Trips through rain forests, maybe

• Trips for nature lovers
• Environmentalists' excursions
• Trips to support conservation
• Trips to environmentally protected areas
• Safaris without guns, say
• Nature excursions
• Trips to the Galápagos, e.g
• Trips where a "carry in, carry out" policy may be observed

Wiktionary Word definitions in Wiktionary
n. (plural of ecotour English)