Preserving deadwood

It was once again time to give my Thiuja occidentalis 'Smaragd' its annual clean-up. Nothing unusual only pinching new laggy growth from this year to better show the structure of the tree.

Ponovno je bil čas, da svoj ameriški klek ponovno nekoliko očistim. Nič neobičajnega, le ponovna zaščita suhega lesa in krajšanje letošnjih poganjkov, za bolj razvidno strukturo krošnje.

After cleaning-up the crown.
Po čiščenju krošnje.

Eventually after inspecting the base of the trunk I noticed something I was afraid of, but knew would happen some day. A good part of the deadwood at the base was very soft, wet and rotten.
It is tipical for dead wood to rot faster when in contact with soil because it is in contact with water the better part of time. And since this tree is fairley young, which means that its wood is not very hard, wood rotting accures even faster. Therefor this was no surprise to find such a sight after 9 years of having this tree. 

Naposled sem po pregledu nebarija odkril, da je večina suhega lesa mehka, vlažna in gnila. Nekaj, kar sem vedno vedel, da se bo enkrat zgodilo. 

Za les je zelo značilno, da najbolj gnije ravno na tistih delih, ki so v neposrednem stiku z zemljo, saj je tam ves čas vlažno. Še en razlog pa je to, da je to drevo relativno mlado in ima posledično bolj mehak les. Mehkejši kot je les, hitreje gnije. Skratka, odkriti takšno stanje po devetih letih, odkar sem začel z delom na tem drevesu, ni bilo nobeno presenečenje.

Already a soft scratch with a wire brush or even chopsticks tore off some soft parts of the wood. 

Že z zelo nežnimi potezami krtače ali kitajske palčke sem lahko odstranil gnil les.

So what to do next? If I had left this untouched the rotting would continue until it would eat away the whole dead trunk at the base. You can't really prevent rotting of deadwood at soil level, but there are a few ways to noticably slow it down. First you have to remove all or at least most of the soft rotten wood, until you get to the wood that is still hard.

Kako nadaljevati? Če nebi nič ukrepal, bi se gnitje enostavno nadaljevalo in prav kmalu bi odgnil ves mrtev del debla pri nebariju. Gnitja mrtvega lesa, ki je v stiku z zemljo praktično ni mogoče povsem preprečiti. Obstajajo pa načini, kako ga močno upočasniti. Kot prvo, je potrebno odstraniti ves les, ki je mehak in gnil, da ostane le trd les.

Then you wait a little for it to dry out and then burn it with a torch. Fire is known to make wood harder. But you have to be carefull not to fire it too much which will just turn the wood into coal and you will end up with even less of the trunk.

Malo počakamo, da se les posuši in ga nato nežno oplazimo z ognjem. Ogenj ima to lepo lastnost, da les otrdi. Vendar ne smemo pretiravati, ker hitro lahko pridemo do oglja, ki pa tudi naposled odpade in se obseg debla še dodatno zmanjša.

Next step is to apply lime sulphur. This is the most commen technicque to preserve deadwood on a bonsai, so why bother trying to figure anything new out. But since this part will be more exposed to water apply more layers of the lime sulphur.

Naslednji korak je tretiranje z apnenim žveplom, ki je najbolj uporabljena metoda za zaščito suhega lesa v bonsajizmu. Zakaj bi izumljali nove tehnike, če ni potrebno. Ker pa bo ta les izpostavljen vlagi bolj, kot drugje, za vsak slučaj nanesemo več slojev.

To further harden the wood aply a thich layer of wood hardener. I use a product called Paraloid B72, which works quite nicely. Then wait for it to dry again. 

Za še dodatno ojačanje lesa sem na koncu nanesel še debel sloj trdilca lesa. Uporabil sem sredstvo Paraloid B72. Nato sem spet počakal, da se je les lepo posušil.

At the end add fresh soil to the base. I used a well draining soil - a mixture of pumis and kiryu in a 3:1 ratio. 

As I mentioned earlier, it is impossible to permanently stop wood rot on parts that are in constant contact with the soil, but there are ways to slow it down considerably.

Za konec sem ponovno dodal nekaj svežega substrata. Uporabil sem dobro propustno mešanico pumisa in kirya v razmerju 3:1.

Kot sem že omenil, je gnitje suhega lesa na nivoju zemlje in pod njo nemogoče povsem zaustaviti. Je pa mogoče to močno upočasniti.

This is the tree now, with its slight different new look.
Takšen je nov, malce drugačen izgled bonsaja.

It's hard to belive it was made from this raw material 10 years ago.
Kar težko je verjeti, da se je vse začelo pred desetimi leti s tem materialom.