This document discusses strategies for landowners negotiating gas leases and estate planning regarding subsurface mineral rights. Key points include: - Landowners should negotiate addendums to gas leases to obtain better terms regarding bonuses, royalties, environmental protections and other provisions. - Subsurface mineral rights can be owned separately from surface land rights and transferred separately through various legal mechanisms. - Careful estate planning is needed to ensure subsurface rights pass to future generations as intended, such as through trusts, partnerships and corporations. - The value of property depends on whether subsurface rights are included or separated, as they provide both income potential and use restrictions. Appraisals consider various valuation approaches.