darrenjttu
Member
Can someone explain what pith is? Also how do you cut it out?
Pith
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greenmtnguy
Local Chapter Leader
Not really an issue in most trees. Small trees might have a spongy center, but full grown trees would tend to have a hard center.
From Wilkipedia:
Pith is a light substance that is found in vascular plants. It consists of soft, spongy parenchyma cells, and is located in the center of the stem. It is encircled by a ring of xylem (woody tissue), and outside that, a ring of phloem (bark tissue). In most plants the pith is solid, but some plants, e.g. grasses and umbellifers, the pith has a hollow centre forming a hollow tube except at the points where leaves are produced, where there is a solid plate across the stem. A few plants, e.g. walnut, have distinctive chambered pith with numerous short cavities in the pith.
The word comes from the Old English word piþa, meaning substance, akin to Middle Dutch pit, meaning the pit of a fruit.
The pith varies in diameter from about 0.5 mm to 6-8 mm in solid pith, and up to 150 mm or more in the stems of some plants with hollow pith, e.g. some bamboos. Freshly grown pith in young new shoots is typically white or pale brown, commonly darkening with age. In woody plants (trees, shrubs), the pith becomes surrounded by successive annual layers of wood; it may be very inconspicuous but is always present at the center of a trunk or branch. The cells in the peripheral parts of the pith may in some plants (e.g. Hedera helix) develop to be different from cells in the rest of the pith. This layer of cells is then called the perimedullary region of the pithamus.
From Wilkipedia:
Pith is a light substance that is found in vascular plants. It consists of soft, spongy parenchyma cells, and is located in the center of the stem. It is encircled by a ring of xylem (woody tissue), and outside that, a ring of phloem (bark tissue). In most plants the pith is solid, but some plants, e.g. grasses and umbellifers, the pith has a hollow centre forming a hollow tube except at the points where leaves are produced, where there is a solid plate across the stem. A few plants, e.g. walnut, have distinctive chambered pith with numerous short cavities in the pith.
The word comes from the Old English word piþa, meaning substance, akin to Middle Dutch pit, meaning the pit of a fruit.
The pith varies in diameter from about 0.5 mm to 6-8 mm in solid pith, and up to 150 mm or more in the stems of some plants with hollow pith, e.g. some bamboos. Freshly grown pith in young new shoots is typically white or pale brown, commonly darkening with age. In woody plants (trees, shrubs), the pith becomes surrounded by successive annual layers of wood; it may be very inconspicuous but is always present at the center of a trunk or branch. The cells in the peripheral parts of the pith may in some plants (e.g. Hedera helix) develop to be different from cells in the rest of the pith. This layer of cells is then called the perimedullary region of the pithamus.
Dario
Member
Check this link
http://www.wonderfulwood.com/articles/logcutting.html
Pith as mentioned above is soft when the tree/plant is young. It does turn to heartwood in most cases and the problem is cracking while drying. Wood shrinks while drying both tangentially and longitudinally. Pith cannot/doesn't shrink as much as the outer layers and if not removed will most likely cause the cracking.
For pen blanks, it might not matter as much.
http://www.wonderfulwood.com/articles/logcutting.html
Pith as mentioned above is soft when the tree/plant is young. It does turn to heartwood in most cases and the problem is cracking while drying. Wood shrinks while drying both tangentially and longitudinally. Pith cannot/doesn't shrink as much as the outer layers and if not removed will most likely cause the cracking.
For pen blanks, it might not matter as much.
darrenjttu
Member
I guess I have the wrong wording. I have some cedar and have small "rays" of heart wood. These rays are cracking on me and I am just wondering what they are.
Dario
Member
probably branches...same reason I gave you earlier.