Are trees weaker in the spring?

[oldboy]

I remember hearing that many trees are at their weakest during the late spring months of May and June, when the pitch starts really flowing. I can't find more any info about this.

If this is true, is it best to avoid climbing skinny or weak wood species during this time?

Thanks,

Dan

 

[sgreanbeans]

I think what you heard maybe about working in them while pushing buds. The two times that trees are in their weakest state is during bud swell and leaf drop. The tree uses a immense amount of energy to do both. So working on them during this time, stresses them pretty bad. If you prune a tree while it is doing either, you take away from precious resources, as the tree will divert energy away from those actions to begin compartmentalization and wound closure. As far as actually being structurally weaker. I have not heard of that. Once it starts pushing buds, its best to wait until it is leafed out. In the fall, once it starts to drop, wait until the tree is empty.