Please refer to Question ID #191295. Per the suggestion, I scraped the
bark of the larger diameter tree, and it is bright green on the trunk,
but not so on the bark of the branches (when scraped). By contrast,
the smaller diameter tree, which does have emerging buds, is reen both
places. What does this mean for the larger tree? Is it dying, or could
the branches come back?

Hi Boomering,

Well... now we're getting somewhere.  It appears your larger but
non-productive tree has suffered from cold damage.  This can happen to
younger trees and I've had this happen even living out in the
Southwest... if the temperature drops below freezing.

The damage from cold will kill the least hardy tissue - sensitive
branches but not the trunk.

Care after damage - Wait before pruning because even dead-looking
plants may still be alive. The extent of winter damage can best be
determined after new growth starts in the spring. Damaged plants may
be delayed in starting spring growth.

Prune all dead twigs or branches back to within 1/4 inch above a live
bud or flush with the nearest live branch. Do not remove branches that
reveals a green layer underneath when scraped with a knife. They
should eventually develop new growth.

Disclaimer:  I'd suggest calling in a tree expert or nursery before
doing any major pruning because it's always best to have it examined.

Best regards,

tlspiegel
Google Anwsers Researcher