Forested land can play a critical role as a possible area for biodiversity offsetting projects. This would reduce the pressure on agricultural land caused by spreading settlement area and related offsetting requirements. This raises the following question: to what extent have offset regulation and clearance compensation rules become more flexible to allow for compensation projects in the forest due to increased land-use conflicts? To address this question, we draw on the institutional change literature, which proposes that different modes of institutional change towards a flexibilization of offset regulation can be expected in different institutional contexts. Empirically, we focus on the sub-national contexts of two European countries: Bavaria in Germany and the Berne in Switzerland. Although in both cases the forest comprises one-third of their land cover, the cases exhibit quite different forest policies and biodiversity offset regulations. Making the forest area available for habitat compensation projects generally depends on the need (e.g. due to implementation deficits) and the political will to loosen the mitigation hierarchy in both realms. The analysis demonstrates that the preconditions of such institutional change (veto-power of opponents and discretion in implementation) favoured more radical reforms in German biodiversity offset regulation but allowed only tentative adaptions in Swiss forest clearance regulation.