I rewatched that video Brian, and Ryan did indeed say the more foliage mass, the more photosynthesis there is, and a less of a need for longer needles. So shorter needles are the result.
Yet Walter stated in Larry's book, pg. 90:"Long needles are the result of a combination of much water and feeding as avised here. Therefore a 'finished' bonsai will finally get less water and feed, but this only after more that a decade in development". And continued on pg 92:"For getting shorter needles one can also practice the following method: In May with all the whorls (cluster of 3-5 branches from one spot on older branches)the needles are cut back to the length that one woud have liked. The buds must remain intact. These buds will develop candles with have a bit shorter needles, because the get somewhat less energy from the shortened needles. The tips of the needles will look sl. ugly though for one season"....But during development of a bonsai one can well work with very high nitrogen contents in organic feed. Long needles will create a alot of energy that leads to lots of back budding. Later, when the bonsai is 'finished' one can feed less"
Per Jerry Meislik, pg. 87: "...the normal needle length can be shortened a it. Signif. needle reduction can easily be produced by cutting all the needles to half their length after they harden off in early summer. The next yr. this will activate many latent buds and produces shorter needles and more branching"
And Dan Robinson on pg 79: He talks about water starvation technique where you use this technique "for several weeks, or until the needle has hardened off. Then resume normal watering to promote good bud formation. Then needles will not extend after they have hardened off. Most of my Ponderosas in my collection are lg. trees and the natural needle is somewhat diminished by being in a container in which the scale is appropriate For smaller trees, shorter needle length is critical, and this is an interesting but demanding method to try."
So it seems, there are sev. different approaches to be tried. But Walter def. seems to want to water and feed highly for trees in dev., have the long needles, and only when it is 'finished', one can feed less and try the needle cutting. Pretty much what Ryan said.
He is definitely one of the good guys out there.
