Section 91.14 - Expiration of plan certification(1) Except as provided under sub. (4), the certification of a farmland preservation plan that was certified under s. 91.06, 2007 stats., expires on the date provided in the certification or, if the certification does not provide an expiration date, on the following date:(a) December 31, 2011, for a county with an increase in population density of more than 9 persons per square mile.(b) December 31, 2012, for a county with an increase in population density of more than 3.75 but not more than 9 persons per square mile.(c) December 31, 2013, for a county with an increase in population density of more than 1.75 but not more than 3.75 persons per square mile.(d) December 31, 2014, for a county with an increase in population density of more than 0.8 but not more than 1.75 persons per square mile.(e) December 31, 2015, for a county with an increase in population density of not more than 0.8 person per square mile.(2) The certification of a farmland preservation plan that the department certifies under s. 91.16 expires on the date specified under s. 91.16(2).(3) For the purposes of sub. (1), a county's increase in population density is the number by which the county's population per square mile based on the department of administration's 2007 population estimate under s. 16.96 exceeds the county's population per square mile based on the 2000 federal census.(4) The secretary of agriculture, trade and consumer protection may delay the date for the expiration of a county's farmland preservation plan for up to 2 years beyond the date under sub. (1) upon a written request from the county demonstrating to the secretary's satisfaction that a delay would allow the county to concurrently develop a farmland preservation plan and a comprehensive plan or an update to a comprehensive plan.