Our plant pathologist suggests either pruning them just before bud-break or after bloom, the reason being that this is when the cuts will seal the fastest due to active tissue growth, which lessens the likelihood for infection by opportunistic pathogens. (The infection window for one prevalent pathogen, for example, coincides with bloom time.)

If you are not hiring an arborist or tree-care professional to do this trimming, make sure your cutting tools are sharp and clean, and that you follow the guidelines under the "proper pruning cuts" and "removing larger branches" sections on this page: https://extension.umd.edu/hgic/topics/pruning-trees. This will lessen the risk of bark damage, which cannot seal as effectively. If you follow the three-cut technique further out from the trunk at first, this will also create lighter branch pieces for safety. You can follow-up with a second three-cut procedure at the appropriate point on the branch for the final piece; with some of the weight taken off, it should be easier.

If you would like to consult an arborist regarding tree-trimming (or find one to do the work), you can use the second and third links on this page to help locate one: https://extension.umd.edu/hgic/topics/how-do-you-decide-when-remove-tree

Miri