Tree Ordinance Guidelines

26. Situations which are declared to be public nuisances

Purpose: To define unacceptable situations which are subject to abatement by the local government.

Notes: Conditions and situations that jeopardize public health and safety are most commonly declared to be public nuisances. Hazardous trees and trees which obstruct travel or line of sight may fall into this category. Situations that threaten the health of the urban forest or are contrary to the community forest management strategy may also be declared nuisances. This second category includes trees which harbor diseases or insect infestations that may readily spread to adjacent trees and species which are considered undesirable. Improper maintenance practices which can lead to tree death or disfigurement have also been declared to be public nuisances in some communities. Abatement procedures are typically contained in a separate provision (see provision 27 - Abatement of hazards and public nuisances). 

27. Abatement of hazards and public nuisances

Purpose: To set forth procedures for abating the public nuisances described in provision 26 (Situations which are declared to be public nuisances).

Key elements:

• Authority to determine nuisance (if not noted in provision 15-Designate administrative responsibilities)
• Procedure for notification and appeal, including time limits
• Method of abatement and assessment of costs incurred

Notes: Communities vary in the detail to which they prescribe the procedures which must be followed for nuisance abatement and assessment of associated costs. Notification and appeal procedures may be simple or involved. 

28. Licensing of private tree care firms

Purpose: To improve care of private trees by ensuring that firms performing tree maintenance are qualified and have appropriate liability insurance coverage.

Key elements:

• Types of tree maintenance that require special licensing
• Requirements for professional qualifications
• Liability insurance requirements
• Method of documentation
• Authorization to suspend or revoke licenses for violations

Notes: Improperly performed tree maintenance work, including pruning, cabling, and removal, can cause property damage and endanger public health and safety. Therefore, many community tree ordinances require that firms engaged in tree work carry liability insurance. 

Furthermore, improper pruning practices can irreparably disfigure and harm trees. In the interest of protecting community tree resources, it is reasonable for the local government to require proof of professional competence from those performing tree work for hire. Such proof might take the form of certification from the International Society of Arboriculture, completion of course work and training in arboriculture, passing an examination, or other criteria. 

Purpose: To prohibit negligent or intentional damage to trees and other plants growing in the public right of way.

Key elements:

• Designation of which trees and other plants are protected
• Prohibited activities and actions

Notes: This is one of the most common provisions in street tree ordinances. It is primarily targeted at preventing vandalism and negligent damage. Some ordinances have elaborate lists of many different ways which trees can be harmed. Others include prohibitions against fastening animals to trees and allowing animals to browse trees. Some ordinances extend protection to tree guards or supports as well as to trees. If damage is properly defined in the definitions section (see provision 4), it may be possible to cover all types of damage rather simply, and avoid long (and often incomplete) litanies of damaging practices. Legal staff should be consulted in this regard. 

30. Permit required for activities that may damage city owned trees

Purpose: To provide for municipal review and approval of any activity which could be detrimental to public trees.

Key elements:

• Activities that require a permit
• Position with authority to issue permits (if not noted in provision 15 - Designate administrative responsibilities)
• Guidelines for approving or denying permits, including conditions that may be required to prevent or compensate for damage
• Permit application and appeal procedures, including time limits

Notes: In order to safeguard the public investment in street trees and other public trees, many local governments reserve the right to regulate a variety of potentially damaging activities. The authority to approve regulated activities should normally be vested with the tree program manager. Each community needs to decide what activities it will regulate. Some of the activities that might require a permit include:

• tree removal,
• pruning,
• grading or trenching near trees,
• installation of pavement over tree rootzones,
• transport of buildings or other large items which could break city street tree branches.

To prevent a net loss of trees, all trees removed should be replaced in a manner consistent with the overall tree management plan. If a community's goals include conservation of tree resources and establishment of maximum canopy cover, guidelines for approving tree removal permits should clearly establish the precedence of trees over hardscape or turf (see also provision 19 - Resolution of conflicts between trees and structures). 

As part of the procedure for granting tree removal permits, some communities require that a notice be posted or published in the newspaper. 

In some communities, local public utilities may be given a yearly permit that allows them to prune public street trees. In such cases, the local government should set minimum pruning standards and provide for inspection to enforce these standards. 

31. Permit required for activities that may damage protected private trees

Purpose: To protect designated individual trees on private property from indiscriminate removal and damage.

Key elements:

• Classes of trees protected
• Activities subject to regulation
• Criteria and standards for approving regulated activities
• Permit process, including requirements, fees, time limits, and appeals
• Conditions or compensation required to mitigate for adverse impacts
• Monitoring of protected trees and mitigation areas

Notes: This type of provision is typically known as a heritage or landmark tree protection provision. It is best suited to protecting conspicuous individual trees that are of unique historical, ecological, or aesthetic value, and therefore constitute an important community resource. A mature tree is a significant community resource that required many years to develop and can provide community benefits for generations, but can be destroyed in as little as a few minutes. This is the main reason that trees may be provided a higher level of legal protection than is usually afforded to other plants in the urban landscape.

Although trees can be long-lived, the life spans of individual trees are still limited, especially in the urban environment. Hence, this type of provision may not address the long-term sustainability of the urban forest. Furthermore, because of its focus on individual trees, this type of provision may not be appropriate or effective for protecting woodlands and forests. Woodland or forest conservation is addressed in provision 32 (Conservation of forest and woodland resources during development).

Provisions that regulate private trees are unlikely to be effective without community support. Unless residents strongly support tree protection, it is probably advisable to link tree protection with some sort of benefit or incentive to balance the additional burden imposed by the provision. The local government might provide tree care assistance, consulting, reduce certain assessments, or institute a recognition program to provide a tangible benefit to owners of protected private trees. Education and incentive programs are needed to ensure that protected trees are seen as an asset rather than a liability.

If your community is interested in preserving native trees, you may want to consider options beyond limiting tree removal on private property. For example, you might consider a policy which calls for planting native trees in public places (see provisions: 7 - Policies regarding trees, 24 - Permit required for planting trees in the public right-of-way, and 25 - Planting requirements).

Classes of trees protected. Private tree protection regulations are commonly directed toward desirable, long-lived locally native trees and/or trees of historical significance. Most commonly, protected trees are designated by species, size, and/or location, although other criteria may also be used (see Defining special trees: heritage, historic, and landmark trees). These criteria should takes into account differences between species and the influence of local environmental conditions on tree growth rates.

One disadvantage of using a size criterion is that some property owners may elect to remove trees before they grow large enough to come under the protection of the ordinance. This is obviously a counterproductive situation, since it has the effect of destroying future tree resources. Unfortunately, this behavior has been observed in various communities. If the goal of the community is to protect woodlands or forests, rather than individual trees, a forest/woodland protection provision (see provision 32) may be more appropriate. In some communities, both types of provisions may be needed to address the range of situations involved. If both individual tree and woodland protection provisions are used in the same ordinance, ordinance language must be clear as to which provision applies to a given tree or group of trees.

Some communities apply tree protection provisions only to commercial properties by exempting single-family residential parcels. This may greatly limit the impact of the provision because most of a community's trees are typically located on residential parcels. On the other hand, if tree loss and poor tree care in commercial districts are serious problems in a community, focusing the provision on those problem areas may be appropriate.

In the following example, the various classes of protected trees are clearly stated. Another example is included on the Defining special trees: heritage, historic, and landmark trees page. It is important to grant protected status to trees planted or retained in compliance with the ordinance to establish a basis for long-term protection of tree canopy.

• ratios based on the number of trees removed (e.g., one or more new trees for each tree removed)
• ratios based on the diameter or cross-sectional area (or basal area) of trees removed (e.g., one inch of replacement tree caliper for each inch of diameter of removed trees)
• planting standards based on overall canopy cover, density, or basal area standards for a given land use category (e.g., a residential zoning has a standard of 35% canopy cover, replacement planting must be sufficient to provide 35% canopy cover for the parcel within 10 years)

• Types of woodland or forest land subject to regulation
• Activities regulated on lands covered with woodlands or forests
• Criteria and standards for approving regulated activities, including mitigation requirements
• Permit process, including requirements,fees, time limits, and appeals
• Monitoring

Notes: The purpose of this provision is to establish a process for conserving woodland and forest resources that is invoked when land use is intensified to the degree that a discretionary permit is required. A provision that seeks to conserve functional forest or woodland systems must at minimum include the following features:

• natural stands or groups of trees are given priority over individual specimens;
• activities that fragment the woodland into small units are minimized;
• meaningful standards for tree canopy retention and reforestation are set;
• provisions are made to allow for natural regeneration of woodland/forest species;
• components of forests and woodlands other than trees are taken into consideration.

Relatively few local governments have implemented woodland protection provisions to date, but interest in this approach has been increasing in recent years. Some communities have attempted to use individual tree protection provisions (see provision 31) to protect woodlands, primarily by lowering the minimum diameter for tree protection. However, these tree protection provisions usually lack the necessary features noted above, and as a result, they often do not provide for satisfactory woodland or forest conservation.

The state of Maryland has one of the most progressive forest protection ordinances, the Maryland Forest Conservation Act (Natural Resources Article Section Title 5, Subtitle 16) passed in 1992. The Act requires local governments with planning and zoning authority to develop a local forest conservation ordinance and program which is at least as stringent as that spelled out in state law. This allows for a certain degree of program alteration to suit the particular needs and desires of a community. Local programs are audited every two years for compliance with the standards and requirements of the state law. Failure to comply results in administration of the local program by the Maryland Department of Natural Resources until such time as deficiencies in the local program are corrected. According to Galvin et al, in the first 5 years after its enactment, the Forest Conservation Act was responsible for 22,508 acres of forest retention and 4,314 acres of reforestation compared with 12,210 acres of forest cleared as a result of development.

Regulated lands: There are three basic a approaches that can be used in developing woodland conservation ordinances. Ordinances may use one approach or a combination of these approaches to determine what areas should be subject to conservation and reforestation or afforestation standards.

Existing forest resources. In the first approach, only lands with existing woodland or forest resources are subject to the ordinance. This approach is most applicable in areas where current forest cover is at or near historical or potential levels. Establishing the resource baseline is a potential source of problems for this approach. Unscrupulous individuals may destroy or alter much of the resource prior to development in an attempt to avoid conservation requirements that would be invoked upon application for a discretionary permit. To encourage good resource stewardship prior to development, historical aerial photos can be used to establish the forest resource baseline.

Potential forest resources. In the second approach, regulated lands include all those that have current forest cover as well as those that historically supported forests or woodlands. This approach is especially applicable in areas where current tree cover is well below former levels and the community has the goal of restoring lost or degraded woodlands and forests. In areas where the historic vegetative cover includes both forest and non-forest vegetation cover types, a delineation of potential or historical woodlands and forests should be prepared. A technical assessment of soils, historical records and photos, and local vegetation types should be conducted to establish a base map of areas that did or could support woodland or forest cover. These non-forested areas and areas with existing forest cover would then be subject to reforestation and afforestation standards. This approach allows for conservation of both existing resources and restoration of lost or degraded resources while taking into account the different capabilities of lands to support forest cover. Minimum afforestation standards could vary by area to reflect the differing capabilities of lands to support tree cover. The use of both current forest baseline data and minimum afforestation standards discourages landowners from clearing lands prior to initiating the development process.

Universal application. In the third approach, regulations apply to all lands irrespective of current forest cover. In the Maryland Forest Conservation Act, all landowners seeking to intensify land use on nonurbanized lands are responsible for a given level of woodland or forest canopy whether or not their lands are currently forested. This approach is appropriate