Trunk Splitting Bonsai

	This is a Thuja occidentalis 'Aurea' I collected during 2002 from a garden where it had been growing for 5 or 6 years. After a year's recovery, I started to address the long branches that only had foliage at their very ends. I pruned the branches hard to create backbudding and slowly shortened each branch back to it's new growth. Here's the tree during the Summer 2003. As can be seen, it has inverse taper at the base as well as a large wound where I removed a large branch. Given the very straight trunk, I could only see this tree having a future as a formal upright bonsai, but the general lack of taper as well as the inverse taper at the base, made the tree look ugly. Having successfully split a thick branch earlier in the season to thin it (first branch on left- still wrapped in black tape), I decided to try splitting the trunk and opening it up to increase taper at the base. This technique is very stressful to any tree; given the vigorous nature of this particular specimen, I felt that it had every chance of surviving. However, it was work I wished to carry out before investing any more time developing its branch structure. Trunk splitting is not recommended for use on deciduous species or species especially prone to rot, particularly if the exposed wood will be directly exposed to the soil.
February 2004. Late last year, anticipating the trunk splitting, I created a shari on the trunk that encompassed the large wound on the front/left of the trunkbase. (The yellowing of the leaves are the winter colour of this tree).
	The tree was lifted from its pot and the roots were cleaned of soil. The roots were found to have grown very vigorously since the tree was originally collected. A path up the trunk was found that would allow the trunk to be sawn in half from the rootbase up into the main body of the trunk. For the whole period that the tree was out of its pot (around an hour) the roots were misted frequently to ensure that they would not dry out.
Given the necessity to work quickly and accurately, the trunk is sawn from below using a reciprocating saw.
	A clear cut, straight through the trunk. Notice that the cut has been made between two major roots that grow beneath each side of the shari.
.A piece of bamboo was then slowly inserted from the bottom of the cut, slowly forcing the split to open. Great care was taken that the cut/split was not allowed to continue unabated up the trunk. The tree was then repotted with the tree slightly rotated toward the right (with the bamboo still in place to hold the split open). Further work was carried out, the shari was extended higher up the trunk to encompass another wound from a previous branch removal; the shari and the split/cut were carved to create a more natural appearance and the previous small first branch was jinned.
	Over the past few weeks, the shari has been painted with a mixture of lime sulphur and black paint to exaggerate the hollow. For now, the tree will be allowed to recover and the next few years will be spent developing the branching and foliage density. At the time of writing, the tree has budded out very strongly for Spring and the only sign of weakness to the tree is in the first right branch just above the shari.

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