Section 2. The board, having first complied with all the preliminary requirements prescribed by law, shall adopt an order of intention to take, which shall contain a description of the property to be taken sufficiently accurate for identification, and shall state the interest therein to be taken and the purpose for which such property is to be taken, and, if betterments are to be assessed therefor, shall so state; otherwise, it shall state that no betterments are to be assessed. In case there are trees upon land so to be taken, or structures affixed thereto, the order shall state whether the same are to be included in the taking, and, if they are not to be so included, shall allow the owner a reasonable time after the taking becomes absolute to remove the same, to be specified in the order.