Proposed wilderness designations for parts of the Colorado mountains could threaten the Army's only high-altitude training site for helicopter pilots, an Army officer said Tuesday. The proposed "Hidden Gems" wilderness designations would put all of the high-altitude landing zones used by the High-Altitude Army Aviation Training Site off-limits, said Col. Joel Best, senior aviation officer for the Colorado Army National Guard. "We really can't afford to lose any of that land for the security of this nation," Best said. He spoke at a briefing for Colorado county commissioners and legislators. The site, known by the acronym HAATS, is the only...