Patmore Ash losing leaves
I have a Patmore ash and the leaves are dying on several of the smaller branches. These smaller branches are on different parts of the tree.
I think the tree is watered adequately, but if it could it be water stress, why only certain small branches?
Larimer County Colorado trees and shrubs
Trees move water to branches via different transport systems...it's not unusual for a tree to exhibit signs of stress on one side of a tree...or in the case of spruce, in a spiraling pattern. Physiologically, trees will shed unnecessary leaves and/or branches in times of stress. It could be that these branches are unnecessary for the tree's health. It's been very hot and dry lately with little rain (until today). Prior to that, we had a wet spring, but a very hot and dry summer in 2012 and one of the driest and coldest winters on record.
Because fall is near and our first frost is approaching, the leaves will soon be shed and forming their abscission layers.
I would encourage you to continue with your watering practices throughout the fall and winter (even after you blow out your sprinkler system). Drought-stressed trees may not have the ability to withstand as much cold hardiness, plus moist soils release heat, which is beneficial to the root system.
Monitor the tree, remove any dead/diseased branches in late winter/early spring and see how the tree leafs next year.