Crimson King Maple Root Loss Needs Top Loss

Q. I have a pair of mature crimson king red maples in Arlington ma that are showing signs of stress due to recent construction close to them and coinciding drought their canopy has reached its limits to receive water easlily from rain or the surrounding irrigation that is in the lawn under them I was told fertilizer and lots of water should bring them back before pruning any suggestions would be appreciated 

Crimson King maple picture  from University of Arkansas Extension

A. I think water and fertilizer is pushing your luck this time of year. It is possible to lose quite a bit of roots and not have many canopy problems but that just depends on which roots were cut and how many. 

General rule of thumb is to correct root loss with decreasing the size of the canopy. Don’t have pictures so I would tell you to prune back the canopy ¼ to 1/3 by reducing the canopy size at the furthest distances from the roots. 

Trees have the most difficult time getting water to leaves and stems furthest from the roots. They show stress first...leaf scorch and limb dieback. This will probably mean you many have to “drop crotch” the canopy. If done by a good arborist, they should be able to maintain its beautiful characteristic shape and you will notice very little change in appearance except size.

Of course putting about an extra ½ inch of water under the canopy weekly beyond irrigating the 

grass will help because of the tree’s shallow roots. They aren't very drought tolerant due to their shallow roots.

I think Crimson King is a Norway maple.