Q.Container Cherry Tree
I have a flowering cherry tree, only a year or so old. The roots were starting to show in the small pot it was in so I have moved it to a larger pot but only realised near the end of repotting it that I had been putting in top soil! Should I repot it using a different type of soil/compost?
Top soil may be to compact for the tree. The roots may not be able to breath and take up nutrients.
I would either amend the soil or start over with a good quality potting mix.
Here are some links to help you.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/using-topsoil-and-potting-soil.htm
https://www.gardeningknowhow.com/special/containers/proper-soil-mix-for-evergreen-container-plants-and-trees.htm