Tree Preservation Ordinance Review

An action item of the current Work Plan is to consider/develop tree replacement standards for inclusion in the Tree Preservation Ordinance.  The ordinance, as presently written, essentially requires a tree inventory to be completed by an ISA Certified Arborist or a Society of American Foresters Certified Forester for all 'significant' trees with no specific replacement requirements.   

City Code defines significant trees: (1) All oaks with a DBH of four (4) inches or more; (2) All evergreens with a DBH of four (4) inches or more; and (3) All other trees with a DBH of eight (8) inches or more. When a development proposal is contemplated, the submittal must include a tree inventory. Typically, the inventory simply locates the existing trees and identifies those that will be removed and those that will remain after the initial rough grading and infrastructure improvements. Often times, additional tree removal is also necessary as individual lots are developed with homes.

As previously mentioned, there are no specified replacement requirements for single family home developments.  The ordinance does state that the City may require clustering of homes or alternate locations of homes to avoid removal of significant trees, although practically applying this during the plat review/approval process is difficult. All lots are required to be landscaped with a minimum of two (2) trees (minimum planting size of one [1] inch DBH for deciduous trees and five [5] feet in height for evergreen trees).

In multi-family developments, the ordinance does require a project to retain forty percent (40%) of the inches of tree DBH existing on the site after development.  There is a replacement requirement in this scenario that requires a one to one replacement of desirable trees if in excess of sixty percent (60%) of the inches of tree DBH are removed.   This is in addition to the required landscaping, which is determined by a canopy cover formula (determine ratio of impervious area to entire site area, multiply the impervious area/site area ratio by the square footage of the pervious area to determine the required canopy cover square footage).

Staff is not seeking any immediate action this topic.  Rather, Staff wanted the Board to have an opportunity to familiarize itself with the current regulations, which may lead to further discussion on the matter.  A significant question that should be contemplated is whether the Board believes, in general, that the landscaping requirements are sufficient in lieu of any replacement standards or if further review and research is warranted related to replacement standards that would be in addition to the landscaping requirements.  This is also a good time to review at least one complication that arises occasionally between tree preservation and requiring topsoil.