Advice re the best time to start shaping the trunk. Can you do it now during the dormant growing period or is it best to wait till spring when the tree starts to grow again

Knowing the subject of the shaping operation, where it's being kept, how it's doing (and for how long) would be minimum requirements to provide any meaningful answer to such question, I'm afraid...

and species

m5eaygeoff wrote: and species

indeed. that's what I meant by " the subject of the shaping operation", but worth clarifying

I think the tree is a Japanese Yew / Podocarpus, but not sure as it is the subject of another post with images asking for any thoughts on ID. I bought it from a reject section of a garden centre so not sure of age but at least 4/5 yrs.
It has been outdoors during the summer but as I am not sure if it is frost hardy I am keeping it in a greenhouse overnight and outdoors when weather permits.

I think the tree is a Japanese Yew / Podocarpus, but not sure as it is the subject of another post with images asking for any thoughts on ID. I bought it from a reject section of a garden centre so not sure of age but at least 4/5 yrs.
It has been outdoors during the summer but as I am not sure if it is frost hardy I am keeping it in a greenhouse overnight and outdoors when weather permits.

What do you mean shaping the trunk?

Maybe it would be usefull if you posted a picture?