Submitted to Seattle Parks & Verdant LLC on May 31st 2018
Here for your consideration and critique is my strawman proposal for experimental restoration in two small die-off regions at Seward Park.
- Paul
Premises:
1) We do not know the cause/s of the die-off, nor its expected duration
and eventual extent. Crucially, we do not know if this is a transient, cyclic,
or endemic phenomenon.
2) We DO know that in Seward Park, die-off of formerly sword fern dominated
areas are not, after four years, regenerating. This is in marked
contrast to post-disturbance regimes of natural restoration described
by Swanson, Franklin et al (2002), "The Forgotten State of Forest: Early
Successional Ecosystems on Forest Sites". The cumulative effects, upon
general forest health, of unregenerated bare ground, may be significiant.
3) The selection of restoration strategies may benefit from an evaluation of
the differennce between S&F's intense disturbances(fire, volcano,
clearcut, insects, wind) and the context in which their regeneration
occurs. Specifically, our sites have an intact overstory and
a possibly reduced local seed sources.
4) Ground Zero is in GSP zone "MF4", with target forest type PSME-ARME/HODI/LOHI
(doug fir, madrone, ocean spray, hairy honeysuckle). "Extended
ground zero" - across the Hatchery Trail to the north, MF7, has
target forest type PSME-TSHE/MANE-POMU. A good case can be made
that ground zero is PSME-TSHE/MANE-POMU as well.
5) My immediate concern is with the previously sword fern dominated bare
ground sites. That fern dominance may not be a necessary feature of
those bare ground sites: this may have been a contingent assemblage
produced by quirks in the plant geography and historical dynamics of the forest.
Given that the (still unknown) cause of the die-off may be still be present,
or may return, it is unwise to restore these areas to anything like the
sword fern (near) monoculture which existed there before.
Proposal:
1) To choose two small currently mostly bare areas (70' x 70'?), one north and
one south of the Hatchery Trail for restoration planting and seeding, using
the characteristic species of the PSME-TSHE/MANE-POMU forest type, as
described in Christopher Chappell's DNR report, "Upland Plant
Associations of the Puget Trough Ecoregion", 2004, page 109, as listed below.
2) Perhaps conventional 1-gallon pot seedling planting can be accompanied by
judicious experiments with direct seeding.
3) There may be some urgency to returning these moribund areas to
good health - made up from a heterogeneous community with complex
food webs, nutrient flows and physical structure inspired by some of the
intact heterogeneous late succession plant communities found elsewhere
in the forest at Seward. We may therefore wish to perform careful
monitoring of survival rates for both seeds and plants, and to
inistitute manual watering protocols through the first two summers,
to maximize the chances of successful restoration, and to refine
practices for reuse elsewhere.
Candidate Plant species
Douglas-fir Pseudotsuga menziesii var. menziesii 100 48
western hemlock Tsuga heterophylla 87 38
western redcedar Thuja plicata 82 35
bigleaf maple Acer macrophyllum 60 19
grand fir Abies grandis 22 7
Shrubs and Dwarf-shrubs
dwarf Oregongrape Mahonia nervosa 100 18
red huckleberry Vaccinium parvifolium 80 3
trailing blackberry Rubus ursinus var. macropetalus 78 1
salal Gaultheria shallon 73 3
vine maple Acer circinatum 49 15
beaked hazelnut Corylus cornuta var. californica 42 5
baldhip rose Rosa gymnocarpa 40 1
Graminoids
Coast Range fescue Festuca subuliflora 33 1
Forbs and Ferns
sword fern Polystichum munitum 100 23
sweet-scented bedstraw Galium triflorum 62 2
western starflower Trientalis borealis ssp. latifolia 62 2
bracken fern Pteridium aquilinum var. pubescens 49 1
western trillium Trillium ovatum ssp. ovatum 47 1
spreading woodfern Dryopteris expansa 42 1
vanillaleaf Achlys triphylla 36 3
twinflower Linnaea borealis ssp. longiflora 31 3
inside-out flower Vancouveria hexandra 29 5
threeleaf foamflower Tiarella trifoliata var. trifoliata 29 1
- Paul
Premises:
1) We do not know the cause/s of the die-off, nor its expected duration
and eventual extent. Crucially, we do not know if this is a transient, cyclic,
or endemic phenomenon.
2) We DO know that in Seward Park, die-off of formerly sword fern dominated
areas are not, after four years, regenerating. This is in marked
contrast to post-disturbance regimes of natural restoration described
by Swanson, Franklin et al (2002), "The Forgotten State of Forest: Early
Successional Ecosystems on Forest Sites". The cumulative effects, upon
general forest health, of unregenerated bare ground, may be significiant.
3) The selection of restoration strategies may benefit from an evaluation of
the differennce between S&F's intense disturbances(fire, volcano,
clearcut, insects, wind) and the context in which their regeneration
occurs. Specifically, our sites have an intact overstory and
a possibly reduced local seed sources.
4) Ground Zero is in GSP zone "MF4", with target forest type PSME-ARME/HODI/LOHI
(doug fir, madrone, ocean spray, hairy honeysuckle). "Extended
ground zero" - across the Hatchery Trail to the north, MF7, has
target forest type PSME-TSHE/MANE-POMU. A good case can be made
that ground zero is PSME-TSHE/MANE-POMU as well.
5) My immediate concern is with the previously sword fern dominated bare
ground sites. That fern dominance may not be a necessary feature of
those bare ground sites: this may have been a contingent assemblage
produced by quirks in the plant geography and historical dynamics of the forest.
Given that the (still unknown) cause of the die-off may be still be present,
or may return, it is unwise to restore these areas to anything like the
sword fern (near) monoculture which existed there before.
Proposal:
1) To choose two small currently mostly bare areas (70' x 70'?), one north and
one south of the Hatchery Trail for restoration planting and seeding, using
the characteristic species of the PSME-TSHE/MANE-POMU forest type, as
described in Christopher Chappell's DNR report, "Upland Plant
Associations of the Puget Trough Ecoregion", 2004, page 109, as listed below.
2) Perhaps conventional 1-gallon pot seedling planting can be accompanied by
judicious experiments with direct seeding.
3) There may be some urgency to returning these moribund areas to
good health - made up from a heterogeneous community with complex
food webs, nutrient flows and physical structure inspired by some of the
intact heterogeneous late succession plant communities found elsewhere
in the forest at Seward. We may therefore wish to perform careful
monitoring of survival rates for both seeds and plants, and to
inistitute manual watering protocols through the first two summers,
to maximize the chances of successful restoration, and to refine
practices for reuse elsewhere.
Candidate Plant species
Douglas-fir Pseudotsuga menziesii var. menziesii 100 48
western hemlock Tsuga heterophylla 87 38
western redcedar Thuja plicata 82 35
bigleaf maple Acer macrophyllum 60 19
grand fir Abies grandis 22 7
Shrubs and Dwarf-shrubs
dwarf Oregongrape Mahonia nervosa 100 18
red huckleberry Vaccinium parvifolium 80 3
trailing blackberry Rubus ursinus var. macropetalus 78 1
salal Gaultheria shallon 73 3
vine maple Acer circinatum 49 15
beaked hazelnut Corylus cornuta var. californica 42 5
baldhip rose Rosa gymnocarpa 40 1
Graminoids
Coast Range fescue Festuca subuliflora 33 1
Forbs and Ferns
sword fern Polystichum munitum 100 23
sweet-scented bedstraw Galium triflorum 62 2
western starflower Trientalis borealis ssp. latifolia 62 2
bracken fern Pteridium aquilinum var. pubescens 49 1
western trillium Trillium ovatum ssp. ovatum 47 1
spreading woodfern Dryopteris expansa 42 1
vanillaleaf Achlys triphylla 36 3
twinflower Linnaea borealis ssp. longiflora 31 3
inside-out flower Vancouveria hexandra 29 5
threeleaf foamflower Tiarella trifoliata var. trifoliata 29 1
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