100__Berryessa_Creek_Tree_Mitigation_Specifications.pdf

UPPER BERRYESSA CREEK

TREE MITIGATION PLANTING PROJECT

100% CONSTRUCTION SET: 4/1/16 SEED COLLECTION

WRA Inc., Project 19004 02925 - 1

SECTION 02925

SEED COLLECTION

PART 1 - GENERAL

1.1 SUMMARY

A. This section includes but is not limited to:

1. Site preparation.

2. Furnishing and installing seed.

3. Maintaining seeded areas until acceptance by the Landscape Architect.

1.2 SUBMITTALS

A. Seed Collection Report: Within 14 days of completion of seed collection, the Contractor shall provide a memo with the results of the seed collection effort. The memo shall include:

1. Date Collected

2. Botanical name of each species collected

3. Location collected for each species (provide hand drawn map, latitude/longitude, or detailed description)

4. Quantity of each species after removing poor quality seed

5. Describe any seed quality or quantity short-comings and provide a plan for meeting the required quantity of seed shown in the drawings. Any substitutions or deviation from the planting plans shall be clearly identified to the Landscape Architect. Upon rejection of any plant substitutions, new plant material shall be collected until all of the plant material is in compliance with the specifications as determined solely by the Landscape Architect.

1.3 QUALITY ASSURANCE

A. Plant species identification shall be in accordance with The Jepson Manual - Higher Plants of California, James C. Hickman, editor, University of California Press, Berkeley.

B. Acceptance Criterion for Materials and Workmanship: The Landscape Architect shall inspect all materials and workmanship for compliance with the plans and specifications. Acceptance of all materials and workmanship is at the discretion of the Landscape Architect.

PART 2 - PRODUCTS

2.1 MANUFACTURERS

A. None.

TREE MITIGATION PLANTING PROJECT

100% CONSTRUCTION SET: 4/1/16 SEED COLLECTION

WRA Inc., Project 19004 02925 - 2

2.2 MATERIALS AND FABRICATION

A. Species and Seed Quantities: Species and seeding quantities are specified on the planting plans in the plant legends.

B. Criterion for Accepting Seed:

1. See Tree and Shrub Planting Specification

PART 3 - EXECUTION

3.1 COLLECTION AND STORAGE

A. Seed or acorns shall be collected within the Coyote Creek watershed from wild trees not pollinated by nearby landscape trees. A map of potential seed collection locations will be provided upon request to the contractor by the Santa Clara Valley Water District.

Priority for seed collection is as follows: 1) Berryessa Creek Right of Way, 2) Coyote Creek Watershed, 3) approved alternative location. The Contractor shall inform the Owner at least 14 days in advance of any collection day in order to alert the Owner that the Contractor will be on-site.

B. Seed shall be collected within September 1 and November 30 of the year of planting.

C. Criterion for Acceptance of Acorns or Buckeye Seed:

1. Acorns shall have caps removed and shall not have damage to the base of the acorn.

2. Acorns shall not be cracked, desiccated, mal-formed, very small or have obvious weevil or other pest damage. Acorns that float or have already germinated shall be discarded. Other non-viable or damaged seed shall be removed from the collected seed according to standard industry practices.

D. Collected seed shall be stored in separate bags by species and collection date.

E. Collected seed shall be stored in open plastic bags in a refrigerator at refrigerator temperature to retard mildew and sprouting.

F. Collected seed shall be handled and stored until the time of delivery to ensure that viability is preserved to the maximum extent practical.

G. Collected seed shall be collected, handled, and stored according to the phytosanitary practices described in Technical Specification 02932 Nursery Plant Pathogen Prevention.

END OF SECTION

TREE MITIGATION PROJECT

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 1

SECTION 02931

PLANTING TREES AND SHRUBS

PART 1 - GENERAL

1.1 SUMMARY

A. Section includes (but is Not Necessarily Limited to):

1. Furnishing and installing trees and shrubs, including soil amendments, and mulch.

2. Furnishing and installing accessories such as wire cages.

3. Maintaining plants until acceptance by Landscape Architect.

4. Maintaining plants during guarantee period.

B. Related Sections:

1. Submittal Procedures, Section 01330.

1.2 SUBMITTALS

A. Soil test results: The Contractor shall submit a memorandum that contains the soil test results within 45 days of the award of the contract.

B. Mulch: Submit sample and manufacturer’s/ distributor’s analysis.

C. Nursery records: See Technical Specification 02932 Nursery Plant Pathogen Prevention

1.3 QUALITY ASSURANCE

A. Plant species identification shall be in accordance with The Jepson Manual - Higher Plants of California, James C. Hickman, editor, University of California Press, Berkeley.

B. Plant Establishment Guarantee: The Contractor shall guarantee the survival of all of the plants for this section for the duration of the guarantee period. The guarantee period shall be 365 days after completion of the planting and approval of the installation by the Landscape Architect. At the end of the guarantee period, the Contractor shall replace, at no additional cost to the Owner, plant material that is determined by the Landscape Architect to be either dead or in poor health. Subsequent replacement plant material shall be subject to an identical guarantee.

1. For acorn planting where multiple acorns are planted per planting hole, only one acorn per planting hole must be alive and in good health to satisfy the plant guarantee.

C. Acceptance Criterion for Materials and Workmanship: The Landscape Architect shall inspect all materials and workmanship for compliance with the Drawings

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 2 and special construction provisions. Acceptance of all materials and workmanship is at the discretion of the Landscape Architect.

D. Soil Test: Soil test shall be defined as the following tests and be performed by a certified soil and plant test laboratory:

1. Fertility – Half saturation percentage, pH, salinity, nitrate nitrogen and sodium.

2. Agricultural Suitability: saturated extract salinity, potassium, calcium, magnesium, boron, sodium, sulfate, SAR.

PART 2 - PRODUCTS

2.1 MATERIALS AND FABRICATION

A. Species, Size, and Spacing: The plant legends on the drawings indicate the species, size, and spacing requirements for this section.

B. Plant Quantities: The drawings contain estimates of the plant quantities required for this section. Plant quantities are provided as a convenience to the Contractor and do not supersede the quantities calculated directly from the drawings.

C. Soil Amendments: The Contractor shall add additional amendments to the soil amendment in accordance with the type and rates recommended by the soil test laboratory with the exception of any organic material. Organic material such as compost, paper pulp, wood chips, etc. shall not be incorporated into the soil in the planting hole. Organic mulch is acceptable as a top-dressing. These amendments shall be considered incidental and shall be provided at no additional cost.

D. Criterion for Accepting Acorns and Buckeye Seed

1. Acorns and buckeye seed shall be those collected as described in Specification 02925 – Seed Collection.

2. At the time of delivery, seed shall not have been stored longer than 120 days.

3. Acorns and buckeye seed shall not be partially filled seed, exhibit cracks, have evidence of weevil damage (holes), or other pest damage.

4. Acorns shall not have caps or other non-seed material.

5. The seed shall be supplied as single species as indicated on the plans.

a. Seed bags for hydroseed mix shall be labeled and labels shall indicate certified net weight, date of collection, and certified guarantee of analysis including the composition, purity, germination percentages, and percent weed seed.

E. Criterion for Accepting Containerized Trees and Shrubs:

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 3

1. The container size shall be at least as large as indicated in the plant legends on the drawings. Plants shall not be rejected if supplied in containers larger than specified.

2. Upon removal of the plants from the containers, the soil/root masses shall be the size of the specified container size. If the soil/root masses are substantially smaller than the specified container size and loose soil exists on the bottom of the containers, the plants shall be rejected since they have not been grown sufficiently long in the containers to root into the soil contained therein.

3. Should spiraling primary woody roots exist on the outside of the soil/root mass upon the removal of the plants from the containers, the Contractor shall be instructed to either cut these roots or separate and spread them out from the soil/root mass prior to planting.

4. If growing, the plants shall appear healthy with no leaf spots, leaf damage, leaf discoloration, chlorosis, leaf wilting or curling, or evidence of insects on the leaves.

5. If dormant, woody plants shall have an abundance of well-developed terminal buds on the leaders and branches, and have a cambium, which is light green to yellowish green in color.

6. The soil and root mass of containerized plant material shall be moist upon delivery to the job site. Plants that are dry or lightweight shall be rejected. If not planted immediately after delivery to the job site, the plants shall be stored in a area that is not exposed to direct sun or wind and shall be maintained moist, through periodic watering, until time of planting.

7. The container stock shall be Coyote Creek watershed ecotypes.

F. Tree and Shrub Growth Form: Contract grown trees and shrubs shall be of a natural form such that they have an irregular or asymmetrical crown and lack a strong leader. Nursery stock shall be selected for the natural form whenever possible.

G. Soil Amendment: Soil amendment for trees and shrubs shall be comprised of soil from the planting hole and soil amendment as recommended by the soil testing lab.

H. Mulch: Organic weed-free mulch with a one-half (½) inch minimum and three (3) inch maximum particle size and low salt content. Mulch shall not be made of plant materials with allopathic chemicals or root pathogens, such as Phytophthora.

Mulch shall be made from recycled, kiln-dried wood products. Submit sample and mulch analysis for approval by Landscape Architect.

I. Planting Staples: When specified, plant staples shall be seven (7) to nine (9) gauge erosion control staples.

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 4

J. Planting Accessories: As shown on the drawings.

PART 3 - INSTALLATION

3.1 INSTALLATION

A. Soil testing: One four-point composite soil sample from each planting area shall be collected and analyzed by a certified soil and plant testing laboratory.

1. The composite soil sample should consist of at least four sub samples taken from the planting area. Equipment used for sampling shall be clean and free of deleterious materials.

2. The sample amount should be sufficient for the analysis selected, per the instructions of the certified soil testing laboratory.

3. Sub-samples should be collected of an equal amount at each sub-sample site and should be representative of the anticipated root zone which includes soil from a depth of one to twelve inches.

4. Samples shall be placed in a plastic bag, bucket, or pot and descriptively labeled for reference. Sub-samples may be mixed into the same container.

B. Planting Window: Trees and shrubs shall be planted between October 15th and December 31st unless approved by the Landscape Architect.

C. Layout: Trees and shrubs shall be located in accordance with the planting plans.

The Contractor shall use pin flags to mark the location of the trees and shrubs in the field for review and approval by the Landscape Architect prior to the installation of the trees and shrubs. The Contractor may demonstrate a typical layout of trees and shrubs for each of the various sections of the riparian plantings and request that the Landscape Architect review and approve these typical layouts prior to flagging all of the trees and shrubs. A demonstration layout shall consist of a thirty-foot wide area that extends from the edge of the access road to the edge of the right of way.

D. Planting Holes: Planting holes for trees and shrubs shall be twice the diameter of the container size and equal in depth to the container size. Planting hole shall be flat bottomed. Plants grown in flat-bottomed containers shall not be planted in V-shaped holes that result when using a dibble or pointed spade in the planting operation. Otherwise the air pockets at the bottom of the holes may lead to plant mortality.

E. Soil Amendment: Soil amendment shall be mixed with native soil and backfilled into the planting hole. Replaced soil shall be watered in and boot compacted to eliminate air pockets. The leftover soils from creating the planting holes shall be used to create the watering basin and/or raked about the plants as not to alter the surrounding grades significantly.

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 5

F. Planting Trees and Shrubs: Refer to the applicable planting details on the planting plans for clarification of planting parameters

G. Accessories for Trees and Shrubs: Install plant accessories according to details on the drawings. Plant accessories are indicated in the plant legends on the drawings.

H. Watering: Newly planted trees and shrubs shall be watered regularly to prevent plant material from wilting. Watering shall be incidental to this item.

I. Mulch: Provide mulch as indicated in the planting details.

J. Team planting by several people, where one person performs a single task, is encouraged.

K. Upon completion of work, the Contractor shall remove all materials, tools, rubbish and debris associated with this work.

L. Plant Pathogen Control Best Management Practices:

1. Objective: To avoid contaminating restoration sites with exotic pathogenic Phytophthora species or other plant pathogens during activities related to planting.

2. Definitions:

a. Planting area: area where plant material is being planted, typically for habitat restoration, erosion control, or other purposes. Plant material may include nursery stock that has been produced under Santa Clara Valley Water District (SCVWD) Nursery Contract Specifications, vegetative propagules such as cuttings or divisions, or seed.

b. Planting site: an individual planting basin or other spot, typically no larger than one square yard, where an individual plant or several grouped plants will be installed.

c. Nursery stock: refers to container nursery stock that was produced under clean propagation conditions described in the SCVWD Nursery Contract Specifications and has passed any required testing. Such material is assumed to be free of exotic Phytophthora to the maximum degree attainable.

d. Job site: The boundary of the job site will be determined by SCVWD for each planting site. Typically, the job site includes the planting area, staging areas, parking areas, and access roads within and leading to these areas.

3. Overview: Three general routes for the spread of Phytophthora and other soilborne plant pathogens are addressed in these BMPs. These routes include (I) contamination of planting inputs, including clean nursery stock and other materials installed at the site, (II) introduction of pathogens to a planting

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 6 area, and (III) potential movement of undetected contamination within the planting area.

a. Prevent contamination of clean nursery stock or other clean plant materials:

Planting materials shall be protected from potential contamination from the point that materials leave the production nursery or collection site until materials they have been planted. Note that container nursery stock has a high risk of infection by Phytophthora species if exposed to these pathogenic agents. Exclusion of these pathogens provides the only viable option for maintaining nursery plants free of Phytophthora.

i. Nursery plants shall be transported on or in vehicles or equipment that has been sanitized before loading the stock. Truck beds, racks, or other surfaces will be cleaned (swept, blown with compressed air and/or power washed as needed) to be free of soil and plant detritus. Cleaned surfaces shall be sanitized by (a) spraying with 70% ethyl or isopropyl alcohol, (b) rinsing with diluted bleach (at least 0.525% NaOCl) or (c) rinsing with a quaternary ammonium solution used at the concentration and exposure time described on the product label. See “Approved procedures” in the SCVWD Nursery Contract Specifications for further information about sanitizing tools and surfaces.

ii. Delivered nursery plants that will be held before planting shall be transferred to cleaned and sanitized raised benches and maintained as described in the SCVWD Nursery Contract Specifications (see provisions 16-56 and others if applicable).

iii. At the job site, plants shall be handled to prevent contamination until delivered to each planting site. Nursery stock shall not be staged on the soil or other potentially contaminated surfaces except that plants may be placed on the soil surface at their specific planting sites.

iv. Keep plants in sanitized vehicles or on sanitized carts, trailers, etc. until delivered to their planting sites if possible.

v. If it is necessary to offload plants at the job site, plants may be placed on clean waterproof plastic tarps or other clean, sanitized surfaces. If tarps are used for holding plants, one surface will be dedicated for contact with nursery stock and will be cleaned and sanitized as needed to maintain phytosanitary conditions.

vi. On-site or off-site collection of plant materials including seed and cuttings shall be conducted as described under “Clean planting materials” (provisions 1-9) in the SCVWD Nursery Contract Specifications.

vii. Washing, soaking, or irrigation of plant material shall be conducted using clean water sources as specified in SCVWD Nursery Contract

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 7

Specifications 16-18. Untreated surface waters shall not be used for these purposes.

viii. Mulch, compost, soil amendments, inoculants and other organic products shall be pre-approved for use before delivery to the planting site. Materials shall be free of pathogen contamination due to composition, manufacturing conditions, or through effective heat treatment and subsequently handled and maintained in a manner to prevent contamination. If appropriate, testing may be required as specified by SCVWD. At the job site, delivered materials shall be handled to prevent contamination until delivered to each planting site in the same manner specified for plant material (bullet # I.3, I.4, I.5 above).

ix. All other materials to be installed at the site shall be of new material that has not been stored in contact with soil or other potentially contaminated materials. This includes irrigation supplies (such as pipe, fittings, valves, drip line, emitters, etc.), erosion control fabrics, fencing, stakes, posts, and other planting site inputs.

b. Prevent contamination of planting area by infested soil or plant debris from other locations.

Phytophthora contamination can be present in agricultural and landscaped areas, in commercial nursery stock, and in some infested native or restored habitat areas. Contamination can be spread via soil, plant material and debris, and water from infested areas. Practices are based on the SCVWD’s approved BMP for Plant Pathogen Control at Contaminated Sites and Sensitive Sites, with additions specific to planting operations:

Prior to entry at a planting area:

i. Vehicles, equipment and large tools must be thoroughly cleaned before arriving at the planting area.

a) Compliance with this provision is achieved by demonstrating that the vehicle or equipment has been cleaned at a commercial vehicle or appropriate truck washing facility.

b) Equipment must be free of soil and debris on tires, wheel wells, vehicle undercarriages, and other surfaces. (A high pressure washer and/or compressed air may be used to ensure that soil and debris are completely removed).

c) The interior of equipment (cabs, etc.) must be free of mud, soil, gravel and other debris (interiors may be vacuumed or washed).

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 8

ii. Foot wear and small tools must be thoroughly cleaned before arriving at the planting area. This includes hand-held garden hoses, hose nozzles, quick couplers and irrigation wands.

a) Shoe soles must be free of debris and soil. (Water, a stiff brush, screwdriver or similar tool can be used to remove soil from shoe treads).

b) Once soil or debris have been removed, an appropriate sanitizing agent of ethyl or isopropyl alcohol (at least 70% concentration) must be used to kill pathogen spores which may be present on boot soles or tools (sanitizing agent may be applied by using spray bottles filled with alcohol to thoroughly wet the surface). Boot soles and hand tools must be sprayed with enough alcohol that surfaces are fully coated and wet. (Brushes and other implements used to help remove soil will be cleaned with alcohol after use.)

iii. At the start of each work day at the job site, worker clothing shall be clean (laundered) and free of mud, soil or detritus.

iv. Gloves must be new (if disposable) or laundered / sanitized at the start of each work day. Non-disposable gloves should be made of or coated with material such as nitrile that can be sanitized with alcohol.

v. Vehicles should stay on established roads whenever possible.

vi. Travel on unpaved roads should be avoided when such roads are wet enough that soil will stick to vehicle tires and undercarriages.

c. Prevent potential spread of contamination within planting areas.

Planting operations have the potential to quickly spread Phytophthora contamination throughout an entire planting area. Good working practices shall be followed at the job site to minimize the likelihood that undetected contamination will be spread. It is not possible to guarantee that every portion of a planting area is free of Phytophthora contamination. Areas with higher risk of contamination include areas adjacent to planted landscaping, areas with existing or recently removed woody vegetation, and areas directly along watercourses. Areas with low risk of contamination include those with only grassy vegetation or where surface soils have been removed. SCVWD may designate specific portions of a planting area as having high or low risk of contamination.

i. Before entering the job site, field workers shall receive training that includes information on Phytophthora diseases and how to prevent the spread of these and other soil borne pathogens by following approved phytosanitary procedures. Contractors shall provide documentation that such training has been provided.

100% Construction Document Set: 4/1/16 PLANTING TREES AND SHRUBS WRA Project No. 19004 02931 - 9

ii. Conduct planting operations under conditions that allow for adequate decontamination of equipment, tools, gloves, and shoes. Unless absolutely necessary, avoid planting under wet conditions or when soil is muddy.

iii. Phase work to minimize movement between areas with high and low risk of contamination. Where possible, complete work in low risk areas before moving to higher risk areas. Alternatively, restrict personnel to working in either high or low risk areas exclusively to reduce the need for decontamination.

iv. Minimize unnecessary movement of soil and plant material within the planting area, especially movement from higher risk to lower risk areas.

v. Clean soil and plant debris from large equipment and sanitize hand tools, buckets, gloves, and footwear when moving from higher risk to lower risk areas or when moving between spatially separated portions of the planting area.

vi. Brush off substantial soil contamination from tools, and gloves when moving between successive planting sites to prevent repeated collection and deposition of soil across multiple sites.

vii. Avoid contaminating clothing with soil during planting operations. Use nonporous kneeling pads that are cleaned between planting sites if kneeling is necessary.

viii. When possible, plant nursery stock from a given block in the same local area rather than spreading it widely. If a problem is associated with a given block of plants, it will be easier to detect and deal with it if the plants are spatially grouped.

ix. All other materials to be installed at the site (irrigation equipment, erosion control fabric, fencing, etc.) shall be handled to prevent movement of soil within the site, especially movement from higher risk to lower risk areas. Materials should be kept free of soil contamination by maintaining them in sanitized vehicles or on sanitized carts, trailers, etc., or stockpiling in elevated dry areas on clean tarps until used.

TREE MITIGATION PLANS

100% Construction Document Set: 4/1/16 02932 – 1 WRA, Inc., Project 19004

SECTION 2932

NURSERY PLANT PATHOGEN PREVENTION

PART 1 – GENERAL

1.1 Summary

A. Section Includes (but Is Not Necessarily Limited to):

1. This document describes the practices required to produce nursery plants that are free from exotic Phytophthora species to the degree possible. The nursery environment is highly favorable for the reproduction and spread of these pathogens. A thorough, integrated systems approach to clean plant production is needed to produce plants that have a minimal risk of being infected or infested with Phytophthora. The outline of a clean production system described here is based on the use of clean starting components (plant propagules, containers, potting media, water) that are maintained using clean production practices. The goal of these specifications is to prevent the introduction and spread of Phytophthora into the material produced by the nursery. Documentation of practices followed throughout the production cycle, including monitoring and testing conducted as part of quality assurance, is required to provide a basis for certifying compliance with the specifications.

2. These specifications provide an overall outline for producing container-grown plants free of Phytophthora species, but do not cover every practice or contingency that may arise in nursery plant production. A systems approach to clean plant production takes constraints and properties of the production system into account. Multiple approaches may be used to meet clean production standards. Nursery growers are responsible for adopting practices that address additional risk factors (aka critical control points) that may exist in their nurseries.

Suppliers are referred to the “Safe Procurement and Production Manual: A Systems Approach for the Production of Healthy Nursery Stock,” http://grunwaldlab.cgrb.oregonstate.edu/sites/default/files/SafeProduction.pdf for further discussion of using a systems approach. It is expected that nurseries will at minimum observe the BMPs described in Chapters 3-9 of that document for all planting stock. In the event that any practice described in the above document is less stringent than specific practices or procedures described below, the practices described herein shall be followed.

3. The Owner’s objective is to avoid contaminating restoration sites with exotic pathogenic Phytophthora species. To this end, the Owner will not accept for planting any block of plants that tests positive for Phytophthora species and may reject any or all plants from the same batch or related batches if the source and extent of contamination is not determined. It is in the best interest of nursery contractors to closely adhere to specifications and to thoroughly document procedures and practices followed for all plants grown under contract to avoid possible rejection of plant material.

100% Construction Document Set: 4/1/16 02932 – 2

B. Definitions

1. Batch – a group of plants with a common risk profile with respect to potential for contamination in the propagation process. Generally, a group of plants of a single species with a common source of propagative material that is started at the same time using the same potting media (composition, treatment, handling). Plants within the batch are normally handled in the same way after potting and may or may not be spatially grouped (see block).

2. Related batches are those that share one or more common risk factors (e.g., same potting media batch but different propagative material or date of planting).

If a Phytophthora detection is made within a given plant batch, that batch and related batches are considered potentially contaminated until the source of contamination can be determined via testing and records.

3. Block – a spatially grouped array of plants on a bench, normally from a given batch. A block of plants normally has a common risk profile with respect to potential for contamination associated with nursery practices after potting (e.g., accidental introduction via contaminated hands or tools) related to potential for pot to pot splash. If a Phytophthora detection is made within a given plant block, that block and adjoining blocks are considered potentially contaminated until proven otherwise via testing and records.

4. Clean — sanitized, sterilized, or new (e.g., plastic pots), and maintained in a way to prevent subsequent contamination.

5. Clean production area — Entire nursery production area or fenced, posted, separated portion of a nursery producing plants following the contract specifications outlined in this document.

6. Clean production system — an integrated system for producing plants that are free of soil borne Phytophthora species as specified in these contract specifications.. Plants produced following these specifications are also likely to be free of most significant soil-borne pathogens, but will not necessarily be free of all pathogens and pests.

7. Contaminated or potentially contaminated — any surface or material that is not sterile or freshly sanitized. The ground, soil or potting media that has not been sterilized, used pots, plants (including any not produced following these specifications, including all plants from other nurseries), and anything that has been in contact with these should be considered as potentially contaminated.

8. Infected – a plant that has a pathogen that has grown into its tissues. Infections normally involve internal colonization of plant tissues and are not eliminated via surface treatments such as disinfectant dips. Only plants or plant parts are referred to as infected (see also infested).

9. Infested – containing or superficially contaminated with propagules of a pathogen. Soil, potting media, tools, and surfaces may be infested with spores of pathogens (see also infected).

10. Phytosanitary — the condition of being free of plant pathogens; as an adjective it describes techniques or practices that prevent materials from being infected or infested with plant pathogens (e.g., phytosanitary measures).

11. Potting media — substrate used for germinating, rooting, or growing plants in containers. Typically a mixture of organic and inorganic materials.

12. Sanitized — cleaned to remove debris and soil particles and subsequently treated with a disinfecting/disinfesting agent such as sodium hypochlorite

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(chlorine bleach), quaternary ammonium compounds, or alcohol in a manner that destroys any residual plant pathogen propagules.

13. Sterile (in regards to potting medium, containers, etc) — free of plant pathogens by virtue of source materials (e.g., new plastic pots) or treatment (e.g., sanitized containers, potting media heat treated according to standards that kill plant pathogens, and maintained in a manner to prevent contamination) but not necessarily free of all micoroorganisms.

1.2 Submittals

A. Nursery shall maintain records needed to verify compliance with clean production practices and facilitate traceability of materials during the production process as described in Part 3.

B. Sample log templates will be provided by Owner

1.3 Quality Assurance

A. This specification describes approved procedures and methods. Note that alternative methods may be acceptable if the Contractor can provide published data or other valid test results that document that the methods are effective. Alternative methods must be approved by the Owner.

B. Inspection and testing

1. Identify potentially diseased material at the earliest possible stage so it can be culled in a timely manner to prevent further contamination. Note: compliance with steps listed above should minimize the need for the testing procedures described below. If Phytophthora contamination occurs, there will be a need for re-evaluation of compliance with above steps, and a search for possible avenues of contamination.

2. All plants shall be visually inspected at least weekly for poor plant growth or appearance.

3. Dead, dying, or poor-performing plants shall be inspected and possible cause(s) shall be identified to the extent feasible. The number and locations of affected plants shall be recorded.

4. Root systems of poor performing, dying, or dead plants shall be inspected for evidence of root or crown decay. If possible root decay is detected, plants shall be tested for the presence of Phytophthora, or other pathogens if deemed appropriate, following an approved protocol listed below. Cost of required testing shall be negotiated between Owner and the contractor prior to finalizing contract.

5. Dead and dying plants and any other plants with possible root disease symptoms shall be culled, tested, and subsequently destroyed. The positions of culled plants on a bench should remain unoccupied at least until testing has been completed so that spatial patterns of disease can be determined.

6. Any removal of suspected diseased or rejected plants from the clean production area must be conducted in a manner that will prevent contamination of other remaining plants. In particular, water or potting media from removed containers shall not be allowed to fall into other containers or clean surfaces.

7. The bench surfaces beneath any plant testing positive for Phytophthora shall be sanitized before any other plant material is placed there.

8. Sentinel plants (hosts that are highly susceptible to Phytophthora infection) shall be used as a screening tool for possible Phytophthora infection in the nursery, 100% Construction Document Set: 4/1/16 02932 – 4 and shall be incorporated into each block of Owner nursery stock as described under approved procedures below. Sentinel plants shall be inspected along with ordered plants. If symptoms of decline or plant death are observed in sentinel plants, they shall be immediately removed from the block and tested for Phytophthora following an approved protocol.

9. All nursery areas involved in production for the project shall be available for inspection at random by an Owner’s representative to ensure compliance.

During the inspection, representatives may inspect roots of any plants and may perform baiting of effluent from nursery plants (irrigation runoff) to test for the presence of Phytophthora species in plant material.

10. A positive result from testing or symptomatic plants (ordered or sentinel) will require an in-place quarantine of the block tested as well as any other stock within 7 ft. A smaller zone may apply if barriers are present that prevent horizontal splash between adjacent blocks. Follow-up testing of adjoining blocks of plants and other plants from the same and related batches will be required.

11. Upon a single positive Phytophthora detection within a block, all pots within a 1 ft radius of the edge of the affected container shall be removed from the block and subjected to further testing. If additional detections are made in this sample, all containers within 7 ft from the edge of the detection shall be rejected and must be removed from the clean production area. A smaller zone may apply if barriers are present that prevent horizontal splash between adjacent blocks. Blocks adjoining the removed plant will be quarantined in place pending further testing.

12. The quarantine of plants adjacent to a detection will be lifted if an approved testing protocol (bench level effluent baiting) is negative for two successive tests conducted at least 2 weeks apart. Additional testing may be required before plant acceptance.

PART 2 - MATERIALS

2.1 Plant Material - Start with plant material that is free from infection or external contamination by Phytophthora species as well as other possible pathogens.

A. Seeds, cuttings, and other plant propagules shall not be collected from the vicinity of past restoration plantings or other areas where Phytophthora infestations are known, suspected, or likely. In the unusual situations where this is not possible (e.g., for rare populations), seed or tip cuttings may be collected if collected at a distance of 1 m or more above the ground. Material propagated from such sources shall be kept segregated from plant material propagated from pathogen-free areas. Protocols for seed collection from diminutive species such as delicate annuals or those with mat-forming habits (with height stature less than 1 m above the ground) shall minimize the risk of potential Phytophthora contamination and shall be approved by Owner in advance.

B. Owner shall evaluate and approve plant propagule collection areas in advance and may require testing of proposed sites. Cost of required testing shall be negotiated between Owner and the contractor prior to contract agreement.

C. Plant propagules, including seeds, fruit, and vegetative propagules shall be free of apparent disease symptoms, including sporulation, decay, and atypical discoloration.

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D. Phytosanitary procedures shall be followed when collecting seed, cuttings, and propagules. All propagules shall be collected with clean hands/gloves and equipment (pruning shears, etc.) and placed in new bags/envelopes and new or clean containers.

E. Seed/fruit shall not be collected directly from the ground. Seed can be knocked onto clean tarps placed on the ground. An exception can be made upon prior authorization by the District. Exceptions may be granted based on the following criteria: 1). Site not known or not likely to be contaminated; 2). Seed has recently dropped on dry ground or leaf litter. Ground-collected seed will be kept separate from other collected material during seed processing and outplanting.

F. Vegetative materials (stems, rhizomes, roots, divisions) shall be surface-sterilized following an approved procedure (see Approved Procedures section below “Surface sterilization for vegetative materials [stems, rhizomes, roots, divisions]”) as soon as practicable after collection. Additional surface sterilization may be needed before propagation if material is stored for an extended period.

G. Plant material used for propagation shall be stored in clean or new containers in an area that is segregated from potentially contaminated areas and is managed to maintain phytosanitary conditions. Storage conditions shall minimize the potential for cross-contamination between different collection sites and species.

H. Seed collected in bulk shall be sorted and cleaned of debris before storage or stratification. Where compatible with seed storage and germination requirements, seed should be treated using heat or appropriate disinfecting/disinfesting chemicals to eliminate seedborne pathogens or external contamination. Seed treatment may be omitted for species where it is impractical or the risk of seedborne or contaminating pathogens is negligible. Contractor shall provide Owner a list of species whose seeds are not treated and the justification for omitting treatment. .

I. Plants vegetatively-propagated from belowground materials may harbor internal infection and shall be kept segregated in the nursery from plant material propagated from seed or tip cuttings and from other vegetatively propagated material from different localities. The goal is to avoid introducing pathogens, including pathogens that may be endemic to a given site, to new areas or native plant populations via plants that become infected in the nursery.

2.2 Clean containers

A. Use only clean, sterile pots/flats/containers to eliminate these as a potential source of pathogens.

B. New pots/flats shall be stored and handled to prevent contamination before use (i.e., no contact with potentially contaminated surfaces, water, or soil).

C. Used pots/flats must be cleaned of prior potting media and plant material and sanitized following an approved procedure (see Approved Procedures section below “Sterilization of recycled containers”) and subsequently stored and handled to prevent contamination before use.

D. Bins for holding sterile potting media shall be sanitized before refilling.

2.3 Clean potting media

A. All potting media shall be heat treated unless components are certifiably pathogen free and have been handled and stored in a manner that precludes contamination.

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B. A sterile germination media and sterile potting media will be used; media may be heat treated using aerated steam or other approved procedures (see Approved Procedures section below “Sterilization of potting media”).

C. Commercial vermiculite and perlite in sealed bags from the primary manufacturer or bagged potting media that has been heat-treated do not require heat treatment if handled in a manner to prevent contamination.

D. All sterilized potting media shall be handled in a manner to prevent contamination with non-sterilized media or other sources of contamination and shall be stored in clean, covered bins.

2.4 Clean water

A. Use only uncontaminated, appropriately treated water for irrigation. Surface waters, especially recycled nursery runoff, are known sources of Phytophthora contamination.

B. Water used for irrigation shall be from treated municipal water supplies or wells and delivered through intact pipes. If recycled water is used, it must be tertiary-treated municipal recycled water.

C. If well water is used, wellheads shall be protected from contamination by surface water sources.

D. Untreated surface waters and recycled nursery runoff shall not be used, and plants shall not be held where potential contamination from such sources is possible via splash, runoff, or inundation

PART 3 – EXECUTION

3.1 Clean production practices

A. Prevent contamination of initially clean plant materials by consistent, comprehensive phytosanitary working practices.

B. Irrigation wands, nozzles, hose ends shall be kept free of contamination by being hung on a clean hook or rack least 3 ft above the ground. The same standard applies to any portion of a hose that may come in contact with or will be held over plants or benches during use. If allowed to contact the ground or other potentially contaminated surfaces or if otherwise contaminated, these shall be sanitized before use.

C. Tops of growing benches must be a minimum of 2 ft above the underlying surface (3 ft is preferable) to minimize the risk that water splashed from that surface will contact containers.

D. Benches shall have a surface of expanded wire mesh or similar to prevent water movement between pots. Plywood, wood pallets or similar solid surfaces that allow water to pool or run laterally are not acceptable.

E. Irrigation shall be conducted in a way to minimize splash of potting media between containers.

F. Surfaces underneath benches shall be managed to prevent puddling of water, minimize potential for splash, and remain free of weedy vegetation.

G. Clean and sanitize benches prior to placing new or sanitized pots on them.

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H. Plant stakes, irrigation emitters and all other items placed on or in pots shall be new or freshly sanitized before use.

I. Container stock may not be placed on the ground at any time during the production period. Stock that accidentally contacts the ground or other unsanitized surfaces shall be removed from the clean production area.

J. Items (including workers’ gloves or hands) that have been in contact with the ground or other potentially contaminated surfaces or materials shall be sanitized before being placed in contact with clean plant materials, pots, soil, or benches.

K. Owner stock shall be maintained in clean production areas isolated from any other plants at the nursery or adjacent properties that are not maintained according to these specifications. Isolation shall prevent movement of water, soil, plant material, pots or other potentially contaminated materials into the designated clean area.

L. Clean production area shall be separated by a buffer of no less than 20 ft from non-clean areas and shall be bounded by a fence or other physical barrier to prevent direct movement of personnel or equipment into the clean area without passing through a designated decontamination area. A buffer of less than 20 ft may be acceptable if the clean production area is surrounded by a solid wall (e.g., greenhouse wall).

M. The clean production area shall be identified by signage at all access points that specify decontamination procedures required before entry and working practices required.

N. Personnel entering clean production areas shall sanitize shoes, hands, gloves, tools, carts, and other equipment that may serve as a source of contamination. Clothing should be clean (laundered) and free of mud, soil or detritus. Dedicated coveralls or aprons laundered daily may be necessary for specific nursery areas or activities to minimize the risk of cross-contamination.

O. Where feasible, separate tools and equipment should be assigned to the clean production area for exclusive use there. Tools and equipment shall be sanitized at intervals as appropriate to prevent cross contamination.

P. Nursery workers shall be trained in approved phytosanitary procedures and follow the procedures at all times. Training shall be conducted before workers commence working with Owner stock and at least annually thereafter.

Q. No use of chemical fungicides or phosphites (including use of fertilizers containing phosphite salts) is allowed on Owner stock.

R. Use of biological control agents (e.g., soil bacteria or fungi) or other microbial additives applied to plants or potting media must be approved by Owner. All such inoculants need to be certified as free of plant pathogens. The use of such agents is discouraged unless there are adequate data showing a lack of adverse effects when these agent are released into natural environments. Use of products as biofungicides (i.e., to suppress disease expression in infected plants) is not allowed.

S. Plants should be arranged with adequate spacing between pots and blocks of plants to minimize potential for cross contamination and to minimize the size of blocks that may need to be eradicated if a spot Phytophthora infestation is detected. Separation distances to prevent potential cross contamination are related to the potential for water splash, which can be as far as 1 to 2 m from large rain drops (example separation distance needed is 1 m). Smaller distances (for example, 50 cm) will apply where measures are taken to prevent splash between pots or groups of plants.

For example, solid barriers, such as clear acrylic sheet, could be used to separate adjacent blocks on a bench.

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3.2 Surface sterilization for vegetative materials (stems, rhizomes, roots, divisions)

A. Sodium hypochlorite dip: Propagules should be brushed or rinsed to remove soil or other surface contaminants. Propagules are immersed in a freshly diluted bleach solution (0.525% to 0.6% NaOCl, or approximately 15/1 chlorox solution) for a minimum of 1 minute, followed by a rinse with clean noncontaminated water.

Concentrations of sodium hypochlorite vary in available bleach products, so the concentration in any given product should be checked before preparing solutions.

3.3 Sterilization of recycled containers

A. Chemical sanitizers - Various sanitizing chemicals that have been shown to be effective against Phytophthora propagules may be used. However, sanitizers with long-lasting residues that can be transferred to the field are not acceptable.

Contractor shall provide Owner documentation for materials used (other than sodium hypochlorite) to support efficacy and environmental safety.

1. Containers should be brushed or rinsed to remove as much potting media as possible before treatment.

2. Containers must be unstacked or loosely stacked so that the solution can circulate freely to all portions of the pots.

3. Sanitizing solutions shall be freshly made or tested to ensure target concentrations.

4. Containers should be fully immersed in the sanitizing solution for at least the minimum specified time before removing to rinse or dry.

B. Sodium hypochlorite: Containers are immersed in a freshly diluted bleach solution (at least 0.525% NaOCl) for a minimum of 5 minutes. Solutions must be made fresh daily and replaced if contaminated with substantial amounts of organic debris.

Chlorine concentrations should be tested before reuse (e.g., using commercial test strips) and shall be no lower than 2000 ppm in the solution being used.

C. Quaternary ammonium compounds: The product must be used at the concentration and exposure time described on the product label. Concentration should be tested before reuse (e.g., using commercial test strips) and replenished or replaced in accordance with label specifications to attain the required concentration.