Conclusion

Mar. 23rd, 2015 09:00 am
holyoutlaw: (me meh)

From late August through December, 2014, I was publishing roughly a chapter a week of my MEH project on Nature Intrudes. I got close to the end but hit a sticking point for some reason. Here, for what it’s worth, is the final chapter of the project, called… wait for it… Conclusion. In fact, this was newly revised this week.

Immediate Plans

This document was originally written in Summer, 2014. At that time, implementation of the WNPS stewardship grant, further monitoring and control of the south plateau street runoff, and monitoring of the 24th ave. wall conduit during a rain event were considered primary.

This revision of the original document is being written in March, 2015. We will look at the plans for 2014 as originally outlined and how they have been carried out. For 2015, we will look at the efforts to date, and project for the rest of the year.

We then look at possible scenarios for 2021 and 2061, ten and fifty years after restoration began, respectively.

The rest of 2014

August

The August work party returned to the areas cleared in January and February to prepare them for planting in November. August work parties are generally the lowest-attended of the year, and there were only three volunteers.

September

The September work party was held in the South Plateau, and included almost twenty students from Seattle Pacific University participating in their “CityQuest” program. We did extensive weeding, mulched some bare areas, and built a couple composting platforms.

October

The October work party featured the first phase of planting for the WNPS stewardship grant. Please see “Stewardship Grant” for details. Working with students from North Seattle College’s iCare program, we planted 450 plugs of obligate wetland, which were 50 each of Carex amplifolia, Deschampsia Caespitosa, and Juncus ensifolius; and 100 each of Carex stipata, Glyceria striata, and Scirpus microcarpus.

November

In November, we executed the first phase of installing the plant provided by Green Seattle Partnership. The work was carried out in the Central Valley, Headwaters Bowl, and the North Slope. We were joined by students from North Seattle College’s iCare program and Circle K International, from the UW.

December

In early December, a large Acer macrophyllum (Big leaf maple) at the base of the North Slope fell across the trail to the Central Valley, landing in areas A and B (see figure below). It blocked access to an area that had been cleared in 2011 and had received heavy planting in the meantime. Luckily, a lot of plants survived the collapse. Enough of the main stem remained standing to create a new snag, and the fallen wood and brush added a lot of woody debris to both the stream and the wetlands.

The tree fell from the North Slope side of the trail across area A (blue) and into area B (red) in this image.

The tree fell from the North Slope side of the trail across area A (blue) and into area B (red) in this image.

The tree fall created a large gap on the North Slope. Forest stewards removed many holly suckers and shoots from the ground and logged the holly trees for removal. This gap will receive some attention from Natural Area Crews in 2015, focusing on invasive removal, erosion control, and upland planting.

2015

January

The January work party featured the installation of some upland plants into open areas of the South Plateau. We were joined by members of the Delta Tau Delta fraternity from the UW. One forest steward worked on the water channel, creating a meander to help spread the flow across the surface of the plateau.

February

The February work party featured the implementation of the second half of the WNPS stewardship grant. In this case, we were planting facultative wetland trees and shrubs. Doug Gresham (a wetland scientist) helped immensely by sorting the trees and shrubs by where they fell in the gradient from wetland to upland. Although this planting was late in the season, the plants are likely to do well because they are in fairly wet areas of the park.

March

March will have a site review with Parks Department staff and forest stewards to prioritize Natural Area Crew work in the park for 2015. March will also feature Friends of North Beach Park tabling at and participating in Groundswell Northwest’s “Civic Social.” The March work party will feature clearing new areas for the fall planting.

April

In April, Friends of North Beach Park will table at the “Natural Area and Greenbelt Mini Summit Open House,” sponsored by the Parks Department. Some plans to open parks designated as Natural Areas to more active recreation are very controversial. The April work party will again feature clearing new areas for fall planting.

May

We have not previously had a work party in May for a couple reasons: First, it’s the height of nesting season, which is a good reason to stay out of the forest if at all possible. Second, the 4th Saturday schedule puts in in Memorial Day weekend, when many people want to get out of town if at all possible. However, an opportunity presented itself to have a largish group work in the park. We will work in the South Plateau with middle school youth from the “Bureau of Fearless Ideas.” The work will be weeding of quick-seeding annual weeds such as wall lettuce and nipplewort. This will be part one of a two-part writing workshop for the youth, coordinated by Green Seattle Partnership.

June through November

The work done in these months has started to follow a regular pattern: In June and July, we use the stream to water plants located at the rim of the park and other dry areas. August might feature more watering or a return to invasive removal. In September, we again hope to host students from Seattle Pacific University at the South Plateau. October and/or November will feature planting from GSP supplied plants.

2016

The Seattle Metropolitan Parks District comes into being in 2016. Many groups are already meeting to make sure the new funding has a positive impact. Exactly how this will affect forest stewards and Green Seattle Partnership is unclear, although it is likely to increase funding for Natural Area Crews and forest steward resources.

2021

2021 is ten years after the start of restoration. If FoNBP is able to keep working with the same energy and quality of work, it’s likely that all of the volunteer and forest steward-accessible areas of the park will be in at least Phase 1 of restoration, and that all the slopes requiring crew time will have received at least an initial invasive removal.

The existing monocultures will have been eradicated, and forest stewards will work on restoration using methods that avoid disrupting the soil and shrub layer as much as possible. During the early stages of Phase 1 of new restoration, we will introduce a new conifer generation. During the Phase 2 and 3 restoration, we will increase shrub and groundlayer diversity and introduce a new deciduous generation.

Some well-established areas of restoration, such as the South Plateau and the Headwaters Bowl, will be approaching Phase 4. When a restoration site enters Phase 4 restoration, we will introduce a new conifer generation. Please see “Success Metrics” for a discussion of the restoration phases.

On the other hand, NBP loses one to three deciduous trees a year to age and failure. This means that by 2021 we will have lost between 10 and 30 mature deciduous trees, with a consequent enlargement of canopy gaps. These gaps can provide beneficial edge effects, and the greater light levels on the forest floor will stimulate conifer and shrub growth. But the increased light will also make the park more susceptible to sun-loving weeds and grasses. Each fall must be dealt with on a case-by-case basis. The rate of fall means that removing ivy from trees has to continue to be a priority. A tree with ivy on the trunk and into the canopy that fell into a cleared area would recontaminate it.

2061

This is much more difficult to predict, not least because of the possible effects of climate change. But 50 years is also much longer than the lifespan of a typical “Friends of” group. It would be unrealistically optimistic to suggest that the “Friends of North Beach Park” will have continued in a recognizable form for so long. However, continuing restoration, whether through FoNBP or another agency, is the only prediction I can make.

It’s likely that by 2061 North Beach Park will have a well-established young conifer forest. Surviving conifers that had been planted at the start of restoration will be at the mid-canopy, halfway between the shrub layer and mature trees. The mature canopy is likely to be made up of the few current mature conifers, with some regenerating deciduous trees that are currently at the mid-canopy level. This layer will be much patchier than currently.

Even optimistic scenarios say that the average temperature will be noticeably warmer mid-century than it is now. It is likely the increasing warmth will disrupt existing plant communities. There will be new invasive plants, both from the introduction of new exotic species and plants from southern areas moving north.

If we can maintain enough canopy, the shade and cooling will help mitigate the effects of climate change. The wet, nutrient rich soils will also greatly aid the establishment and survival of the plants installed there, mitigating to some degree the stress of increased temperatures.

I have two optimistic hopes for the future, in regards to North Beach Park. Neither can be considered a “prediction.”

One is that this ravine, and other riparian ravines in Seattle and the lower Puget Trough, will be restored with an eye to becoming refugia, habitats for plants and trees at all forest layers that would otherwise be threatened or endangered by climate change. They might be completely novel ecologies compared to plant communities today, incorporating plants from different ranges.

The other is that socially, I hope that stewardship is seen not as something done for five or even ten years, but is something that one does for one’s entire life, and that it affects all phases of life choices. The forest doesn’t end, why should stewardship?

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

Description

Figure 1: The South Slope

North is to the top. (Source: Green Seattle Partnership Reference Map on ArcGIS.com.)

North is to the top. (Source: Green Seattle Partnership Reference Map on ArcGIS.com.)

The South Slope is the slope just north of the South Plateau. It connects the main body of the park with the South Plateau. The northern border of the South Slope is the south loop social trail to the west and the Headwaters Bowl to the east. The southern border is a mixture property lines and the South Plateau.

Some trees in the South Slope have received ivy survival rings. There has been some planting at the lower reaches of the east section of the South Slope, along the border to the Headwaters Bowl. Other than that, the South Slope has received little or no attention.

The South Slope is split by a very steep social trail that connects the South Plateau to the rest of the park. During the dry months, this trail is very fragile and breaks into powder. During the rainy months, it is more stable but also more slick. The two sides of the trail also have different water regimes and different levels of invasive species. Because of this, the trail splits the South Slope into two subareas. This is the only HMU subdivision not based on who can do the work.

The lower reaches of Subarea A (Figure 2, below) are accessible to forest stewards. The trailside reaches of Subarea B are accessible to all volunteers. These are very small sections in the South Slope. Because the South Slope has the steepest slopes in the park, the vast majority of it is accessible only to Natural Area Crew.

The South Slope has less than 1% conifer cover and no observed regeneration of any trees. The canopy is mostly Acer macrophyllum, with 75% percent cover.

The target forest type for the South Slope is Tsuga heterophylla – Pseudotsuga menziesii/Polystichum munitum – Dryopteris expansa (Western hemlock – Douglas fir/Sword fern – Spreading wood fern; TSHE-PSME/POMU-DREX). The reference ecosystem is Mesic-moist conifer and conifer-deciduous mixed forest.

Water Flow

Subarea A (Figure 2, below) is above a number of seeps in the Headwaters Bowl that feed into the stream. These seeps flow over gleyed soils. Water and soil movement has been observed in these seeps even in high summer. The slopes above the seeps might receive some attention from the Stewardship Grant, but most attention will focus on the Headwaters Bowl and the Central Valley (as discussed in Stewardship Grant).

Subarea B receives the run off from the South Plateau. It is critical that we explore this area during a heavy rain. There is evidence that the run off from the South Plateau is eroding a section of the south loop social trail and affecting the immediately adjacent section of the Central Valley. How the runoff is affecting the slope, underneath the ivy, needs to be examined. Please see Uplands and Slopes: South Plateau and Water Flow: South Plateau Street Runoff for further discussions of water flow issues affecting the South Slope.

Vegetation

To the west side of the trail (left in the figure below), the South Slope is heavily invaded, with mature Alnus Rubra (Red alder) and Acer Macrophyllum (Big leaf maple) standing above a near-monoculture of Hedera helix (ivy). There is some remnant Polystichum munitum (Sword fern) and a stand of Rubus parviflorus (Thimbleberry).

On the east side of the trail, the section bordering the Headwaters Bowl and the Olympic Terrace properties is less invaded. The canopy mixture is the same, with more sword fern. This area has received some planting during restoration work. There is still a low diversity of native plants.

There has been no systematic plant survey in the South Slope HMU. Table 1, below, lists those plants that have been observed growing there through casual observation or have been planted during restoration activities. It also includes plants listed in the target forest type description but not observed or planted.

Table 1: Vegetation in the South Slope

Scientific Name Common Name Inv TFT So. Slope
Abies grandis Grand Fir   1  
Acer circinatum Vine maple   1  
Acer macrophyllum Big Leaf Maple   1 G
Alnus rubra Red Alder   1 G
Athyrium filix-femina Lady Fern   1  
Blechnum spicant Deer Fern   1  
Bromus vulgaris Columbia brome   1  
Carex deweyana Dewey’s sedge   1  
Cicerbita muralis Wall lettuce 1   G
Corylus cornuta Beaked Hazelnut   1  
Daphne laureola Spurge Laurel 1   G
Dryopteris expansa Spiny Wood Fern   1  
Galium triflorum Sweet-scented bedstraw   1  
Gaultheria shallon Salal   1  
Geranium robertianum Herb robert 1   G
Hedera helix English Ivy 1   G
Ilex aquifolium English Holly 1   G
Lapsana communis Nipplewort 1   G
Mahonia nervosa Dull Oregon-grape   1 G
Polystichum munitum Sword Fern   1 G
Pseudotsuga menziesii Douglas-fir   1  
Pteridium aquilinum Bracken Fern   1  
Rubus armeniacus Himalayan Blackberry 1   G
Rubus parviflorus Thimbleberry     G
Rubus spectabilis Salmonberry   1  
Rubus ursinus Trailing blackberry   1 G
Sambucus racemosa ssp. pubens Red Elderberry   1  
Thuja plicata Western red-cedar   1  
Tiarella trifoliata Threeleaf foamflower   1  
Trientalis borealis ssp. latifolia Western starflower   1  
Trillium ovatum Western Trillium   1  
Tsuga heterophylla Western Hemlock   1  
Urtica dioica Stinging Nettle     G
Vaccinium parvifolium Red Huckleberry   1  
Vancouveria hexandra Inside-out Flower   1

Key: “1” in Inv column indicates the plant is considered invasive. “1” in TFT column indicates the plant is listed in the Target Forest Type description for the 91st St. Slope. “G” or “R” in the So. Slope column indicates the plant has been observed growing or has been planted as part of restoration activities.

14 plant species have been observed growing in the South Slope HMU. Of these, seven (50%) are invasive. Of the 26 plants listed in the target forest type, five (19%) have been observed growing in the South Slope HMU.

Invasive Removal and Restoration Plan

Figure 2: The South Slope

Subarea A is to the east; Subarea B is to the west.

Subarea A is to the east; Subarea B is to the west.

Subarea A

Subarea A lies between the property lines of Olympic Terrace and the Headwaters Bowl. This means it will be affected by the work done in Subarea D of the Headwaters Bowl. It also lies above the seeps in the HWB that will receive some of the attention of the Stewardship Grant. Work here will have to be coordinated with these other projects.

The northern reaches of Subarea A have received numerous tree and shrub plantings in the last two years. These appear to have established well. Unfortunately, we did not keep accurate records, so we do not have accurate mortality rates.

In the parts of Subarea A that have been explored, there are few invasive plants. The efforts here will be to control what invasiveness is there and add to diversity, particularly at the shrub and groundcover layers.

Suggested Tasks for Subarea A:

  • Continue exploration and control of existing invasives. This can be done by forest stewards.
  • Monitor plantings for survival and growth. Replenish as necessary. Plant trees for buttressing in the lower sections; above that, plant shrubs for diversity and to maintain view corridors into the park from Olympic Terrace.
  • Coordinate work in Subarea A with the Stewardship Grant from the Washington Native Plant Society (HWB Subarea B) and with the homeowners of Olympic Terrace (HWB Subarea D) as necessary.

Subarea B

Trailside reaches of Subarea B are accessible to forest stewards and volunteers. There is a stand of Rubus parviflorus (Thimbleberry) along the trailside that can be spread through berry spreading and live staking.

Suggested Tasks for Subarea B:

  • Spread the Rubus parviflorus (Thimbleberry) with a mixture of berries and live stakes.
  • Attend to the trailside weeds such as Lapsana communis (nipplewort) and Cicerbita muralis (wall lettuce).
  • Subarea B cannot receive crew attention until water control efforts on the South Plateau have improved.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

Description

The 91st St. Slope is a long, narrow strip that runs between the main social trail at the lower end and property lines at the upper. It is 23,313 square feet. Because of its steepness, it’s relatively unexplored.

The southeast corner is known as “Knotweed Hill” because it had a thicket of Reynoutria japonica (Japanese knotweed) that was treated in 2012. There is some knotweed resurgence that has been reported and is being monitored. For the full story of Knotweed Hill, please see “Park and Restoration History.”

The majority of the 91st St. Slope has no conifer canopy and less than 1% conifer regeneration. However, at the north end, where the 91st St. Slope abuts the 92nd St. wetlands, there is close to 10% Tsuga heterophylla (Western hemlock).

The target forest type for the 91st St. Slope is Tsuga heterophylla – Pseudotsuga menziesii/Polystichum munitum – Dryopteris expansa (Western hemlock – Douglas fir/Sword fern – Spreading wood fern; TSHE-PSME/POMU-DREX). The reference ecosystem is Mesic-moist conifer and conifer-deciduous mixed forest.

Water Flow

One section of the trail bordering the 91st St. Slope dips below the water table. No other water flow has been observed from the 91st St. Slope.

Vegetation

Trailside, there are canopy gaps along this HMU that encourage the growth of blackberry and even grasses. There are dense laurel thickets, which were treated in the summer of 2014 with stem injection. Most of the rest of the trailside vegetation is Rubus armeniacus (blackberry) with Hedera helix (ivy) and some Rubus ursinus (trailing blackberry).

In October, 2012, three Alnus rubra (Red alder) trees fell from the 91st St. Slope across the main social trail and into a laurel thicket. This enlarged a canopy gap and blocked the trail until February, 2013, when it was cleared by the Natural Area Crew.

Because of the steepness of the rise from the trail, it’s difficult to see what is on the slope. The 91st St. Slope still has some trees that need ivy survival rings, but they are on nearly vertical sections of the slope.

No systematic monitoring has been done for the 91st St. Slope. However, what we have observed growing is listed in Table 1, below. Please see the key below the table for an explanation.

Table 1: Plants observed growing on the 91st St. Slope.

Scientific Name Common Name Inv TFT 91st Slope
Abies grandis Grand Fir   1 R
Acer circinatum Vine maple   1  
Acer macrophyllum Big Leaf Maple   1 G
Alnus rubra Red Alder   1 G
Asarum caudatum Wild ginger     R
Athyrium filix-femina Lady Fern   1  
Blechnum spicant Deer Fern   1  
Bromus vulgaris Columbia brome   1  
Carex deweyana Dewey’s sedge   1  
Claytonia sibirica var. sibirica Siberian spring beauty     G
Corylus cornuta Beaked Hazelnut   1  
Daphne laureola Spurge Laurel 1   G
Dryopteris expansa Spiny Wood Fern   1  
Galium aparine Bedstraw     G
Galium triflorum Sweet-scented bedstraw   1  
Gaultheria shallon Salal   1  
Hedera helix English Ivy 1   G
Hydrophyllum tenuipes Pacific Waterleaf     G
Ilex aquifolium English Holly 1   G
Impatiens glandulifera Policeman’s helmet 1   G
Lonicera involucrata Twinberry     R
Mahonia nervosa Dull Oregon-grape   1 G
Malus fusca Pacific Crab Apple     R
Oemleria cerasiformis Osoberry (Indian plum)     G
Osmorhiza berteroi Sweet Cicely     G
Polystichum munitum Sword Fern   1 G
Pseudotsuga menziesii Douglas-fir   1  
Pteridium aquilinum Bracken Fern   1  
Ranunculus repens Creeping buttercup 1   G
Reynoutria japonica Japanese Knotweed 1   G
Rosa gymnocarpa Baldhip rose     R
Rosa nutkana Nootka rose     R
Rubus armeniacus Himalayan Blackberry 1   G
Rubus spectabilis Salmonberry   1 G
Rubus ursinus Trailing blackberry   1 G
Rumex occidentalis Western dock     G
Sambucus racemosa ssp. pubens Red Elderberry   1 G
Taxus brevifolia Pacific Yew     G
Thuja plicata Western red-cedar   1 G
Tiarella trifoliata Threeleaf foamflower   1  
Tolmiea menziesii Piggyback Plant     G
Trientalis borealis ssp latifolia Western starflower   1  
Trillium ovatum Western Trillium   1  
Tsuga heterophylla Western Hemlock   1  
Urtica dioica Stinging Nettle     G
Vaccinium parvifolium Red Huckleberry   1  
Vancouveria hexandra Inside-out Flower   1

Key: Bold plant names indicate plants listed in a target forest type but not observed growing in any HMU. “1” in Inv column indicates the plant is considered invasive. “1” in TFT column indicates the plant is listed in the Target Forest Type description for the 91st St. Slope. “G” or “R” in the 91st St. Slope column indicates the plant has been observed growing or has been planted as part of restoration activities.

Of the 30 plant species observed growing in the 91st St. Slope HMU, seven (23%) are invasive. Of the 26 plants listed in the target forest type for the 91st St. Slope, nine (34.6%) are found growing in the HMU. These numbers would probably change with systematic observation.

Invasive Removal and Restoration Plan

Figure 1: 91st St. Slope

A: Accessible to volunteers. B: Contract Crew.

A: Accessible to volunteers. B: Contract Crew.

Subarea A

Subarea A measures 9,400 square feet and is accessible to all volunteers. It is separated from a similar volunteer-accessible area in the Central Valley HMU by a narrow social trail.

EarthCorps, in the fall of 2013, did some invasive removal in the Central Valley adjacent to the 91st St. Slope, reaching to about the dogleg in Figure 1, above.

In the winter of 2014, Friends of North Beach Park leap-frogged this restored area and cleared about 800 square feet on both sides of the trail of blackberry brambles.

Our intention was to continue clearing back towards the EarthCorps-cleared area over the summer months. However, in May and June we instead worked on aftercare for plants installed in dryer areas of the park, particularly near the entrance. In August, we did some re-clearing because the area had had a resurgence of invasives, particularly Ranunculus repens (creeping buttercup).

In August, a contract crew from the Parks Department injected a laurel stand with herbicide.

In November, Friends of North Beach Park cleared and planted in the area. Most of the plants were installed on the Central Valley side of the trail.

Suggested tasks for Subarea A:

  • Survey the area to be cleared between where the Friends of North Beach Park worked in January 2014 and EarthCorps worked in Fall of 2013.
  • Plan a series of public and forest steward workparties to bring the two areas together.
  • Work closer to the trail during wet weather, move to the streambank in the summer.
  • Use burlap and mulch to cover bare areas.
  • Use GSP provided plants to fill in in the fall.

The tasks above were written in the summer of 2014. As of the fall of 2014, work on the 91st St. Slope has been demoted in favor of concentrating on the Headwaters Bowl.

Subarea B

Subarea B is unexplored as of fall 2014. It is lower priority than the South or West Slopes, which have a much higher extent of invasion; consequently, there is no crew time scheduled or predicted for this subarea.

Suggested tasks for Subarea B:

  • Explore as much as possible.
  • Put survival rings on any trees that need them.

References

Green Seattle Partnership, 2014. GSP Reference Map on ArcGIS.com. http://www.arcgis.com/home/webmap/viewer.html?webmap=9be9415001144aa383e5b86e481d2c45&extent=-122.5312,47.374,-121.7945,47.7577 Dates of accession various.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

Description

The South Plateau is an isolated upland with a separate, unofficial entrance. From the main body of the park, it is only accessible via a steep social trail that is slippery in the winter and friable in the summer. If you think of North Beach Park as a boot, the South Plateau is the heel. The floor of the plateau is surrounded by steep, short walls.

The South Plateau, at 25,000 square feet, is also the largest flat area in the park. As explained in “Park and Restoration History,” the South Plateau was intensively cleared in the summer of 2012 by an independent forest steward.

For more than a year, the only work done in the South Plateau was by Parks Department Natural Area Crew. In the summer of 2014, forest stewards watered and did some after care for the plants in June and July, and there was a work party in September.

The South Plateau has less than 1% conifer cover, but at least 75% deciduous cover.

The target forest type for the South Plateau is Tsuga heterophyllaPseudotsuga menziesii/Polystichum munitumDryopteris expansa (Western hemlock – Douglas fir/Sword fern – Spreading wood fern; TSHE-PSME/POMU-DREX). The reference ecosystem is Mesic-moist conifer and conifer-deciduous mixed forest.

Water Flow

During the rainy season, water accumulates from NW 85th St. and 26th Ave NW (310 feet) (all elevations from Seattle DPD GIS map). It runs to the north uninterrupted by any green scape or drainage system the length of 26th Ave. to 88th St., where it turns to the west. Once at 27th Ave., it turns again to the north and enters the park. The floor of the South Plateau is at 250 feet, giving this run about a 5% grade.

Figure 1: Path of water flow into the South Plateau.

The blue line indicates path of water, which flows toward the top of the map, from 85th St. to the South Plateau. (Source: Seattle Department of Public Development DPDGIS map.)

The blue line indicates path of water, which flows toward the top of the map, from 85th St. to the South Plateau. (Source: Seattle Department of Public Development DPDGIS map.)

Before clearing, the dense ivy and blackberry cover dissipated a lot of the energy of this water flow, spreading it out over the surface of the plateau. However, invasive removal caused a serious erosion problem was caused.

The Parks Department has installed rip rap and forced meanders into the water flow using plantings and fascines (water barriers made of bundles of salmonberry live stakes).

Figure 2: Water flow in May, 2014

Looking up towards the entrance of the park (the gray rocks in the upper right.) This is from about the middle of the fascines.

Looking up towards the entrance of the park (the gray rocks in the upper right.) This is from about the middle of the fascines.

There is still some water flow control to be done on the South Plateau, and it will have to be studied during rain events of different sizes during the fall and winter.

Water control can be improved in this area by adding meanders to the downstream end of the storm runoff, maintaining the existing meanders and fascines, and working with the stream to slow it down and let the water percolate through the plateau.

During the summer drought, the South Plateau has no water source. This leads the soil to dry and harden, becoming very compact. Plant establishment is very slow, but improving.

For more recent observations on South Plateau water issues, please see Water Flow: South Plateau Street Runoff.

Vegetation

At the start of restoration, the South Plateau was a mix of Acer macrophyllum (Big leaf maple) and Alnus rubra (red alder), with a shrub layer almost exclusively of Hedera helix (English ivy) and Rubus armeniacus (Himalayan blackberry). Other notable invasives included Lamium galeobdolon (Yellow archangel) and Clematis vitalba (Wild clematis).

There is still a fair amount of remnant and resurgent Hedera helix (ivy). Calystegia sepium (bindweed), Lapsana communis (nipplewort), and Geranium robertianum (herb robert) have also made inroads.

A forest monitoring plot following the Green City protocol was established in the South Plateau in July, 2012, and revisited in August, 2013. Note the difference, in Figures 3 and 4 below, in regenerative invasive trees. This is what happens with overclearing followed by neglect.

Figure 3: Invasive regenerative trees, South Plateau, 2012.

This was the extent of invasive trees in 2012, when the South Plateau was just starting to be cleared. (Source: EarthCorps, 2012)

This was the extent of invasive trees in 2012, when the South Plateau was just starting to be cleared. (Source: EarthCorps, 2012)

Figure 4: Invasive regenerative trees, South Plateau, 2013.

The South Plateau was cleared aggressively in 2012 and early 2013, and then neglected.

The South Plateau was cleared aggressively in 2012 and early 2013, and then neglected.

Invasive Removal and Restoration Plan

Figure 5: South Plateau.

A: Accessible to volunteers. B: Contract or Natural Area Crew. (Source: GSP Reference Map on ArcGIS.com)

A: Accessible to volunteers. B: Contract or Natural Area Crew. (Source: GSP Reference Map on ArcGIS.com)

Subarea A

Subarea A (outlined in blue in Figure 5, above), at 13,000 square feet, is the largest and driest flat area of the park and the most volunteer friendly. Even though it’s surrounded by Subarea B, it can be accessed by walking carefully down some rip rap. This was the area the independent forest steward and her crew worked in.

The over-clearing followed by neglect has left the South Plateau with a plant community that is still very much out of balance. It’s in better shape than when the ivy and blackberry dominated, but it’s still at risk of an invasive-only plant community.

There is still a lot of invasive removal in Subarea A, including annuals such as Lapsana communis (nipplewort). Subarea A could use a lot of wood mulch, both around the establishing plants, and in large areas of relatively bare ground. In the long term, this would ease the compaction of the soil and aid in plant establishment.

Suggested tasks for Subarea A:

  • Mulch around existing plants, and spread mulch to a depth of at least 4” in bare areas of South Plateau.
  • Monitor water flow during rain events. Adjust and repair fascines as necessary.
  • Add meanders to further reaches of South Plateau. The goal is to slow and spread the water, so it stays on the South Plateau and percolates into the soil.
  • Investigate mycelium inoculation as a means of improving soil conditions.
  • Forest stewards continue working in South Plateau one day a month for after care and weeding.
  • Have two work parties a year (one for planting, one for invasive removal and/or after care).

Subarea B

Subarea B is the walls surrounding the plateau part of the South Plateau. It measures approximately 12,000 square feet. The walls are nearly vertical, making it only available for work by the Parks Department Natural Area Crew. There is a rim of the plateau accessible from 27th Ave NW, but it is so narrow that the best approach is to have the Natural Area Crew work on the rim, and the forest stewards or volunteers do aftercare.

Either the Parks Department Natural Area Crew or the volunteers in the summer of 2012 (or both) have done some work on the western slope. On the eastern and southern slopes of the wall, property lines might be an issue.

Further work on Subarea B will be done by the Parks Department Natural Area Crew. Some of the work could be done at the same time as working on the South or West Slopes (see below).

Suggested tasks for Subarea B:

  • Remove resurgent invasives and increase density in cleared areas.
  • Remove ivy and put survival rings on trees on the northern edges of the South Plateau.
  • Coordinate work on the northern edges of the South Plateau with work done on the South Slope.

References

Department of Planning and Development. 2007. City of Seattle Department of Planning and Development GIS map. http://web1.seattle.gov/dpd/maps/dpdgis.aspx (Dates of accession various.)

EarthCorps. 2012. North Beach Park South Plateau Baseline Report. (unpublished document). EarthCorps, Seattle.

EarthCorps. 2013. North Beach Park South Plateau Monitoring Report. (unpublished document). EarthCorps, Seattle.

Green Seattle Partnership, 2014. GSP Reference Map on ArcGIS.com. http://www.arcgis.com/home/webmap/viewer.html?webmap=9be9415001144aa383e5b86e481d2c45&extent=-122.5312,47.374,-121.7945,47.7577 (Dates of accession various.)

Mirrored from Nature Intrudes. Please comment over there.

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