Trimming an Aspen tree
We would like to cut off the lowest branches on our tall Aspen tree in order to place a bench under the tree. Is now a good time to do this (late March into April)? I was also wondering ... Should we cut a branch off flush with the trunk or leave a little stub? Should we apply some kind of protective coating on the wound(s)? A Google search revealed conflicting answers. We'll trust your expert answer. Thanks in advance.
Arapahoe County Colorado
Aspens (Populus tremuloides) will produce a lot of sap so you may want to wait until the spring flush of growth has happened. That means wait until mid-summer. Pruning now won't hurt an aspen, but it may become unsightly.
With regards to adding a protective coating to the stub, we don't recommend that.
Here is some general information about pruning.
And if you want to read even more about pruning, here is an extensive document that will tell you all you want to know about pruning and more. http://cmg.colostate.edu/Gardennotes/612.pdf