The extractives are produced or deposited by the tree, generally in an effort at protection (especially in the case of tannins, phenolics, fats, and waxes); these extractives help protect the tree from fungi and boring insects and even beavers.

Aaaah. Thank you. 8)

They meant “extractives”—it’s mentioned above in the section about sapwood and heartwood.

What is an “extrative”, please? I’ve never heard that term.

It is, in fact, loaded with tannin, which is why a drop of lye (or even ammonia) will make the wood turn very black.

I second the black cherry. Your phone app is far off base; that looks nothing like yellow birch.

No, wait. That looks a little more to me like a very old pin cherry.

The definitive test would be to put one drop of lye or ammonia on a piece of scrap. The wood should turn shocking black almost instantly if it’s black cherry, and if you follow with a drop of higher-concentration vinegar or saturated citric acid (mixed with hot water until no more will dissolve), the black should lighten a great deal, perhaps even becoming lighter in color than the wood around it.

If it does not react in that manner, then that would strengthen my guess of pin cherry.

Which continent do you call home, Sherry? That would make a tremendous difference in our guesses. Each continent hosts its own various species of woods, and some from each continent closely resemble others from different continents.

If you live in North America and I were to make a wild, poorly educated guess, I’d guess that the wood you have there is butternut, perhaps partly decayed.

https://www.wood-database.com/butternut/

It is not. Bamboo isn’t a tree, it’s a grass. In some respects, it’s similar to wood, however.

I am writing a paper on the concise topic of wood ;) and, while I know there is difference in opinion on the subject, I wanted to know your take on the question: from shrubs to trees, from the pith to the bark, from the roots to the stems, from the seed to the grown tree, where and when does the substance we call wood begin and end? I think for practical purposes “what is wood” is intuitively obvious, but I’m looking for the technical boundaries between what is defined as wood and other organic material in a tree/plant.

Kind regards,
Calvin

I tried attaching photos the first time that I posted. Hopefully these will work on this attempt. In advance, thank you.

This is an off-the-wall question, but I’ve been experimenting applying iron acetate to various woods. Of course, they all react differently, but I noticed that the wood I asked about goes nearly jet black. Do you know if the black cherry would be loaded with tannins? Thanks again for all you do here.

Interesting! Thanks for the insight.

Possibly black cherry. The sapwood/heartwood demarcation in the wood looks close, as does bark in last pic.

I’m sorry, I don’t see any streaking in the pictures. If you are referring to the redder portions in the center of the boards, that is just heartwood and is a normal part of the wood coloration.