Trunk size on eucalyptus tree

Question

Why does the trunk on my eucalyptus tree stay skinny (about 1″ in diameter) and does not fatten up. It had grown to 8′ and after 2 seasons I trimmed the top about 1 foot hoping to fatten the trunk. Is something wrong?

Answer 1

Avoid high Nitrogen fertilization which tends to stimulate height and not trunk caliper (diameter). Use a balanced fertilizer with NPK numbers under 10, preferably an organic slow release product like this:
https://www.domyown.com/dr-earth-organic-all-purpose-fertilizer-p-9485.html
The Calcium, Magnesium and Sulfur and other nutrients content is important for balanced growth and you don’t always get that with chemical fertilizers.

Stake the tree loosely so that it can move around a little and not be strapped tightly to the stake. The movement will help to develop caliper and standing strength. I use the two or three stakes method and tie loosely so that the trunk can move but not bang or rub on the stakes.
http://m.espacepourlavie.ca/en/staking-tree

Don’t strip off lower growth that develops along the trunk; you can shorten branches that will eventually be removed, but allowing “temporary branches” on the lower trunk now will help develop caliper.

Hope that helps, Don