Exhibit A-8 - BMP-Tree-Care-for-Birds-Other-Wildlife-2.26.18-2.pdf

Tree Care for Birds & Other Wildlife Kara Donohue, Ryan Gilpin, and Corey Bassett www.treecareforbirds.com bmp@treecareforbirds.com

February 26, 2018

Tree Care for Birds & Other Wildlife

Best Management Practices in California

RFP PW25-648

Exhibit A-8 mailto:bmp@treecareforbirds.com

Best Management Practices in California

TREE CARE FOR BIRDS

& OTHER WILDLIFE

Kara Donohue, Ryan Gilpin, and Corey Bassett i

RFP PW25-648

Table of Contents Acknowledgements ............................................................................................... v

Purpose

Introduction

Minimizing Impacts to Wildlife

Project Preparation

Fieldwork

Considerations for Work Performed Near Active Nests

Managing Wildlife Habitat

Species Specific

Diversity Approach

Glossary

References

Additional Resources

Appendix I - Tree Care Industry Overview

Appendix II - Wildlife in California

Appendix III - Laws and Regulations

Appendix IV - Bird Group Breeding Information Table

Appendix V - Pre-work Inspection Form iii

Acknowledgements The authors would like to acknowledge the funders, businesses, organiza�ons, and individuals who have made significant contribu�ons to this publica�on. We would like to start with thanking our employers for allowing us to use work �me to prepare this document. Thank you, Southern California Edison, (Kara Donohue), HortScience Inc. (Ryan Gilpin), and West Coast Arborists, Inc. (Corey Basse�).

This project would not have been possible without grant funding from our two primary funders and financial support from our secondary funders.

Primary Funders

Secondary Funders

Altacal Audubon Pomona Valley Audubon California Urban Forest Council Sea and Sage Audubon Cavity Conserva�on Ini�a�ve West Coast Arborists, Inc.

We would like to thank some of our fellow Tree Care for Birds & Other Wildlife members for their organiza�onal support, recommenda�ons and experiences:

Thomas Dietsch, US Fish and Wildlife Service Anne Fege, City of San Diego Community Forest Advisory Board Chris Guenther, City of Escondido Star Howard, Sea and Sage Audubon David Lee, Davey Resource Group Gillian Mar�n, Cavity Conserva�on Ini�a�ve Mike Palat, West Coast Arborists, Inc.

Amelia Oliver, California ReLEAF Diana Ruiz, Riverside Corona Resource Conserva�on Magen Shaw, Davey Resource Group v

Susan Sims, Sims Tree Learning Center Andrew Trotter, West Coast Arborists, Inc.

We are also grateful to everyone who has commented on the development and drafts of these Best Management Practices.

Illustrations created by Brian French and Monica Edwards.

Fiscal management for the Tree Care for Birds & Other Wildlife Project was provided by vi

Purpose This document was written to provide guidance to the California tree care and landscape industry about how to minimize impacts to wildlife during the course of tree work and manage wildlife habitat. While many tree care workers and managers wish to act responsibly around wildlife, little information has been available about how work can best be accomplished while minimizing impacts to wildlife. In addition, Federal and California wildlife regulations are not widely known within the tree care industry, thereby putting uninformed workers at risk of significant fines and public criticism.

This guidance document is meant to be voluntary. These Best Management Practices (BMPs) are not meant to impose new regulations on the tree care industry but rather aim to help those in the industry follow current laws and regulations.

Introduction The tree care industry is different from conventional forestry in that it focuses on the selection, planting, and care of trees of all ages located in city centers, suburban neighborhoods, rural areas and some relatively wild areas with human influences such as roads and utility lines. Tree care activities vary in their level of labor intensity, equipment, frequency, noise, and expense. Managing trees is critical to their success and can maximize their potential environmental benefits. At their most basic, tree care activities include planting, pruning, removal, plant health care, ground maintenance activities, utility clearing, planning, and management (Appendix I - Tree Care Industry Overview, page 30).

One of the important values of trees in urban areas is providing habitat for wildlife. Because of habitat loss due to development, urban landscapes are more vital than ever to wildlife. Wildlife (including birds, mammals, reptiles and amphibians) rely on trees and landscapes for food and shelter as they feed, roost, and reproduce. In turn, wildlife control insects, provide food for other wildlife, pollinate plants, distribute seeds, and are good indicators of environmental health. When trees are managed to support wildlife, landscapes can be more diverse and ecologically rich. Knowledge of breeding, nesting, and foraging habits of wildlife can empower tree care workers to positively manage habitat and encourage the enjoyment of wildlife (Appendix II - Wildlife in California page 33).

The project team determined there is a gap in the resources available to aid the tree care industry in the management of work performed in proximity to wildlife. Unlike most Best Management Practices in the tree care industry, this project:

• is a grassroots project with no large supporting organization,

• has no ANSI A300 Standard on which to base the Best Management

Practices,

• is intended for an audience wider than the tree care industry, and

• is focused only on California because of the state’s unique environment and regulations.

Extensive expert knowledge of tree care and wildlife biology from the team’s roster of professionals provided diverse backgrounds to apply to the writing of this document. The project team also reviewed the limited scientific literature on impacts from tree care practices on wildlife populations and habitats. The scientific literature that exists is primarily conducted in natural areas which may not pertain to most tree care situations.

There are many federal and state laws and regulations about wildlife pertinent to the tree care and landscape industry in California. Local regulations and policies may also exist and should be researched for individual areas. These laws and regulations are broad and results based. They tend to focus on whether or not wildlife were disturbed, injured, or killed. The agencies provide little information about what type of activities may be in violation of the laws. A list and brief explanation of the relevant laws and regulations can be found in Appendix III - Laws and Regulations (Page 46). Of particular note are the Migratory Bird Treaty Act and California Fish and Game Codes 3503 and 3503.5 which apply to the majority of birds.

The section Minimizing Direct Impacts to Wildlife (Page 4) outlines procedures to help keep tree care industry workers from violating these laws and regulations. Many factors go into whether tree care near nesting wildlife is lawful, including: wildlife biology, intensity and duration of work, and proximity of work to nests. These Best Management Practices are recommendations that can help minimize the chance of violating the law but cannot eliminate the possibility. Most importantly, nests with eggs or young should not be removed, moved or worked near. Similarly, these Best Management Practices are only recommendations and should not be viewed as regulations or the only way to minimize impacts to wildlife.

The tree care industry’s impact on wildlife goes beyond disturbing nesting wildlife. Habitat structure is altered by pruning and planting trees. The 2017 update to the ANSI A300 Pruning Standard includes “Manage Wildlife Habitat” as a pruning objective. The section of these Best Management Practices titled Managing Wildlife Habitat (Page 18) introduces new and old ideas for tree care industry workers to think about while working in landscapes.

Lastly, it was necessary in writing these BMPs to create a hierarchy of various activities and mitigation strategies appropriate for professionals with different levels and types of training in both tree care and wildlife biology. The roles and titles used, like Wildlife Trained Arborist and Wildlife Biologist, are defined in the text and the Glossary (Page 24) but do not refer to specific certifications that existed at the time of writing. Rather, the project team hoped to provide recommendations on the type of training and expertise necessary to minimize impacts to wildlife in different situations and to set the stage for the development of certification programs. Educational resources and training information will be available at www.treecareforbirds.com.

Minimizing Impacts to Wildlife This section provides guidance to help tree care workers organize their work to comply with California state and U.S. federal laws and regulations. The step-by-step process guides what level of training and expertise may be most appropriate for different situations. Tree care workers should plan projects appropriately. In the field, tree care workers should be aware of wildlife and respond to their presence by involving people with adequate training.

Some companies may choose to develop a programmatic approach to minimizing impacts to wildlife. For example, rather than evaluating BMP recommendations as they apply to each individual work site, a company program could assess their area as a whole for potential conflicts and develop a program specific to their activities and impacts. A company with a program in place may not need the aid of these BMPs, but for a company just starting to develop a program these BMPs may provide a starting point.

Providing training and materials for workers prior to work can aid in the ability to recognize and respond to situations with the potential to harm wildlife.

Training materials, an Awareness Training video, and other resources can be found at www.treecareforbirds.com.

• Tree care worker with minimal training: Awareness Training can be provided by a Wildlife Trained Arborist at the project site during the daily job briefing. Awareness Training is a brief crew training provided by a Wildlife Biologist or Wildlife Trained Arborist that covers general information about looking for signs of nesting wildlife or may be specific to a location.

• A Wildlife Trained Arborist is a tree care worker with training and/or experience in: determining habitat value, conducting pre-work nesting inspections, identifying signs of nesting wildlife, determining if nests are active, responding to wildlife emergencies, and contacting Wildlife Biologists when needed.

• A Wildlife Biologist is a person with knowledge and experience in identifying wildlife species that may occur in an area, and is familiar with wildlife behavior, nesting requirements, tolerance to impacts, and suitable survey methods.

If the project is covered by a California Environmental Quality Assessment (CEQA) determination, the mitigations identified in the final decision must be followed. If the project is covered by US Fish and Wildlife Service or other agency consultation, the conditions of that consultation must be followed. If the project has permit requirements, the requirements must be followed. These BMPs do not attempt to replace those processes in any way.

This section is divided into two phases of work: Project Preparation and Fieldwork. Each phase of work has a narrative. Project Preparation is represented by Table 1 (Page 8), and Fieldwork has a flowchart (Figure 5, Page

13) to guide tree care in ways that minimize impacts to wildlife.

Project Preparation The goals of the Project Preparation phase are to establish the breeding season and habitat value of a work site and use this information to select a Category for the Fieldwork phase (Table 1, Page 8). Adult mammals and birds will likely flee when tree care workers arrive to a work area so work can proceed. During nesting, however, eggs and young wildlife cannot move from nests. Because they are vulnerable and stationary during this time period, nesting wildlife are those most likely to be impacted by tree and shrub care. To minimize impacts, it is critical to identify, avoid, and protect wildlife nests. Nesting wildlife can be found in any type of habitat at any time of year. However, certain types of habitats are more likely to contain nesting wildlife. Most wildlife nest during the spring and summer.

Tree care projects can be divided into three categories based on two criteria:

the time of year of the work (breeding season or non-breeding season) and the habitat value of the work area. See Appendix IV - Bird Group Breeding Information Table (Page 51) for general breeding season periods for various groups of birds. It is important to note that breeding seasons vary by factors such as location and species, and that climate change will also likely impact the breeding season timing in the future. Different types of landscapes have different habitat values. Habitat value is defined by the likelihood of finding wildlife using an area throughout the year. Appendix V - Pre-work Inspection Form (Page 54) is a pre-work inspection form to help decide the habitat value.

The habitat values listed in this document are: riparian habitat (Figure 1, Page 6) high value habitat (Figure 2, Page 7), and low value habitat (Figure 3, Page 7).

Figure 1. Riparian habitat is the interface between land and constant or intermittent rivers or streams and generally provide the highest value habitat for wildlife.

Riparian areas can be identified by their distinctive soils and vegetation, particularly willows (Salix spp.), mulefat (Baccharis salicifolia), sycamore (Platanus spp.), and cottonwood (Populus spp). This may include concrete channels when the associated riparian vegetation and soils are present.

Illustrator - Brian French

Figure 3. Low value habitat generally has high human use, high impervious surfaces, low plant species diversity, far from water bodies, few mature trees, few dead and dying trees, and few/no wildlife present.

Illustrator - Brian French

Figure 2. High value habitat generally has low human use, low impervious surfaces, high plant species diversity, high plant structural diversity, close to water bodies, many mature trees, many dead or dying trees, and abundant wildlife.

Illustrator – Monica Edwards

Conducting a desktop review of the biological resources potentially present at a project location can help identify the appropriate category choice prior to beginning tree care activities. Sources of information include USFWS Critical Habitat designations and Wetland Mapper, CNDDB, public lands (USFS, BLM, State Parks, etc.), and local Audubon chapters. Should a desktop review reveal the project location is in or near USFWS designated critical habitat, sensitive species locations, or wetlands/riparian areas, the project activities may require more caution.

Tree care work can be broken into three categories based on the value of the habitat and whether or not the work is scheduled during the breeding season (Table 1). The level of expertise required for these projects may be dictated by other factors. Many construction projects, permit requirements, and CEQA documentation will require Wildlife Biologists to be involved in the project. In those cases, a Wildlife Biologist should be contacted rather than using the below categories.

Table 1. Determining Category

Low value habitat

High value habitat

Riparian habitat

Non-breeding season

Category 1 Category 2 Category 3

Breeding season Category 2 Category 3 Category 3

Category 1 is low value habitat during the non-breeding season where nesting wildlife are least likely to be encountered. A pre-work inspection by a tree care worker with Awareness Training is recommended. This inspection should be completed before equipment has been turned on at the site, preferably within a week of the start date as many birds can build nests quickly.

Category 2 covers two situations. The first is low value habitat during the breeding season where nesting wildlife are more likely to be encountered. The second is high value habitat during the non-breeding season where sensitive habitats are more likely to be encountered. Sensitive habitats are habitats which are home to special status species or are themselves rare. A pre-work inspection by a Wildlife Trained Arborist is recommended.

Category 3 covers high value habitat during the breeding season or riparian habitat at any time of the year, nesting wildlife and sensitive habitats are more likely to be encountered. It is recommended a Wildlife Biologist be contacted

Figure 4. A tree care worker conducting a pre-work inspection is looking for signs of wildlife including wildlife breeding behavior such as carrying sticks or food, acting agitated, distress calls, as well as concentrations of bird droppings, nests that may be active, eggs, young, or wildlife reliant on nest. See Appendix V (Page 54) for a sample pre-work inspection form.

Illustrator – Monica Edwards for direction. However, companies who have taken a programmatic approach to protecting wildlife may be able to use a well-trained arborist to minimize impacts in these locations. Ideally the Wildlife Biologist provides advice on how the project can proceed. The biologist will collect information about the job, timing, and location to provide recommendations. They may be able to approve the work as planned, but more likely will need to visit the site and may recommend timing or methodological changes to the project. For projects in riparian areas, permits from regulatory agencies may be required for tree and vegetation pruning and removal (Appendix III, Page 46).

Because wildlife can nest year round in any type of habitat, the Category level assessed at the time of planning may change during the fieldwork. Encountering signs of wildlife during fieldwork may require further expertise to handle the situation.

After scheduling the work with assistance from someone with the appropriate level of training based on the Category, the final step of project preparation is to gather contact information for a Wildlife Biologist and local wildlife rehabilitator. Contact information for both of these resources will be important if a wildlife emergency or situation that needs expertise arises during fieldwork.

A wildlife emergency is a situation where wildlife are injured, orphaned, or in danger or where nests are abandoned or disturbed.

Fieldwork After following the Project Preparation phase (Page 5) the appropriate Category of BMP determines how to proceed in the Fieldwork phase. For a Category 1 job, a person with Awareness Training should perform a pre-work inspection.

For a Category 2 job, a Wildlife Trained Arborist should perform a pre-work inspection. For a Category 3 job, a Wildlife Biologist is recommended to advise workers when and how to safely work in the area. For any job, contact information for a Wildlife Biologist and wildlife rehabilitator should be on-hand in the field. Figure 5 (Page 13) is a graphical depiction of this text.

Category 1

• Low value habitat during the non-breeding season,

• Nesting wildlife are unlikely to be encountered, and

• Awareness Training is recommended.

A pre-work inspection performed by someone with Awareness Training is recommended. This inspection can occur prior to starting work, or in the days before the work is scheduled, but not more than a week before the work is planned to begin. The pre-work inspection can be part of the site walk to discuss the work for the day, safety precautions, etc. but is best done at a quiet time when wildlife activity can be observed. Wildlife being present on a site does not mean that they will be negatively impacted by the work. It is important to look for nests that may be active and signs of wildlife. Signs of wildlife include:

wildlife breeding behavior such as carrying sticks or food, acting agitated, distress calls, as well as observing concentrations of bird droppings, nests that may be active, eggs, young, or wildlife reliant on nests. If any of these signs of wildlife are observed during the site walk or during the work, a Wildlife Trained Arborist or a Wildlife Biologist should be contacted.

If there are no signs of nesting wildlife during the pre-work inspection, the work can proceed as normal. While working, be aware of wildlife, cavities, and nests.

Category 2

• Low value habitat during the breeding season, or

• High value habitat during the non-breeding season where

• Nesting wildlife are more likely to be encountered, and

• A pre-work inspection by a Wildlife Trained Arborist is recommended.

A pre-work inspection by a Wildlife Trained Arborist should be completed before the work is started. This inspection can occur the morning of the work or in the days before the work is scheduled but not more than a week before the work is planned to begin.

If no active nests are found that may be impacted by the tree work, the crew can proceed with the work. If active nests are found that may be impacted by the tree work, the best option is for the Wildlife Trained Arborist to delay the work until the young have fledged from the nest and work can safely proceed.

Most Wildlife Trained Arborists will not be able to identify the species of wildlife and predict when the nest is likely to become inactive, but Appendix IV (Page 51) provides some typical time frames. In some cases, the Wildlife Trained Arborist may be able to suggest that work starts on a portion of the site, but that some areas are left until after the young have left the nest.

When a nest is discovered during the pre-work inspection or during work, a Wildlife Trained Arborist should perform an evaluation to determine whether the nest is active. If it cannot be determined whether the nest is active or whether the nest is a raptor nest (typically a platform nest or cavity nest), a Wildlife Biologist should make this determination. Raptors may reuse their nests and should not be removed without consulting a Wildlife Biologist. If necessary due to tree removal, inactive non-raptor nests can be destroyed provided no possession of the nest occurs. U.S. Fish and Wildlife Service details guidance for nest destruction in their 2003 Migratory Bird Permit Memorandum.

Category 3

• Riparian habitat anytime,

• High value habitat during the breeding season,

• Nesting and/or sensitive wildlife are likely to be encountered, and

• A pre-work inspection by a Wildlife Biologist is recommended.

For high value habitat during the breeding season or when working in or adjacent to riparian habitats, there is a higher chance of disturbing nesting wildlife or impacting special status species or their habitat. The direction provided by the Wildlife Biologist should be followed. This may mean work may proceed as planned similar to Category 2, but more likely the Wildlife Biologist will recommend an inspection and periodic monitoring until the work is complete.

If no active nests are found that may be impacted by the tree work, the Wildlife Biologist will instruct the crew to proceed with work while maintaining awareness of any wildlife in the area. If active nests are found that may be impacted by the tree work, the best option is for the Wildlife Biologist to delay the work until the young have fledged from the nest and work can safely proceed. In some cases the Wildlife Biologist may be able to suggest alternative methods to use near the nest (Considerations for Work Performed Near Active Nests, Page 14) or suggest that work starts on a portion of the site, but that some areas are left until after the young have left the nest.

Emergencies Wildlife emergencies occasionally occur during tree work. While the first priority is to try to avoid these emergencies, the second priority is to respond appropriately. If wildlife are injured or young wildlife and eggs are abandoned by their parents as a result of the tree work, a local wildlife rehabilitator should be contacted. Explain the situation to these experts in wildlife emergencies. The wildlife rehabilitator likely can provide guidance on how to proceed. In some situations, they may advise doing nothing and allowing the parents to return and care for the wildlife. In other situations, they may advise bringing the injured wildlife immediately to a care facility. To continue working after a wildlife emergency, a Wildlife Biologist should be contacted.

If no wildlife emergencies occur and no signs of nesting wildlife are observed, continue working while being aware of wildlife, cavities and nests. If at any time the crew feels uncomfortable or unsure of how to work in the area, a Wildlife Trained Arborist or a Wildlife Biologist should be contacted.

In the case of a human health and safety emergency, a Wildlife Biologist can help coordinate permission to remove an active nest with the US Fish and Wildlife Service and the CA Department of Fish and Wildlife. Human health and safety emergencies pose immediate risk to human health and/or safety and require action to alleviate imminent danger circumstances. These agencies can grant permission for removal of an active nest when deemed appropriate. If a tree with an active nest needs to be removed for human health and safety, a Tree Risk Assessment Qualified (TRAQ) arborist should perform a Level 2 inspection and show that tree risk exceeds risk tolerance of the property owner and seek USFWS and CDFW approval. In a time-sensitive situation, action may need to be taken before permission can be received, but this should only be done in the most extreme situations.

Figure 5: Project Preparation and Fieldwork phase decisions flowchart

Considerations for Work Performed Near Active Nests When an active nest is discovered in a work area, it is best to delay work until the nest becomes inactive. In the absence of direction from a Wildlife Biologist, setting larger, conservative buffers may help reduce the likelihood of impacts.

However, there are circumstances when it may be possible to continue work in the vicinity of an active nest without resulting in the abandonment of a nest. In particular, when circumstances are such that imminent danger exists that may result in an emergency or there is a public safety concern, it may be necessary to complete a minimal amount of work until the nest becomes inactive.

Key considerations for work near active nests include:

• the duration of the work to be completed,

• the tools used,

• the species involved,

• distance of the work to the active nest,

• the status of the nest,

• location specifics (e.g. urban vs. rural), and

• environmental conditions (temperature and wind).

It may be necessary to communicate with a Wildlife Biologist to determine the appropriate methods for work to continue. Typically, a no activity buffer should be established around the nest. A nest buffer is an area in which no work should occur in order to prevent the abandonment of the nest by the adults. For example, if an active nest is discovered in a tree near a project, a no work zone should be established. This area can be cylindrical or circular and radiate out from the nest an appropriate distance that the adult birds can continue normal activities of tending to their nest without being disturbed (Figure 6, Page 15).

Appendix IV (Page 51) recommends buffers for different types of birds depending on the habitat value of the work area. These buffers should be large for most situations, Wildlife Biologists may be able to recommend smaller buffers depending on specific situations.

Work Duration and Temperature An active nest is less likely to fail if the work duration nearby is kept to a minimum. Adults kept away from an active nest during moderate weather conditions for 30 minutes or less are unlikely to abandon the nest or have mortality to the eggs or young occur. However, if work duration is several hours or if weather conditions are extreme, the adults are likely to abandon their nest and/or mortality may result due to starvation, predation, or the eggs or hatchlings being too hot or cold. Bird embryos are more sensitive to overheating than to cold.

Tools Often disturbance level can be minimized by tool selection. Hand tools may be recommended over gasoline powered tools to reduce noise. It should be taken into consideration that if hand tools significantly increase the duration of work at a location, the benefit from reduction of noise may be canceled out by the longer duration of work.

Figure 6: Three dimensional no activity buffer around a nest

Species, Species Behavior, and Distance Considerations Buffers for active nests should consider species-specific tolerances for disturbance, if known. Typically, larger buffers are used for large bird species and for species that are not tolerant of disturbance. Smaller buffers are generally used for smaller avian species and also species that have a high tolerance for disturbance, such as those that are commonly found nesting close to development.

Some species differ in tolerance based on location and therefore the appropriate buffer may vary. A blue-gray gnatcatcher (Polioptila caerulea), for example, nesting in a thicket or understory is less likely to be disturbed than one nesting in a more exposed location in a shrub or small tree even though both nests are the same distance from the activity. Likewise, a red-tailed hawk (Buteo jamaicensis) that has acclimated to human activities is less likely to be disturbed at its nest than one that is not accustomed to human activity.

For ground-based activities, vertical separation of the nest from the construction area may be considered when selecting the appropriate buffer.

Some species build their nests very high in trees and structures. For example, a nest 50 feet off the ground is less likely to be affected by ground work occurring directly below than a nest 10 feet off the ground. Nests close to the ground may be better suited to a cylinder shaped no work buffer area while spherical no work buffer areas may be suitable for nests farther from the ground (Figure 6).

The observed behavior of an individual bird during the nest search process and consequent nest monitoring will help determine the appropriate buffer distance. For example, an incubating adult that appears more skittish and is readily disturbed could receive a larger buffer than an incubating adult that sits tight and appears more acclimated to disturbance.

Nest Status Generally, nesting birds are most susceptible to failure early in the nesting cycle when fewer resources have been invested towards the nest. Therefore, it is more important to reduce disturbances during egg laying rather than later in the nesting cycle, which could result in the determination of a larger buffer being necessary early on, then reducing its size later in the nesting season.

When a nest is close to fledging, if disturbance occurs young may be more likely to leave the nest prematurely, unable to adequately fly, and therefore more susceptible to predation or injury. Similar to early in the nesting cycle, a larger buffer may be necessary until the young have fledged.

Environmental Conditions Extreme weather events may produce conditions that would increase the likelihood of nest failure. Combined with the stress of nearby activity, a nest might fail that would otherwise succeed. On unseasonably hot, cold, or windy days, buffers may need to be increased.

Summary The appropriate buffer (area surrounding the nest in which no activity may occur) for each nest often should be determined in consultation with a Wildlife Biologist. The Wildlife Biologist can use information from the above categories in combination to judge the buffer size needed to avoid or reduce the likelihood of the abandonment of an active nest. When long work duration is combined with hot weather and the nest is in the early incubation stage, larger buffers will be needed when compared to work that will take only 30 minutes, requires only hand tools, occurs during cool weather, and has a nest of older chicks. Taking into account the variety of factors when establishing buffers minimizes work activity impacts to nesting birds.

Managing Wildlife Habitat When tree care crews work in landscapes, they change the structure and availability of potential habitats for wildlife. Many factors go into tree care decisions such as: plant health, branch structure, clearance requirements, aesthetics, risk, and climber safety. Many within the tree care industry are interested in including managing wildlife habitat into their tree care decisions.

The laws protecting wildlife apply to habitat management. Any time that a crew is working near, or may encounter, nesting or sensitive wildlife, they should be following the recommendations for Minimizing Impacts to Wildlife (Page 4). This section is not intended to provide mitigation for removing active nests or sensitive habitat, but to provide guidance for those managing wildlife habitat.

Managing wildlife habitat includes more than improving habitat. In certain situations, land managers may be looking to decrease the habitat value of their landscapes. Possible reasons include minimizing human wildlife conflicts due to planned construction, excessive feces or noise in use areas, wildlife damaging infrastructure, etc. While this section focuses on improving habitat, the opposite approach may be more appropriate in areas of human-wildlife conflicts.

However, the benefits of trees should be considered.

Hundreds of different species of wildlife live in California landscapes. Many of these species have different nesting, dietary, and behavioral needs. It is not possible to guide the management of landscapes to increase or decrease the habitat values for all species. However, research, experience, and common sense can guide tree care workers in managing wildlife habitat. Two approaches can be used separately or together to accomplish habitat goals: a species-specific approach and a diversity approach.

Species Specific Land managers may be interested in increasing the numbers of a particular species or type of wildlife. This could be for practical purposes (e.g. increased raptors to reduce rodent populations) or for ecological reasons (e.g. acorn woodpeckers are underrepresented in the area). Research into the life cycle of that species and what is likely restricting its numbers in this area can be conducted. Based on that research, the landscape can be managed in a particular way to potentially increase the numbers of the desired species. For example, Nuttall’s woodpeckers typically excavate their nests in trees with heart rot. Rather than remove trees that are declining in health (and selecting those that are not a safety risk), tree care workers may be able to recommend management for tree risk via such means as height reduction and limb removal or reduc�on, and recommend monitoring their stability for future woodpecker use.

In order to help determine the requirements and management op�ons for specific species, contact a Wildlife Biologist or your local Audubon chapter.

Diversity Approach In general, single-species habitat management limits the poten�al benefits to other wildlife. An ideal goal is to encourage landscape managers to consider establishing natural condi�ons that support a broad variety of wildlife. Larger and more diverse habitats with minimal human disturbance are likely to benefit a greater number of species.

Plant Management Generally, expanding landscapes through tree, shrub and ground cover plan�ng will create more habitat for wildlife. Proper pruning, plant health care, planning, irriga�on, pest and disease management, and managing risk will be important to keep trees and shrubs from declining. Decades of research and experience have gone into growing and maintaining landscapes and many of these topics are covered in Interna�onal Society of Arboriculture Best Management Prac�ces. Some prac�ces in the tree care industry that are par�cularly important to wildlife include:

● Plant young trees and provide young tree care programs: irriga�on, support, structural pruning, etc.

● For healthy trees, follow pruning Best Management Prac�ces in which branches are removed only to meet par�cular objec�ves. Whenever possible, use a Natural Pruning System and follow the standard that “pruning opera�ons should remove no more living material than what is necessary to achieve specified objec�ves” (ANSI A300 Pruning Standards). Prune trees only when necessary; trees should be on an inspec�on cycle not a pruning cycle.

● Use an Integrated Pest Management approach to plant health care.

Limit broad spectrum pes�cides which kill non-target insects.

● Retain mature trees whenever possible.

Diversity of Habitats The hundreds of species of wildlife that visit and live in urban landscapes have many different habitat requirements. Each community is different and should offer different habitats within its community and different habitats from neighboring communi�es. This focus on diversity will also drive resiliency, ensuring that landscapes survive into the future. Some metrics of natural forest structures can be used to manage and improve diversity in landscapes: diversity of species, ages, structures, and distribution.

● Increase tree species diversity. A common recommendation for a city in the tree care industry is to have at least 30-20-10 diversity. No more than 30% of a city’s trees should be of any one family [such as Fagaceae which include oaks (Quercus), beeches (Fagus), and other genera]. No more than 20% of a city’s trees should be of any one genus [such as oaks (Quercus)]. No more than 10% of a city's trees should be of any one species [such as coast live oak (Quercus agrifolia)]. These targets may be too high and could be even lower. Regardless of current diversity, when planning tree planting, look to increase species diversity.

● Increase tree age diversity. Diverse landscapes have young trees and mature trees. Young trees are planted each year and mature trees are managed and protected to extend their lifespan.

● Increase dead, dying, and declining trees. Many species of wildlife rely on dead and dying trees or on large dead limbs of live trees for nesting in cavities inside of trees. When risk can be adequately managed, consider retaining defects traditionally removed during tree care. Dead, dying, and declining trees are also important for insects and wildlife that feed on insects. These benefits should be balanced with pest species outbreaks and fire risk.

● Increase groundcover and shrub cover. Landscapes contain shrubs and groundcovers important for wildlife. Habitats of lawns with trees are probably over-represented throughout California. A more diverse groundcover palate accompanied with increased shrub and small tree layers are likely to increase habitat value. The shrub layer is especially important for escape cover, allowing wildlife to hide from predators and seek shelter from the elements. Ideally a mix of wood chips, ground covers, and bare earth can be used in the landscape.

● Increase native species when it is appropriate and where doing so increases diversity. The small number of California native trees currently available in the landscape trade and their low suitability to many urban situations makes it difficult to meet tree diversity targets, including the 30-20-10 guideline, using only native trees. In many communities, native trees can be added to the landscape while still increasing overall species diversity. A wider variety of native bushes and ground covers are available and are underused in many California landscapes.

● Increase spatial diversity. The above factors will be more beneficial if distributed unevenly throughout an area. For example, a new species should be planted throughout a city, not just in one area. But an overly organized pattern is also not ideal because some species require pockets of a particular habitat type.

Retaining Dead, Dying and Decaying Trees, and Branches One area that the tree care industry has a high potential to increase habitat in is in dead, dying, and decaying trees and branches. Many wildlife species are reliant on trees or parts of trees that are routinely removed with no thought about the habitat that they provide. Wildlife that nest exclusively in dead, dying, and decaying trees and branches would benefit greatly from greater awareness of their habitat requirements and effort in preserving these types of trees. Local Audubon Chapters and the Cavity Conservation Initiative may be able to help with specific needs and recommendations for a particular area or project.

Priority must be given to human safety when managing dead, dying, and decaying trees and branches; however, when risk does not exceed tolerance, many of these important habitats can be retained. The Tree Risk Assessment Best Management Practices lists cavity openings and nesting holes as positive indicators of decay or internal voids. Trees with cavity nests are given a higher likelihood of failure and recommended for removal more often than trees without cavity nests. Decayed trees and branches are considered less structurally stable because their capacity to withstand force diminishes according to the size and location of decay. However, no scientific studies have conclusively demonstrated the loss of strength from these cavities. Not all dead, dying, and decayed trees can or should be retained, but extending the life of a dead or dying tree a few years could be beneficial to wildlife.

Trees and branches for which risk exceeds risk tolerance do not always need to be removed, other mitigation methods can be employed. Pruning techniques that are not commonly used on healthy trees can be employed on unhealthy or hazard trees in order to preserve the tree while mitigating for risk. For example, Figure 7 (Page 22) shows a branch with a cavity growing over a house. If risk outweighs risk tolerance, a reduction cut is unlikely to adequately mitigate the risk, and a removal cut will remove the potential nesting cavity. A heading cut could adequately mitigate risk and preserve habitat in these cases, though heading cuts are generally not recommended because of the physiological effect on the tree. This branch would likely need to be completely removed to mitigate risk if not using a heading cut, and the branch is already decayed, so future decay from the heading cut is less of a concern.

Figure 7. Different types of cuts may be appropriate to accomplish different pruning objectives. In this situation, a heading cut may be able to preserve a potential cavity nest site and mitigate risk.

Some mature, declining trees can be severely pruned to reduce risk while leaving some available habitat. Even a tall stump may provide important habitat to cavity nesting wildlife in areas where decayed wood is not abundant.

Retrenchment is a natural progression that many trees go through later in life, and retrenchment pruning is practiced more often in the United Kingdom to extend the life of declining mature trees.

Nest boxes may be one way to mitigate loss of cavities from dead, dying, and decaying tree and branch removal. When nest boxes are provided, they can be quickly occupied and sometimes lead to an immediate rise in breeding density.

Cavity nesting bird populations are not solely limited by the availability of cavities. When considering creating habitat for these species, the availability of suitable food and types of predators in the habitat need to be considered. Dead, dying, and decayed trees and branches are complex ecosystems and simply attaching a nest box to a young tree cannot replace the lost value of those ecosystems. If installing nest boxes, the correct type, height, protection, and maintenance need to be considered. Local Audubon groups may be able to provide important information regarding these requirements (Additional Resources, Page 28).

Once on the ground, tree parts continue to be used by wildlife and are important features of landscapes. If sections of trunks and branches, brush piles, or toppled trees can be incorporated into the landscape aesthetically and with an acceptable level of risk, wildlife may benefit.

Forestry research has led to more invasive ways of increasing habitat value such as girdling trees to kill them in areas where dead trees are not common, cutting the tops off of trees to create snags, and using chainsaws to cut artificial cavities into trees to increase the habitat value for secondary cavity nesters. Some of these techniques are being experimented with by tree care workers and may become more prevalent as awareness of wildlife increases.

Glossary Awareness Training - crew training provided by a Wildlife Biologist or Wildlife Trained Arborist that covers general information about looking for signs of nesting wildlife or may be specific to a location. Awareness training typically takes no more than 15 minutes. A video is available at www.treecareforbirds.com.

Breeding season - the time of year when most wildlife breed, nest, and care for offspring that cannot care for themselves. Across the different habitats of California, most wildlife breed between February 1st and August 31st, in most years. However, this varies by region and species. In some years variable weather patterns or abundance of food may cause early or late breeding.

Buffers - areas established around an active nest in which no work is allowed to occur to prevent abandonment or destruction.

Category 1 - For a low value habitat during the non-breeding season, no trained personnel are required.

Category 2 - For a low value habitat during the breeding season or a high value habitat during the non-breeding season, pre-work inspections by a Wildlife Trained Arborist are recommended.

Category 3 - For a high value habitat during the breeding season or riparian habitat areas at any time of the year, the project should follow recommendations from a Wildlife Biologist.

Human health and safety emergency - immediate risk posed to human health and/or safety. Requires action to alleviate imminent danger circumstances.

Habitat value - the likelihood of finding wildlife using an area throughout the year.

Riparian habitat - areas are the interface between land and constant or intermittent rivers or streams and generally provide the highest value habitat for wildlife. Riparian areas can be identified by their distinctive soils and vegetation, particularly willows (Salix spp.), mulefat (Baccharis salicifolia), sycamore (Platanus spp.), and cottonwood (Populus spp).

This may include concrete channels when the associated riparian vegetation and soils are present.

High value habitat - generally areas with low human use, low impervious surfaces, high plant species diversity, high plant structural diversity, close to water bodies, many mature trees, many dead or dying trees, and with abundant wildlife.

Low value habitat - generally areas with high human use, high impervious surfaces, low plant species diversity, far from water bodies, few mature trees, few dead and dying trees, and few/no wildlife present.

Nest - a structure or place made or chosen by wildlife for laying of eggs or sheltering its young.

Active - eggs or young present

Inactive - no eggs or young present

Abandoned - eggs or young present, but adults are no longer returning to tend the nest

Non-breeding season - the time of year when most wildlife are not breeding, nesting, or caring for offspring that cannot care for themselves. Across the different habitats of California, most wildlife are not breeding between September 1st and January 31st, in most years. However, this varies by region and species. In some years variable weather patterns or abundance of food may cause early or late breeding.

Raptor - birds of prey such as owls, hawks, eagles, vultures, and falcons which are in the orders Strigiformes, Accipitriformes, and Falconiformes.

Signs of nesting wildlife - wildlife breeding behavior such as carrying sticks of food, acting agitated, distress calls, as well as observing concentrations of bird droppings, nests that may be active, eggs, young, or wildlife reliant on nest.

Sensitive habitat - habitat that is home to special status species and/or the habitat itself may be rare and could be easily disturbed or degraded by human activities and developments.

Tree - a woody perennial, usually having one dominant vertical trunk and a height greater than 15 ft.

Tree Care Worker - a term that can describe any professional working with trees including but not limited to arborists, tree climbers, trimmers, ground workers, consultants, managers, etc.

Wildlife Trained Arborist - a tree care worker with training and/or experience in: determining habitat value, conducting pre-work nesting surveys, identifying signs of nesting wildlife, determining if nests are active, responding to wildlife emergencies, and contacting Wildlife Biologists when needed.

Wildlife Biologist - a person with knowledge and experience in identifying wildlife species that may occur in an area and is familiar with wildlife behavior, nesting requirements, tolerance to impacts and suitable survey methods.

Wildlife rehabilitator - an individual or organization with training, experience, and (if required) applicable permit(s) allowing them to care for injured or abandoned wildlife.

Wildlife emergency - a situation where wildlife are injured, orphaned, or in danger or where nests are abandoned or disturbed.

Wildlife - undomesticated living animals especially birds, mammals, amphibians, and lizards.

Native species - species that is present by a natural process with no human intervention.

Non-native species - species that has been brought to a new geographic region beyond its normal range.

Invasive species - species exhibiting a strong ability to colonize an area and harm other species.

Special status - species of wildlife that have one or more designations from authorities. The US Fish and Wildlife Service and California Department of Fish and Wildlife each have their own list of endangered, threatened, and…