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Thread: Log sizes

  1. #1
    Join Date
    Jun 2006
    Location
    Northern California
    Posts
    60

    Log sizes

    Good evening everyone. I have a question regarding how small in dia. a log can be to be worth milling. Some background info. I have a lot of oaks on my property that are any where from 6" to 18" in dia. at the base. The wood would be for my own use. I currently mill the logs on my vertical bandsaw setup. The main question would be what is the minimum dia. log for milling? I just milled some logs that were between 8 - 10" in dia but there wasn't much lumber when I was done. Time is not an important factor but I don't want to saw up smaller trees if it is not worth it. Any ideas or suggestions?

  2. #2
    Mark,

    Much depends on what you want from your logs. I operate a TK portable bandsaw mill and, for me, the sweet spot for logs is 12-24" diameters.

    When discussing logs, we commonly use the average small end diameter - inside the bark. The bark and taper will be cut away. For standing trees, the standard is DBH, diameter at breast height (4.5' above the ground) and you'll have to make an allowance for bark thickness. A log will normally square up at 70% of the diameter. A 10" log (small end diameter, inside the bark), will normally square up at 7x7". By modifying the cut pattern you might get a couple of slightly wider boards but that would be an average, or maybe 5 - 4/4 boards, allowing for saw kerf too.

    It seems that productivity goes down when log diameters go below 10". There is also some concern about species. For example, walnut has a chocolate brown heartwood with a creamy sapwood. Smaller walnut logs often have substantial sapwood, say 1.5" of sapwood on a 10" diameter log. That means the diameter of the heartwood is about 7". Many people associate the term walnut with the dark brown and won't accept sap wood. In that case you might want larger logs.

    If the wood has other property differences between heart and sapwood (insect resistance) that may affect how small you want to consider milling. If the wood's value increases significantly with quartersawn grain (sycamore, white oak, cherry) you'll want to wait on harvest since you would get board widths less than half the diameter (for a 10" log, maybe 3" wide).

    Unless you have a strong need for those particular small trees, I would wait until the DBH was at least 16".

  3. #3
    Join Date
    Dec 2010
    Location
    WNY
    Posts
    8,119
    Same as Tom; I don't bother with anything less than 16" DBH, and prefer them to be > 18". I can mill all the way up to 32" max., and have, but beyond 24 - 26" they get really hard to move working alone or even with two people when you're doing it by hand.

    What's your mill look like? You said vertical BS. Do you mean a normal BS? If that's what you are using and you have to lift the log sections up to the table manually, that would limit what's feasible to pretty short and smaller diameter sections of logs.

    John

  4. #4
    Join Date
    Jun 2006
    Location
    Northern California
    Posts
    60
    DSCN1818.jpgDSCN1820.jpgGentlemen, thanks for the info. I guess my question would be better asked, What is the minimum log size for useful wood regardless of the amount of work or waste? I don't mind cutting up smaller logs say 8-10" dia. if the wood will be useful. I plan on using the wood for cabinet frame and drawer construction. If I don't use the smaller trees they end up as firewood and I have plenty of that. I have an 18" Rikon bandsaw with a 12" resaw capacity. I built infeed and outfeed tables with sleds so I can mill logs up to 8' in length. Larger dia. logs say 16-20" I can cut in half with my chainsaw. The longer and larger logs I put up on the saw with my tractor. Attached are some photos of the trees on my property. They are what are called Valley or Black oak around here. They tend to grow in clumps and not very large.

  5. #5
    The core of a log is juvenile wood. For at least the first 2" on either side of the pith, that wood, formed when the tree was young, has different properties from the mature wood that forms after the first 5 - 8 years of growth. Juvenile wood in oak behaves badly, especially splitting and cracking at the pith. Also, unlike mature wood, juvenile wood will shrink longitudinally, leading to crook. So, small oak logs will have a high proportion of juvenile wood to mature wood, and is not a candidate for quality lumber. If you slice boards off the four faces of outside of the log, and contain the juvenile wood in a 4x4, you will yield better quality lumber with less cracks and split, and less warp and crook.

    When I saw oak, most times I leave the juvenile core in a 4x4, that even though it is low grade, has some practical uses.

  6. #6
    Join Date
    Jun 2006
    Location
    Northern California
    Posts
    60
    Danny, That is the information that I was ultimately looking for. I have plenty of time since I retired and I am learning a great deal about wood and the best ways to use it. Thanks again to everyone who answered.

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