Hello. Every year at this time my 2 Linden trees drop about half their leaves at the same time their seeds ripen and drop. Some yellow leaves remain on the trees for about another 2 weeks until they fall as well. The trees remain that way until fall. In the spring they’re normal and healthy looking as they get their foliage. Any thoughts?
The leaf drop is a stress reaction that is not uncommon with linden trees. It is hard to miss the amount of energy they put into flower and fruit and they need ample nutritional resources to recover.
In addition to soil with good organic content, they need water as well as soil that drains well. That's harder to provide in an area covered with lawn. Lawns are apt to become more compacted and depleted of nutrition than other areas. An area free of grass and foot traffic that is as wide as the tree drip line is healthier. That area can then be mulched to hold in moisture and the organic content can be refreshed with compost occasionally. Make sure that the tree is getting enough water in dry periods.