Tell One Wood from Another: Basic Wood Anatomy

[phinds]

As a long-time woodworker, I have an interest in being able to tell one wood from another, and in the process of learning how to do that, I’ve developed some knowledge about wood anatomy that I think will be of interest to Biology students as well as woodworkers. There is an enormous variety of wood anatomy characteristics and this article discusses just a few to spark interest more than to provide an extensive exposition on those characteristics. Since this article is introductory and doesn’t even express all of my limited knowledge of the subject, I’ve included at the end some references for those interested in further information. There are quite a large number of different characteristics of wood that would be of interest to a wood anatomist, but I have limited my knowledge to the subset of those characteristics that are readily discernible to the average woodworker in his shop/garage/basement with minimal effort and no elaborate equipment.
It usually comes as QUITE a surprise...

Continue reading...

 

[BillTre]

Nice article.
I have read one of your references, the "Understanding Wood" book and was really impressed with it.

I like wood with unusual grain (seen longitudinally), like curly maple and related effects with other names.
I realize that is viewing the wood from another axis and think it is due to waviness in the way the longitudinal components are laid down, but don't fully understand it.
Any insights on that? (Maybe another Insight)

 

[phinds]

Nice article.
I have read one of your references, the "Understanding Wood" book and was really impressed with it.

I like wood with unusual grain (seen longitudinally), like curly maple and related effects with other names.
I realize that is viewing the wood from another axis and think it is due to waviness in the way the longitudinal components are laid down, but don't fully understand it.
Any insights on that? (Maybe another Insight)

curlyfigure

 

[chemisttree]

I like wood with unusual grain (seen longitudinally), like curly maple and related effects with other names.

And the unique names for the effects like “chatoyance” borrowed from gemology.

 

[anorlunda]

That was fun to read. Thanks for the good article. There is much more to it than I imagined.

You label the pictures with the species of tree. How did you know those names? By sight? Did you order a piece by species name?

The mass of a tree is mostly carbon, fixed from the atmosphere. The tree top needs mass. The roots need mass. Do those pores just move water and nutrients or do they move masses of carbon also? If carbon is produced in the leaves, then it must flow inward then downward, correct?

Trees also need a lot of water. How many liters per day are lifted from the roots to above ground? Is there a kg/sec flow rate for water in the biggest trees?

The pores of sugar maples are critical to syrup production. Are they extra big? Are they clustered near the outer bark so that they freeze/thaw every day in spring?

 

[chemisttree]

The mass of a tree is mostly carbon, fixed from the atmosphere. The tree top needs mass. The roots need mass. Do those pores just move water and nutrients or do they move masses of carbon also?

For roots to grow, it would imply that carbon is moved up and down the xylem and phloem. Perhaps as bicarbonate or sugars?

Carbon is certainly translocated.
https://www.ncbi.nlm.nih.gov/m/pubmed/23049893/

 

[256bits]

so one characteristic of interest is how many growth rings does a particular piece of wood have

Excellent.
Branches should have growth rings as well.
I suppose one could count the truck rings and compare to the branch rings and find out the ages of each.
The higher up one goes along the truck, or main branch, the number of rings should diminish.
Is there any size or age of truck/branch that it needs to be for "good" wood to work with.
Does the heartwood age in quality as the tree itself ages, the deeper in one goes the better it gets.
Sapwood, I suppose is not too well favoured for woodworking.

 

[phinds]

Excellent.
Branches should have growth rings as well.
I suppose one could count the truck rings and compare to the branch rings and find out the ages of each.
The higher up one goes along the truck, or main branch, the number of rings should diminish.
Is there any size or age of truck/branch that it needs to be for "good" wood to work with.
Does the heartwood age in quality as the tree itself ages, the deeper in one goes the better it gets.
Sapwood, I suppose is not too well favoured for woodworking.

Heartwood is dead wood so it doesn't change characteristics particularly with age. Some woods are almost all sapwood so, no, sapwood in general is not a bad thing. Depends on the wood.

I assume you mean "trunk" not "truck". Branches can start well after a tree has grown a bit so are not useful for telling the age of the tree, just the branch itself and there's not much point in that. Some small trees/bushes produce very small pieces that are favored by pen makers, so size relevance has to be measured against what you want to do with the wood.

 

[davenn]

A wonderful write-up
I definitely learned a few things

 

[phinds]

That was fun to read. Thanks for the good article. There is much more to it than I imagined.

Glad you enjoyed it. There is MUCH more to it that the little bit that's in the article.

You label the pictures with the species of tree. How did you know those names? By sight? Did you order a piece by species name?

Uh ... did you not get the POINT of the article? Identifying wood is what the whole thing is about. People send me wood from all over the country for me to try to ID it, and I run a wood identification sub-forum on the Wood Barter forum. When I buy wood, I rarely trust the seller's ID unless it's a very common domestic. Many exotics I can now identify with a quick glance but a lot of them require verification (or re-identification) using the techniques discussed in this article.

The mass of a tree is mostly carbon, fixed from the atmosphere. The tree top needs mass. The roots need mass. Do those pores just move water and nutrients or do they move masses of carbon also? If carbon is produced in the leaves, then it must flow inward then downward, correct?

I have no idea about the carbon. Never thought about it.

Trees also need a lot of water. How many liters per day are lifted from the roots to above ground? Is there a kg/sec flow rate for water in the biggest trees?

No idea. I just know that even for amazingly tall trees, the sap moves all the way to the top.

The pores of sugar maples are critical to syrup production. Are they extra big? Are they clustered near the outer bark so that they freeze/thaw every day in spring?

No, surprisingly enough the pores of sugar maple are not significantly different than the pores of other maples. Here's a sugar maple (acer saccharum) end grain on the left and a silver maple (acer saccharinum) on the right.

 

[phinds]

Glad you enjoyed it. There is MUCH more to it that the little bit that's in the article.

Uh ... did you not get the POINT of the article? Identifying wood is what the whole thing is about. People send me wood from all over the country for me to try to ID it, and I run a wood identification sub-forum on the Wood Barter forum. When I buy wood, I rarely trust the seller's ID unless it's a very common domestic. Many exotics I can now identify with a quick glance but a lot of them require verification (or re-identification) using the techniques discussed in this article.

I have no idea about the carbon. Never thought about it.

No idea. I just know that even for amazingly tall trees, the sap moves all the way to the top.

No, surprisingly enough the pores of sugar maple are not significantly different than the pores of other maples. Here's a sugar maple (acer saccharum) end grain on the left and a silver maple (acer saccharinum) on the right.

View attachment 254518

The pores of sugar maples are critical to syrup production. Are they extra big? Are they clustered near the outer bark so that they freeze/thaw every day in spring?

By the way, in case you are not aware of it "maple syrup" when it comes out of the tree is essentially indistinguishable from water (it's about 97 to 98% water and only about 2% sugar).

 

[anorlunda]

Uh ... did you not get the POINT of the article?

Sorry, I did not get the point. I missed this sentence midway through the text. "You have to have a reference source or sources to help you understand what you are seeing. I have provided links to a number of those at the end of this article."

So the real subject of the article is not about the identification step, but rather the anatomy data gathering steps.

 

[phinds]

Sorry, I did not get the point. I missed this sentence midway through the text. "You have to have a reference source or sources to help you understand what you are seeing. I have provided links to a number of those at the end of this article." So the real subject of the article is not about the identification step, but rather the anatomy data gathering steps.

Actually, that's a good point. In my more extensive expositions I spend more time discussing the pros and cons of some reference sources since they are, as you point out here, at the heart of the whole thing. I just take it for granted that the point of the data identification and collection is ultimately to ID the wood so kind of slid past the fact that I was making an assumption here that may not have been obvious (Although the title of the Insight is a big clue )

 

[jim mcnamara]

Very, very nice article.
Fixed carbon moves around in trees via sugars in sap.

Carbon fixation - Photosynthesis fixes carbon in the leaves
CO₂ + H₂O -> C₆H₁₂O₆ (glucose) + O₂
Translocation - Sucrose, derived from glucose, moves from the leaves down to the rest of the plant. (phloem)
Transpiration - movement of water with soil derived nutrients up to the leaves. (xylem - the wood cuts @phinds shows)
Rays - cells in xylem that allow horizontal movement of water.

 

[jim mcnamara]

-- quick note.
Hardwoods (what @phinds ) covered nicely is a group name, and isn't helpful sometimes. Same thing can be said about softwoods (pines, larch, redwoods) which is a group name too.

The names have very little to do with how hard the wood may be. Hardwoods are Angiosperms -they have flowers, softwoods are gymnosperms and have cones (like pine trees).

Furniture quality bamboo is commercially available. It's Janka hardness is moderate, higher than red oak, for example.

Janka hardness measures the resistance of wood to crushing, like you might get from high heeled shoe traffic on wood flooring. Very high Janka hardness is not tool friendly, it can wreck blade and chisels.

Some softwoods, like yellow pine, are harder than some so-called hardwoods, like basswood.

Please look at the article that shows how this Janka number is derived. Flooring companies post these kinds of values for jobbers who make and install wood flooring. Woodworkers looking for novel wood often blunder into super hard species that eat their tools for lunch.

https://tinytimbers.com/janka.htm

Before you ask: AFAIK the species with the highest Janka hardness is an Australian tree:
https://en.wikipedia.org/wiki/Allocasuarina_luehmannii with 5060lbf hardness. Good luck machining this stuff.

Lignum vitae is discussed as being hardest. This article is likely wrong, but it has the correct value (~4500lbf) hardness for lignum vitae.

https://www.woodmagazine.com/wood-supplies/wood-species/what-is-the-worlds-hardest-wood

Ever see either of these, @phinds ?

PS: I do not give a darn about the "hardest" species. When a wood is too hard to work well, `working it is more of an exercise in ego than anything else useful. Except maybe for places selling replacement blades.

 

[phinds]

Yes, I'm aware of all you (correctly) pointed out. I would add that bamboo is not a wood, it is, like palm (coconut) trees, a grass. Hardness is irrelvant to my article so I did not mention it, along with thousands of other wood fact that are also irrelevant to the article.

 

[jim mcnamara]

Bamboo is a monocot in the grass order, yes. So this must be trade defintion?

 

[phinds]

Bamboo is a monocot in the grass order, yes. So this must be trade defintion?

Do you mean designating bamboo as a wood for commercial purposes. It's just words. It's like the preposterous names that are made up in the flooring industry for woods that have perfectly good names but which (names) are not euphonious enough for sales people. For example, "Patagonian rosewood" instead of goncalo alves.

 

[sysprog]

I much enjoyed this article. I was reminded of when I was allowed to select a hardwood from the school's stock from which to build a small book-rack in woodworking class. I chose afromosia. I wish every kid could have such an opportunity. *Sigh*.

 

[phinds]

I much enjoyed this article. I was reminded of when I was allowed to select a hardwood from the school's stock from which to build a small book-rack in woodworking class. I chose afromosia. I wish every kid could have such an opportunity. *Sigh*.

My understanding is that "shop" doesn't exist any longer. Kids could hurt themselves on the power tools, or even the hand tools for that matter. Every woodworking show I've been to in the last 10 years has been a sea of white hair. Young folks are into electronic stuff (USING it of course, not experimenting with it).

By the way, "afromosia" is the way I spell it for a long time too, but it's actually "afrormosia".

 

[sysprog]

My understanding is that "shop" doesn't exist any longer. Kids could hurt themselves on the power tools, or even the hand tools for that matter.

Of course 'back in the day', the teacher could and would paddle you (this was rare, but in my grade school at least, most of the male teachers, and some of the women, had a paddle hanging on the wall by the blackboard -- and it wasn't merely a symbol) if you did something dangerous, and kick you out of the class permanently on his own authority if he decided that was warranted.

Every woodworking show I've been to in the last 10 years has been a sea of white hair. Young folks are into electronic stuff (USING it of course, not experimenting with it).

It was 1969 in Oxford -- I was 11 years old -- we had woodworking and metalworking in separate classes. The previous year (5th grade) in the US we had regular shop class. After 2 years in England I returned with my family to the US. In HS there were auto mechanics and interior-exterior construction classes for the vocational track students, but there was no regular 'shop' class for any students. In '75 they offered (premiered) an electronics class, which I took -- 60 kids signed up for it -- no girls the first year -- the second year one brave lass broke the invisible barrier, and the third year it was almost half girls.

By the way, "afromosia" is the way I spell it for a long time too, but it's actually "afrormosia".

That's true -- from 'afr', prefix form for Africa, + 'ormosia', the genus to which the plant was originally attributed -- Greek 'hormosia' meant necklace -- the seeds of the plant were used as necklace, bracelet, and hair beads -- 'afromosia' is listed as a secondary or alternate spelling due to the more usual prefix form being 'afro' and the tendency to omit repeated letters (both 'o' and 'r' in this instance) especially in portmanteau-like formations -- 'afrormosia' is preferred, but my teacher spelled it 'afromosia' so that's what I learned then.

I wonder how many injuries have occurred due to people trying to imitate youtube videos instead of working under the watchful eye of a competent teacher.

 

[darrell1NZ]

Great analytics!

 

[KWolf12]

Does the heartwood age in quality as the tree itself ages, the deeper in one goes the better it gets.
Sapwood, I suppose is not too well favoured for woodworking.

Heartwood is variable in its properties compared with sapwood, varies a lot in different species, and those variations are especially important to bowyers and boat-makers. However, what fascinates me is that for oaks, heartwood eventually can become a liability, and its removal is of benefit.

The weight of a piece of oak lumber is impressive; it's a strong, dense wood compared with a lot of other species we commonly encounter. So now you put all that weight into the limbs of a 400 year-old oak tree, and throw high winds and heavy loads of snow onto it all--even though oak is so strong and also resilient, at some point, it seems like the weight would become a problem.

Instead, a lot of mature oaks have resident fungi inside them, Grifola frondosa, Laetiporus sulfurous, and various others, which eat the unguarded, deceased heartwood, converting it to fungal tissue, soil carbon and glomular proteins, and atmospheric carbon, and in the process, the steadily emptied out heartwood transforms the still-living tree into a lighter-weight creature, and better yet--the tree trunk becomes a cylinder. The strength of a vertical cylinder is the basis of all the largest skyscrapers in the world.

Then there's the peculiar advantage/disadvantage of another fungus, Chlorociboria, the green-stain fungus. The wood it invades turns a beautiful teal color, and it's used as a decorative element in woodworking. Chlorociboria defends its heartwood territory from other fungi, meaning that the heartwood of the trees it occupies will not begin to rot for a very long time, even after the exterior of the tree has died of other causes. The very fact that oak heartwood is being protected from rot may lead to an earlier death for the tree, if it falls victim to its own weight--blown over in a storm, for instance.

In my nearby woods, I know of two trees in particular that show that circumstance; one is an almost completely eroded, decayed "stump" (15 feet tall) with very little left but its green center, now full of insect-borer holes. The other was apparently a single tree with two main trunks, rare for an oak, but when half of the tree fell down, it now appears that it may have spent its 150 year-old life as two conjoined trees, sharing roots and trunk in some spots but distinctly separated at the base. The fallen tree, or half-tree, has no loss of bulk inside; instead, the small crack that runs up the center is lined in Chlorociboria green. The other half of the tree looks like it's working on a certain amount of de-bulking of its heartwood. With half of its root-base broken away, I doubt it will survive for long, but if it does, it'll probably be because a lighter weight bole allows it to withstand winds with all the strength of a hollow cylinder.