Do gymnosperm needles pull water through the xylem produced in the same year as the needle?

This research investigated the longevity of functional connections between leaf traces and stem xylem in 16 species of conifers to better understand the spatial use of sapwood for water transport. The first question was which ring(s) stained when a vacuum was applied to the distal end of the cut surface of a needle attached to a short stem segment. The vacuum was applied to either 1- or 2-yr-old foliage taken from 4-6-yr-old saplings.