Habitat loss and habitat fragmentation are major factors leading to forest biodiversity decline. This paper discusses landscape planning as strategy to improve connectivity in a landscape with a heterogeneous distribution of ecologically valuable areas across land owners. A tax-fund system is proposed, that following the principle of common but differentiated responsibility, tries to spread the burden of conservation equally across land owners while optimizing the environmental outcome. Design options of such a tax-fund system are discussed along the lines of a simple theoretical model. Financial effects of a tax-fund system are computed for a small model landscape set in Sweden. Two design questions stand out as particularly important. The first is whether the policy is intended to be self-sustained among the land owners or if the budget can be supplemented by general tax money. The second is whether the land owners or the relevant authority select the stands for conservation set-aside.