Experience has indicated that many of the oldest five-needled pines have experienced cambial dieback to varying degrees.    From Wordnik.com.  [Wahl and Ammann Again #1 « Climate Audit] Reference

However, there have been a number of whitebark pine trees found to be resistant to the nonnative pathogen white pine blister rust, which has been a major threat to whitebark and other five-needled pines since the early 20th century.    From Wordnik.com.  [Louisa Willcox: Whitebark Pine: Functionally Gone in Much of the Greater Yellowstone] Reference

These mycorrhizal fungi are specific to five-needled pines, including whitebark and limber pines.    From Wordnik.com.  [innovations-report] Reference

Whitebark pine (Pinus albicaulis) is a five-needled conifer species whose coastal distribution extends from the Bulkley Mountains in British Columbia to the northeastern Olympic Mountains and Cascade Range in Washington and Oregon to the Kern River of the Sierra Nevada Range of east-central California.    From Wordnik.com.  [KTVZ.com - Local Headlines] Reference