative humidity due to the activity of the occupants (e.g. cooking, drying clothes, breathing etc...). When this air comes into contact with cold surfaces such as windows and cold walls it can condense, causing dampness.[2] the change from water vapor to liquid water (dew,fog,clouds)
Apply the above quote to Lang type hives with stacked supers. The heat has no where else to go except up, now it hits the cold inner cover and turns to ice. Eventually the cluster moves up and the heat generated by the bees melts the ice or some other temperature related scenario causes the ice to melt dripping on the cluster. This dripping has been blamed for colony failure and disease related to mold and moist environments.
Apply the same scenario to a TBH, first the bees are already at the top. Heat from the cluster has to move laterally to encounter cooler air or surfaces to condense. In the TBH this would most likely bee the follower boards, front and rear walls or the ceiling of the hive at the perimeter, not above the cluster. A set volume of air can hold a set volume of moisture, the more air available the more moisture will be held. Moisture will not be released from the air until the temperature reaches the dew point. This is why ventilation works; ventilation adds air to absorb the moisture or provides the warmed air with a means of escape to a larger volume of air. Managing ventilation is like managing honey stores. Too much creates one problem whereas too little creates a whole different problem!
I have heard and read thousands of times beekeepers intention of helping the bees through the winter conserve stores and work less heating the hive by using follower boards. Follower boards are false walls that can be moved to constrict the empty space in the hive. Once again we are trying to help without studying the effects of what we are actually doing. First the bees do not heat the hive they keep the cluster warm. The bees are trying to maintain a 92 degree F environment in the cluster regardless of the size of the space. Constricting the space around them also constricts the space the warm air has to mix with cooler air you are in effect speeding up the condensation process. In my opinion follower boards are part of the problem not part of the solution.
Keep in mind moisture/condensation in a hive may only be a regional problem!!!!! Beekeepers in colder climates like Canada go to extremes to protect their investment through the winter. Some will move the hives into warehouses, some will wrap them in some sort of insulating material, some put hay bails around them to block the wind and some just shovel snow on top making sure the entrance is open for when it thaws. The point here is there is no silver bullet answer to the problem you find what works for you by experimenting and stick with it. This brings me to what worked for me. As I mentioned before I tilted my hives slightly to one side, just in case. I left the extra space behind the last comb open, no follower board; this was 2/3rds of the hive. My hives have a body that sits on a separate bottom board. I silicone calked the crack shut between the two. My lids sit right on the bars. I put a 1 kilo chunk of fondant in the bottom. In my area the temps warmed through the winter my theory was if the bees could break cluster I wanted them to have a food source call it “life insurance.” Finally I closed the entrance to a bee width. I opened this hive the day they started flying and observed a piece of fondant the size of a ping pong ball on the bottom.
Do not take the advice of a beekeeper who lives in Flordia if you live in Maine. The correct answer is to find out what the old timers in your area are doing and copy them, dare to improve their methods. Experience is your greatest friend!
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