Frequent flyer miles are a good thing, be it from the airline industry or within urban forestry. Inside aviation, “frequent flyer miles” are credit miles earned by an airline and linked to other activities like hotel stays, car rentals, or other specific airline programs. Inside urban forestry, “frequent flyer miles” are all about the canopy miles routinely pruned by tree crews “flying” aerial lifts. Here, it’s not about the airlines or the FAA (Federal Aviation Administration); but rather utility arboriculture and other entities such as the UAA (Utility Arborist Association) and ISA (International Society of Arboriculture).
A utility’s cycle-based, line clearance schedule is the core of frequent flyer miles. It is a routine preventative maintenance/risk assessment measure performed before a tree-related utility conflict or catastrophic incident occurs. Frequent prescribed pruning, or cycle-based line clearance, is a proactive approach addressing service interruptions and outages that, once the pruning is complete, will never happen.
Frequent flyer miles of a cycle-based line clearance schedule answer two top, primary pruning questions,
1. What is the pruning objective(s)?
2. When are you coming back?
Line clearance objectives are to maintain an acceptable level of safety for the public, for workers maintaining trees near lines, for trees in close proximity to utilities, for service reliability, and the co-existence of trees and utilities over time.
Scheduled cycles will determine when you are coming back and when the pruning maintenance will be repeated. Frequent flyer miles exist under the assumption that “once is never enough.” Periodic pruning is essential. Baseline intervals (cycles) may be established for an entire system or service territory. However, lengths may vary locally depending on several variables – including canopy conditions, species, growth rates, community norms, weather patterns and events, regulatory requirements, funding, circuit history, performance, and reliability. Cycles should be scheduled at intervals that minimize the need for unscheduled, reactive response to service disruptions, but not so frequently to have cost exceed benefits.
Dynamic trees and infrastructure. Trees are designed and engineered to grow and get big – to take up space. Urbanization is dynamic. The space requirements will change throughout the life span of each. This alone is why flyer miles must be systematic, or frequent.
The stewardship and maintenance of an urban tree canopy is an absolute necessity if the objective is to reduce risks and increase benefits. Frequent flyer miles are a proactive approach to pruning and assessing potential hazards and tree health. At best, utilities strive to keep routine pruning on a predetermined schedule. Deferring maintenance will incur higher costs and risks and will reduce the benefits of trees. Systematic cycle pruning will require periodic inspections and mid-cycle pruning to strengthen the resiliency of utility trees and structures. Relatively short inspections and pruning cycles are effective when achieving reliability and safety objectives; enhancing a system’s resilience against storms; reducing the biological impact on trees; and enhancing the compatibility of trees and utilities. Urban trees that are “trained” or pruned to promote compatible structure will function and remain beneficial, with less potential for failure, than trees that were never pruned. Once the cycle is on schedule, trees within reach of the utility easement are less of a threat. Trees or branches that fail from outside of utility easements are a greater liability and can have a greater impact on service reliability.
Transmission corridors need not apply. Frequent flyer miles are devoted to line clearance of electrical “distribution” systems and not “transmission” of bulk electricity. “Transmission” includes the network of large-scale power plants, high-voltage transmission lines (over 69,000 volts), tall towers, substations, utility corridors, and other infrastructure that make up the bulk and backbone of the electrical grid. Transmission connects and moves mass amounts of electricity over long distances, from where it is generated to our smaller “distribution” centers, communities, and service territories.
Transmission corridors will carry federal regulations, hardline industry standards, and integrated vegetative management practices. The North American Electric Reliability Corp (NERC) requires utilities to have a transmission vegetation management program (VMP). VMP’s will restrict or eliminate the risks, liabilities, hazards, conflicts, and woody vegetation within transmission corridors. VMP’s will require routine inspections and vegetative management thresholds. They will require the skills, talent, and watchful eyes of foresters, arborists, and vegetation specialists; but they won’t require frequent flyer miles.
Though the “wire-zone” within transmission corridors may be void of trees, they do play a role in the integrity, function, and holistic view of an urban forest ecosystem. They are not void of vegetation, biological attributes, or environmental contributions.
The electrical substation is the boundary between “transmission” and “distribution” circuits. Frequent flyer miles start at the substation housing the transformers, switching equipment, controls, and protection devices necessary to step down the high “transmission” voltage to a level (under 69kv) safely “distributed” to the end user – our homes, businesses, industrial centers, rights-of-way, and public spaces. It’s here, at the substation, where overhead distribution circuits first meet the tree line of the urban, utility forest. The utility forest is a segment of the urban forest that extends within a utility easement. It embraces a bold form of urban forestry known as utility arboriculture. It involves trees, or tree parts, that have the potential to affect the operation of utility facilities and services. It involves the shared space between trees, utilities, and hazards. Tree-care professionals (flyers) cannot enter this space without a Line Clearance certification obtained by frequent flyers – the employment of insulated equipment, training, and experience.
It is here, within the utility easement of electrical “distribution,” that frequent flyer miles begin. It’s here that science and professional expertise mitigate risks and optimize the benefits of both trees and utilities. Pruning objectives account for a tree’s natural properties, tendencies, and biological function. They do not, however, prioritize an “aesthetically pleasing appearance.”
Misunderstandings and controversy often follow in the wake of frequent flyer miles. Line clearance and preventative maintenance efforts are often met with alarm and misinterpretation on the part of the public. At first glance, some can’t always see the forest for the trees. The benefits and value of a vegetation management program are seldom understood by all stakeholders – even within sectors of the utility itself.
Line clearance requirements may fall outside the scope of traditional and familiar landscape pruning objectives and guidelines. This does not imply that they are void of proper pruning methods and industry standards. Many of the misunderstandings are carried by those unfamiliar with the application of thinning, reduction, heading, and directional pruning.
Most frequent flyer miles go unnoticed, but not always. In nature, tree abnormalities often go unnoticed. Trees will grow to lean, yield, stretch, bend, bow, gap, and branch away from prevailing winds, the dominance of an adjacent tree canopy, and unfavorable site conditions including urbanization. Alas, trees can’t detect and wittingly avoid utility hazards. Frequent flyer miles can bolster a target’s biological impulses to train and direct tree growth to yield, stretch, bend, bow, gap, and branch away from overhead utility lines (communication cables and electrical power lines).
What is often overlooked is that line clearance contracts can often extend beyond one cycle. It’s not uncommon to have the same “flyer” working on the same tree(s) in consecutive cycles. These are not fly-by-night pruners. They are familiar with specific trees and may have been tending to the balance between canopy and the specific utility for years.
Another error is assuming the physical properties of utilities are not natural. Electricity is no less natural than the biological properties of trees and other vegetation. Lightning, in free-fall, strikes trees. The results can be catastrophic. The electrical current traveling along an overhead wire is lightning. It’s tethered to a conductive wire, but it is no less natural or dangerous than the current carried by lightning when in free-fall.
The natural appearance of an unpruned tree can be an illusion. The appearance is not synonymous with good health, satisfactory form, and the absence of structural defects, disease, ruinous decay, malfunctions, and other hazardous conditions. Trees are often planted with no extended maintenance, care, or pruning timetable. Urban trees especially are left to their own device, misbehaviors, and bad habits. It would be “tree abuse” to knowingly allow a tree canopy to explore the “wire zone” of the utility forest, as it would be abusive to knowingly allow a child to explore an electrical outlet with a fork, or conductive prong.
Unnatural sites can lead to unnatural sights. Utility easements are part of our built environment. They deviate far from the intrinsic, natural environment that would allow for a more presumed, evolutionary appearance of trees. Frequent flyer miles often include only a portion of an individual tree. Utility arborists are not obligated to inspect or prescribe pruning beyond the scope of their work assignment of a utility hazard. When there is little or no likelihood of failure or impact to utility facilities, the remaining portion of the tree, outside of the utility easement, is the responsibility of the tree owner – not the utility’s frequent flyer.
Trail maintenance of backcountry hiking trails was once a big part of my previous career. Frequent Tread miles were an integral part of routine scheduled work by trail crews when providing for a continuous open corridor for safe, recreational passage through trees and forests. Risk assessments and action thresholds are not limited to trails, but include buildings, parking lots, remote campsites, trailheads, junctions, and other support facilities. Utility line clearance is simply maintaining an aerial trail through an upper urban canopy for safe passage of utilities. Risk assessments and clearance thresholds are not limited to wire, but include pole access, transformers, fuses, switch mechanisms, and other support facilities. Utility line clearance is “trail maintenance.”
Directional utility pruning selects and removes the correct stems and branches for trail/utility clearance. Scaffold branches are chosen for good attachment, appropriate size, and direction of growth. Temporary branching may remain and be removed in later cycles.
A tree’s primary growth is diverted away from the established trail of the utility corridor. Shoot growth will resprout, but the tree will be less dependent on the small interim shoots attempting to reclaim the open space following each cycle. During repeated cycles, pruning specifications won’t include the big wood of primary branches that support the overall biological functions of the tree. Cycle cuts target subordinate shoots of interim growth that often camouflage the previously established trail. The visual impact is most striking immediately following a scheduled pruning. Each cycle will reopen and expose the pre-existing trail. This can create an illusion and false alarm that more canopy was removed than what was truly removed. With each completed cycle, shoot growth will resprout. Misunderstandings and controversy on the part of the public will resprout too.
Underground utilities are not independent of frequent flyer miles. Underground utilities are not a silver bullet for utility conflicts. To complete a circuit in most urban settings, underground utilities are installed in conjunction with overhead lines.
Utility arboriculture is not limited to overhead canopies and utilities. Trees and utilities grow underground too. Trees must overstep, or trip over, buried pipes and wires of communication cables; power, water, sewer, and gas lines; storm drain systems; and other built infrastructure. When utilities are cramped underground, planters and planners must be careful not to “bury their heads in the sand” along with the utilities. Just because they can’t be seen doesn’t mean that the physical properties, risks, hazards, conflicts, maintenance, and special prerequisites don’t exist. We’ve built a world where the distribution of safe and reliable utility service is not an option. We’ve built a world where the absence of urban trees and forests is not an option. Frequent flyer miles will be needed where undergrounding is not possible, practical, feasible, or affordable.
Upon final approach, frequent flyer miles are proactive, preventative measures in sync with other pruning needs to include capital projects, system restoration following storms or tree failures, assisting private tree workers, mutual aid requests, and other interim utility vegetative management needs. Urban forestry will find it difficult to achieve canopy objectives without frequent flyer miles. The routine pruning cycles contribute to both the safe delivery of reliable utility service and a resilient urban tree canopy. As with the field of aviation, frequent flyer miles enable the utility to fly high with confidence and precision.
