TREES and other vegetation provide environmental benefits and contribute to the overall recreational experience. Proper planning and design of greenways are key to a successful project.
In a state that is over eighty percent forested, any land use
activity will impact forest resources. But because of the very
nature of forests and trees, a renewable and manageable resource,
most impacts can be reduced through proper planning.
Trails and greenways provide an opportunity for the user to experience the natural world. Forests and trees provide wildlife habitat, improved water quality, recreation, forest management opportunities, and aesthetic enjoyment. Merging forest resource values with trails and greenways requires identification of critical resources, recognizing property owner constraints, and tree friendly construction standards.
There are six major areas where trail and greenway planning needs to consider forestry issues:
Much of the value and appeal of Vermont's scenery comes from the "working landscape," whether its farm fields or managed woodlands. During the planning stage, landowners should be identified and consulttd on present and future management activities. Path design should facilitate access onto forestland. This may be in the form of trail crossings or landing areas for harvesting equipment. Be sure to discus the primary season of use; is the access for maple sugaring, Christmas tree production, or forest product removal? Even if a deeded right-of-way is transferred, the property owner may still need to maintain access onto the land. Forested areas requiring frequent entry are incompatible with trail use and should be avoided. Typically, trail crossings need to be 25 feet wide and landing sites approximately one-half acre in size. The County Forester or a private consultant forester may be able to assist you with design considerations.
Trees and other vegetation provide many benefits in urban areas. Environmental benefits include improved air quality, water cycling, shading, wildlife habitat, and soil conservation. Social and psychological benefits include aesthetics, noise abatement, visual screening or buffers, and a sense of bringing the natural world closer to where we live or work. The trees and forests within our cities and towns are impacted by stresses not normal to natural forested areas. Soil compaction, air pollution, competition for space with the "grey infrastructure" of roads and utilities, and people pressures take their toil on urban vegetation. Proper location and design of paths can reduce the impact to existing trees and associated plants. Maintaining groups of trees and plants is better than isolated, individual trees. Pay particular attention to maintaining vegetation along water courses.
A natural resource inventory should be conducted on all proposed greenway developments. One element of this inventory is the identification of cultural and historic trees, and specimen trees including unique shapes, large diameters or unusual species. A protected root zone area of no disturbance equivalent to either the extent of the dripline or a distance equal to forty percent of the overall tree height should be maintained around these trees. A landscape architect or forester may be consulted for assistance in conducting an inventory.
As previously stated, urban vegetation and unique trees provide environmental and social benefits on greenways. Excavation and grade changes impact the ability of tree roots to absorb water and nutrients, as well as breathe. A protected root zone can be maintained by using snow fence or other barriers. If excavation is necessary, exposed roots should be hand pruned and trees adequately watered following construction. In some instances fertilization, pruning or vertical mulching may be necessary post construction treatment. An arborist or landscape architect should be consulted for specific recommendations.
New road constructiqn designs often recognize the funct'ional value of street trees for aesthetics, buffers, traffic calming, and separation of uses. Paths and trails whih follow along existing roads should be designed with street trees, with provisions made for maintaining existing trees. Species selection should be based upon space and line-of-site limitations, as well as the soil fertility and drainage, hardiness zone, and maintenance requirements. The Town Tree Warden, landscape architect, or Urban and Community Forestry Program can provide assistance.
Trees develop conditions over time which result in the potential for failure. Signs such as fruiting bodies, damaged or broken roots, cankers, broken and dead limbs, and cavities are all signs of tree health problems. Trees along proposed and existing trails need to be evaluated periodically for hazardous conditions. Corrective maintenance may be performed or the tree may need to be removed Trees that appear to have problemt during the initial design phase are probably poor candidates to leave and should be removed during construction. A forester or arborist can perform a hazardous tree evaluation.
For more information about this report, or a list of consultants in your area, please contact: