B08_Attachment_5_Enclosure_3_Hazardous_Tree_Management_Plan.pdf

I. PURPOSE:

This is a comprehensive mitigation plan, utilizing composite risk management methodologies, in order to reduce the threat of injury, death, or property damage caused by mechanical/structural tree failures, while preserving the natural environment and identified exceptional specimens.

II. SCOPE:

The existence of compromised and defective trees is part of the natural scene across the park.

Given limitations and constraints necessitated by the park's mission, management objectives, and funding, it is not prudent nor feasible to render the entire park risk free of hazard trees. Efforts to identify and address hazardous trees are conducted via tiered priorities of work, optimizing the use of the park’s human and material resources, while acknowledging and accepting the existence of residual risk.

This does not attempt to remove every tree with defects, but endeavors to preserve as many trees as possible in the local greenscape in accordance with park policies, conservation best practices, and sound principles of risk management. Overzealous removal of trees in an area can not only compromise the cultural landscape and the natural environment, but initiate a cascade of adverse effects, both immediate and second-order, on remaining trees.

III. GENERAL DEFINTIONS

a) Arborist – An individual engaged in the profession of arboriculture who, through experience, education, and related training, possesses the competence to provide for or supervise the management of trees and other woody plants.

b) Contracting Officer’s Representative (COR) - is a designated federal employee who acts as the "eyes and ears" for the Contracting Officer (CO) on a specific contract, providing crucial technical oversight, monitoring performance, inspecting deliverables, and serving as the primary technical liaison with the contractor, ensuring the government gets the quality products/services it paid for

c) Defect – An injury, growth pattern, decay, or other condition that reduces structural integrity and strength

d) Drive-by Inspection – Limited visual inspection performed on one side of a tree from a slow moving vehicle (also called windshield inspection).

e) Hazardous Tree – A tree identified as a likely source of harm. NOT all defective trees are hazards.

f) Level I Inspection (limited visual assessment) -A limited visual assessment from a specified point of view (such as drive-by inspections) of individual trees or populations of trees in relation to targets.

g) Level II Inspection (basic assessment)– A 360-degree visual assessment and evaluation of a tree’s crown, trunk, trunk flare, above-ground roots, and site conditions in relation to targets.

h) Level III Inspection (advanced assessment) - Includes any risk assessment that would exceed the Level II category including aerial assessments, decay detection through drilling or tomography, and root zone excavation.

i) SPE – Risk management assessment based on Severity, Probability, and Exposure

j) Subject Matter Expert (SME)- A person, who by training and experience, has a attained a high level of expertise in managing hazard trees, and bears de facto duty-of-care burdens. SMEs include, but are not limited to, ISA Certified arborists, TRAQ qualified arborists, SAF Certified Foresters, and Board-Certified Master arborists. The ISA certified arborist(s) serve as internal SMEs.

k) Target – Something that could be struck or damaged when a tree experiences mechanical failure. Not all targets have the same value; human life is the highest priority to protect.

l) Tree Management Information System (TMIS) – The chosen data management system used by the park in order to document the tree risk management process. (NPS

ARCGIS).

m) Walk-by Inspection – Limited visual inspection performed on one side of a tree while walking.

n) Zones – Areas of the park developed using fundamental planning assumptions in order to facilitate risk management planning and execution.

IV. Trade Standard Risk Management Process Definitions and Terms

FIGURE 1: Risk Management Terms

* Tree Risk Assessment, 2nd Edition, Best Management Practices, 2017, International Society of Arboriculture (Companion edition to the ANSI A300 Part 9).

MATRIX I: Likelihood of Failure

Imminent

Failure has started or is most likely to occur in the near future, even if there is no significant wind or increased load.

Probable

Failure may be expected under normal weather conditions within the expected time frame.

Possible

Failure may be expected in extreme weather conditions, but it is unlikely during normal weather conditions within the specified timeframe.

Improbable

The tree or tree part is not likely to fail during normal weather conditions within the specified time frame.

MATRIX 1: Likelihood of Impacting a Target

High

The failed tree or part is likely to impact a target. This is the case when there is a constant target, with no protection factors, and the direction of fall is towards the target.

Medium

The failed tree or part could impact the target, but is not expected to do

so. This is the case for people in a frequently used area when the direction of fall may or may not be toward the target.

Low

There is a slight chance that the failed tree or tree part will impact the target. This is the case for people in an occasionally used area with no protection factors and no predictable direction of fall; a frequently used area that is partially protected, or a constant target that is well protected.

Very Low

The chance of the failed tree or tree part impacting the specified target is remote. Likelihood of impact could be very low if the target is outside the anticipated target zone or occupancy rates are low, or in areas of occasional use affording protection.

MATRIX II: Likelihood of Failure and Impact This is the ascertained outcome utilizing MATRIX I and is undefined

MATRIX II: Consequences of Failure

Severe Serious personal injury or death; high value property damage; major disruption of critical activities/infrastructure

Significant

Substantial personal injury; property damage of moderate - high value;

considerable disruption of activities/infrastructure

Minor

Minor personal injury; low-moderate property damage; small disruption of activity (e.g. routine towpath blockages)

Negligible

Do not result in personal injury; involve low value property damage;

disruption of activities/infrastructure are easy to replace or repair

MATRIX II: Risk Rating Outcomes

Extreme

Failure is imminent and there is a high likelihood of impacting the target, and the consequences are severe.

Failure is very likely or likely and consequences are significant OR failure is likely and consequences are severe

Moderate

Failure is very likely or likely and consequences are minor OR failure is somewhat likely and consequences are severe

Failure is unlikely and consequences are negligible OR failure is somewhat likely and consequences are minor

V. Hazard Tree Risk Management Process

Risk management is the process of assessing conditions related to an activity and following a process to mitigate or reduce risks to an acceptable level. The risk management process is sequential, with one step in the process serving as the springboard for others. As it applies to hazard tree risk management, the steps are as follows:

Inspect Document

Document Program

Action

FIGURE-2

Programming is the process of coordinating mitigation action or controls for identified hazards trees.

Mitigation and control actions are documented to complete the record.

During inspection, risk assessments are performed in the field for individual trees and tree populations

During documentation, risk assessments are archived in the Tree Management Information System or other designated location, creating a living record.

Action is the implementation of mitigation efforts or controls.

When visitors are involved as a potential target, NPS prefers to use the Severity, Probability and Exposure (SPE) Model for risk management decisions; The primary advantage of the SPE model is that it considers the number of visitors exposed. The SPE model conflates the overall relationships of event severity (result/impact), probability within a specific time frame, and the rate of target exposure, into a single numerical rating. The numerical rating is used to inform risk decisions on a standardized basis and allow for optimal understanding of assumed risks. The numerical rating can be used to prioritize mitigation work and assess residual risks.

This type of numerical based system is known as a Qualitative Numeric Assessment in arboricultural literature.

For individual tree risk assessment, the process is nearly identical with the NPS SPE model, but follows industry trade standards as established in the American National Standards Institute (ANSI) A300 -2017, Part 9 (Tree Risk Assessment: Tree Failure) and its companion best practices manual. In the park, a Qualitative Numeric Assessment criteria is not overlaid to establish a hazard rating, but instead a matrix based hazard rating is applied using defined trade terminology and best practices. The parity of trade praxis and language is necessary in order to align procedures internally with those of the greater national standard and ensure a common professional terminology when engaging intra-agency peers, inter-agency partners, commercial trade professionals servicing NPS contracts, and the public. Standardized terminology also reduces ambiguities under legal scrutiny. The hazard rating produced (outcome) is used to inform development of control measures and mitigation actions.

FIGURE-3: Matrix I: Likelihood Matrix

Likelihood of

Failure

Likelihood of Impact (target)

Very Low Low Medium High

Imminent

Unlikely

Somewhat Likely

Very Likely

Probable Unlikely Unlikely Somewhat Likely Likely Possible Unlikely Unlikely Unlikely Somewhat Likely Improbable Unlikely Unlikely Unlikely Unlikely Matrix I is used to ascertain the likelihood of tree structural failure in relation to target impact potential.

Matrix 2: Risk Rating Matrix

Likelihood of Failure and

Impact

Consequences of Failure

Negligible Minor Significant High Very Likely Low Moderate High Extreme Likely Low Moderate High High Somewhat

Unlikely Low Low Low Low

Matrix II conflates the rating from Matrix 1 against the consequences of failure in order to determine an overall hazard rating.

* Tree Risk Assessment, 2nd Edition, Best Management Practices, 2017, International Society of Arboriculture

(Companion edition to the ANSI A300 Part 9).

FIGURE-4: C&O CANAL HAZARD TREE RATING ACTION MATRIX

Rating Required action

Extreme

Immediate passive and active control measures implemented to isolate human traffic into the strike zone. As soon as possible, arboreal assets mitigate the hazard if it is within capabilities. Emergency service contract and micro-purchase options shall be leveraged when necessary.

Temporary warning signs may be placed at applicable public access points or other associated locations. Mandatory mitigation actions shall be programmed for completion within twelve (12) months of assessment.

Appropriate mitigation actions are programmed and shall be performed based on resource availability. High rated hazards in a zone, or other zones, shall receive priority of effort over moderate hazards. Where possible, opportunistic actions may be taken in conjunction with other operations for efficiency of logistics, as well as funds/resource optimization.

Low Optional opportunistic mitigation only. No action required.

*The Action Matrix applies the hazard rating to determine the course of action

Tree Risk Assessment does have practical limitations. Tree failure by nature is subjective due to the unpredictable characteristics of trees as they thrive, exist, and fail based on a myriad of external and internal factors in combination. This subjectivity is further complicated by the variety of species-specific considerations. The specialized knowledge and experience of properly trained personnel (such as ISA certified arborists) is essential for deriving appropriate outcomes. Applying tree risk assessment in mass across the spectrum of the C&O Canal’s unique riparian forests intermixed with managed landscapes and campsites is full of statistical uncertainties.

Attempting to over impose concrete conclusions about risk beyond reliable data availability is futile. The goal of the program therefore is to create a systematic framework that can be used to reduce reactivity and increase efficiencies related to identifying and targeting trees for hazard mitigation across the entire park.

For this reason, the park is divided into hazard assessment zones that use fundamental planning assumptions about exposure rates to balance the need to concentrate resources on high exposure sites while recognizing that the C&O Canal Towpath represents the location of the park’s historical tree related fatalities. Hazard assessment zones also serve as a planning tool that aids budget and resource allocation while ensuring no portion of the park is neglected.

VI. TREE INSPECTION:

Tree inspection is the process of applying the tree risk assessment process to an individual tree or population of trees. Ideally, tree risk inspection for an individual tree is executed with documentation for each step. However, due to the expansive linear nature of the park and the high density of trees in relation to available arborists, an inspection methodology is required that facilitates, speeds, and increases the efficiency of risk assessment and follow-on actions. While not as robust under scrutiny as time consuming and document heavy methods, streamlined assessment is the only practical means for achieving park objectives and avoiding stagnation in the public safety mission.

a) Inspection Methods:

The three predominant inspection methodologies utilized within the park are:

• Drive-by Inspection/Survey

• Walk-by Inspection

• Individual Tree Inspection

The most commonly applied inspection method shall be the drive-by inspection/survey. This method facilitates inspection of large stands of trees within a constricted time frame driven by an inspection schedule. By utilizing this method, the arborist is able to achieve balanced inspection coverage throughout the park with reasonable frequency. The arborists shall make every good-faith effort to conduct level I inspections in accordance with Best Management Practices, Tree Risk Assessment 2nd Edition and ANSI A300 Part 9, 2017. At the discretion of the arborist(s) in coordination with the COR, a specimen may be identified for more intensive level II/III assessments. For trees anticipated to require more robust documentation, the International Society of Arboriculture Basic Tree Risk Assessment Form may be utilized to create a more thorough record of the assessment process. In the case of scenic easements, the private property owner impacted by the easement shall have a tree risk assessment performed by an ISA Certified Arborist utilizing the aforementioned form to document the inspection (and submitted to the park point of contact). All inspections performed by commercial/private arborists shall be complete and utilize the most current revision of the ANSI A300 standards as the basis for the assessment.

Assessment conclusions performed by commercial/private arborists are subject to verification as the discretion of the COR.

b) Inspection Frequency:

a. Standard towpath inspection frequency shall be in accordance with zones identified in the park’s five (5) year cyclic management schedule.

b. Certain areas where visitors are encouraged to congregate in static and vulnerable environments shall be inspected on a two (2) year cycle. This is based on the extended duration of exposure in accordance with risk management best practices.

Examples of such areas include drive-in and wilderness campgrounds and high density parking areas. Areas ranking in the top ten (10%) of visitor use, utilizing a five (5) year median average shall, also be inspected on a two (2) year cycle.

The five (5) year median visitation average shall be reassessed every fifth (5th) year on calendar years divisible by five (5) (e.g. 2020, 2025, 2030, etc.).

Schedule changes based on visitor use data shall be applied at the start of the next two (2) year cycle.

c. In some cases, it may be necessary to perform ad hoc or out-of-cycle inspections when changes in conditions warrant (e.g. post-wind event, post high-water event, etc.). Determination authority of non-standard inspection schedules shall reside with the arborist with approval from the COR.

c) Inspection Documentation

a. The primary method for documenting inspection results is the park’s Tree

Management Information System (TMIS). Currently the park utilizes an organically produced data information system custom designed for tree management and supported on the National Capital Area’s ArcGIS platform. This system offers the advantage of near-real time tree inventory and workflow visibility mated with precision location data. Data inputs are conducted in the field remotely using personal electronic devices (PEDs) and shall include the following:

i. Action Status (Options identified in ArcGIS)

ii. Common Name

iii. Condition Notes

iv. Condition Concern (Options identified in ArcGIS)

v. Hazard Rating (Options identified in ArcGIS)

vi. Latitude

vii. Longitude

viii. Treatment (Options identified in ArcGIS)

ix. Side of Towpath (Options identified in ArcGIS)

x. Tag Number Label

xi. Example:

• FY27 (MP 0-5) (Park Location) 1

xii. Tree Stump Action (Options identified in ArcGIS)

b. In addition to the above, other useful information may be included such as an image of the specimen, special notes, contract package data, and any other data the arborist(s) deems prudent in order to create a comprehensive record.

c. When assigning a hazard rating, the arborist(s) shall determine the type of corrective action required and a completion timeframe. Both the required action and timeframe shall be based on the arborist’s best judgement utilizing accepted tree risk assessment principles. Only hazard trees (trees requiring a corrective action) shall be entered into the TMIS.

Inspected trees that do not require corrective action shall not be recorded in order to facilitate planning by reducing unnecessary entries.

d. Work methodologies shall be included in the prescribed remediation entered into the TMIS. Generally, pruning of the defective portion of the tree, or removal of the entire tree will be warranted. However, there may be circumstances where other courses of action are more appropriate to remediate the hazard. In such circumstances, the arborist(s) shall make necessary entries in the “special notes” in order to clarify any requirements. The arborist may also select the party responsible for executing the work by identifying whether it will be performed by contracted service providers.

e. Individual records shall be updated upon work completion and archived in the TMIS. Tabulated data shall also be archived when inspections of targeted zones are completed or an area designated for workflow has been completed. Furthermore, all pending and completed workflow for a given fiscal year shall be archived for no less than (10) ten years.

VII. CHOH CYCLIC MAINTENANCE ZONES AND PRIORITIES:

a) Due to the large management area and generally constricted resources, a cyclic inspection and mitigation schedule has been determined to be the most effective means of accomplishing balanced workflow across the full spectrum of the park. A (5) five-year cyclic strategy with two (2) year site exceptions marries the ability to plan, budget, and allocate resources with NPS mechanisms as well as accounts for the general progression of forest conditions. Furthermore, a cyclic strategy ensures that no areas are neglected regardless of their remote location.

b) Towpath Cyclic Maintenance Zones are designed to disperse workflow evenly each fiscal year and facilitate synergizing contract labor services with organic staff efforts. With slight variation, each year for the (5) five-year cycle will address (40) forty linear miles of the park’s towpath, and encompass the surrounding picnic areas, parking lots, bathrooms, and other areas that merit special consideration when those areas are excluded from the two (2) year schedule. In any given zone, priority of effort will be devoted to the highest risks followed by more generalized hazard mitigation (based on resources). The highest priority for the park is the safety and protection of our visitors, volunteers, and employees. All material target exposures are secondary in consideration to the health and welfare of human beings.

c) Both NPS-77, risk management best practices, and legal precedent recognize the increased need for risk assessment and mitigation in areas where the public is encouraged to congregate. These areas shall be maintained on a two (2) year cycle and shall be the priority areas to receive inspection and mitigation actions during any given fiscal/calendar year. During periods of constrained human and fiscal resources, every good faith effort should be made to service two (2) year cyclic zones at the same level of quality and completeness. Assessment outcomes and mitigation actions in these areas may differ significantly from areas maintained on the five (5) year cycle due to the increased frequency of monitoring and surveillance, thus allowing greater flexibility for pruning and non-removal solutions.

C&O CANAL NHP

FIVE-YEAR CYCLIC MAINTENANCE ZONES

Cycle Year

Name of Package

Mile Post

Year 2 Lock 5 - Carderock 5-10.5

Year 2 Edward Ferry - Dickerson 30.84-39.63

Year 2 Taylors - McMahons 81.0-88.1 Year 2 Dam 5 - Parkhead 106.8-117.0 Year 2 Evitts Creek - Cumberland 179-184.5

YEAR TWO (WEST)

Cumberland Valley Campground Williamsport Visitor Center Area Visitation Threshold

Jordan Junction Campground Four Locks Area Picnic Area / Boat Ramp McCoys Ferry Campground / Picnic Area / Boat Ramp Licking Creek Campground

Little Pool Campground Little Tonoloway Picnic Area / Boat Ramp

White Rock Campground Leopards Mill Campground

Cacapon Junction Campground Indigo Neck Campground

Fifteen Mile Creek Campground / Boat Ramp Devils Alley Campground Stickpile Hill Campground Sorrel Ridge Campground

Paw Paw Tunnel Campground / Picnic Area Purslane Run Campground

Town Creek Aqueduct Campground Potomac Forks Campground Pigmans Ferry Campground

Spring Gap Campground / Picnic Area / Boat Ramp Irons Mountain Campground

Evitts Creek Campground

VIII. RESOURCES AND COMPLAINCE

a) Data flow for contract packages

a. Data Flow: In order to ensure that hazard tree management processes are executed in a manner that encompasses all statutory and policy considerations that protect natural and cultural resources all tree workflow data shall be packaged and delivered in shapefile format to the designated Resources Division contact(s). The shape file shall be delivered as soon as practical after identification and development of a hazard management project. The shapefile shall enable Resources personnel to collate and compare trees targeted for mitigation actions against the following digital catalogs:

i. The List of Classified Structures (LCS)

ii. Archeological sites or and areas/features of ethnographic significance

iii. Areas of known to contain endangered flora and fauna

iv. U.S. Fish and Wildlife Service, Information for Planning and Consultation (IPaC) system

b. Actions by Resources COR: The COR shall provide guidance for any special requirements, protections, and considerations that shall be integrated into the work plan based on analysis of the submitted shape file data. The Resources Division may need to consider unique situations where workplans cannot be practically synthesized with Resources Division guidance and facilitate the development of workable solutions with Maintenance personnel.

c. Contract work performed reactively on an emergency basis shall follow the same procedures as outlined in Section VII(b)b below.

d. In accordance with requirements to preserve northern long-eared bat maternity roost trees, contract tree packages shall prohibit active removal of trees from 15 May through 15 August, annually, excluding threats to public safety with a rating of EXTREME.

IX. ARBORIST RESPONSIBILITIES:

a) ISA Certified Arborist(s):

a. Scheduling - The Arborist(s) is responsible for developing and adhering to an inspection schedule as outlined the SOW and approved by the COR.

Deviations to scheduled inspections are permitted due to weather, natural events and other factors beyond the control of the arborist(s). Any deviations from the (5) five-year cyclic maintenance schedule shall be approved, in writing, by the COR.

b. Recordkeeping – The Arborist(s) is required to maintain records of inspections conducted, hazards assessed, and corrective actions taken.

Records shall be kept for a minimum of (10) ten years. The TMIS is the primary record keeping system though back-up methodologies are encouraged.

c. Mitigation – The Arborist(s) is required to develop a hazardous tree mitigation report as a result of the inspection. The report shall identify the hazardous trees and assign a rating to the tree that will allow management to prioritize workflow and implementation of controls In accordance with this policy. Excepting special circumstances that require detailed formal reporting, the TMIS shall be the data repository.

IX. REFERENCES

a) ANSI A300 Best Management Practices, Tree Risk Assessment, TCIA 2nd Edition,

b) ANSI A300 Part 9-2017, Tree, Shrub, and Other Woody Plant Management- Standard Practices (Tree Risk Assessment a. Tree Failure)

c) The Natural Resource Management Guideline (NPS REFMAN-77), pgs. 349-358

Effective: May 16, 1991

d) Management Policies 2006, US Government Printing Office, 2006

e) Director’s Order #50B: Occupational Safety and Health Program. Effective:

September 3, 2008

f) Reference Manual 50B: National Park Service Occupation Safety and Health Program. Effective: September 2008

g) Director’s Order #50C: Public Risk Management Program, Effective: May 7, 2010

IX. REFERENCES