Rotten Wood or Good Wood

It isn’t my main business, but I mill lumber for customers on occasion, since I have all of the equipment and I have a hard time saying no. Often they will have a log in mind that they found laying in the woods or even one that they intended to mill sooner, but just never got around to it. Anyway, the log looks less than fresh and they want to know if they should spend the money having it milled.

Of course, I need as much information as possible before I can answer them, but there are some rules that I use to decide. First of all, think of logs as produce. For the color to be the brightest, with as few defects as possible they should be milled quickly. If they have been sitting for a while, I try to determine, in this order, what species the logs are, how long they have been on the ground, what seasons they have been through,  and the environment they have been stored in (shady and wet, high and dry, etc.) and finally what it will be used for (hopefully something rustic).

This white oak looks worthless on the outside. But, looks can be deceiving...

Species is first because logs decay at different rates. For example, silver maple starts to discolor in just a few weeks in the summer, while walnut can sit for years and the heartwood will show no signs of its age. Woods that are white are the first to go, because, as noted in an earlier post, the white wood is the sapwood and it rots

... the heartwood was like brand-new

much faster than the heartwood. Next to go are some open-pore hardwoods like red oak and honey locust. Last to go are logs like cherry, walnut and white oak.

This little, tiny, cute beetle was very close to having his day ruined by a sawblade.

For fun, I have photos of a white oak that I just quarter-sawed that inspired this post. Notice that the sapwood has turned to foam, falls apart in your hands, and has big beetles in it (I have regular size hands).

The difference in the heartwood is amazing. It was like a brand new log on the inside. I don’t know how long this log sat, but it was definitely years.

After considering species, time on the ground is the next indicator as to the soundness of logs. Here are some estimations based on three groupings. White woods will be absolutely no good after about four years, show considerable age after just one and be off in color after a couple of months. The open-pore hardwoods like red oak will be worthless in about five years, show their age after two years and start to be off in color in the heartwood after four. The heartwood of the third and final group can definitely go much longer. White oak and cherry heartwood will begin to discolor after six years, but have sound lumber for much longer. Walnut, as far as I can tell, never rots. I’m sure it does, but very slowly. Walnut is the last log I cut because I know it will not go bad on me.

All of these logs can start to show some signs of age after a short time depending on the season. During the summer the logs will get bugs in them and the heat can quickly cause discoloration. These problems will be worsened if the logs are stored in a wet spot versus a spot that is dry. The

winter is the best time to store logs. If it is cold enough, almost no degrade happens and the bug issue is moot. If stored in a shady and dry spot, off of the ground, and in the winter the logs will last the longest.

The last thing to consider is what level of degrade is acceptable, knowing that logs that have sat for more than a couple of months will have some “character”. Worm holes and spalting are common and can happen quickly in the summer, but still leave the lumber stable. Even lumber that is structurally impaired can be used for panels and other areas just for show. If you are alright with less than perfect lumber than you can easily use logs that have sat for a long time.

When checking on a logs condition, simply cut the ends back a couple of inches to see what is inside. Logs rot more quickly on the outside and from the ends. Trimming the ends may reveal wood in the middle that is still good, or it may not. Look at the color and check the hardness of the wood. If the color is marbled or there are soft spots, the wood is decayed. If it seems too soft/rotten, trim back further, a foot at a time, until you get to solid wood. If you get done trimming the ends and the remaining log is firewood length, your log is too rotten to mill.

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About wunderwoods

Hi! My name is Scott Wunder and I am the owner of WunderWoods Custom Woodworking. We build wine cellars, built-ins and furniture from local woods, here in St. Louis, MO. Recently, I finished a three-year term as the President of the St. Louis Woodworkers Guild, which had me writing a monthly article for our newsletter. I love to write, especially about wood, and found that I still had more to say. Every day I run into something wood related that I realize some of my customers don't know and this seems like a great forum for sharing what I have learned (instead of telling the same story to each person). The main thing to remember is that I try to keep it light and as my wife always reminds people that have just met me, "He is joking."

4 responses to “Rotten Wood or Good Wood”

  1. Dana says :

    Hi Scott..My husband and I are planning to build a log cabin. Just recently there was an add in the paper for a log package for sale. It was supposedly left over from a planned community in Branson, Ms. which fell apart because financing became a problem. The cost of the package would save us money, but I am concerned about buying wood that sat at the construction site for two years. Supposedly it had “layers” between the logs to keep them dry? They didn’t have it treated for critters b/c they were told to wait until the cabin was built? Yes we are skeptical about buying it, however it would save us quite a bit of money up front. The wood is oak. What say you? Thanks so much!

    • wunderwoods says :

      Dana,

      First check to see if it is white oak or red oak. White oak is many more times durable than red oak. Also, verify that they were on sticks with air between them. If they were “dead stacked” on the ground, with no air-circulation they will rot much quicker. As a safety precaution check to see that none of the areas that would be prone to stay wet, for example, on the bottom, are soft or punky. Any piece of metal can be used to test for the soundness of the wood. Just hit it and literally listen to the sound. If it is hard it sounds very different than if it is soft. I would also cut the end off of one of the pieces and get a look inside. A fresh cut will tell you a lot about it.
      So, here is my final answer. Look at the wood and how it was stored closely. If it is red oak, and it was thrown in a pile on the ground to rot for two years, it is probably no good, at least in spots. White oak in the same situation might be alright. If stored correctly both, red and white oak should be fine. Just hope it is white oak.
      As far as bugs go, there are probably some in there, but most likely none that cause structural damage, they just add character. Termites are the real issue and they take a little while to work. For your peace of mind, I would have the wood sprayed before installation and have pest control maintenance performed regularly no matter where the logs came from.
      Good luck with your investigation!

  2. nataliejoymcbride says :

    We have a shagbark hickory tree that I am wondering if it is good enough for milling. I wanted to attempt a table top out of it. I believe it has been lying on the ground for 3-5 years and seems to be hard in the middle. I have about a 9 ft. length with an average of about 24 inches in diameter. At first I couldn’t see almost any of those little splits in the wood that come from the wood drying out as you look at the end grain, but after moving the log I can see some little splits speckled about all pointing towards the heartwood. Do you think this would be worthy to take to a sawmill if I am trying to make a table top out of the slabs, maybe two 9 ft. long x 18 in. wide x 2 in. thick slabs connected together to make 1 table top 9ft. long x 36 in. wide x 2 in. think?

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