Floss silk trees (Ceiba speciosa) like these at the District Office in Ventura are sometimes briefly deciduous in the fall. They aren’t consistent which is a bit unusual but normal for this species. These trees are stressed from too much water.
I can clearly see dead branches in the canopies of most of the ten trees but many of the bare branches may simply be deciduous at this time of year. Up close you can tell if the branches are alive but from the ground I can’t say for sure.
I numbered the trees starting on the east end. I attached a map as Figure 1. All ten need to be pruned to clean all dead branches over 1 inch. Trees 5, 7 and 8 near the middle of the group appear to have more dead branches than the others.
When you prune, the objectives should be to reduce risk and improve appearance. To accomplish that clean the canopy by removing dead, broken, crossing or wayward branches.
These trees are under stress because they are growing in turf. I checked the soil and it was pretty wet and dense, conditions that cause root problems for this otherwise trouble free tree.
These trees are unique, related to the baobab and you can see that form in some. Unlike most landscape trees, silk trees are grown from seed so each one is genetically unique. Most landscape trees are grown from rooted cuttings from a “mother” plant so each one is the same.
These trees are just reaching maturity. The water is the problem. If you can switch to a moderate water using groundcover you may be able to restore them to health.
Sunset Western Garden Book says, “Fast drainage and controlled watering are keys to success. Irrigate established trees about once a month during growing season; ease off in late summer to encourage more flowers.” Your trees are drowning.