Thursday, October 30, 2014

Bolstering Dead Wood, Before it Disintegrates—Experiments

by Michael Rusnak

No doubt, everybody loves dead wood—at least is seems that way.

Juniper and other evergreens can retain their deadwood for a lot of years, especially when given the typical lime-sulfur treatment.

Deciduous trees of course are another matter. On many species, such as grape, it rapidly rots away.  Rotted areas can create interesting hollows along the trunk that can add great character.  However when live sections become small,  the rot can lead to a total collapse. 

The two concord grape vines in my collection are examples of where the trunk was to the point that it only had a few live veins, and despite the fact that I work with the vines a lot over the last couple of years, the difference in the color between what is live vein and what is dead on the grape is hard to distinguish.  The colors are just so similar—and there is that paper-like peeling that the trunk gets each year that again makes you wonder what is alive on the plant. 
At the beginning of this season while repotting the vines, the trunk of the smaller grape collapsed.  This trunk had a large hollow that was a visible and interesting feature.   I watched helplessly as it crumbled away, leaving a kind of half-shell look to the trunk, still kind of interesting, but not nearly as awesome as it had been.  I felt like crying.  The thing that you have to learn to deal with if you work with bonsai, is that because it is a living thing, you can work with a tree for years, and then lose it in a heartbeat. I think of the winter a few years back when I lost three maples that I had for 18 years, maples that the preceding season were becoming specimens. 
This magnificent grape was one of my favorites, and it was obvious that for the large grape, disintegration was imminent. 

The problem is that the vine itself was in danger of collapse.  So there was a choice: let the vine just disintegrate and see what is left, or do something to try to preserve the beautiful undulations, movement, spiraling grain patterns and hollows that are all present on the old trunk. So I choose to try to preserve this wonderful trunk.
On the smaller grape, I slathered outdoor wood glue onto the inner side of the now completely hollow shell of the trunk (See photo at left).  This did serve to help give it some structure, but not very well.
Having worked on some natural wood slab tables, where epoxy is often used to fill and control cracking, I decided to try to use an epoxy on the trunk of the larger grape.  I put it on in small batches, trying to press it deeply into the cracks and openings all along the dead portion of the trunk.  Over an hour or so I had covered most of the dead wood.  The epoxy hardened nicely and it did give the dead soft wood some rigidity, perhaps even preserving it for a few more seasons. 

One problem though is the shiny, plastic-like, almost artificial quality that the hardened epoxy creates. I have been spending some time working a wire brush along the surface to cut down on this shine with limited success.  If anyone has more solutions please help me an offer them.

Since then, I found a suggestion to try using penetrating epoxy In the book Bonsai from the Wild, by Nick Lenz.  I noticed via the internet, that this is a marine product and is sold in large quantities, as it is typically used to cover portions of boats.  If you work with a lot of deciduous trees it might be useful to make the investment and keep some penetrating epoxy on hand.

In any case, I think the result was a better alternative to letting the wood disintegrate. Beyond the wonderful shape of such trunks, when I look at such an old tree, the dead portions of the wood, complete with its twists, movements and hollows are its stories—and it tells those stories visually.  They are a kind of record of each year, both wet summers and droughts, as well as what it has endured at the mercy of animals, disease and severe weather.   In that sense it is something important, something to keep and not just rot away.  

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