Given the close proximity of large populations, the diverse functions of and demands on urban forests and trees, and the unique physical environments presented by urban landscapes, urban foresters, arborists and urban forest planners require different skill sets to those commonly found among forest managers in rural settings. Urban and peri-urban forests differ from forests in rural areas in various ways:

• Diversity and complexity. Urban and peri-urban forests are often highly diverse in terms of land use, land ownership and management objectives. Multiple land uses create complex landscapes with a wide range of tree species, ground covers, soil types, microclimates and wildlife and diverse people, buildings and other infrastructure.
• Fragmentation and connectedness. Urbanization inevitably leads to landscape fragmentation. Compared with forests in rural areas, urban and peri-urban forests are usually sparsely distributed and poorly interconnected, although they are often highly connected with other elements of the urban environment, such as roads and buildings, and they have a close relationship with people living in and around them.
• Dynamics and human dimension. Urban and peri-urban forests are subject to powerful human forces that drive often rapid changes in urban land use and management. Human activities and attitudes strongly influence the planning, establishment, maintenance and conservation of urban and peri-urban forests.

Urban and peri-urban forest management faces many challenges, such as:

• competition and conflict with other land uses (e.g. infrastructure and farmland);
• the perception of urban and peri-urban forests as obstacles to urban development;
• the perception that urban and peri-urban forests pose hazards to urban dwellers (e.g. wildfire and tree falls) and, linked to that, a lack of understanding of the benefits of urban and peri-urban forests;
• the diversity and complexity of urban and peri-urban forests, including in their ownership;
• a harsh growing environment;
• the lack of a legal framework and policy support;
• inadequate funding;
• the lack of professional staff;
• limited educational and training resources; and
• insufficient communication among stakeholders.

The first step in the preparation of an urban and peri-urban forest management plan is an inventory of the resource, including its history, status and existing issues. The type and scope of data will vary depending on management objectives (e.g. production, protection or recreation), which may differ within an urban landscape and between cities (and countries). The scope of the inventory will also depend on the availability of funds and technologies such as remote sensing. 

There are several ways to conduct inventories. They may be simple “windshield surveys” in which tree data are collected from a slow-moving car, or statistical samples of an entire urban and peri-urban forest estate.

In addition to the information typically collected in forest inventories, urban and peri-urban forest inventories should include assessments of risks to human health and safety, maintenance needs, and existing conflicts over management and use. Tree health is an important parameter in urban and peri-urban forests because decayed and fallen trees can pose risks to people in densely populated cities as well as to urban infrastructure. Some tree pests, such as the processionary moth, may also be of concern to human health and safety.

Information should be gathered on land availability and tenure, water resources, and tree nurseries – including the availability of seedlings of different species.

The management objectives of urban and peri-urban forestry should be identified and prioritized. They may include the provision of goods such as wood, woodfuel, food and fibre and environmental and recreational services. 

Data from the forest inventory and other sources (e.g. urban plans and social-impact surveys) can help identify potential issues and future management needs, planting sites, tree-related risks, and the potential for the production of goods and environmental services. Such data provide the basis for multistakeholder priority-setting processes that aim to achieve an appropriate balance among legitimate competing interests.

The success of urban and peri-urban forest management depends on public support and participation. The involvement of the community in priority-setting and other decision-making processes, therefore, is essential from an early stage. 

Management plans for urban and peri-urban forests may vary in scale (e.g. local, city, national or regional), duration (short-term to long-term) and type (e.g. master or strategic). Their development requires adequate baseline data, professional guidance, time, funding and the collaboration of multiple stakeholders. Ideally they will encompass an entire urban and peri-urban forest estate, even though different segments of the estate are managed by different entities.

A standard management plan for urban and peri-urban forests should include sections on the followin

• Background
• Current status and issues
• Analysis of potential for urban and peri-urban forest development
• Administrative and legal framework 
• SMART (specific, measurable, achievable, realistic and timely) goals and objectives
• Cost–benefit analysis
• Budget
• Tree establishment, maintenance, protection, removal and use
• Outreach and public education activities, including safety
• Community involvement process
• Gaining political endorsement
• Workplan with timeline.

Those responsible for implementation (e.g. government agencies, other stakeholders, or combinations of entities) should take the actions specified in the management plan in a timely, effective and efficient manner. Detailed workplans should be developed with clearly delineated responsibilities and specified actions.

The approach taken to implementing the management plan will vary depending on the nature of the administrative system and laws, the stage of development of the urban environment, and the level of public involvement. Typically, however, the implementation of an urban and peri-urban forest management plan includes the following steps:

• clarifying and reaching agreement on the respective responsibilities of the entities managing the urban and peri-urban forest and tree resources;
• passing tree ordinances, regulations or policies;
• making available the necessary financial resources;
• hiring tree-care professionals and/or planning community management programmes; 
• developing public education programmes; and
• conducting activities according to the detailed workplan.

Ensuring the sustainability of urban and peri-urban forests requires a long-term monitoring programme so that the effects of management interventions can be evaluated and the achievement (or otherwise) of management objectives can be assessed. An effective monitoring programme also generates information that can be used to adapt the forest management plan in light of experience and to inform the development of future management plans.

The following points should be considered when planting trees in urban and peri-urban environments:

• A site evaluation includes an analysis of the site factors likely to affect tree growth or be affected by it, both above-ground (e.g. light, slope, wind, salt, surrounding vegetation, overhead wires, street/security lights, buildings, signs and vandalism) and below-ground (e.g. rooting space restrictions, soil pH, soil compaction, soil drainage, soil depth, and the location of underground utilities).
• Site modification  – such as by relocating lights and wires, changing soil pH, improving drainage and incorporating compost – may be required to ensure adequate tree establishment and reduce seedling mortality.
• Key elements to be considered in tree species selection include their suitability to site conditions, the potential for achieving management objectives (e.g. the production of goods and environmental services), longevity, pest resistance and maintenance needs. Native species may be best adapted to the local environment and most able to provide suitable habitat for local biodiversity.
• Tree-planting should be guided or performed by professionals. Plantings should be tended to ensure survival, optimal growth and the achievement of management objectives: interventions may involve, at various stages, mulching, weed control, irrigation, fertilization, pruning and thinning.

Additional tips:

• Consider species diversity and human needs.
• Select high-quality planting material and prepare it adequately.
• Use species suited to the climate and the site.
• Use species and cultivars with inherently resilient structures capable of adapting to harsh urban conditions.
• Plant trees in locations with adequate space for development.
• Avoid tree–sidewalk conflicts by using trees that are tolerant to root damage and planting trees at the right depth.
• Avoid species that produce pulpy fruit, allergenic pollen or unpleasant-smelling flowers, and those likely to drop “honeydew” (a sticky, sugar-rich fluid secreted by aphids and some scale insects feeding on plant sap), especially close to roads and parking areas.
• When planting under power lines or other overhead cables, choose species whose maximum height at maturity will be significantly less than the height of the cables.
• Involve local people as much as possible.

Urban and peri-urban environments exert many pressures that may result in the loss, damage or decline of forest resources. The protection of those resources requires an adequate legal framework and the use of best management practices.

Legal framework: tree ordinances, regulations and public policies

Legislation is a powerful tool for protecting existing forests and trees and for enabling local communities to develop and use urban and peri-urban forests sustainably. Urban and peri-urban forest estates are often dispersed in diverse locations and involve complex management arrangements on both public and private land. Policies, laws and regulations can provide authority, offer guidance to residents, specify rights, responsibilities and minimum standards, and regulate human activities affecting the resource. They may include the following:

• Policies establish principles or guidelines for future decisions, actions, laws and regulations and provide an overview of the general approach to be taken to urban and peri-urban forest establishment, management and use.
• Tree ordinances and by-laws may provide authority, establish required conditions or actions, offer guidance, set standards, identify agents responsible for management activities, and provide incentives for maintaining a healthy, vigorous and well-managed urban or peri-urban forest. Common types of tree ordinances and by-laws include street tree ordinances, tree protection ordinances (including compensatory measures for damage), tree preservation ordinances and by-laws, and view ordinances (i.e. protecting scenic views from trees on neighbouring properties that might block them).
• Permits are usually defined in tree ordinances and may encompass both publicly and privately owned trees. Permits commonly address issues related to tree removal, tree work, and the encroachment of construction in defined tree protection zones.
• Standards and specifications are guidelines for work performance, including tree-planting, tree maintenance and tree protection. Standards and specifications should be site-specific in order to best suit local circumstances.

Best management practices

Best management practices [see cases] can be used to protect trees before, during and after the development of a new urban area, such as a housing, industrial or commercial centre.

Pre-development. A well-designed urban forest management plan is essential for ensuring that an urban development retains and protects an appropriate number of pre-existing trees and is able to establish and manage an urban forest that meets the needs of the new community. Making use of existing trees can reduce the need for tree-planting, which is expensive, and reduces the time required before the urban community benefits from the presence of mature trees and forests.

Key elements in a successful tree retention and protection plan are:

• the definition of development zones;
• the identification of forests and trees to be retained; and
• planned protection measures.

During development. Care is needed to avoid damaging pre-existing forests and trees during the development of new urban centres. Some municipalities develop codes of conduct to regulate interventions affecting trees and forests while construction is in progress. Such codes may include the following:

• Design spaces to avoid conflicts.
• Install protective structures.
• Avoid root damage.
• Reduce soil compaction.
• Prepare forests and trees for construction disturbance, such as by ensuring that they are as healthy as possible before work begins (e.g. by watering and fertilizing).
• Protect and preserve (e.g. by stockpiling) soil for future tree-planting.

• Provide public education about the value of forests and trees in urban environments.
• Coordinate with other departments.
• Monitor the construction process.

Post development. A long-term plan should be put in place to protect trees from vandalism, disease and other threats. The plan may include periodic interventions, such as:

• mulching;
• pruning;
• thinning and tending;
• “training” young trees and caring for old trees;
• stability and risk assessment;
• pest and disease monitoring and related phytosanitary treatments; and
• tree removal.

Most of the planning and management activities described in this module refer to urban and peri-urban forests under the jurisdiction of municipal governments. Cities can have major impacts well beyond municipal boundaries. Management plans for peri-urban forests under the jurisdiction of national or provincial forest departments should aim to alleviate the pressures and demands on such forests arising from urbanization. The management plans of the various jurisdictions should be compatible, interlinked and, as much as possible, aligned with the needs of growing urban populations.