Iris,

I think the clue here is the habitat not the species. Trees growing in harsh
climates are more likely to have injuries to the cambium which produce trees with
only living strips of bark. Deserts and high altitudes are likely places for this
to occur, but I have seen it in the odd tree in more temperate climates. There is a
cherry tree not too many miles from here that has a wonderfully spiral bark
produced by some sort of injury many years ago.

Perhaps junipers and pines are just more likely to survive after the sort of
massive injury that produces these bizarre trunks. I suspect that the
susceptibility of the exposed wood to damaging rots is an important factor.

Gene Newcomb in the temperate Willamette Valley of Oregon

Iris Cohen wrote:

OK, here's one. I was recently told that junipers differ from other trees in
that pruning cuts never heal over the way they do on other trees. If there us a
split in the bark, the live part of the tree will grow on one side, leaving the
grotesque deadwood which is sought after by bonsai collectors. Why? What is the
difference between the growth habits of junipers & other trees?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885

I am dubious. Obviously trees in harsh climates are very vulnerable. They
often are few and far between, inviting damage from evil-doers. Also they
grow slowly and will be slow to repair such damage.

A durable heartwood (truewood to the Aussies) may help exposed parts in
resisting rot. On the other hand the bristlecone pines do not have seem to
have particularly durable heartwood.

The way Iris phrased it concerned the entire genus Juniperus, which occurs
all over the Northern hemisphere (and in montane Africa). Actually I find it
hard to imagine that wounds in this genus would not close as in other trees,
but I can not say I have any real experience with it.
PvR

Gene Newcomb schreef

Iris,

I think the clue here is the habitat not the species. Trees growing in
harsh climates are more likely to have injuries to the cambium which produce
trees with only living strips of bark. Deserts and high altitudes are likely
places for this to occur, but I have seen it in the odd tree in more
temperate climates. There is a cherry tree not too many miles from here that
has a wonderfully spiral bark produced by some sort of injury many years
ago.

Perhaps junipers and pines are just more likely to survive after the sort
of massive injury that produces these bizarre trunks. I suspect that the
susceptibility of the exposed wood to damaging rots is an important factor.

Gene Newcomb in the temperate Willamette Valley of Oregon

Iris Cohen wrote:

OK, here's one. I was recently told that junipers differ from other
trees in that pruning cuts never heal over the way they do on other trees.
If there us a split in the bark, the live part of the tree will grow on one
side, leaving the grotesque deadwood which is sought after by bonsai
collectors. Why? What is the difference between the growth habits of
junipers & other trees?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so
much that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885