Q.Health Of Katsura Trees In Neighborhood
Our neighborhood has 40+ Katsura trees lining our alley. They have grown tall over the last 15 years and now are creating lots of damage on the fences and rooflines that end up being under the canopy (especially during summer and fall). It seems that the trees drop a lot of “stickiness” on everything and anything that lies temporarily or permanently under them. Cars have even been damaged from the “sticky sap”. Do these Katsura trees typically do this after mature, or is it that they are potentially unhealthy or diseased?

Certified GKH Gardening Expert
This can be normal with high variability in temperature and humidity. This can be a sign of insect pest infestation, though, as well as bacterial infections.
Unfortunately, your photos did not come through. I will be unable to assess the situation, further.
These articles can help:
https://www.gardeningknowhow.com/ornamental/trees/katsura/japanese-katsura-tree-care.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/wetwood-bleeding-trees.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/aphids-tree-disease.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/control-plant-scale.htm