Wood Term "?"

[Harold Hanson]

I am new to the forum, there are two wood terms that I am seeing being used which I do not under stand the meaning of the term Burl, Spalted.
Harold

[Jamie Donaldson]

A burl can be considered something like a wart or a tumor, a knot on the side of a tree that has interlocking grain that is sometimes quite desirable as turning material. Spalting is the first stage of decay in wood, sometimes exhibiting lines of contrasting color in the body of the wood that adds contrast or detail that enhances the appearance of some plain wood as turning material.

[Norm Zax]

Jamie's and adding this: burl is beautiful (and expensive) but tough to turn as grain direction is everywhere.
Spalting for woodturning is farther down the road than 'fresh wood' but stopping before 'rotten'. If spalting goes too far the wood becomes punky and soft and is unusable for us turners. Very beautiful wood gone bad is sometimes saved by immersing in wood stabilizers. Also, note that some trees spalt easy (and nicely) while others resist or spalt poorly. Maple spalts nicely, for example.
To see several examples of both terms, go to Google, press Images and write spalted bowls. Next try burl bowls. You'll get it!

[John Keeton]

Harold, welcome to the creek!! Lots to learn, so just be patient and ask questions - this is a great bunch of folks and they will be glad to help.

Couple of additional comments - the two desirable characteristics of burl are "rays" and "eyes". In makeup, a burl seems to be a clump of very small efforts on the part of the tree to grow branches, but all in one spot. So, on the outside surface of the burl, the "tips" of the branches will produce an "eye" and the "branch" itself will produce a ray. If the burl is cut through the middle (cut running from the outside surface in toward the center of the tree) you will see rays.

The attached image is a piece in the initial stage of a box elder burl being formed. The center/pith of the tree would have been running vertically to the right of the turning, and the outside edge (natural edge) of the burl is on the left. You can see the rays, and in the area of the turning where the concave surface is being formed, you can see that cutting across the rays produces the "eyes".

Some species of burl are much easier to turn than others, and some produce much more desirable burl figure. Oak burl, while beautiful, tends to be more "gnarly" with less distinct eyes and rays. Maple burls are similar in appearance to the box elder burl shown (box elder is also called Manitoba Maple or Maple Ash). Big Leaf Maple, a west coast wood, produces a large number of burls that are easy to turn, and have beautiful coloration.

On spalting, spalt is caused by a fungus and is different than rot, but they both are usually present at the same time as the wood is diseased and dying - or dead. The presence of moisture is a required condition of both, so usually the spalting and rot are progressing together to the point the wood becomes punky.

[phil harold]

I am a fan of Wikipedia for definitions
Here is Burl:
http://en.wikipedia.org/wiki/Burl
and spalting:
http://en.wikipedia.org/wiki/Spalting

nothing like pictures to go with explanations...

[Harold Hanson]

Thank you, Jamie, Norm, John, and Phil, for your replies, I understand the meaning of them two terms and I recall seeing that on trees and wood chunks. I’m sure I will have many more questions as I get into this hobby, I know I will love it.
Harold

[Joe Watson]

As time goes by, you might find this thread helpfull (i know i did/do):
http://www.sawmillcreek.org/showthread.php?27040-List-Of-Acronyms-Updated-12-1-05

[Dan Hintz]

I'll add a new term: Ambrosia

It's similar to a spalt line, but whereas a spalt line is thin (1/32-1/16"), very ragged and many are often running together, an ambrosia line is usually quite thick (comparatively speaking, usually 1/8-1/2"). Both are caused by fungus.

A spalt line is caused by two different fungi types meeting, which causes them to create a chemical boundary between the two colonies... this boundary is the dark spalt line. An ambrosia line is caused by the ambrosia beetle (a generic term for a number of similar beetles) boring a tunnel into the wood. The sides of the tunnels allow fungus to grow, which is what the beetle eats.