holyoutlaw: (me meh)

In June of 2014, Friends of North Beach Park received a $500 stewardship grant from the Puget Sound Chapter of the Washington Native Plant Society.

The main body of this chapter was written in summer of 2014. The “Addendum” section, following “Plant List” below, was written in November 2014, after some work had been done.

Purpose of grant

The purpose of the grant is to help rebuild the wetland basins of the park into a scrub-shrub plant community, with trees surrounding the wetlands to stabilize the upland slopes. The planting pallet will follow recommendations for the reference ecosystem, riparian forest and shrubland.

The replanting will be done in phases, using obligate wetland plants to begin holding the soil, followed by reintroducing woody plants to build deeper root structures.

Timeline (projected)

The timeline below was written in summer of 2014.

  • September: Invasive removal in the wetlands. This will be done by small groups of forest stewards. Care will be taken not to overclear an area and not to disturb the soil structure too much.
  • Early October: installation of obligate wetland plants. This is done just prior to rain return, so the ground is relatively stable. The work will be done by experienced forest stewards.
  • Late October: installation of facultative shrubs and woody plants at the wetland borders. This work can be done by volunteers during a regular Friends of North Beach Park work party.

For the timeline as the project is being executed, please see “Addendum,” below.

Plan

The work will be centered on the social trail dividing Headwaters Bowl Subarea B and Central Valley Subarea B. See Figure 1, below.

Figure 1: Area of work for the Stewardship Grant.

The projected work area for the WNPS Stewardship Grant.

The projected work area for the WNPS Stewardship Grant.

The stream will be the northern boundary. In the Central Valley, the southern boundary will be the south loop social trail. In the Headwaters Bowl, the southern boundary will be the wetland border established by Doug Gresham in 2011. This is the entire area referred to as “Central Valley Subarea B” and the western edge of the area referred to as “Headwaters Bowl Subarea B.” The actual work area will be smaller than illustrated above.

The planting is intended to increase diversity and density in three locations:

  • Mixture of shrub and herbaceous plants streamside.
  • Herbaceous plants in seeps.
  • Shrubs at the toe of the slopes, above the seeps.

Headwaters Bowl Subarea B

Streamside

The substrate of the stream in this location is mostly silt and fine sand, with occasional patches of small cobbles where the channel has narrowed.

There is a large Thuja plicata (Western red-cedar) stump in the stream, covered with moss and hosting numerous Vaccinium parvifolium (Red huckleberry). This could host some Cornus canadensis (Canadian dwarf dogwood) but would be unlikely to support Tsuga heterophylla (Western hemlock).

Plants already growing streamside (based on a visual survey):

  • Rubus spectabilis (Salmonberry)
  • Lysichiton americanum (Skunk cabbage)
  • Oenanthe sarmentosa (Water parsley)
  • Carex amplifolia (Broad-leafed sedge)
  • Polystichum munitum (Sword fern)
  • Athyrium filix femina (Lady fern)
  • Urtica dioica (Stinging nettle)
  • Sambucus racemosa (Red elderberry)
  • Tolmeia menziesii (Piggyback)
  • Cardamine hirsuta (Shotweed)
  • Lonicera involucrata (Twinberry)

Above the stream

About five feet above the stream, there is a nurse log and a large amount of coarse woody debris holding the stream bank. I think the seep is eroding the soil from underneath the CWD, and it will eventually collapse. Upland of this the substrate is mostly decayed wood, which makes it a good place for Tsuga heterophylla. On either side of this substrate, the seeps reach to the wall of the ravine.

Growing in this area:

  • Polystichum munitum (Sword fern)
  • Rubus spectabilis (Salmonberry)
  • Ilex aquifolium (Holly)
  • Hydrophyllum tenuipes (Pacific waterleaf)
  • Tolmeia menziesii (Piggyback)
  • Sambucus racemosa (Red elderberry)
  • Ribes bracteosum (Stink currant)
  • Spiraea douglasii (Douglas’ spirea)
  • Germanium robertianum (Herb robert)

Growing in the seep between the CWD area and the social trail:

  • Tolmeia menziesii (Piggyback)
  • Glyceria elata (Tall mannagrass)
  • Oenanthe sarmentosa (Water parsley)
  • Hydrophyllum tenuipes (Pacific waterleaf)
  • Rubus spectabilis (Salmonberry) in dryer areas
  • Thuja plicata (Western red-cedar) (planted)
  • Cardamine hursuta (shotweed)

Central Valley Subarea B

Streamside

The stream itself is similar to the stream in HWB Subarea B: The wider sections have a substrate of sand and fine silt, and with narrower sections have a substrate of small cobbles.

The red cedar stump in this section has a wider variety of plants than the one in the HWB section. In addition to the red huckleberry and mosses, there are also salmonberry and a Tsuga heterophylla (Western hemlock) seedling that is naturally regenerating.

Above the Stream

There is also a nurse log holding the bank, but there is not the woody debris substrate above it as with the HWB.

Salmonberry and red elderberry form a thicker canopy than on the HWB side. There is also much more Hedera helix (English ivy) that comes down from the South Slope and lies across the seeps.

In the stream, but closer to the right bank, is a red alder root ball, with the tree itself lying across the width of the seep. The root ball has red huckleberry, ivy, and a couple Acer macrophyllum (Big leaf maple) seedlings growing in it. There is holly in the stream and around the root ball that will need to be removed.

Integrating into Work Flow

Between Sept. 15 and Nov. 27, there are nine possible Monday sessions and the October work party. The September work party will be on the South Plateau, and the November work party will be dedicated to planting GSP-provided plants. It is possible that some work on the stewardship grant could take place at the November work party.

Plant list

Table 1, below, is the plant list submitted to the WNPS for the grant. The actual planting list will vary considerably from this list, but that variance is within the scope of the grant. The wetland status, size, and number were obtained from the Fourth Corner Nurseries Catalog.

Table 1: Plant list and estimated planting time.

Early October
Genus Common Name Wetland Size # plants
Carex deweyana Dewey’s sedge FAC bareroot 100
Carex obnupta Slough sedge OBL bareroot 100
Fraxinus latifolia Oregon ash FACW 6-12″ 50
Glyceria elata Tall mannagrass FACW bareroot 100
Viburnum opulus v. americanum Highbush cranberry FACW 3-6″ 50
Late October
Genus Common Name Wetland Size # plants
Holodiscus discolor Ocean spray FACU 6-12″ 50
Lonicera involucrata Black twinberry FAC 6-12″ 50
Berberis nervosa Low oregon-grape FACU 3-6″ 100
Sambucus racemosa Red elderberry FACU crown 50
Vaccinium parvifolium Red huckleberry FACU 2″ pots 50

OBL = obligate, plant has to grow in a wetland; FACW = facultative wetland, plant grows in a wetland most of the time but can occasionally be found in drier areas; FAC = facultative, plant grows equally well in wetlands and drier areas; FACU = facultative upland, plants grows mostly in drier areas, but can occasionally be found in wetlands.

For the purchased plant list and the actual planting times, please see “Addendum,” below.

Addendum

This is the revised timeline, written after some work had already been done.

  • Plants were ordered in October for October and February delivery.
  • The October plants were wetland obligate graminoids.
  • The February plants were facultative wetland shrubs and trees.
  • The plants will be installed during regular public work parties.

In October 2014, the following orders were placed with Fourth Corner Nursery, for delivery in October and February.

Table 2: October order of Obligate plants.

Scientific Name Common Name Wetland Quantity
Carex amplifolia (1) Broad-leaved sedge OBL 50
Carex stipata (2) Sawbeak sedge OBL 100
Deschampsia caespitosa (3) Tufted hair-grass FACW 50
Glyceria elata (1) Tall mannagrass FACW 100
Juncus ensifolius (2) Daggerleaf rush FACW 50
Scirpus microcarpus (3) Panicled bulrush OBL 100

1 = observed growing with limited distribution; 2 = introduced to North Beach Park with this planting; 3 = previously introduced by restoration planting.

Table 3: February order of Facultative Wetland Shrubs and Trees.

Scientific Name Common Name Wetland Quantity
Physocarpus capitatus (3) Pacific ninebark FACW 50
Fraxinus latifolia (1) Oregon ash FACW 50
Malus fusca (2) Pacific Crab Apple FACW 50
Salix lucida (2) Pacific willow FACW 50
Salix sitchensis (2) Sitka willow FACW 50

1 = observed growing with limited distribution; 2 = introduced to North Beach Park with this planting; 3 = previously introduced by restoration planting.

The October order is the actual quantities delivered and planted during the October work party. As discussed above, the work occurred in the Central Valley Subarea B and Headwaters Bowl Subarea B.

The planting was done by volunteers led by forest stewards. Duckboards were used to minimize disruption to the wetlands wherever possible.

The work area actually became larger than illustrated in Figure 1, above. Planting was done further east in Headwaters Bowl.

The second order will be delivered in time for the February work party (February 28, 2015). Approximately ten of each shrub will be held back for a year or so, to test is survival rates are increased with an extra year of nursery care.

The second planting will also happen further east than the original prospect in Figure 1.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)
The Central Valley is the area in light green (planting) and pale yellow. The blue line is the stream. (Source: GSP Reference Map on ArcGIS.com.)

The Central Valley is the area in light green (planting) and pale yellow. The blue line is the stream. (Source: GSP Reference Map on ArcGIS.com.)

At 1.97 acres, the Central Valley (“CV”) is the largest HMU in North Beach Park. Its northern border is a stream crossing; its eastern border is the main social trail; its southeastern border is a stream crossing and the start of the south loop social trail; its western border is the south loop social trail. The gradient between the eastern side of the central valley and the main social trail varies from almost nothing to very steep. The gradient between the south loop social trail and the floor of the valley is very steep throughout.

The slopes of the valley are heavily invaded, but explorations of the middle of the valley reveal an area not in such bad shape. The Rubus spectabilis (salmonberry; RUSP) layer of the canopy is so dense that it makes exploration very difficult. In the summer of 2014, we did a belt transect through the widest part of the CV; please see “Vegetation” below for a discussion of the results of the transect, and “Belt Transect” in “Monitoring” for a discussion of the protocol.

The tree canopy percent cover for the CV is 60% deciduous, almost exclusively Alnus rubra (Red alder). There is less than 1% coniferous cover, Thuja plicata (Western red-cedar), located in the southwest corner. There is about 5% cover of regenerating deciduous trees, and less than 1% of regenerating coniferous trees. The CV has the largest canopy gaps in the park, allowing Calystegia sepium (bindweed) to establish in the sunlight.

The reference ecosystem and target forest type for the CV are the same as for the Headwaters Bowl: “riparian forest and shrubland” for the ecosystem and ALRU/RUSP/CAOB-LYAM (Red alder/salmonberry/slough sedge – skunk cabbage) (Chappell 2006) for the target forest type.

The existing plant community is ALRU/RUSP (Kunze), and the soil is correspondingly relatively dry. The saturated areas of the CV are much smaller than those in the Headwaters Bowl.

The RUSP layer is so dense that it forms a closed canopy and prevents any other shrubs or trees from establishing. The most noticeable groundcover under the RUSP canopy is Tolmiea menziesii (Piggyback) and Hedera helix (ivy). Care must be taken during restoration not to disrupt the RUSP canopy lest the ivy take off.

The southeastern section of the CV (part of Subarea A, below) is in phase one of restoration, invasive removal. See “Monitoring Protocols and Success Metrics.”

As with the Headwaters Bowl, the CV is split into four sub areas, depending on who can do the work or the technique for best restoration. See “Invasive Removal and Vegetation Plan,” below.

Water Flow

Again, as with the Headwaters Bowl, most of the water flow in the Central Valley is from the southern wall of the park towards the stream channel. The water appears to be more channelized than in the HWB; perhaps this is because the RUSP canopy provides greater soil control.

Vegetation

1/10th Acre circular monitoring plot

There was one 1/10th acre circular forest monitoring plot established in the south eastern corner of the Central Valley (Subarea B). Please see “Green City Monitoring Protocol” in “Monitoring Protocols” for a discussion of this protocol. The baseline monitoring was taken in September 2011, and the plot was revisited in August 2012. As with the HWB plot (above), percent cover was determined by consensus of the people doing the surveying, and reported in broad categories for city-wide consistency.

2011 invasive groundcover for Central Valley monitoring plot.

2011 invasive groundcover for Central Valley monitoring plot.

2012 invasive cover in Central Valley monitoring plot.

2012 invasive cover in Central Valley monitoring plot.


Key: Groundlayer and shrub percentages are for percent cover. Tree density is trees per acre. Red bar indicates immediate attention needed; light orange bar means attention needed soon. Source: EarthCorps, 2011 and 2012.

The figures below compare native groundlayer change between 2011 and 2012. Note in particular the return of Hydrophyllum tenuipes (Pacific water leaf) and Lysichiton americanum (skunk cabbage) both of which returned from the seed bank.

2011 native groundcover in the Central Valley monitoring plot.

2011 native groundcover in the Central Valley monitoring plot.

2012 native groundlayer cover in the Central Valley monitoring plot.

2012 native groundlayer cover in the Central Valley monitoring plot.

Belt transect

In the summer of 2014, a cross-gradient belt transect was done in North Beach Park that crossed the Central Valley along the 90th St. right of way. Eight 4’x16’ plots were established in the Central Valley. The transect went from west to east, through subareas C, D, and A.

The following table lists the target forest type species for the Central Valley, all the species found in the belt transect, their percent cover across the entire transect, and what the percent cover of their TFT goal is. Percent cover was determined by one person consistently, and is given in specific amounts. Please see the key below the table for a full explanation of the numbers.

Scientific Name Common Name Pct. Cover TFT Goal
Acer circinatum Vine maple 0.00 4.00
Acer macrophyllum Big leaf maple 26.11  
Alnus rubra Red alder 32.22 93.00
Angelica genuflexa Kneeling angelica 0.00 20.00
Athyrium filix-femina Lady fern 2.44 4.00
Atrichum selwynii Crane’s-bill moss 0.33  
Calystegia sepium false bindweed 0.33 0.00
Carex amplifolia Bigleaf sedge 0.89  
Chrysosplenium glechomifolium Pacific golden saxifrage 0.00 15.00
Circaea alpina Enchanter’s nightshade 0.00 3.00
Dryopteris expansa Spiny wood fern 0.22  
Equisetum telmateia Giant horsetail 2.22  
Erhythranthe guttata Yellow monkey-flower 0.00 4.00
Hedera helix English Ivy 14.28 0.00
Hydrophyllum tenuipes Pacific waterleaf 3.33  
Ilex aquifolium Holly 3.00 0.00
Lysichiton americanum Skunk cabbage 5.22 30.00
Moss   0.44 20.00
Mycelis muralis Wall lettuce 0.06 0.00
Oenanthe sarmentosa Water parsley 0.67 6.00
Oxalis oregana Oregon oxalis 0.00 8.00
Picea sitchensis Sitka spruce 0.00 8.00
Poa trivialis Rough-stalk bluegrass 0.00 30.00
Polystichum munitum Sword fern 3.06 6.00
Prunus laurocerasus Cherry laurel 0.39 0.00
Ranunculus repens Creeping buttercup 0.33 0.00
Ribes bracteosum Stink currant 0.11  
Rubus armeniacus Himalayan blackberry 0.67 0.00
Rubus spectabilis Salmonberry 53.89 57.00
Sambucus racemosa Red elderberry 0.44  
Stachys chamissonis var. cooleyae Coastal hedgenettle 0.00 4.00
Stachys mexicana Mexican hedge-nettle 0.00 4.00
Tolmiea menziesii Piggyback 2.17 34.00
Urtica dioica Stinging nettle 2.72

Key: “0.00” in Pct. Cover column indicates a target forest type indicator species not found during the survey. No value in the TFT Goal column indicates a native species not listed in the target forest type. “0.00” in the TFT Goal column indicates an invasive species to be removed.

Plots 4 through 10 of the transect were on the floor of the Central Valley. The following chart illustrates the relationship between density of salmonberry and red alder cover and ivy. How this will affect restoration is discussed in “Subarea D,” below.

Interaction of Salmonberry, Red alder, and English ivy.

Interaction of Salmonberry, Red alder, and English ivy.

Invasive Removal and Restoration Plan

There are four distinct subareas to the Central Valley.

North is to the top. A: All volunteers can work here. B: Forest stewards and experienced volunteers. C: Parks District Natural Area Crew (slope). D: Forest stewards and experienced volunteers.

North is to the top. A: All volunteers can work here. B: Forest stewards and experienced volunteers. C: Parks District Natural Area Crew (slope). D: Forest stewards and experienced volunteers.

Subarea A

Subarea A (outlined in blue above) measures approximately 17,350 square feet. It lies between the social trail and the stream and is relatively flat and accessible. A holly thicket was cleared from the southeastern portion in 2011. The ground returned with Hydrophyllum tenuipes (Pacific waterleaf) and was replanted with shrubs and ferns in the subsequent planting seasons.

The dark green section of Subarea A (approximately 9,600 square feet) was cleared and planted by EarthCorps volunteers in 2013. This work will be extended and monitored by the Friends of North Beach Park. In January 2014, Friends of North Beach Park cleared about 800 square feet of black berry past the north end of the dark green section of Subarea A. This received some Deschampsia cespitosa (Tufted hair grass) and Fraxinus latifolia (Oregon ash) in March that has established well. Ribes bracteosum (Stink currant) is spreading into the cleared area from nearby. The clearing did not reach the streambank because the ground was still very wet.

Work in Subarea A can be done by any volunteers or forest stewards. Parks Department Natural Area Crew will be requested for large laurel and holly removal.

Care must be taken working close to the stream to not disrupt the streambank. A section of Subarea A lies across the trail from an area called Knotweed Hill. This area should receive extra attention and monitoring.

Suggested tasks for Subarea A:

  • Plant newly cleared area in Fall of 2013.
  • Work with Parks Department crews to eradicate the holly and laurel.
  • Monitor invasive resurgence and native establishment in the Earthcorps-cleared areas.
  • Connect the cleared areas.

Subarea B

Subarea B, outlined in red above, measures approximately 4,800 square feet. It is a large, active seep with water flowing from the south wall of the ravine. The soils are permanently saturated and can bear little or no walking. The ground is too wet for all but such obligate plants as Oenanthe sarmentosa (Water parsley) and H. tenuipes.
This seep is bordered by a social trail, the soil compaction of which provides a little stability. There are also three large Acer macrophyllum (Big leaf maple), two of which are visible below, taken before any restoration work was done.

Central Valley Subarea B in 2011.

Central Valley Subarea B in 2011.

There is a large conifer nurse log (obscured in the photo above) lying across the seep that provides some stability. Tsuga heterophylla (Hemlock) trees have been planted into the nurse log and are doing well.

Hedera helix (English ivy) grows down from the slope, under the trail, and then over the seep. The ivy is not firmly rooted in the seep and provides little or no stability or erosion control. However, clearing the ivy would destabilize the sides of the seep and disrupt the trail.

In November, 2013, some planting was done in Subarea B. They are listed in the table below.

Scientific Name Common Name #
Alnus rubra Red alder 1
Carex deweyana Dewey sedge 6
Carex obnupta Slough sedge 4
Cornus stolonifera Redtwig dogwood 6
Juncus acuminatus Tapertip rush 6
Picea sitchensis Sitka spruce 1
Physocarpus capitatus Pacific ninebark 4
Salix lucida Pacific willow 4
Scirpus microcarpus Panicled bulrush 2

The C. stolonifera were livestakes. All others were potted.

These were installed in two locations in Subarea B. In both cases, only the minimum amount of clearing was done to allow planting. As of summer 2014, all the plants appear to be doing well. We’ve also spread seed berries from Lysichiton americanum (skunk cabbage) into bare areas.

Suggested tasks for Subarea B:

  • Plant shrubs in areas of stable soil, at the base of the slope and around the trees and nurse log.
  • As these establish, spread planting into less stable areas.
  • When the shrub layer establishes, remove ivy from beneath it and increase groundcover diversity.

For further plans for Subarea B, please see “Stewardship Grant,” below.

The ivy comes down to Subarea B from the West and South Slopes. For a discussion of the plans for those HMUs, please see the “Uplands and Slopes” chapter.

Subarea C

Subarea C, outlined in green above, is the least volunteer-accessible area of the Central Valley. It measures approximately 26,490 square feet. The western border is the south loop social trail, and the eastern border is on the floor of the valley. The social trail is frequently 50 and more feet above the floor of the valley, with well over 40% grade. Work here will have to be done by contract or natural area crew, either arranged through Green Seattle Partnership or secured through a grant.

Subarea C is heavily invaded by Rubus armeniacus (Blackberry), Calystegia sepium (Bindweed), and many other ornamental and invasive plants. The true extent of the invasiveness, or what remnants of native plant cover under the blackberry or bindweed, is not known at this time.

Subarea D

Subarea D, at approximately 38,970 square feet (yellow outline above), is the largest area of the Central Valley. The belt transect cut across it at the widest point, but the rest of Subarea D has not been fully explored.

As discussed in “Vegetation,” above, the dense salmonberry and red alder canopy might be controlling the ivy and other invasives – at the cost of preventing tree succession or shrub and groundcover diversity. Care must be taken not to disrupt the salmonberry layer, as this would allow the ivy to take off, and perhaps choke out restoration plantings.

We plan to remove the ivy from underneath the salmonberry in test sections beginning in early spring 2015, before the salmonberry and red alder are fully leafed out. This will allow the sun to reach the soil and promote any seedbank or native growth resurgence. In the summer, we’ll spread seeds from piggyback and other plants already growing in Subarea D. Live stakes from other shrubs growing in the park will be introduced as well, drawing from a number of different plants to avoid problems caused by dense cloning. Deep-shade groundcover will be planted or spread by seed.

As diversity increases, we will remove more ivy and thin the salmonberry to start tree succession. We’ll begin with Alnus rubra. Although this is already the dominant tree cover, it is mainly large, old trees, with no seedlings or sub-canopy examples yet seen. As the next generation of A. rubra establishes, we will begin planting Thuja plicata (Western red-cedar) and Tsuga heterophylla (Western hemlock).

This is a modification of the Bradley method (Bradley, 1988). Although it might sound like it would take longer than the general clearing and replanting, it will have less disruptive impact on existing habitat and aquatic systems (Apastol & Berg, 2006)

Suggested tasks for Subarea D:

  • Remove ivy from under Rubus spectabilis before leaf out
  • Monitor for native plant return from seedbank
  • After seed set, spread seeds from plants already growing under the salmonberry (mostly Tolmeia menziesii [piggyback]).
  • Live stake with stakes taken from other shrubs in the park, particularly Sambucus racemosa (Red elderberry) and Rubus parviflorus (Thimbleberry).
  • In the fall, spread seeds of plants that like deep shade under the salmonberry.
  • When an alder falls, take advantage of the extra light to encourage conifer succession.

All tasks are to be done with as little disturbance to the salmonberry cover as possible.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

This post gives an overview of the wetlands in North Beach Park and looks specifically at the Headwaters Bowl. The next post looks at the Central Valley. The third post in this series will discuss the stewardship grant from the Washington Native Plant Society to the Friends of North Beach Park. The 92nd St. Wetlands will be discussed later, with Fletcher’s Slope.

Approximately 4.5 acres of North Beach Park are designated as wetlands. These wetlands are formed by broad, horizontal, groundwater seeps emerging from the sides of the ravine. These join to form the stream that leaves the park. The seeps are perennial, and have lasted through record droughts.

The wetlands have many areas that are permanently saturated, and walking in them quickly disrupts whatever soil structure there is. Other places are more stable.

Figure 1: Wetlands in North Beach Park. Thick green lines indicate park boundaries. Light grey lines indicate HMU boundaries. The filled blue area are the wetlands. Wetland delineation by Doug Gresham of Gresham Environmental (2012). (Map by the author.)

Figure 1: Wetlands in North Beach Park. Thick green lines indicate park boundaries. Light grey lines indicate HMU boundaries. The filled blue area is the wetlands. Wetland delineation by Doug Gresham of Gresham Environmental (2012). (Map by the author.)

Doug Gresham, of Gresham Environmental, delineated and typed the wetlands in 2012:

North Beach has both Palustrine (freshwater) and Riverine (riparian) wetlands. The plant community is scrub/shrub and the water regime ranges from saturated soil to permanently flowing streams. The groundwater seep wetlands would be called palustrine, scrub/shrub, saturated (PSSc). The stream would be called riverine, upper perennial, unconsolidated shore, permanently flooded (R3USh).

The hydrogeomorphic classification system groups wetlands based on functions and values. … The groundwater seep wetlands would be called slope wetlands and the stream is a riverine wetland.

The Washington Department of Ecology classifies wetlands into four categories based on their hydrogeomorphic class and score from a rating form. King County and City of Seattle governments rely on this classification system to create their critical area ordinances. The highest quality wetlands (Category I) are rare, while low quality wetlands (Category IV) are somewhat rare also. Most wetlands fall into the Category II and III level depending on how well they function. North Beach would probably be Category III because it is degraded. (Gresham, 2014)

In October 2005, the US Fish and Wildlife Service did a fish habitat survey of streams in the Seattle area. “Unnamed PS08 West Fork” is the stream that flows through North Beach Park (see figure 2, below). At their sample site (which would now be in the Headwaters Bowl HMU), they found the stream to have a mean wetted width of 1 meter (m); a mean depth of 0.03m with a max depth of 0.1m; and to consist of 100% riffles with no pools or glides. The substrate was 100% silt/sand. They did not catch any fish in the sample site. (Tabor 2010)

Figure 2: Location of US Fish and Wildlife 2005 survey sample in North Beach Park.

Figure 2: Location of US Fish and Wildlife 2005 survey sample in North Beach Park.

The Central Valley, at 1.97 acres, and the Headwaters Bowl, at 1.39 acres, are the two largest HMUs in North Beach Park. For restoration purposes, we have split them into four subareas each. The subdivision is based on who can do the work: all volunteers, experienced forest stewards, Parks Department Natural Area Crew, or privately-contracted restoration crew.

Headwaters’ Bowl

Description

Figure 3: Headwaters Bowl. The Headwaters Bowl is the area in light green (planting) and blue (establishment). The blue line is the stream. North is to the top.

Figure 3: Headwaters Bowl. The Headwaters Bowl is the area in light green (planting) and blue (establishment). The blue line is the stream. North is to the top. (Source: GSP Reference Map on ArcGIS.com.)

The Headwaters Bowl (“HWB”) is the easternmost HMU of North Beach Park.

The northern boundary is the main trail of the park, the eastern boundary is 24th Ave. NW, the southern boundary is property lines and the South Slope, and the western boundary is the stream crossing and the social trail between the Headwaters Bowl and the Central Valley.

The property lines cut the bottom of the bowl and the 24th Ave. slope in half, and remove the southern slope entirely. Parks Department volunteers and Natural Area Crew are not allowed to work on private property. This complicates restoration of the HWB as discussed below in “Invasive Removal and Restoration Plan.”

At the start of restoration, nearly half the trees in the HWB had severe Hedera helix (ivy) infestations which frequently reached into the canopy. There were large pockets of ivy monoculture on the ground.

The percent cover for trees was approximately 70% deciduous, with Alnus rubra in the wetlands and Acer macrophyllum on the dryer slopes and uplands. There was 5-10% conifer cover, exclusively Thuja plicata (Western red-cedar). The remaining 15-20% cover was open gaps, either over areas too wet to sustain trees or where A. rubra had fallen. The percent cover of the regenerative trees (tall enough to be above the shrub layer) was less than 5% for deciduous and less than 1% for coniferous trees.

Ilex aquifolium (English holly) and Prunus laurocerasus (English laurel) formed occasional dense thickets. Most of these have been removed, either by uprooting or cutting and painting with herbicide.

The HWB native plant communities at the start of restoration were very similar to the Alnus rubra/Rubus spectabilis (Red alder/Salmonberry; ALRU/RUSP) and Alnus rubra/Lysichitum americanum (Red alder/skunk cabbage; ALRU/LYAM) communities described by Kunze (1994). The differences were largely that the communities in the park lacked herbaceous diversity compared to the reference communities.

These communities are dominated by an Alnus rubra (red alder) canopy, with either Rubus spectabilis (salmonberry) or Lysichitum americanum (skunk cabbage) as the undercanopy. Kunze describes the ALRU/LYAM community as being wetter than ALRU/RUSP, and that is the case in NBP. (Plant communities are discussed in more detail in “Target Forest Types”).

There is a canopy gap over the most saturated, eastern part of the HWB. This area is dominated by skunk cabbage and horsetail, with some Salix sitchensis (Sitka willow) shrub. The invasive plants here include Rubus armeniacus (blackberry) and Calystegia sepium (bindweed). Numerous A. rubra lean over this part of the HWB from the slopes. As they die and fall, the gap will enlarge. This will also increase the amount of coarse woody debris in the wetland and the number of rootballs on the slope walls.

Progressing to the west, the topography and soils become more complicated. Some areas are more stable, and some are seeps that have reached down to the gleyed soils. As the ravine narrows, Acer macrophyllum (Big leaf maple) on the south slope add their shade.

The majority of the HWB is in phase two, “planting,” of restoration. A section of Subarea C is considered to be in “establishment,” phase 3. For a discussion of the phases, please see “Monitoring Protocols and Success Metrics.”

Water Flow

Groundwater emerges from several places at the base of the 24th Ave. slope. One of these areas has a number of displaced conduits. During heavy rainfall, water emerges from a conduit in the southeastern corner of the hillside.

Through the rest of the Headwaters Bowl, the water emerges as seeps or occasionally channels from the south slope of the ravine. In many places the seeps have carried away most of the soils.

These seeps join the stream, which runs along the northern edge of the headwaters bowl. Water flow in North Beach Park, in general, needs a lot more research and observation.

Vegetation

As discussed above, the plant communities in the HWB are currently a mixture of ALRU/LYAM (to the east) and ALRU/RUSP (to the west).

The reference ecosystem for the Headwaters Bowl is “riparian forest and shrubland.” The target forest type is ALRU/RUSP/CAOB-LYAM (Red alder/salmonberry/slough sedge – skunk cabbage) as described by Chappell (2006).

There has been one circular, 1/10th-acre, monitoring plot established in the Headwaters Bowl. Baseline monitoring was taken in August 2012, with a follow-up in August 2013. See “Green City Monitoring Protocol” in “Monitoring” for a discussion of this protocol. This monitoring plot was established in the middle of the most saturated section of the Headwaters Bowl.
The following table presents the vegetation findings from the 2012 and the 2013 monitoring and the change. Native plants listed as 0 in the “2012 % Cover” column were planted in autumn 2012. Percent cover was determined by consensus of the people doing the monitoring plot, and is reported in broad categories to enable the data to be consistent across the city.

Table 1: Forest Monitoring Plot report, Headwaters Bowl.

Scientific Name Common Name 2012 % Cover 2013 % Cover Change
Athyrium filix-femina Lady fern 1-5% 1-5% None
Cardamine hirsuta Shotweed 0 <1% Increase
Carex obnupta Slough sedge 0 <1% Increase
Convulvus arvensis Field bindweed <1% 6-15% Increase
Crataegus douglasii Black hawthorne 0 <1% Increase
Epilobium ciliatum Willowherb <1% <1% None
Equisetum arvense Horsetail 26-50% 26-50% None
Fraxinus latifolia Oregon ash 0 <1% Increase
Glyceria elata Tall mannagrass <1% <1% None
Hedera helix English Ivy 26-50% 26-50% None
Lonicera ciliosa Orange honeysuckle 1-5% 1-5% None
Lysichiton americanum Skunk cabbage 1-5% 6-15% Increase
Malus fusca Pacific crab apple 0 <1% Increase
Oenanthe sarmentosa Water parsley <1% <1% None
Polystichum munitum Sword fern <1% <1% None
Ranunculus repens Creeping buttercup 6-15% 6-15% None
Rubus armeniacus Himalayan blackberry 26-50% 16-25% Decrease
Rubus spectabilis Salmonberry 26-50% 26-50% None
Rumex crispis Curly dock <1% <1% None
Salix sitchensis Sitka willow 1-5% 1-5% None
Scirpus microcarpus Small-fruited bulrush 0 <1% Increase
Solanum dulcamara Bittersweet nightshade <1% <1% None
Spiraea douglasii Hard hack 0 <1% Increase

Only one invasive plant decreased in cover, Rubus armeniacus (blackberry). This was the plant we most vigorously removed. The native plants that went from 0 to <1% cover had been planted in the fall of 2012. Lysichiton americanum (Skunk cabbage) increased from the seed bank. Calystegia sepium increased noticeably all over the park in 2013.

Although this gives a good representation of the most-saturated areas of the HWB, it does not give a good representation of the HWB as a whole. A couple dozen feet to the west of this monitoring plot, there is a stand of A. rubra that indicates dryer conditions. This allows greater shrub establishment.

Invasive Removal and Restoration Plan

I have divided the Headwaters Bowl into four subareas, based on who can perform the needed restoration work (see below).

Figure 4: Headwaters Bowl and subareas. A: All volunteers can work here. B: Forest stewards and experienced volunteers. C: Parks District Natural Area Crew (slope). D: Privately contracted crew (slope, private property).

Figure 4: Headwaters Bowl and subareas. A: All volunteers can work here. B: Forest stewards and experienced volunteers. C: Parks District Natural Area Crew (slope). D: Privately contracted crew (slope, private property).

Subarea A

Subarea A is between the main trail and the stream bank. It is relatively flat and dry, making it accessible to all volunteers. It measures approximately 16,500 square feet (all areas calculated using the measurement tool on GSP Reference Map on Arcgis.com).

Subarea A has received the most attention of any area in the park, beginning with the very first work party. As a consequence of it receiving such early attention, no good record was kept of its pre-restoration state; the notes below are reconstructed from memory.

There were few areas of Hedera helix (English ivy) monocultures in Subarea A. There were some areas of Ilex aquifolium (English holly) and Prunus laurocerasus (Cherry laurel) dominance. The ivy has been removed by hand. The holly was removed by uprooting. The laurel was removed by cutting and painting.

In late summer and fall of 2013, several EarthCorps work parties concentrated on invasive removal in this section.
Plants have been installed and invasives removed every year, and it is now in an establishment phase.

Suggested tasks for Subarea A:

  • Explore the western end in further detail.
  • Continue monitoring the planted area for native plant establishment and invasive resurgence.
  • Track mature Alnus rubra and naturally regenerating Thuja plicata and Acer macrophyllum.
  • Start a new generation of deciduous trees.
  • Add to the herbaceous diversity annually.
  • In 2021 (ten years after restoration began), add a new generation of conifer trees.

Subarea B

Subarea B is the center of the bowl, and because of the saturation and fragile soil structure is more difficult to work in than Subarea A. This makes it accessible to small groups of experienced forest stewards only. It measures about 45,000 square feet.

The widest part, to the right in the image, is permanently saturated. It receives invasive removal in the late summer, when it’s relatively dry. It has received plantings of graminoids and shrubs. The eastern edge of Subarea B is the location of the circle monitoring plot discussed above. The part of Subarea B not in park property needs further exploration.

The narrower part has many seeps, separated by tongues of soil held in place by Carex obnupta (slough sedge) and/or Rubus spectabilis (salmonberry). In the spring and summer, these seeps contain forbs such as Oenanthe sarmentosa (Water parsley). However, there is no woody vegetation to hold the seeps during winter.

Some Picea sitchensis (Sitka spruce) and Thuja plicata (Western red-cedar) have been planted in the seeps.

In June 2014, Friends of North Beach Park received a $500 stewardship grant from the Puget Sound Chapter for the purchase of wetland plants. These plants will be installed along the streambank and in the seeps of the western (left) edge of Subarea B of the Headwaters Bowl, and across to Subarea B of the Central Valley. This grant is discussed in more detail in “Stewardship Grant.”

Suggested tasks for Subarea B, in the lobed area to the east:

  • Continue removing blackberry.
  • Establish shrubs where possible, graminoids elsewhere.
  • Explore the base of the slope and the bowl during a rain event.

Suggested tasks for Subarea B, in the narrow part to the west:

  • Implement the WNPS Stewardship Grant in autumn of 2014.
  • Continue removing invasives as necessary.
  • Monitor seeps for erosion.
  • Establish obligate wetland plants in the seeps.

Subarea C

Subarea C measures roughly 10,200 square feet. It is the slope along 24th Ave NW and around the entrance to the park along the main trail. Because it is a greater than 40% grade, only Parks Department Natural Area crew or contract crew can work on it. Volunteers have worked on it in the past, however.

In 2011, trees along the rim and slope received survival rings and there was some clearing of the slope.

In 2012 and 2013, the rim received some planting by the Friends of North Beach Park. During the summer months, these plants are watered and weeded. These plants include shrubs such as Aruncus dioicus var. acuminatus (Goatsbeard), Rosa nootkana (Nootka rose) and trees such as Pseudotsuga menziesii (Douglas-fir) and Pinus contorta var. contorta (Shore pine).

In 2013, the slope was partially cleared by a group of EarthCorps volunteers. The clearing was completed by a contract crew, who also put down jute rolls and planted in the fall.

Figure 5: Steep slope jute erosion control by contract crew.

Figure 5: Steep slope jute erosion control by contract crew.

The remainder of the clearing, following the curve of the slope along 24th Ave. and ending at the property line, will happen in 2014 or 2015.

Volunteers and forest stewards can maintain the plants at the rim and the base, but further tasks along the slope in this subarea will be executed by the Parks Department.

Subarea D

Subarea D measures approximately 13,800 square feet. It has not been explored in any great depth. Some trees were given survival rings during the first work parties in 2011. One house appears to have impermeable erosion control fabric, held down by sandbags, on the slope beneath it.

Subarea D is entirely private property on a very steep slope. The houses were built between 1959 and 1963 (King County Parcel Viewer), long before there was any movement to make the ravine a park or any attempt to preserve urban wetlands. The property lines, as shown below, extend into the bowl of the park, which allows the owners to have addresses on 24th Ave. This group of houses, as a whole, is called Olympic Terrace.

Figure 6: Property lines and park boundaries of HWB. The green area is North Beach Park. The red lines are parcel boundaries for private property. (Source: Seattle Department of Public Development DPDGIS).

Figure 6: Property lines and park boundaries of HWB. The green area is North Beach Park. The red lines are parcel boundaries for private property. (Source: Seattle Department of Public Development DPDGIS).

Due to the steepness of the slope, and the fact that it is private property, Subarea D can only be worked on by a privately contracted crew.

Working in Subarea D depends on securing the cooperation of the homeowners. We plan to contact them in autumn 2014 or early 2015 by doorbelling or leaving door hangers. If this contact is successful, we will

  • Explore the area along the bowl and the base of the slope to get an estimate of its invasiveness and what work needs to be done.
  • Design restoration plans that range from one-year brute force through multi-year phased work (which plan gets executed would depend on the size and time span of the grant).
  • Work with neighbors to write a grant that can be applied to private property (with King Conservation District or other organization).
  • Restore Subarea D per grant.

The large contingencies in this plan are (a) successfully contacting and securing the cooperation of the neighbors and (b) obtaining the very competitive King Conservation District grants.

The constraints against working in Subarea D would make it low priority if it were in another section of the park. However, its proximity to the headwaters increases its importance.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

Planting season has hit the Pacific Northwest, and restoration projects all over the place are getting their shovels dirty. No less is happening in North Beach Park — we have planting parties planned for the next FOUR work parties, October, November, January, and February!

October
The October work party happens Saturday, October 25, from 9 a.m. to noon. Please sign up here. The Friends of North Beach Park will be joined by international students from North Seattle College, volunteering with their I-CARE program.

October features wetland graminoids (grasses) and one forb. These plants will come from 4th Corner Nursery in Bellingham, and are purchased with monies from a stewardship grant from the Central Puget Sound Chapter of the Washington Native Plant Society. We also appreciate the support of our fiscal sponsor, Seattle Parks Foundation, for processing the money.

These will be planted in the Headwaters Bowl and Central Valley habitat management units of North Beach Park.

Scientific Name Common name Size Form Number
Carex amplifolia Broad-leaved sedge br Gr 50
Carex stipata Sawbeak sedge br Gr 100
Deschampsia caespitosa Tufted hair-grass br Gr 50
Glyceria elata Tall mannagrass br Gr 100
Juncus ensifolius Daggerleaf rush br Gr 50
Scirpus microcarpus Panicled bulrush br Gr 100
Veronica americana American brooklime br Fo 100

Although this is 550 plants, they’re all pretty small.

November
The November work party will happen on Saturday, the 22nd. Build up that appetite and enjoy your Thanksgiving feast that little bit more, because you’ve done some good for Seattle parks! Sign up here. Friends of North Beach Park will be joined again by international students from the North Seattle College I-CARE program.

November will see more plants installed in the main body of North Beach Park. These plants are provided by Green Seattle Partnership. There will be one tree, one shrub, and two grasses and two forbs.

Scientific Name Common name Size Form Number
Acer macrophyllum bigleaf maple 1 gal Tr 6
Asarum caudatum wild ginger 1 gal Fo 20
Oplopanax horridus Devil’s club 1 gal Sh 10
Petasites frigidus coltsfoot 1 gal Fo 20
Scirpus acutus hardstem bulrush 1 gal Gr 8
Scirpus microcarpus panicled bulrush 1 gal Gr 8

For the first three years of restoration, we planted hundreds of conifer trees in North Beach Park. Now we’re going to switch gears for a while: Let the new conifers establish and get well-situated for the next three to five years, and do some replacement of the deciduous canopy.

We skip December, because the 4th Saturday falls between Christmas and New Year’s Eve. We hope you have a good holiday.

January
In January, we return to the South Plateau to plant the last of the plants provided by Green Seattle Partnership. The entrance to the South Plateau is at NW 88th St. and 27th Ave. NW. The January work party will happen on Saturday, the 24th. The event is not posted to Cedar yet, but it will have full directions and information. We DO know what we will be planting, though.

Scientific Name Common name Size Form Number
Holodiscus discolor oceanspray 1 gal Sh 11
Lonicera involucrata twinberry 1 gal Sh 7
Mahonia nervosa dwarf Oregon grape 1 gal Sh 25
Malus fusca Pacific crabapple 1 gal Tr 5
Polystichum munitum sword fern 1 gal Fe 25
Pseudotsuga menziesii Douglas fir 1 gal Tr 5
Rosa gymnocarpa bald-hip rose 1 gal Sh 25
Rosa nutkana Nootka rose 1 gal Sh 25

February
This will be our last planting work party for the 2014-2015 planting season. Well, that we’re planning on as we write (four months in advance). Who knows what the future portends?

This work party will feature shrubs and small trees, the second half of the stewardship grant purchase from the Washington Native Plant Society.

Scientific Name Common name Size Form Number
Fraxinus latifolia Oregon ash 6-12″ br Tr 50
Malus fusca Pacific Crab Apple 3-6″ br Tr 50
Physocarpus capitatus Pacific ninebark 6-12″ br Sh 50
Salix lucida Pacific willow 6-12″ br Tr 50
Salix sitchensis Sitka Willow 6-12″ br Tr 100

The February work party will be back in the main body of the park, and will happen on the 28th. As soon as the information gets posted to Cedar, we’ll link to it on Nature Intrudes.

We also plan to do a little experiment: Hold back some of the plants of each species, and keep them in a well-tended nursery for a year or two. The question is: Will the plants that get the extra attention have a better survival rate than the plants installed immediately?

That’s a little over a thousand plants altogether. Most of them are going into wetter areas of the park, which means they should make it through the summer drought fairly well.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

Green Seattle Partnership splits each park into different zones called “habitat management units” (HMUs). This allows GSP to assign different target forest types and reference ecosystems to the different HMUs, and the forest stewards to use techniques and approaches best suited to each HMU.

North Beach Park is split into 11 HMUs; nine of these are discussed in this document. The other two are only accessible by crossing private property lines.

The HMUs were delineated by Nelson Salisbury and Ella Elman when they mapped North Beach Park for EarthCorps in late summer of 2011. The names of the HMUs were decided by the forest stewards. All of the names are descriptive in some way.

The HMUs in North Beach Park are based on two basic characteristics: slopes and uplands, and wetlands. There is some mixture in that all the wetland areas contain some upland slopes, and the upland areas frequently contain some seeps or wet areas in their lower regions.

Within these two divisions, slopes and uplands are assigned their name based on nearby property (ie, Fletcher’s Slope is below Fletcher’s Village; 91st St. Slope is below 91st St.; 92nd St. Wetlands is below 92nd St.), characteristics (the South Plateau is the largest flat area of the park and 80 feet above the rest of the park), or aspect (South Slope, West Slope, North Slope). The Headwaters Bowl is where the groundwater enters the park and begins to form the stream; the Central Valley is in the middle of the park.

Each of these HMUs received a reference ecosystem at the time of mapping, based on broad category of the plant species seen. There are two reference ecosystems for NBP: “mesic-moist conifer and conifer-deciduous mixed forest” and “riparian forest and shrubland.” These are based on NatureServe classifications.

The table below shows the nine HMUs discussed in this book sorted by size, and listed with their target forest type and reference ecosystem. The target forest types are explained in “Target Forest Types,” next week.

Name Size Target Forest Type Reference ecosystem
Central Valley 1.97 ALRU/RUSP/CAOB-LYAM Riparian forest and shrubland
Headwaters Bowl 1.39 ALRU/RUSP/CAOB-LYAM Riparian forest and shrubland
North Slope 1.14 TSHE-PSME/POMU/DREX Mesic-moist conifer and conifer-deciduous mixed forest
West Slope 0.84 TSHE-PSME/POMU/DREX Mesic-moist conifer and conifer-deciduous mixed forest
South Slope 0.76 TSHE-PSME/POMU/DREX Mesic-moist conifer and conifer-deciduous mixed forest
92nd St. Wetlands 0.69 THPL-TSHE/OPHO/POMU Mesic-moist conifer and conifer-deciduous mixed forest
South Plateau 0.57 TSHE-PSME/POMU/DREX Mesic-moist conifer and conifer-deciduous mixed forest
91st St. Slope 0.54 TSHE-PSME/POMU/DREX Mesic-moist conifer and conifer-deciduous mixed forest
Fletcher’s Slope 0.53 TSHE-THPL-ACMA/ACCI/LYAM Riparian forest and shrubland

The Central Valley, Headwaters Bowl, and 92nd St. Wetlands are all primarily wetlands and are discussed first. The other six HMUs are primarily uplands and slopes and are discussed after the wetlands. Within each category, the HMUs are discussed in the order of greatest amount of restoration effort they have received.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (picture icon iv)

Floating Islands to the Rescue

Using floating islands as artificial wetlands to absorb nutrient runoff from commercial monocrop farms.

Mirrored from Nature Intrudes. Please comment over there.

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June 2017

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