One of the first cork oaks I started working on has developed quickly. I let a couple of sacrifice branches grow freely and they have now adequately thickened the branch that will become the new leader. It’s time to make a big cut.

Field grown cork oak

The decision to cut has also been influenced by the health of the lower branches. Because the top of the tree is growing so strongly, the tree hasn’t invested in the lower branches which are turning yellow and may soon die back.

Here is the yellowish foliage I noticed on the lowest branch on the left.

Yellow foliage

And here is healthy green from the top of the tree.

Healthy foliage

I started by shortening the sacrifice branches on the old trunkline.

After cutting the first two sacrifice branches

I then reduced the new trunkline.

After reducing the new trunkline

Next, I carefully removed the stub with a saw.

The wound after cutting back to the new trunk line

Here’s what the tree looked like after reducing the trunk and shortening the branches.

Cutback complete

As now is a good time to repot the tree, I removed it from the box and reduced the size of the rootball.

After initial root work

Looking closely at the remaining rootball, it was clear that some of the roots were growing in good bonsai soil while others were still in field soil.

A patch of field soil

A patch of bonsai soil

I decided to remove the field soil by using a root hook and an aluminum pick to scrape the soil away from the roots. There weren’t a lot of fine roots in this area.

After removing the field soil

I repotted the tree in a training pot with a mix containing 30% akadama with a mix of lava, pumice and kanuma making up the remaining 70%.

Repotting complete

I’m curious to see how the main branches fare after making the big cuts, but I won’t be surprised if there’s some dieback.

For those curious about the work on this tree over the past couple years, see “Stimulating new buds on cork oak” and “Developing a young cork oak bonsai” for details.

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