Eastern Hemlock

[Coconut]

Can you use Eastern Hemlock logs for log construction? Also is it better to cut them in the winter?                                                                                           Needing your help . Thanks !

[Don P]

Sure, make sure they don't have shake, ring separation, check at the butt end. If you are asking about the old wive's tale, sap doesn't go down in the winter. Wood does stay brighter if felled and processed in the cold when fungi and bugs aren't around and if it can begin drying during that cool period. The bark is also hardest to peel that time of year. We noticed drawknifing poplar logs over the past month, the bark is now tight and will be so until next spring, glad we're almost done with that chore!

[S.Hyland]

Hi Don,
   Just curious why you think it an old wives tale to use winter cut timber. I notice a decrease in movement and checking when timbers are winter cut. I also sawed at a local sawmill for a couple years before going into timber framing full time. This  tended to be very prominent in Maple. If we brought in maple logs felled when the sap was first coming up in the spring, boards sawn from these would warp to an incredible degree.
   I'm not saying that you're wrong, just curious what your reasoning is?

[Don P]

It's always interesting to hear from others experience. I think maple is probably an exception that doesn't make the rule.
what I was talking about is that many people think that sap, moisture, goes down in winter. That is not so. The moisture content of wood is at least as high in winter as it is in summer. If the cells emptied, they would not be able to re-establish water column and die... there is no pump and an emoblized cell in a living organism dies.

This does not mean that I think there is no truth to the saying that it is good to cut in winter. Bugs and fungi are not active and wood cut during the cool months has a jump on drying which makes the wood less appealing to both bugs and fungi when warm weather returns. Wood is difficult to peel when the cambium is not actively dividing though, in the spring/summer the bark "slips" as those cells are dividing, one half of the division becomes bark, one half becomes wood, at that juncture the bark is loos during that time. As the season closes the division stops and the bark is tight. We were drawknifing tight bark today.. I'm sitting here with a nice little gash in my middle finger, yup the knife was nice and sharp  :D :. Checking is a result of gradient and is lower in winter, drying is slower so the surface is not shrinking as rapidly and drawn as tight over the still fully saturated core, it moderates the drying conditions as compared to that hot low humidity day in June when you can hear exposed wood checking. Always open to hearing other thoughts, those are just my reasonings.

[S.Hyland]

Hi Don,
    Thanks for the reply, that all makes good sense. There is also one other aspect I would be interested in your input on.
     I was not under the impression that the water in the cell was necessarily the issue with winter cut wood's greater stability. My thinking was that the living non water components of the sap such as sugars, hormones, etc. played the role. This would explain, to return to the example of Maple, why the wood becomes so volatile during a sudden onrush of these components. I would agree that Maple exhibits this more definitively than many other woods, but it seems to be hold true to some degree.
     This would also explain why timber that was rafted or stored in a mill pond would have been considered desirable for it's higher quality. Soaking in water would replace the sap with pure water.

    I suppose that wood with a lower sugar content would also be more rot resistant, since the sugar is a primary food source for fungi and bugs.

[Don P]

The little I do know about that shift period when the trees go into spring is there is a night length signal that triggers the release of auxins that tell the tree to convert stored starch to sugar, energy, there has to be something in the absence of capillary action through the leaves, which aren't on yet, "pumping" the sweet sap in maples during warmup, I've read somewhere that it is dissolved CO2 alternately freezing and going into solution and thawing, expanding and going into big gas state, creating pressure. Googling... here we go;
http://blog-yard-garden-news.extension.umn.edu/2009/04/the-mystery-of-maple-sap-flow.html

Is that pressure responsible for your observations? Thoughts?

In Evergreens the needles stay on the tree to photosynthesize through the winter, the normal processes are going on whenever sap can flow. The tree is idling through the winter. If you scrape the thin bark off of branches on many deciduous trees you'll hit a green layer, chlorophyll, the tree is maintaining basic life processes through the winter by photosynthesizing through that bark. It has dropped the leaves to conserve water which is hard to come by during that time but it is not totally shut down. The horizontal stripes, lenticels, on trees like cherry act much the same as the stoma on a leaf, the water molecule enters the root and in this case exits the lenticel which runs that capillary water column.

My FIL was Dutch, he left the old country after WWII. He remembered woodworkers ponding timbers in the canals to flush the sugar out of them. I noticed Wranglestar on youtube visited a historic Dutch wind powered sawmill and forwarded the same notion. I can't say one way or the other but it didn't appear to have flushed the starch, the old mill in his video was eaten up with powderpost holes and I know the females of those bugs taste the wood for starch content before depositing eggs. It might be interesting to try ponding half of a sapwood board while freezing the other half and then break them out at bluestain time to see if there is a difference in growth of that sugar loving fungus.

As long as I'm rambling way off the original topic, I think it is neat that trees use the same building blocks to make sugar, convert and store that energy as starch and can convert it back to energy, or they can take the same building blocks and create cellulose, structure. They cannot convert the cellulose back to energy but a termite or a ruminant can. When we figure that out the energy and food problem is solved. The most efficient solar energy panel out there is a leaf.

Apologies Coconut I've dragged 2 hemlock threads way off into the weeds in as many days, feel free to set us back on track 

[Coconut]

Great Info Thanks !   I will let you all know when I start cutting. Ring shake or not we will find out, lets hope for the blessing.   Coconut.