Flushing a cutting's foliage depletes stem reserves. Plants need and seek root/foliage balance. A plant with foliage removed, ideally will replace foliage as a response, not root initiation. Likewise loss of roots ideally will be followed by new root generation. Reducing stem temperatures, while maintaining root warmth is one path toward initiating new root development .
I rooted many woody plants in the past. The plants were maintained under shade cloth, with about 50% of the foliage removed to reduce transpiration. Additionally the cuttings were automatically, periodically misted/fogged to cool the stems and retain turgor.
Woody plants differ in rootability by season, by species and cultivar, by degree of lignification (maturity within season), by rooting hormone dosage, by juvenility of propagation materials, and rooting media selected. Mother trees are often deliberately keep in a vegetative state by severe pruning to force new, more easily rooted growth. The base of a cutting (the lowest portion of a flush of growth) has the greatest rooting potential.