AusBonsai

I have a Chinese Elm (smooth bark, not sure of the latin name) that I have just started to develop. I purchased it before I learned what to look for in stock and have just noticed it has reverse taper in the trunk.

I have read elsewhere that to rectify this, you cut vertically down the drunk to promote swelling. Can anyone tell if this is correct or have had any success with it? When is the best time?

Thanks.

The technique you mention will help Concept. you can make a number of vertical cuts in the area you want to thicken. the vertical cuts will not interfere with sapflow but will initiate scar tissue under the bark as the cuts heal. The scar tissue is thicker than the natural growth so the cut are gets thicker than other areas. You can make cuts one one side only if you want the trunk thicker in one specific spot or all around the trunk for overall thickening.

You can do this at any time of the year and may need to do it a few times (every month or so??) until the desired thickness is achieved.

I have also heard of stabbing the area repeatedly with a needle or gently hammering the bark to bruise the canbium below to cause thickening.

You can also hit it with a hammer to bruise it, Pierce lots with a nail, carve out the bulges.

Many ways to do it and none are guranteed.
if you want to try then spring while actively growing would be my pick.

Ken

Thanks for the tips.

I'll keep you posted of how it goes.

If you posted a photos some of the pros might be able to tell you the best approach. You could find for example that you'd be better off doing an air-layer than bothering with trying to rectify it. But no way to tell without photos.