North Rim Trail, Early and Late Trees and Leaves

Returned to the Woods' North Rim Trail on this Thanksgiving morning for the first time this year. Cool morning 45F. Saw two groups of three large deer each running away south.  The trail segments are in reasonable shape, if somewhat overgrown from lack of use.. No massive blockage or saw required. The north portion of the Woods is the wilder part, less visited and more homes for animals of the woods. Many burrows in active use. I used my cedar walking stick as a scythe to cut old asters and a short clippers to clear greenbrier.
Most (97%) of canopy leaves are down now. But a curious thing, some individual trees and some branches still hold their leaves. Why? Is there an advantage to holding leaves a bit later? What are the species, apart from Sideroxylon Chittamwood,  that are likely to do this? What are the trees that put out their leaves before everyone else? It continues to be very dry..