Dan, a professional arborist with North
Country Tree Service, sent the following question. It contains
some technical terms & issues, which you don't need to understand to get
information from the response. His letter follows, then my
Hello, I am an arborist with 22 years
of pruning and removal experience. I have visited your web site because
it is very professional and interesting. I thank you for your dedication
to bonsai and the art and science it involves. I do not own a bonsai at
this point but was wondering if a bonsai is similar to the trees I prune
on a regular basis. For instance:
1. Is 'tipping' and 'topping' of the tree considered
mutilation like it is in my profession? You achieve undesirable results
and damage roots when internodal cuts are made outside the branch collars
or when proper techniques like crown reduction, drop crotching or crown
raising are not utilized.
2. Do bonsai have branch bark ridges and swollen collars?
And if you prune these parts incorrectly do you risk non-compartmentalized
decay and splits?
3. When wiring your bonsai are you concerned about branch
or trunk girdling or damage to the bark and cambium?
There are many other questions but if these three situations are parallel
to my profession than I'll assume bonsai have the same tree biology as
my 100' specimens I work in and that the same rules for inclusions, epicormic
sprouting, micro and macro elements, mycorrhizae, pH, apical dominance
meristems, phloem, xylem... all apply???
Do you think they do? I would appreciate your expertise and it would surely
be of interest to me and my profession. Thank you again for devoting your
knowledge to a beautiful living thing. Trees were here millions of years
before man and they remain a privilege for us all.
A tree has the same environmental range limitations in nature as it does
when cultivated as a bonsai (a Japanese White Pine won't survive the warm
Florida winters, a Serissa won't survive the cold Northern winter outdoors,
a New Zealand Tea Tree won't survive if the soil is dry, etc.) From there,
they would seem to part ways. There appear to be parameters for pruning
full sized trees that I was unaware of, in the same way as you are unaware
of corresponding aspects of bonsai cultivation. The reason is simple.
While we are both dealing with trees, we are dealing with them from diametrically
opposed angles. You deal with them in their "natural habitat." I deal
with them "in captivity." The same rules do not apply in all cases, but
do apply in many.
A naturally developed, centuries old bonsai
can cost as much as a house, and like a house, can be valued at well below
a hundred thousand dollars, or well above a million.
By employing "artificial" methods of growing
a tree, we can create a nice, aged-looking bonsai for 1/10th of one percent
of the cost of a corresponding "natural dwarf." In bonsai cultivation,
"tipping & topping" are a necessary evil, which, when done properly, have
minimal impact on the overall esthetics of the bonsai. As you know, a
tree has a genetic maximum height, which, in nature, is reduced correspondingly
by the amount of available soil, the quality of that soil, the amount
of available nutrients, the amount of available water, daily exposure
to sunlight, wind conditions, the climate, and other factors.
In bonsai cultivation, we can control
the first five, but it would be impractical for someone like myself who
lives in New York City to raise a tree near the timber line of a mountain
in the Adirondacks to expose it to the severe winters. I can't change
the prevailing winds to create a windswept style, or the climate, which
affects the overall growth, and ratio of wood to foliage growth. These
are things which we do with wire, scissors, and other tools and methods.
Decay in cuts is controlled by the use of things like cut paste and lime
sulfur. Splitting is not a problem because you don't have branch sections
of a bonsai that weigh as much as a car, and cause stress on the tree's
structure. We usually make cuts just above the node, then later, as new
bark begins to form, the "stump" can be trimmed & shaved to give a natural
appearance In some cases, we "jin" the branch. That is where the bark
and foliage is stripped from the branch. Lime sulfur is applied to give
the whitish gray "blanched-bone" appearance of natural dead wood on a
tree, and preserve the wood.
As for wiring, it is very important to
choose the proper gauge wire for the branch you're re-shaping, apply it
so as not to dig into the bark and cambium layer, wire the branch in it's
natural shape, then bend slowly into the desired shape little by little
over weeks , months, or sometimes years to avoid scarring and damage.
The wire should be removed and re-applied periodically to avoid damage
to the branch. A Japanese Maple should be re-wired every two to three
months, where a Japanese White Pine can go six months or more without
attention. The duration depends on factors such as the species of tree,
time of year, thickness of the branch, wire gauge, etc.
As for the biology of trees you mention
in the second part of question #3, they all exist to some extent in bonsai
cultivation. Mycorrhizae (a symbiotic soil fungi that attaches itself
to the roots of most trees, which help the host plants absorb more water
and nutrients while the roots provide food for the fungi) is essential
in pines, so you should never wash all the old soil away when re-potting.
It's not too important in Maples, which will eventually develop new growths
of it, so all the old soil can be removed, and the roots washed clean
Soil pH is very important to proper health and development of a bonsai.
That's why we offer three different meters to measure it.
In general, you want everything that is available to a full sized tree
to be available to a bonsai, you just want to control the amounts to control
the growth rate.