Urban Forest Plan

C    What the University Should Do

1        Tree Inventory System
2        Management Program
3        Training
4        Comprehensive Grounds Revitalization Strategy
5        Fundraising
6        Conclusion


The character and size of the urban forest at the Queen’s campus is similar to that of a small town. The development of a management plan for both short and long term strategies requires a thorough, accurate and up to date inventory of all the trees on campus. This will assist in making well-informed decisions on the tree work to be done. Work can be prioritized and a year round schedule of maintenance can be developed. The completed inventory should be entered into a database, forming a recorded history for each tree, the work performed and its effectiveness.

The existing inventory needs to be expanded and should include the following data:
  • Tree identification number (tag each tree)
  • Species
  • Size (caliper measured in cm taken at 4.5 ft. from grade)
  • Form (strength of leader and branch unions, spacing of branches)
  • Condition (dead or dying, hazardous, poor, fair, good, excellent)
  • Work required (pruning, cabling, fertilizing, mulching, insect and disease management)
  • Priority rating of location


The development and implementation of a Plant Health Care Program to enable existing trees to sustain growth and good health is imperative if the landscape is to be retained. Trees must be maintained properly to fulfil their expected purpose within the landscape plan. Fertilizing, pruning, insect and disease control are some of the essentials to sustain health and vigor of trees.

One of the best examples to illustrate the importance of proactive plant care is the ‘Shademaster’ Honeylocust found at various locations on campus. It is a strong and sturdy tree but could not withstand the impact of the ice storm. The weight of the ice broke limbs resulting in a substantial loss of the crown. Earlier preventative pruning would have removed deadwood and eliminated weak branch union, thereby reducing the surface area for ice collection. The installation of cables would have strengthened the structure and lessened the devastation. Proactive plant health care is less costly than reactive interventions; professional plant maintenance is money well spent if the cost is spread over the life span of the tree. The benefits that mature plant material contribute to the campus must also be considered.

Hazardous Tree Evaluation and Management

There is strong evidence that the urban forest on campus is aging and declining. This presents a challenge to those who manage this important asset. It is imperative that hazardous and potentially unsafe trees be identified and the problems abated to prevent accidents and damage to people and property. Detection, evaluation and management of these trees must always be a first priority; however, at present the removal of dying and unsafe trees can be integrated into a replacement plan.

For a tree to be deemed unsafe one of the following conditions must be present:

a A combination of a structural defect and a target
· A structural defect which predisposes the tree to failure if 50% or more of major limbs are dead or removed, major trunk decay or significant root loss.
· A target such as a structure, road, walkway, or area where there is property or people.
b Structurally sound trees may also be considered hazardous if they interfere with the routine activities of people, e.g., raising sidewalks, interfering with utilities, obstructing motorist vision.
Trees should be inspected annually and after a major storm for structural defects. At present the trees on the campus should be inspected every 4-6 months as many have sustained major crown loss from the ice storm and are in declining health. Some hazardous tree conditions can be corrected by pruning, cabling and bracing; other trees will have to be removed. If some trees recover satisfactorily, structural support may not be required and replacement trees should be planted instead to succeed other older trees that eventually die. It would be advisable to have a Certified Arborist inspect and make recommendations regarding the safety of the trees. Arborists are considered “experts” and may be held accountable for unreported or uncorrected tree defects and work performed.


As previously stated, a number of trees will have to be removed and replacement trees will have to be planted. The ice storm destroyed major portions of the crown in the Silver Maples; these trees also have root systems extending onto sidewalk and curbs. The Norway Maple have developed girdling root which wraps around the root crown causing strangulation. Unfortunately, this is not correctable but a tree can continue to grow for up to 10 years. It would be prudent to identify and begin replacement now by planting new trees where these Norway Maples are showing crown decline. One specific site which requires replacement is the Arts Quadrangle; trees were planted in concrete and interfere with the traffic flow. This space should be redesigned to provide a sustainable growing environment so that planting can be re-introduced appropriately.

Where donated trees are in poor condition or do not comply with the design intent and species recommended for a particular space, the donor and the gift should be honoured through replacement plantings of appropriate design, species and location. Existing trees may be transplanted to a suitable location if advised by a Cetified Arborist to be salvagable in terms of condition, size and survival after transplant, and if costs and benefits are in balance.

In general, replacements should follow these principles:

  • Planting should comply with the design intent and species recommended for each space.
  • To brighten the prevailing grey tones of fall and winter, when students are on campus, some evergreen plantings should be used while optimizing visibilility for safety.
  • There is sufficient space to accommodate tree size at maturity.
  • Timing of planting should match design intent, e.g., a row of trees should be planted all at once to maintain uniformity of size, or if planted in stages, subsequent plantings should match size and form of earlier plantings.
  • The planting season preferences of species should also be considered for best performance.
Selection Process

The careful selection of plant material is time well spent as it has long term implications. It is important to locate trees that are structurally viable, of strong form with well-spaced, firmly attached branches and where possible, one central dominant leader. This will ensure that minimum pruning will be required in the future. The size of the bud or leaf, annual growth, soil conditions and climatic zone of the nursery are excellent indicators of overall health. While the initial cost may be somewhat more, purchasing high quality stock will prove more effective in long term cost savings.

To prevent major losses due to insect and disease, over use of a single species in tree plantings should be avoided. No more than 25% of the inventory should be of any one species. Species that are host for diseases should not be planted with those species that are susceptible to such diseases. Species and varieties with pungent fruits and excessive litter should also be avoided, particularly at high use locations.

Planting Procedures

The ideal time to plant trees and shrubs is in the dormant season during the fall after leafdrop or in early spring before bud-break. Successful planting requires proper planting site design, selection of healthy stock, correct planting procedures and a high level of maintenance after installation. Research has shown that up to 95% of the root system of a new plant is lost in the transplanting process. Planting procedures and post planting maintenance must create conditions conducive for root development. Successful establishment of new plantings depends largely on the rapid regeneration of a root system following installation. New plantings usually require at least two years to generate a root system and become established on site.

Planting stock are available from nurseries bare root, balled and burlapped or containerized. Planting procedures differ with the type of planting stock. Therefore all planting should be carried out in accordance with the specifications for Landscape Ontario Planting Details.

Spacing for planting will vary with species and site conditions. General guidelines for spacing of planting are as follows:
  • A minimum of one-third canopy distance from buildings.
  • A minimum 1.5m distance from adjacent paving, curbs and walls.
  • Street tree spacing: for primary streets and drives, more formality and symmetry may be suitable, and for other streets, informality and alternate spacing may be suitable.
  • Evergreens in odd numbers groups of 3 minimum, unless intended as a specimen tree.
Maintenance Program

Planting a tree is a simple act; establishing trees in the community as a permanent part of the landscape is a much more complex job. How well this investment does depends largely on the follow up care the tree receives after planting. The soil around newly planted trees needs to be kept moist but not soaked. When the soil is dry below the surface of the mulch, it is time to water. The rule of thumb is to water well, then allow to dry out. Exterior water faucets at all new building and landscape projects should be provided. Pruning should only be done to remove damaged branches; structural pruning should be done after the tree is established (2 years). The growth of the tree should be monitored to ensure proper growth; as well as regular inspections for insect and disease as this should be controlled immediately. Routine care and favourable weather conditions will assist a new tree to grow and thrive.


It would be ideal if all staff had a background in horticulture or arboriculture, but it may be more realistic to train staff in the basics in tree function and maintenance. Staff would then be able to work more efficiently, e.g., identify obviously hazardous trees and limbs, how to prune shrubs correctly, etc. The introduction of new plant health care services by campus maintenance staff would ensure that trees and shrubs receive the necessary treatments required to maintain growth. The acquisition of a tree root fertilizer would pay for itself in a year. At least one staff member should obtain a pesticide license from the Ministry of the Environment to treat insect and disease problems. If this is not feasible, then it would be advisable to obtain the services of a Certified Arborist (with a background in plant health care) who would monitor the urban forest during the growing season and provide treatments when necessary.

This expansion of services and the further training of staff would be cost efficient and would help increase the effectiveness of each staff member and reduce the use of outside professional services. It would be a major step toward the implementation of a Plant Health Care Program.


Although immediate remedial work and an ongoing plant health care program would restore the health of many trees on campus, these measures alone would not be sufficient to ensure their long term survival. Many areas of the campus require more than maintenance and replacement due to the impact of pedestrians and vehicles on many areas of the campus that have not been properly designed or upgraded to accommodate the needs of pedestrians, vehicles and trees. Comprehensive improvements to the campus grounds are needed to correct the poor growing environment for trees.

Design concepts for landscape reconstruction projects to revitalize the primary open space of the campus should be developed. These individual designs form part of a comprehensive grounds revitalization strategy. The grounds revitalization plan should focus on projects that are good candidates for fundraising. The plan should provide strategic guidance in the form of a general strategy for grounds, design concepts and order of magnitude costs for priority sites, materials palette, priority and sequence of implementation. The grounds plan will be the vehicle for the University to commit to a grounds revitalization program and initiate fundraising. It should also be the basis for detailed construction documents for specific landscape reconstruction projects.


Public awareness of and support for the campus urban forest as a community asset may be promoted through education programs such as establishing an arboretum on campus and hosting annual Arbor Day events to involve the public.

Landscape design concepts and illustrations for high priority spaces should be prepared to raise interest and support for the beautification of campus outdoor spaces. It is important to not only raise funds for redevelopment, but also establish an endowment for implementing the Plant Health Care Program to ensure this valuable community asset--the urban forest and landscapes of the campus--are maintained for the use and enjoyment of present and future generations.


The urban forest is a live, vibrant and constantly changing environment and as such requires continuous monitoring and care. It is a deception to assume that a tree can be self-sustaining in a highly populated, stressful environment. Therefore, the trees at Queen’s University require both landscape improvements to provide an optimum environment and all aspects of urban maintenance to enhance survival. In addition to investments in landscape reconstruction, it is imperative that tree maintenance receive a budget in a similar way that other facilities do. This would greatly facilitate the establishment and implementation of a Plant Health Care Program, thereby increasing the survival rate and life expectancy of young and mature trees. Finally, a management team should be set up for long term urban forest improvement and maintenance.