EUGENE, Oregon — The engines on some of timber company Weyerhaeuser’s log trucks driving around western Oregon may sound the same, but what is in their fuel tanks is definitely not the typical diesel that such trucks have long run on. The company has begun using 10 trucks that run on compressed natural gas and plans to grow that number, phasing out most of the diesel fleet running out of its Goshen facility, just south of Eugene. Company representatives said it is an early adopter of the technology, putting it at the vanguard of running trucks on alternative fuels. …“Ten trucks a year is kind of the plan,” said Travis Ridgway, Director of Harvest and Transportation for Weyerhaeuser. …Ridgway added that continued improvements to the truck’s range that will push them closer to 400 miles per tank of CNG will allow further use of the alternative fuel trucks.