harvesting a self-propelled machine with a grapple or tongs and a supporting structure designed to pick up and discharge trees or logs for the purpose of piling or loading —note 1. the loading operation may be swing-to-load, slide-to-load, or travel-to-load —note 2. a loader is known as a hydraulic loader or knuckleboom if it swings to load and has hydraulically activated boom members —see jammer, shovelThis definition last updated 07/13/2008