Principia Arboreum

Buck Abbey, ASLA, Robert Reich School of Landscape Architecture, Louisiana State University

Conroe, Texas has one of the best tree technical manuals. The city took Clear Channel to court in Nov. 2011 for hiring tree-cutters to clear 15 60-70 feet tall trees blocking the view of one of its billboard along I-45 North. Conroe?EUR??,,????'???s tree preservation ordinance prohibits clear-cutting. The city, unaware of the tree clearing until a resident brought it to their attention, fined Clear Channel $500 per tree.

Principia is Latin for ''first principles'' and the word ''prince.'' The term ''Principia'' is probably most associated with Sir Isaac Newton's 1687 three-volume Philosophi???? Naturalis Principia Mathematica. In his manuscripts he set forth principles of motion and other physical theories that eventually led to classical mechanics and calculus.

As used here, it largely represents standards, values, ideals, and canons, all terms associated with the development of codes and land-
development regulations.

''Principia arboreum'' might very well represent the standards and values associated with tree care for the urban forests of American towns and cities. Knowledge of tree care, first principles, are generally inserted as arboricultural specifications, tree management practices, tree preservation strategies in a written document referred to as a Tree Technical Manual.

Conroe, Texas

Tree technical manuals are used by arborists, landscape architects, horticulturists and urban foresters in their work of managing community trees. More importantly, the manuals give specific supplementary regulation to a community's tree ordinance or landscape code. They are crafted to further a community's goals of tree protection, forest canopy management and care to specimens, groves or populations of trees.

Tree Technical Manuals
Some of the best tree technical manuals are found in communities like Palo Alto, Calif., Tampa, Fla., Montgomery County, Maryland and Conroe, Texas. Similar to how landscape manuals are used to supplement landscape design practice, these documents are attentive to trees and provide useful information for arborists and municipal tree care officials.

Typical tree regulations are generally in text format and supplemented with illustrations, specifications and technical architectural details.

The manual from Conroe, Texas, prepared by Burditt Consultants, is a good example of a well balanced, well thought-out manual that covers the essentials of community tree management: survey standards, analysis, site planning, protection standards, maintenance and planting requirements. Standards are included for tree preservation and mitigation, both of which might be further refined, especially within the tree ordinance itself. For instance: 1) Even though the use of mechanical tree spades is mentioned in the Conroe Manual, there's little technical documentation to show how these machines can be put to work protecting native trees on developments. Tree preservation through relocation is not a well-known principle of urban forestry. 2) Tree technical documents generally do not recognize the importance of designing with trees. Some design standards of public streets, public lands, public forests and public parks should be mentioned. There are several common strategies available for urban tree design and they should be mentioned in tree technical manuals.