Natural_&_Wooded_Area_Restoration_Standards.pdf

City of Pittsburgh Natural and Wooded Area Restoration Standards These standards are meant for use in natural areas owned by the City of Pittsburgh which have become disturbed or otherwise ecologically imbalanced and are in need of restoration. The objective of these standards is to encourage the development of a healthy ecosystem while improving resilience to the ongoing threats posed by invasive species and climate change.

Contents Site Preparation Requirements

Restoration Specifications

Tree Installations

Shrubs and small-statured perennials

Seed Mixes

Soil Amendments & Inoculants

Tree Protection

Option One: Full Site Protection

Option Two: Tree Protection Cages

Option Three: Tree Tubes

Option Four: Trunk guards

Signage

Maintenance Requirements for Ecological Restoration on City-owned Lands

Watering

Invasive Species Control

Removal of Tree Protection

Appendix 1: DCNR Invasive Plant List

Appendix 2: Restoration Species List

Appendix 3: Park Species List

Appendix 4: Prohibited Species List

Appendix 5: Planting Diagram, Level Sites

Appendix 6: Planting Diagram, Sloped Sites

Appendix 7: Plant Spacing Configurations

Site Preparation Requirements Prior to the restoration of the site, the following tasks must be completed. In cases where these tasks are not applicable or appropriate, documentation should be provided in the project planning documents.

• Removal of invasive species – removal of invasive species less than 6” in diameter, defined as rank 1 and rank 2 species on the PA DCNR Invasive Plant List, , shall be conducted prior to the start of work. Use of chemical herbicides is currently prohibited. Mechanical or biological removal methods (goats) are approved for use on City-owned lands

• Garbage cleanup – All large garbage (appliances, tires etc.) and foreign objects larger than 6” in any dimension shall be removed from the site prior to restoration and disposed by whatever means is legal for that type of waste.

• Hazard abatement – Any existing safety hazards, (snags, hangers, damaged utilities, etc.) shall be removed or repaired prior to the start of restoration activities.

Restoration Specifications Restoration of natural and wooded areas must conform to the following standards.

Tree Installations

• Stocking density: 600-800 stems/acre in open areas, 200-500 stems per acre in areas where there is existing overstory canopy.

• Stocking density exception: full-statured trees may not be planted overtop of or within 10’ of the centerline of underground water and gas mains. The overall stocking density of 800-1300 stems per acre is to be maintained, but all planting materials are to come from the shrubs and small trees lists.

• Size: A mixture of balled and burlapped, containerized, or plug stock. Bare-root seedlings are prohibited. Hardwood cuttings may be used only in streambank restorations.

• Size exception: on steep slopes (25% or greater), the use of balled and burlapped stock or containerized stock over 2 gallons is prohibited.

• Species Selection: to conform to the attached City of Pittsburgh approved restoration species list, approved parks species list, and prohibited species list. Plant selection shall adhere to the

10/20/30 principle. At least 20% of the trees planted shall be conifers

• Planting requirements: All trees shall be planted to ANSI A300 standards

Shrubs and small-statured perennials

• Stocking density: 300-500 stems/acre

• Size: containerized or plug stock

• Species Selection: to conform to the attached City of Pittsburgh approved restoration species list, approved parks species list, and prohibited species list. Plant selection shall adhere to the

10/20/30 principle.

• All trees shall be planted to ANSI A300 standards http://elibrary.dcnr.pa.gov/GetDocument?docId=2700788&DocName=dcnr_20033786

Seed Mixes

• Commercially available restoration seed mixes are approved for use on City of Pittsburgh properties.

• Species Selection: Seed mix shall contain no less than 50% native species by weight. Inclusion of species listed on the PA DCNR invasive plant list is strictly prohibited.

• Seed mixes should contain a mixture of no less than 10% perennial, shade compatible tree and shrub species to establish a soil seed bank for closed canopy restoration.

Soil Amendments & Inoculants

• Application of organic soil amendments certified to be free of heavy metals and other contaminants is permitted as part of restoration projects. Material samples, specifications, and source information shall be provided to the City.

Tree Protection The following standards shall apply to all trees planted in natural areas, unmaintained sections of City

Parks, or areas of intense deer browsing pressure. Where appropriate, these standards shall be applied in a manner that best suits the needs of the project, factoring in the amount of deer pressure, size of the trees to be planted, and available project resources.

Option One: Full Site Protection In cases where large areas of trees are to be planted in close enough proximity that individual tree protection is untenable, full enclosure of the site shall be permitted. Perimeter fences shall conform to the following minimum standards:

• Tree protection fences shall be no less than 8’ in height

• Fencing shall be composed of galvanized or plastic-coated wire

• Plastic mesh fencing is prohibited

• Fencing shall be supported by posts no more than 20’ apart

• Fence corners shall be adequately braced using diagonal supports in line with loading forces

• Fencing shall be supported by top and bottom tension wires no more than 12” from the top and bottoms of the support posts

• Fencing shall be secure to the ground using spikes, staples, no less than 12” long at intervals not to exceed 24”

• Fencing shall have two exit gates

• Exit gates shall match the height of the fence, and shall be a minimum of 48” wide

• Project signage may be affixed to the fence itself or installed on posts adjacent to the fence

• Fences are to be removed at the end of five years

Option Two: Tree Protection Cages In cases where only a few trees need to be protected or the installation of full-site fencing is untenable, individual tree protection cages are to be installed. Tree protection cages shall conform to the following minimum standards:

• Tree protection cages shall be no less than 48” in height

• Tree protection cages shall be no less than 12” in diameter

• Cages shall be constructed of welded wire fencing using galvanized or plastic-coated wire not less than 16ga

• Openings in the wire mesh not to exceed eight square inches, with no dimension greater than four inches

• “Chicken wire” fencing is prohibited

• Cages are to be supported by at least one post, fiberglass, metal, or wooden posts extending at least 12” into the ground and least 3’ above ground. Two posts are preferred on cages over 18” in diameter.

• Cages may be secured to the posts with wire ties or plastic zip ties

• All cages and posts are to be removed after five years

Option Three: Tree Tubes The use of tree tubes is strongly discouraged as the negative environmental, health, and social impacts of plastic use continues to worsen in the US. In cases where tree tubes are the only viable option, the following standards apply:

• Tubes shall be 48” in height

• Tubes shall be translucent in white or light green

• Tree tubes shall be supported by wooden or fiberglass posts

• Tubes are to be attached to posts at two points

• Perforated tree tubes are preferred

Option Four: Trunk guards For trees over 2” in diameter or greater than 6’ in height, trunk bark guards are to be installed to prevent deer from causing trunk damage. Bark guards shall conform to the following standards:

• Bark guards shall be constructed of rigid plastic mesh

• The use of flexible trunk wraps is prohibited

• Guards shall be at least 48” tall

• Guards shall be at least 4” in diameter

• Guards shall be secured with biodegradable string or twine at no fewer than three points

Figure 1: 48" tree protection cage supported by two 1" square posts

Signage

• The contractor shall provide no fewer than three signs, mounted to the tree protection fencing or on wooden posts.

• Signage shall include, at minimum, the following items:

o Project Name o Map with legend o Project narrative o Implementing and funding partner branding

Maintenance Requirements for Ecological Restoration on City-owned

Lands

Watering Restoration plantings shall be watered weekly through the first growing season. On weeks where more than 0.75” of rainfall occurs, watering is not required.

Invasive Species Control Failure to adequately suppress invasive species during the establishment phase may lead to failure of restoration efforts as plantings are crowded out by fast growing brush and vines. Restoration projects shall dedicate a portion of their budget to labor and materials for the mechanical removal of invasive species for a 5-year period.

The minimum acceptable requirements for invasive species management are as follows:

• Annual assessment of species composition at the restoration site to determine work needs.

• Hand crew invasive species removal conducted at no fewer than three intervals during the growing season o Emergence: manual removal or flame treatment of newly emerging seedlings and aboveground growth.

o Fruit development: manual removal of aboveground growth following the flowering period of invasive species but prior to the maturation of fruit. In situations where more than one invasive species is being managed this may involve multiple visits or may be done to coincide with the species most in need of management.

o Pre-dormancy: for perennial species, manual removal of aboveground growth to disrupt nutrient and sugar storage.

• Documentation of efforts, to include labor hours and work specifications, provided to the City of

Pittsburgh annually.

Removal of Tree Protection Tree protection fencing and cages shall be removed five years after installation. Tree tubes may be left in place until the tree grows enough to split them naturally

Appendix 1: DCNR Invasive Plant List The following Appendix is copied from the DCNR Invasive Plant List, available at:

https://www.dcnr.pa.gov/Conservation/WildPlants/InvasivePlants/pages/default.aspx (PA DCNR, ND.

Date accessed: 12/7/2022)

DCNR defines invasive plants as those species that are not native to the state, grow aggressively, and spread and dis-place native vegetation. Invasive plants are generally undesirable because they are difficult and costly to control and can dominate whole habitats, making them environmentally destructive in certain situations. Not all non-native plants become invasive. In fact, very few actually do.

The plants listed here have been determined by DCNR to be in-vasive on State Forest and State Park lands and may act aggressively in other parts of Pennsylvania. Some of the spe-cies listed below are only invasive in certain environmental conditions and there may be cases where they may be used with little environmental risk. This list was compiled through coordinated efforts between ecologists in Pennsyl-vania and other natural resource partners. New species cross state borders and some plants that have been here for decades may suddenly become invasive due to changing land uses, changes in weather or climate, or genetic rea-sons, so this list may change over time and will be updated periodically. This list is not regulatory. It is used to guide the management efforts of DCNR lands because of knowledge that these species can become invasive under the right environmental conditions. To learn more about invasive plants in Pennsylvania and how they can be controlled, visit www.dcnr.state.pa.us/forestry/plants/invasiveplants/index.htm.

Invasive plant species have been ranked in terms of the threat they pose to native plant communities.

Each rank is defined below:

Rank 1- Severe Threat. Exotic plant species that possess characteristics of invasive species and spread easily into na-tive plant communities and displace native vegetation. Includes species that are or could become widespread in Pennsylvania.

Rank 2- Significant Threat. Exotic plant species that possess characteristics of invasive species but are not presently considered to spread as easily and aggressively into native plant communities as those species listed as Rank 1.

Rank 3- Lesser Threat. Exotic plant species that spread in or near disturbed areas, and are not presently considered a major threat to undisturbed native plant communities.

Watch List- Exotic plant species that are severe problems in surrounding states but have not been widely reported in Pennsylvania, OR may naturalize and become a problem in the future and require more monitoring.

Vines Scientific Name Common Name Rank

Ampelopsis glandulosa Porcelain Berry 1

Celastrus orbiculatus Oriental Bittersweet 1

Humulus japonicus Japanese Hops 1

Lonicera japonica Japanese Honeysuckle 1

Persicaria perfoliata Mile-a-Minute 1

Pueraria montana var. lobata Kudzu 1

Vincetoxicum nigrum Black Swallow-Wort 1

Vincetoxicum rossicum Pale Swallow-Wort 1

Euonymus fortunei Wintercreeper 2 https://www.dcnr.pa.gov/Conservation/WildPlants/InvasivePlants/pages/default.aspx

Wisteria floribunda Japanese Wisteria 2

Wisteria sinensis Chinese Wisteria 2

Hedera helix English Ivy 3

Vinca major Bigleaf Periwinkle 3

Vinca minor Common Periwinkle 3

Akebia quinata Chocolate Vine Watch

Clematis terniflora Japanese Clematis Watch

Dioscorea polystacha Chinese Yam Watch

Herbs and Forbs

Alliaria petiolata Garlic Mustard 1

Conium maculatum Poison Hemlock 1

Fallopia japonica Japanese Knotweed 1

Fallopia sachalinensis Giant Knotweed 1

Fallopia X bohemica Hybrid Knotweed 1

Ficaria verna Lesser Celandine 1

Galega officinalis Goatsrue 1

Heracleum mantegazzianum Giant Hogweed 1

Lythrum salicaria Purple Loosestrife 1

Centaurea jacea Brown Knapweed 2

Centaurea nigra Black Knapweed 2

Centaurea stoebe Spotted Knapweed 2

Chelidonium majus Greater Celandine 2

Cirsium arvense Canada Thistle 2

Cirsium vulgare Bull Thistle 2

Hesperis matronalis Dames Rocket 2

Iris pseudacorus Yellow Flag Iris 2

Lespedeza bicolor Shrubby Bushclover 2

Lespedeza cuneata Chinese Bushclover 2

Pastinaca sativa Wild Parsnip 2

Perilla frutescens Beefsteak Plant 2

Rubus phoenicolasius Wineberry 2

Securigera varia Crown-vetch 2

Aegopodium podagraria Goutweed 3

Anthriscus sylvestris Wild Chervil 3

Artemisia vulgaris Mugwort 3

Butomus umbellatus Flowering Rush 3

Cardamine impatiens Narrowleaf Bittercress 3

Carduus acanthoides Spiny Plumeless Thistle 3

Carduus nutans Musk Thistle 3

Datura stramonium Jimsonweed 3

Epilobium hirsutum Hairy Willow Herb 3

Epilobium parviflorum Smallflower Hairy Willow-Herb 3

Hemerocallis fulva Orange Day-Lily 3

Lysimachia nummularia Moneywort 3

Pachysandra terminalis Japanese Pachysandra 3

Persicaria longiseta Bristled Knotweed 3

Stellaria media Common Chickweed 3

Amaranthus palmeri Palmer Amaranth Watch

Trees

Ailanthus altissima Tree-of-Heaven 1

Aralia elata Japanese Angelica Tree 1

Acer platanoides Norway Maple 2

Albizia julibrissin Mimosa 2

Alnus glutinosa European Black Alder 2

Paulownia tomentosa Empress Tree 2

Phellodendron amurense Amur Corktree 2

Phellodendron japonicum Japanese Corktree 2

Phellodendron lavallei Lavella Corktree 2

Pyrus calleryana Callery Pear 2

Tetradium daniellii Bee-Bee Tree 2

Broussonetia papyrifera Paper Mulberry 3

Morus alba White Mulberry 3

Acer ginnala Amur Maple Watch

Acer palmatum Japanese Maple Watch

Koelreuteria paniculata Golden Rain-Tree Watch

Quercus acutissima Sawtooth Oak Watch

Ulmus pumila Siberian Elm Watch

Shrubs

Berberis thunbergii Japanese Barberry 1

Berberis vulgaris European Barberry 1

Frangula alnus Glossy Buckthorn 1

Lonicera fragrantissima Sweet Breath Honeysuckle 1

Lonicera maackii Amur Honeysuckle 1

Lonicera morrowii Morrow’s Honeysuckle 1

Lonicera morrowii x bella Beautiful Honeysuckle 1

Lonicera standishii Standish Honeysuckle 1

Lonicera tatarica Tartarian Honeysuckle 1

Rhamnus cathartica Common Buckthorn 1

Rhodotypos scandens Jetbead 1

Rosa multiflora Multiflora Rose 1

Spiraea japonica Japanese Spiraea 1

Buddleja davidii Butterfly Bush 2

Elaeagnus angustifolia Russian Olive 2

Elaeagnus umbellata Autumn Olive 2

Euonymus alatus Winged Euonymus 2

Ligustrum japonicum Japanese Privet 2

Ligustrum obtusifolium Border Privet 2

Ligustrum sinense Chinese Privet 2

Ligustrum vulgare Common Privet 2

Viburnum dilatatum Linden Viburnum 2

Viburnum plicatum Doublefile Viburnum 2

Viburnum sieboldii Siebold Viburnum 2

Viburnum opulus Guelder Rose 3

Aquatic

Hydrilla verticillata Hydrilla 1

Myriophyllum aquaticum Parrot feather watermilfoil 1

Myriophyllum spicatum Eurasian Watermilfoil 1

Potamogeton crispus Curly Pondweed 1

Trapa natans European Water Chestnut 1

Typha angustifolia Narrow-Leaved Cattail 1

Typha x glauca Hybrid Cattail 1

Cabomba caroliniana Carolina Fanwort 3

Egeria densa Brazilian Water-Weed 3

Najas minor Brittle Waternymph 3

Nitellopsis obtusa Starry Stonewort 3

Hydrocharis morsus-ranae Common Frogbit Watch

Ludwigia grandiflora ssp.

Hexapetala

Large Flower Primrose Willow High

Watch

Nymphoides peltata Yellow Floatingheart Watch

Appendix 2: Restoration Species List The following species have been extensively trialed in the City and are recommended for use in restoration projects.

Appendix 3: Park Species List

Appendix 4: Prohibited Species List

Appendix 5: Planting Diagram, Level Sites

Appendix 6: Planting Diagram, Sloped Sites

Appendix 7: Plant Spacing Configurations Plants may be arranged in a grid or hexagonal configuration (not shown) at a spacing which meets the required stocking density for the site, or they may be planted in a block array where each tree is given the same amount of space on average. The more natural appearance and flexibility of the random block design is preferred.