Question
I planted 16 Aspens last fall rangeing height of 10-15 feet tall. All have leaved out but 3. These 3 have lumps on the branches about the size of golf balls (3 per tree). What can I do to save them? And what are the lumps?
Please help, thank you Joan

Answer
These are called gall insects and will not kill the tree. The insect lays its eggs on the twig and secretes a chemical that cause the cells of the twig to grow over the eggs hence the gall. Normally they will be controlled naturally and may if numerous cause some growth loss. I would not worry about them the trees will out grow the infestation. Here is a web link that gives more information on gall insects:
http://kaweahoaks.com/html/galls_article02.html