Summer drying and some-are not?

[CJRages]

Please evaluate the following statements for accuracy and truthfulness:

1. During the summer months (on average) the relative air humidity percentage is lower in most areas than during the winter months.

2. Wood dries faster at a higher temperature if the relative humidity percentage and air flow rate are held constant.

3. The dryness of wood is a function of the size of the piece and air circulation, relative humidity, & heat (or lack thereof) during a given time.

Thanks!

 

[the_dude]

Please evaluate the following statements for accuracy and truthfulness:

1. During the summer months (on average) the relative air humidity percentage is lower in most areas than during the winter months.

False. Winter typically has much dryer air.

2. Wood dries faster at a higher temperature if the relative humidity percentage and air flow rate are held constant.

True. Warmer air has the ability to hold more moisture. At the same relative humidity, warmer air should dry something faster than cooler air (I think).

3. The dryness of wood is a function of the size of the piece and air circulation, relative humidity, & heat (or lack thereof) during a given time.

I think you have covered all the variables, except density and starting moisture content of the wood.

Thanks!

 

[woodsmaster]

Sun and shade also play a role.

 

[wood spliter]

I would have to say humidity is higher in the summer which would be longer drying time. Air flow and heat without humidity would equal faster drying time. My 2 cents and my thoughts with an educated guess.

 

[oldspark]

Wood drys faster in summer even though the humidity is higher, wood does not dry that much as the temp drops.

 

[Black Jaque Janaviac]

1. During the summer months (on average) the relative air humidity percentage is lower in most areas than during the winter months.

I don't know what you have in mind when you say "in most areas", but here in the Midwest this statement is false. RH's are lower in winter than in summer due to the lack of plants actively pumping water vapor into the air.

2. Wood dries faster at a higher temperature if the relative humidity percentage and air flow rate are held constant.

True. Anything to warm the water that is in the wood will help increase evaporation.

3. The dryness of wood is a function of the size of the piece and air circulation, relative humidity, & heat (or lack thereof) during a given time.

True, but not limited to these factors. Species of wood will affect things. Other complicating factor will be crossing that freezing point threshold. In order for the inside of a piece of wood to dry out the water has to move, or wick, from the inside to the outside surface, then evaporate. When the log is frozen the water inside cannot wick its way out, so the dry winter air is of little help. Also the wood grain is designed to transport water up and down the trunk along the grain structure, not against the grain structure. So shorter long lenghts might be more helpful than small diameter splits. Say 16" logs vs. 20".

Another thing that may affect drying time is how much moisture is in the log to begin with. One old feller told me that if you fell a tree with green on leave it be for a while. The leaves are still actively sucking water out of the trunk and will continue to do so until they wilt. I guess this guy used to cut a few trees and leave them lay, then come back in a week or so to chop 'em up. While he was there he would cut down a few more for his next visit.

 

[begreen]

#1 is normally very false for our region. We tend to get Mediteranean summers with low rainfall, then make up for the dryness in the winter months, especially Nov and Dec..
#2 not sure, wood does dry out via evaporation and sublimation in the winter months if they are dry
#3 size of split is a round about way of saying increased surface area. If one splits are smaller, a greater surface area of the inner wood of the tree is exposed to drying.

 

[thewoodlands]

#1 is normally very false for our region. We tend to get Mediteranean summers with low rainfall, then make up for the dryness in the winter months, especially Nov and Dec..
#2 not sure, wood does dry out via evaporation and sublimation in the winter months if they are dry
#3 size of split is a round about way of saying increased surface area. If one splits are smaller, a greater surface area of the inner wood of the tree is exposed to drying.

BeGreen I think we have your weather lately, rain!

zap

 

[begreen]

Sorry, hope we get some sunshine here soon. I'm rusting.

 

[Skier76]

#1 isn't true where we are in VT and CT.

The RH this weekend in VT was 65-70%. The only times I see numbers that high in the winter is when I shower. We run two humidifiers to keep the air a bit most.

I think the sun and wind combo helps quite a bit during the warmer months with regards to drying.