The Jack Pine Project, by David Johnson
Bonsai clubs can contribute to the overall knowledge of the bonsai community by soliciting and publishing the findings of members' experiences with various techniques and plant material. The Toronto Bonsai Society's "Jack Pine Project" tries to do just that.
Jack Pine (pinus banksiana) is a tree that ranges from northern British Columbia eastward as far as Nova Scotia in Canada. It is also grows in the north eastern United States. Although of limited range on a world scale, it is a collectable and available tree for those in the neighborhood.
It is a medium sized tree that can grow up to 80 feet, often less, depending on growing conditions as it can live in sandy and rocky soils. Those growing in rocky outcrops can produce beautifully stunted trees that make them of interest for bonsai. Under normal conditions, the dark green two needle fascicles can be 2 inches long and twisted. Under stressful conditions, the needles can be less than 1 inch.
The bark becomes quite scaly on older trees. The branching can be gangly giving it a lighter appearance compared to other larger indigenous pines like eastern white pine (pinus strobus) and red pine (pinus resinosa). Take a look at Canadian painter Tom Thomson's "The Jack Pine" to get the feel.
I have been attracted to this tree for its short dark green needles and scaly bark as well as its availability for wild collection. My early experiences with collected jack pines have not been happy ones. In fact, I have decided to begin my contribution, a bit ashamedly, based on notes from my "Dead File", bonsai I have loved and lost.
I plan to summarize what may have contributed to these trees' demise on a case by case basis. This will help novices to avoid my errors while experienced hands will ask, what took me so long to figure it out.
The Dead Files:
Case 1
1993
A tree collected in May was dead by September the same year. Tree was planted in ground after collected and treated with diazinon after noticing a borer hole with fresh saw dust.
Case 2
1991
Purchased in fall and then hard pruned, wired and pinched that month.
1993
Planted tree in ground April, pinched candles. Tree started to show signs of dying needles in October. Died shortly after.
Case 3
1992
Purchased April. Hard pruned tree.
1993
Next April, repotted removing some dark collected soil and replaced with bonsai soil. Wired, hard pruned and pinched next month. Pinched later in July.
1994
More pinching and wired Oct.
1995
Repotted April pruning 10% of roots. Candles reacted with very slow growth. Tree dead by Sept./95.
Case 4
1996
Collected May. Pulled out of ground with roots in tact at collection site. Planted in ground. Cutback 10% of foliage and guyed branch down in June. Tree growing well.
1997
Repotted cutting back roots to fit in pot and pruned 25% of foliage. Hard pruned 50% of foliage in July. Cut aerial root and several others in summer.
1998
Tree died June.
Case 5
1997
Collected May. Planted in ground and hard pruned in June and August.
1998
Potted in training box April and pruned 25% of foliage. More foliage pruning May and June. Wiring Aug. Cut large root Oct. Nov. repotted into smaller box.
1999
April slow movement of candle growth. June cut heavy root. Wiring of larger branches and needle plucked July and Aug. Fall wiring.
2000
Repotted pruned some roots ("hopefully I didn't cut too many"). Removed old soil. Pinched candles May. Sept. removed 50% of upper foliage to create a smaller, more compact tree.
2001
Repotted cutting off more root. Needles yellowing by May. Tree dead by July. Notes say I may have killed tree by damaging it when repotting into too small of a container.
I know...make it stop...but there is more.
Case 6
1996
Collected Oct. Potted in wooden training box with 1/3 bonsai soil.
1997
Aug. cut large root. Repotted into same box removing 10% of soil.
1998
Candle pinching and pruning of 15% of foliage. Cut roots on sides in Aug. Put into smaller box pruning 15% of roots in Nov.
1999
Spring slow candle growth. Sept 50% of foliage removed. Wiring tree. Oct. 40% of foliage removed.
2000
April, tree over-wintered in cold room due to wiring and re-bar bending of branch (could have been over watered while inside cold room). Repotted that spring removing 15% of roots. May more wiring. Aug. needles light green.
2001
April repotted removing 15% of roots. More trunk bending and needles more yellow.
2002
May, placed in larger container with better drainage. Tree died.
Case 7
1996
Collected May and planted in large styrofoam box. June, removed 30% of foliage and then a further 40% later that month, and 20% more in July.
1997
April repotted and removed 30% of old black collected soil and 5% of roots.
Nov. raffia applied on branches that were bent using re-bar and tourniquets.
1998
April repotted. Noticed candles elongating very slowly with some yellowing at needle tips. Candle pinched, tree put in partial shade and recovered by July.
1999
April repotted in cascade pot reflecting new design (most of collected soil removed). June and July used re-bar for more branch bending. Sept, wired branches.
2000
April repotted after wintering inside cold room due to fall wiring. Tree slow in coming out of dormancy (due to winter cold room over watering?).
2001
April wired tree and pruned a back branch. Removed a tourniquet and associated heavy wire. May repotted in new container. May, pinched candles. May wired some branches and later re-positioned tree in pot.
2002
April, tourniquet put on main trunk to pull closer to base. Cracks appeared and sealed. Wired rest of tree. June, tree coming out of dormancy slowly and weakened. Candles pinched when elongated and some branches pruned.
2003
April repotted 15% of roots removed as well a more collected soil. May, tree recovering from repotting, some needles browning and other yellowish as before. Died.
Case 8
2001
Purchased May and pruned 50% of foliage. June removing old dark collected soil. Sept. repotted.
2002
April, repotted removed more collected soil and 10% of roots. May, candles stopped growing or doing so very slowly.
2003
Repotted May using turfus/coke breeze mix. Tree weakening and later died.
Case 9
2002
Purchased April repotted removing a lot of old soil and 15% of foliage. June cut portion of heavy root with view of its complete gradual removal. Some needle yellowing. Sept, needle plucking, 15% of foliage pruning and wiring.
2003
April, repotted removing 25% of roots. Tree looks good. June pruned 25% of foliage and cut another portion of heavy root. July pruned 20% of foliage and cut more of heavy root. Sept., Boon said tree weak.
2004
April potted in Boon soil and cut some roots. Tree weakening in greenhouse, candles not growing. June dead.
Case 10
2002
Purchased April, repotted and removed old soil. Wintered in cold room.
2003
May, repotted. Candles very slow to elongate.
2004
May, repotted in Boon soil. Sept. removed old wire and then re-wired.
2005
May, died (perhaps due to freeze/thaw in new greenhouse system).
Case 11
1999
Collected three trunk tree May and planted in ground. July cut large root.
2000
April potted in plastic tub and removed 20% of roots and 25% of foliage. April, another 20% of foliage removed. July removed 50% of foliage. Aug. roots on opposite of previous pruned root, cut. Aug. tree needle plucked and wired.
2001
April, repotted removing 10% of roots. May, pinched strong candles, noticed some candles not moving, moved tree to partial shade. Pinched strong candles later in May. June, needles dying on one tree (due to repotting and root pruning?). Summer, pruned 10% of foliage and removed more of heavy root and replace old collected soil with bonsai soil.
2002
April cut "v" notches to move trunks closer and wired together. April, repotted removing lots of collected soil. No root pruning but bent roots to fit in pot (think it will be OK). May, needles dying throughout all trunks but candles elongating and other needles dark green. July wired branches. Sept. removed 40% of foliage.
2003
April repotted removed more collected soil and pruned 30% of roots including one at back by mistake. May in partial shade as candles on smallest tree growing very slowly. Pruned foliage on two strong trunks July.
2004
Aug., smaller third tree dead. April, a lot of dieback on one of remaining trunks. Tree died in April.
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Thus finishes the end to a sorry history with many dead trees. One will notice some of the errors I have committed are not necessarily a function of jack pines per se but more generally how pines and perhaps other slow growing conifers should not be treated. Slow growing plants mean that they respond slowly to repotting and pruning of any foliage or roots. These examples are case studies about what not to do.
The Roots:
Roots feed the tree with nutrients, supply water, remove gas, store sugars and starches and anchor the tree in the soil. The roots are key to the tree's survival. Hurt the roots, you threaten the tree. The roots are the most important transfer station for the tree. Therefore, strengthening the roots system is key to the tree's survival.
Likewise, the foliage is the energy transformer, transforming sunlight through photosynthesis into sugars and starches to feed the tree and the roots, thus allowing the roots to grow and do more of what they do.
Newly acquired trees have to adjust to a regime from a field grown environment to container grown culture, from infrequent watering to frequent watering. Thus the composition of the soil is critical. In bonsai culture, a free draining soil is needed to allow a quick passing of water and flow of air. All trees whether collected in the wild or purchased at nurseries contain fine field soils that are OK for that culture but lethal in pots because they hold too much water and slow the removal of gas. That field soil must be removed.
Boon Manakitivipart suggests removing 1/3 to 1/2 of the field soil at one time each year until it is all gone. For trees in development which is applies to most, a medium mix of 5/16 to 3/8 inches. This should be the focus of initial bonsai work. That is adjusting the tree to container culture with a change of soil characteristics and developing healthy growth ignoring needle size and internode length. Later, once the transition to bonsai soil is accomplished with vigorous growth, then pruning and pinching with a focus on ramification is next. Leaf/needle reduction is the last concern.
Walter Pall, in a series of articles mentioned below, recommends removing less foliage after collecting a tree because that foliage is necessary for the tree's post collection recovery as opposed to a tendency to "balance" the foliage and root mass.
/B>Patience Practice:
Greg Cloyd makes the case for patience in training in a series of articles in International Bonsai 2001 No.1 to 2004 No. 1 titled "Pine Management Theory". He wrote,
"No more than one major insult should be contemplated per year per tree. An insult is anything which stresses or injures the tree. Insults frequently involve decreasing the tree's photosynthetic capacity by removing needles, or decreasing the stored energy of the tree by removing roots, branches or buds. Severe branchlet thinning, heavy branch pruning, trunk wounding, severe needle reduction, decandling and major bud reductions are all significant insults. Generally they are not done in the same year as repotting or major wiring. The return of vigor must be carefully monitored before the next weakening technique is undertaken.
"After an insult, a period of unchecked growth is frequently necessary to preserve the health of the tree. The unchecked growth period produces a return of vigor, compartmentalization of wounds, replenishment of energy stores and production of defensive chemicals. After vigor returns the grower must then strive to control the strength of the plant in order to avoid coarseness. The unending challenge of bonsai it maintaining miniaturization and vigor distribution without damaging plant health..."
International Bonsai 2001 No. 2
Walter Pall from Germany has lots of good advice in a series of articles he wrote on "Collecting Trees from the Wild" in Bonsai Today Numbers 74, 75 and 76. Many of his comments apply directly to the collection and rehabilitation of wild trees including pines. His articles will be invaluable to anyone who collects trees for bonsai.
Current Experiences:
For my currently living trees, bless their souls, I have gradually been switching over to the conifer soil formula recommended by Boon Manakitivipart which is one part akadama, one part pumice, one part lava rock, plus 1/2 cup each of horticultural charcoal and decomposted granite to each 5 US gallons of the above mentioned mix. For deciduous trees, it is two parts akadama, one part pumice, one part lava rock, etc.
In addition, and equally important, I have reduced the number of "insults" I inflict on my jack pines, thinking of years instead of months between insults. Even if a trees looks OK after one insult, it can also be giving one a false sense of security by saying "this tree is OK, it can handle more" when it is really just holding its own.
Pines are slow to react to insults and expressing the tell tale signs of distress. Growing candles, at that particular stage of growth, seem to be the best barometers of what is going on regarding the tree's vigor by its continuing to grow and show bright green colour at the candle base. Looking at the needles shape, length and colour as well as number and size of buds are other indicators. See Greg Cloyd's article mentioned above.
Conclusions:
1. If the jack pine is a medium sized tree, perhaps it is telling us that it also has a medium level of vigor. Therefore, allowing the tree to recover from "major insults" is more critical. Seeing vigorous growth (seeing and allowing the elongation of candles) should be done before further "major insults" are committed. Work on changing the old collected soil first, letting the foliage grow which will heal and grow more roots. Then reduce branches for design. Followed by a reduction of foliage size for presentation.
2. I promise I will not repot a pine every year hoping to get it into a better pot at the expense of the tree's survival. I will repot every other year or longer. All four jack pine that are still alive have been repotted every other year or longer. That fact plus Boon's soil mix are telling indicators to explain some success.
3. To increase ramification and reduce needle size, I can't say I have a proven strategy. I have over the years pruned, needle plucked and pinched candles. I can't say what the results of the traditional method of candle pinching for most pines that are not Japanese black pines which consists of pinching part of the strongest candles followed by pinching the medium candles and leaving the weakest ones.
4. At Boon's suggestion, I am withholding fertilizer in the spring until the new needles harden off in order to help reduce needle size. This usually occurs in late May but one really has to watch the needle colour turn from a light green to a dark green. The fertilizer will also help bud formation which often occurs in early June. I favour organic fertilizers but augment with chemical fertilizers. I use a balanced amount of nitrogen, phosphorous and potassium.
Experiment One:
As I mentioned, I have pinched candles (strongest first, then the medium ones and leaving the weakest) but without a documented record of the tree's reaction. What I may have to say is just speculation. However, in one case I did document an interesting experiment. For one medium sized tree that was potted in April 2004 and subject to some substantial pruning over the next year, on June 2005 I noticed that new buds had formed. As the tree seemed vigorous, I pruned off all of the new shoots (like is done for Japanese black pine) leaving one to three pairs of needles depending upon the shoot size and strength. My notes have no mention of any candle pinching. By Aug. 1, 2005, new buds have formed and some are opening with needles about 1/4 to 1/2 inch in length.
The tree was repotted in Boon soil in April 2006 and a month later in May 2006, I pruned 40% of the foliage and wired the main branches due to the tree's vigor.
What I find interesting was the tree's response to the severe June 2005 pruning with its replacement of new buds, candles and needles. There is no information as to whether or not a third set of buds were produced on the second set of shoots. However, the notes did say that the tree was vigorous in May 2006 after a repotting in April 2006. I would not carry out this pruning annually unless the tree's vigor allowed it. The needle length at the end of 2006 showed that the needle length is about 1 inch.
The purpose of the June 2005 pruning was to reduce shoots length and encourage back budding and thus ramification. The act of pruning reduced shoot length. But back budding did not appear to have occurred to the extent that I made a note of it, or I just may have missed it altogther. The overall look of the tree showed a denser foliage mass. More pruning and observation is required.
Future Experiment:
I have yet to lock on to a satisfactory method for candle pinching, shoot pruning and needle plucking, I am still at the level of experimentation. The results will have to wait for another installment of the "Jack Pine Project".
I plan to keep three buds, if I have them, then in the spring pinch two of them allowing the third and strongest one to grow. Later, during the first week of June when I have noticed that new buds begin to form, I will completely remove this long shoot. I hope that this method will shorten the internode on the first two candles later shoots while allowing the third stronger one to increase vigor to the branch overall (and the tree cumulatively). Then by pruning it at the time of bud formation, I expect greater back budding.
Whether the strongest one is left to grow or the weakest one depends upon which area of the tree we are looking at. For vigor balancing between the strongest areas at the top and on the tips of branches or the weaker areas on the branch interiors, choose the stronger candle in the strong areas as a sacrifice shoot keeping the weaker candles/shoots and in the weak area let the weak bud become the sacrifice keeping the two stronger candles/shoots for the long term branch structure. Needle plucking can also facilitate vigor balance.
The above only applies if there are three buds to choose from of course and that is not always the case. If there is one bud let it grow and pinch only 1/4, if anything. If there are two buds in a strong area, pinch 1/4 of the weaker bud and let the strong one grow, then remove it completely or if the internode is short, leave four needle pairs. In a weak area, pinch 1/4 of the stronger bud and let the weaker grow. Personal observation has to guide which course of action one takes to strengthen the weak areas and weaken or slowdown the strong areas.
Instead of relying exclusively on candle pinching, use limited pinching plus allow some candle growth into shoots which are pruned later with the goal of promoting greater vigor.
Twisted Needles:
Another observation I wonder about is the tendency of jack pines to have slightly twisted needles. I personally feel that this characteristic is unattractive. In fact I recall the literature about growing pines from seeds in Japan recommending that people avoid parent trees that have twisted needles. This distortion can also be caused by stress. But for the jack pines, it seems that it is a sign of vigor and health. However, many of the naturally stunted jack pines I have seen have straight needles indicating to me that needles reduction actually reduced the twisted affect. In this case, bonsai culture may favour the creation of a more attractive tree.
Summing up:
I think this all I have to say, which is enough. Hopefully it will be of help to readers. More careful study is required which may aid in making jack pine a valuable tree for bonsai.
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