How to Fix Lopsided Norwegian Maple
I recently purchased a home in Howard County. In the front yard, there is a 20 ft tall, ~8" diameter Norwegian Maple. It has a thick branch on the left side of the split which is growing vigorously. The branches on the right side of the split are smaller and not growing as well. It does leaf out, though it dropped the leaves earlier than the left side (as you can see). I am considering making a substantial cut to take off the largest upper branch in an attempt to get the tree to even out the growth, but because it's by far the largest branch I'd like your advice. I'm also worried that the tree will just put out a ton of new growth right around where the cut is. If it does, should I remove that new growth to continue to encourage it to use the right side? I've attached images to show the cut that I'm proposing. I'll also do some standard pruning to remove dead branches and branches that are too close/crossing. I'm also wondering if the abnormality on the trunk may be the cause of this strange growth pattern. Thanks for your help on my last question - I had the dying tree removed this week!
Howard County Maryland
Based on your photos we recommend that you remove the tree and take the opportunity to replant with a native species based on the mature height and width of the tree.
Your tree will never return to its former glory and pruning will not solve the problem. The trunk has been compromised and there is most likely a root problem. In general when you see poor growth and decline it may be attributed to girdling roots (maples are prone to this), planting too deeply, soil grade changes, lower trunk damage, drought stress, etc. See our publication on these types of problems http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG86%20Common%20Abio...
Also, The Norway maple is an invasive species and we do not recommend planting. Its shade-tolerant seedlings out-compete natives and create monocultures. See more http://extension.umd.edu/hgic/problems/invasive-tree-control