The City has a plant material list to provide initial guidance on plants that are known to be reliable in the marine environment of Cannon Beach. The City's coastal location creates unique growing conditions that need to be considered in the design of any planting program. Because of the effects of wind and salt air, growing conditions can change substantially with the proximity of a parcel to the oceanfront. Further, there can be significant changes in micro-climatic conditions. Plants that may be successful one or two blocks away may have difficulty surviving at a particular location. The City's landscaped environment provides one means of maintaining a vital link with the City's historical past. For this reason, the City encourages the use of native plant materials when designing landscape plans. The City also encourages the incorporation of existing plant materials into the landscape design whenever possible. The removal of trees more than six inches in diameter, at chest height, requires a tree removal permit.