Question
Hi. I have two very tall locust trees, perhaps 100 years old, in front of our adobe house in northern New Mexico (elevation 7,500 ft.) They seem generally healthy, but the leaf producing branches are spindly and mostly at the crown. Most of the lower branches die and break off. Would pruning revitalize them, (if so, please instruct)or do they have a terminate life span? The place was neglected for about 50 years before we bought it. I can send photos if it would help. Thanks much, Eileen

Answer
Sounds like it may need fertilizing. I would use 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. IF you apply the fertilizer just before a rain storm you will not need to water it in. I do not know the rain conditions in that part of the US so you will have to make that call. I would go ahead and fertilize now and again this winter after the leaves fall. This will increase the overall health of the tree.

Pruning will not help the tree but could make it look bad. Any pruning should be done this Fall after leaf drop and then remove the whole limb IF it needs cutting.