Mine did the same thing. Now the side branches on top of the trunk are becoming trunks themselves. I'm just leaving mine like that. The
tree isn't hurt and I think it's quite aesthetically pleasing and the birds LOVE it. I have a dozen feeders hanging from the branches like Christmas
tree ornaments and the birds flock in making it prettier still. PLUS, I have a pet rabbit, and when I prune the branches, he goes gah-gah over the fresh
willow leaves, and the dead wood that comes off the
tree he chews on to keep his teeth in good shape. (I checked the internet and fresh
willow branches are EXTREMELY beneficial and nutritious for rabbits and my bunny LOVES them. Plus I get the compost
)