A Schulreise is a field trip taken by the entire class, accompanied by one or two teachers (usually the Klassenlehrer). A school trip takes between 1 - 2 weeks. The idea is to enable teachers and kids to form a closer relationship and study in more relaxed surroundings. Most Schulreisen are subsidized by the government to enable kids of low-income families to take part.
A Landschulheim is a hostel for school children on a Schulreise (field trip). It is subsidized by the government and usually located in rural surroundings. It does not provide hotel service, so kids are encouraged to do kitchen duty and clean up their rooms, make their own beds, etc.. It is usually run by a matron.