What is a trencher? A What is a trencher? A trencher is a special machine used for digging trenches. It is often used in construction and road building projects. Tag: Trenching Related Posts:Trenching with trenchers and Unimog trencherGM 140 H as excavator trencher track constructionGM 1 AF - Trencher for mounting TrenchmasterTrenchers: Versatile applications for efficient trenchingTrenching service GM 140-AFH - 600GM 140 AFH-600 - Trencher for pipeline construction