Wood Identification - Sassafras not persimmon

A land surveyor sent me a piece of a rotten stump that was thought to be from an old persimmon tree that was cited on a boundary map.

Microscopic examination revealed that the wood rays were up to 5 seriate (five cells wide). This rules out persimmon, which only has 1-2 seriate rays. My opinion is that it is sassafras.

Cat safe wood coatings

A homeowner wrote about what to apply to his deck to water proof it without risk of harm to his cat.

There is no risk to his cat (or to anyone) with any water-repellent coating. An evaluation of some available clear coatings for wood is available.

Air Drying Times for Poplar

An email asking about how long to air dry poplar boards for a fence to prevent subsequent warping.

The air-drying time of green yellow poplar lumber depends on a lot of factors, including the temperature, humidity, air flow and thickness. But, if we can assume good drying conditions and 1-inch boards, then about 3 months should suffice. Longer is better and can't hurt if the wood is kept dry.

Poplar is a very decay-susceptible wood and I wouldn't recommend it for a fence. Better to use pressure-treated pine or a naturally durable species (cedar, cypress, white oak).

New Wood Industry Residues Information Available

A new Google-Earth map has been created that shows the location, name and production numbers for primary mills producing wood residues in the state of Tennessee. Click here to learn more.

Mold on hickory stick furniture

A call from a supplier of small, green hickory roundwood. He supplies a manufacturer of rustic furniture who is having problems with mold growing on the wood.

Mold requires free water on the surface of the wood to become established and grow. Rapid drying of the wood surface will be the easiest and most effective way to cure the problem. Chemical treatments can be used to kill mold but for lasting protection drying is the best option. More information can be found here.

Counting tree rings

A call from a property owner in Grainger County who heard that someone from UT had inspected an old barn once to count the tree rings in the logs. Did I know who this would have been.

It probably was Henri Grissino-Mayer or someone from his lab. Dr. Grissino-Mayer is a expert in dendrochonology.

Micronized copper

An equiry from a health and safety official wanting to know about micronized copper.

Micronized (small particles of) copper is now used in some wood preservatives instead of soluble copper. This preservative has lower corrosivity to metal skrews and nails and imparts less color to the treated wood. It should have the same performance and safety characteristics as soluble-copper-based formulations. For more information, click here.

Outdoor Wood Furnaces and Indoor Furnace Systems

An email from a person who is considering buying a house that has an outdoor wood furnace. She hasn't seen the system yet but wonders if it can also have a regular furnace system inside the house.

Most outdoor wood furnaces use a ductwork system to distribute the heat inside the house (some use hotwater radiators). In either case, it should be possible to connect that ductwork (or radiator) system to an ordinary gas, electric (or even wood!) furnace.

Timber sales how-to

An email from a landowner: how to get started on selling timber?

UT's Extension Forestry folks have written a Landowner's Guide to Timber Sale Contracts that is a great place to start.

A follow-up on the yard tree question

The homeowner with the cherry tree wrote back wanting to know how to determine the value of the log.

This publication discusses the main variables in hardwood log variation - species, size and grade.

Dry kiln schedules for foreign woods

An email asking about drying schedules for Jatoba and Tigerwood.

Schedules for these species can be found in Dry Kiln Schedules for Commercial Woods

The only trick in this case is to find the name of the species you want - Jatoba (Hymenaea courbaril) isn't listed under that name in this book. Common names vary a lot but the latin binomial always works!

Milling lumber from a yard tree

An email asking about what to do with a big cherry tree being taken down in a residential area? Can the wood be sold?

I said: "Unless it is a truly exceptional specimen, one tree is probably not going to be worth a great deal compared with the costs of taking the tree down and moving it. Many tree removal companies have connections with sawmills that will take good logs, however many mills are reluctant to take city trees due to the risk of metal and other objects being embedded in the wood.

I would suggest talking to the tree removal companies about your options. If you are interested in having some of the wood for yourself, you may want to contact someone with a portable sawmill – unfortunately, there is no directory of such sawmills in the state that I know of."

Outdoor Wood Furnaces

An email from a homeowner who wanted to know if he should install an outdoor wood furnace.

While outdoor wood furnaces have some advantages, I don't recommend them in general. For more information on such furnaces, click here.

Timber Price Information

A landowner wants to know timber price trend information for Tennessee, to help them make harvesting decisions.

Price information for logs is reported in the Forest Products Bulletin. Stumpage prices (money paid to the landowner) are up in inflation-adjusted dollars over the past 25 years; however, as the warning goes, 'past performance is no guarantee of future results.' Timber prices are highly variable, so it is extremely difficult to 'time' a harvest to maximize monetary returns. The health and productivity of the forest should also be important factors in harvesting decisions.

Drying Hickory for White Color

Sawmiller called wanting to preserve the color in white hickory lumber. A customer had rejected a load because it wasn't the color he was used to.

White color retention lumber drying schedules are available for a number of species, including hickory (T5D4 is recommended, and T3D4 should be even better – “maybe even T3D5.”)

The Wood Web has a forum on wood drying (moderated by Gene Wengert) that is very helpful for questions like this.

Yellow poplar wood identification

Wood ID on a section of beam from an old house. Looks to be yellow poplar (Liriodendron tulipifera), which is, and was, a common species locally.

The wood sample is of medium density and is dark brown with areas of purple and green. Yellow poplar is very variable in color.





In the first picture (cross-section, 30x), there is a distinct band of marginal parenchyma that highlights the growth ring (light band going from bottom left up to the right). The numerous light lines going from bottom right up to the left are the rays. The rays are 'noded' - slightly wider at the growth ring boundary. These features suggest yellow poplar.

Microscopic examination provides more evidence for yellow poplar. In the second picture (tangential, 100x), the 1-5 seriate rays are visible, as is a scalariform perforation plate and large intervessel pits.

For more information on wood identification, visit the Inside Wood website

Chestnut Wood

A visit from a homeowner with some pieces of old lumber from a barn he is renovating. Is the wood chestnut?

Some was and some wasn't. Chestnut was a common building material before the blight hit but so was oak. The two woods can be pretty easily distinguished by looking for the broad rays that are present in oak but absent in chestnut.

More informantion on identifying chestnut can be found here

Sudden Oak Death?

A call from a concerned homeowner on the Cumberland Plateau. Her oak trees are dying - could it be sudden oak death?

I said no. Sudden oak death is not affecting the oak trees of Tennessee. Very likely her big old trees are showing the ill effects of the drought that we had last summer. The dry weather puts stress on trees and can hasten the inevitable decline and death of mature trees.

Mold on house framing lumber

A guy called from Canada where he is having a house built. Some of the framing lumber has black mold growing on it. He is very sensitive to mold and is worried about possibly reactions once the house is completed. He wondered if he could wash the affected lumber with a bleach solution.

I advised him to go ahead with the bleach wash treatment - it will help kill and remove mold on the surface. The bleach treatment will not prevent mold in the future but, once the wood has dried out, no more mold will grow.

For more information on mold, click here

Welcome to the Forest Products Extension Blog

As the Forest Products Extension Specialist at the University of Tennessee, I receive many calls and emails on a variety of topics related to wood and its use. In this blog, I will be posting my responses to these calls in case others have the same questions.

Please contact me with any questions of your own. You may also wish to visit my website.

Thanks,

Adam Taylor