B08_Attachment_2_140P8422Q0127_Inspections-Recommendations_Report.pdf

Tree Inspection and Recommendations Report For Historic Trees Located at the Point Reyes NS

Bolinas Transmitting Station And

Point Reyes Receiving Station

Assessment and Recommendations by

Keith W. Park

Horticulturist & Arborist

4-East Bay Parks

Summary of Trees Evaluated Evaluated a total of 122 trees between both sites, including:

Bolinas Transmitting Station (24 trees) 13 Monterey cypress 11 Monterey pine

Point Reyes Receiving Station: (98 trees)

65 Monterey cypress 15 Monterey pine 12 mousehole trees 3 eucalyptus 2 magnolia 1 spruce tree

General Recommendations for Tree Work

Pruning All pruning work shall be performed by or under the supervision of an International Society of Arboriculture (ISA) certified arborist, according to the ISA A300/part 1 standards for tree pruning https://wwv.isa-arbor.com/store/product/124/

• Utilize bucket trucks or lifts where safe and practical such as along paved driveway areas.

• Utilize climbing arborist(s) for trees that are safely inaccessible to large equipment.

• Prevent undue compaction to tree root zone by utilizing sturdy work mats or similar, to disperse forces from tires and outriggers where necessary within tree root zones.

https://www.treestuff.com/alturnamats-groundcover-mats/

Prune to remove all dead, damaged, or diseased wood (see Figure 4 in Appendix):

• Remove as much deadwood as possible from all tree canopies, from ½” in size and up.

• Remove any broken, split, or otherwise damaged limbs and small branches of any size.

• Remove any diseased or dying branches or foliage, dispose of all diseased material off site.

• Prune to restore tree structure wherever possible by:

o Remove crossing or rubbing branches, broken branches.

o Reduce overly long and heavily end-weighted limbs back to smaller diameter branch

• Remove all ivy and encroaching vegetation from tree trunks to grade, below trunk flare

Practice proper pruning techniques (see Figures 5, 6, & 7 in Appendix):

• Sterilize all pruning tools between each tree or if pruning potentially diseased material

• Utilize target pruning for all branches 1” in diameter or larger.

• Always prune to outside of branch collar and at appropriate angle to minimize wound area.

• Never “flush cut” against trunk or large branches.

• Do not leave stubs.

https://wwv.isa-arbor.com/store/product/124/ https://www.treestuff.com/alturnamats-groundcover-mats/

Removal Remove ten (10) trees that are dead or at risk of failing in the near future:

• Remove four (4) trees at Bolinas Transmitting Station: 6005, 6006, 7006, 7011

• Remove six (6) trees at Point Reyes Receiving Station: 1022, 1058, 2007, 2008, 2009, 2010

• Chip all debris and distribute as mulch or haul off site

• Cut trees trunks flush with soil grade to avoid soil disturbance, or stump grind

• Consider retaining dead trunks of trees 1022 and 1058 along allee at Point Reyes Rx Station as visual placeholders as well as habitat for wildlife, but only if dead trunks are determined to be firmly anchored to the ground and pose no risk of falling or striking targets. (see Figure 8 in Appendix)

Renovation Renovate all mousehole Trees (4001 – 4012) at Point Reyes Rx Station (see Figure 9 in Appendix)

Based on the arrangement and location of the mousehole trees/shrubs, it is assumed that the design intent was to create a hedge effect to screen views of the single-story structures from the driveway turnaround area. Lack of maintenance pruning has allowed the trees to grow taller than the adjacent structures. To return these trees to their original intended form and function, renovation pruning is recommended.

• Renovate all existing mousehole trees by reducing (i.e. “topping”) their height and spread down to at or below the existing roof height of adjacent buildings to encourage new growth to emerge from the trunks.

• Chip and spread removed parts around base of mousehole trees as mulch

• Prune renovated mousehole trees annually for several years at least to restore hedge effect.

Additional Recommendations

• Remove all non-contributing volunteer Monterey Pines and any other sapling trees throughout both sites, particularly around the Point Reyes Rx Station (Figure 1 in Appendix).

• Remove accumulated debris and detritus around all trees to reclaim trunk flare wherever trunks are buried.

• Retain two Leptospermum shrubs flanking north side of main building at Point Reyes Rx Station.

Based upon their location (flanking the northerly axis of the main building) as well as their size and age, it is assumed that these two shrubs are part of the original design intent and should be retained. Removal of encroaching vegetation and limbing up of any over shading branches from adjacent contributing trees will support the growth and health of these two specimens.

• Retain pittosporum hedgerow located north of garage structure at Point Reyes Rx Station (Figure 2 in Appendix). Based on the location and spacing of these trees/shrubs, it is assumed the were intended to perform as a screen and may be historic/contributing to the original design intent.

• Evaluate historic contribution and compatibility of black Acacia trees/shrubs located north-east of main building at Point Reyes Rx Station (Figure 3 in Appendix): Growth may be from below-ground roots of a former tree (no longer extant) or may be volunteer seedlings. Either way this acacia vegetation is somewhat encroaching upon other trees in this location and obscuring views and cluttering the site.

Notes

Discrepancies between SOW map vs. site visit ground truth:

Bolinas Tx station:

• For some trees in the north side of the site and west of the entry drive (e.g. trees 6001-6007), it was sometimes hard to tell which tree on the map corresponded to which tree on the ground, as GIS locations were sometimes inaccurate compared to the actual locations. Reasonable assumptions were made as to which trees were identified for inspection.

• Also, one Monterey cypress (6003) was somehow missed during inspection, or more likely the file was inadvertently overwritten during the inspection. A blank form for 6003 is included in the packet from Bolinas, but the treatment recommendations will likely be similar to all the other trees assessed at the site.

Point Reyes Rx Station:

• 1032 split into two separate tree IDs: 1032.1 and 1032.2 to accommodate an additional tree in the western allee that was captured during inspection but evidently not identified in SOW

• 2001 is a cypress, not a pine, and map location should be switched with 5002

• 2002 is a spruce, not a pine

• 2012 location contains two trees, not one

• 5002 is a pine, not a cypress, and map symbol should be switched with 2001

Tree Descriptions

Monterey cypress (Hesperocyparis macrocarpa; syn. Cupressus macrocarpa)

• Live up to 280 years

• Age of mature specimen trees at Bolinas and Point Reyes sites between 50-90 years old

• Best to prune in spring-fall

• Avoid making large structural limb cuts/removals if possible, as cypress tend not to regrow from large cuts.

• Generally disease resistant species, thus little expectation of encountering transmittable disease during cleaning/thinning pruning work.

• https://ucanr.edu/sites/treefail/files/199067.pdf

• https://thtreeservices.co.uk/best-time-year-prune-monterey-cypress-tree/#:~:text=Monterey%20cypress%20pruning%20should%20only,prune%20the%20young%20 green%20shoots.

https://ucanr.edu/sites/treefail/files/199067.pdf https://thtreeservices.co.uk/best-time-year-prune-monterey-cypress-tree/#:%7E:text=Monterey%20cypress%20pruning%20should%20only,prune%20the%20young%20green%20shoots https://thtreeservices.co.uk/best-time-year-prune-monterey-cypress-tree/#:%7E:text=Monterey%20cypress%20pruning%20should%20only,prune%20the%20young%20green%20shoots https://thtreeservices.co.uk/best-time-year-prune-monterey-cypress-tree/#:%7E:text=Monterey%20cypress%20pruning%20should%20only,prune%20the%20young%20green%20shoots

Monterey pine (Pinus radiata)

• Average lifespan is 90 years

• Some pines at Bolinas and Point Reyes sites are approaching this age, but generally appear to be in decent shape for their age.

• Can become weedy, as observed at both sites.

• Some tip dieback was observed on some pine trees during assessment, but not extensively.

• Potential pest/disease issue is Red Turpentine Beetle, which burrows into bark, creating subsurface galleries and superficial pitch/resin accumulation. No visible signs of this were present during 2020 assessment, but may be present in higher canopy locations.

• There are no practical solutions for bark beetle infestations,

• http://ipm.ucanr.edu/PMG/PESTNOTES/pn7421.html

• https://plants.usda.gov/plantguide/pdf/cs_pira2.pdf

• http://www.ucanr.org/sites/treefail/files/4388.pdf

• https://plants.usda.gov/plantguide/pdf/cs_pira2.pdf http://ipm.ucanr.edu/PMG/PESTNOTES/pn7421.html https://plants.usda.gov/plantguide/pdf/cs_pira2.pdf http://www.ucanr.org/sites/treefail/files/4388.pdf https://plants.usda.gov/plantguide/pdf/cs_pira2.pdf

Corymbia (Eucalyptus sp.)

• Age, species, and historic contribution of these three trees is undetermined

• One eucalyptus is much larger and evidently older than the other two, but all appear to be same species, possibly Red-Flowering Gum or Corymbia ficifolia (syn. Eucalyptus ficifolia), based on the large seedpods observed: https://trees.stanford.edu/ENCYC/EUCfic.htm

• Three additional tree assessment sheets were created for these trees: 8001, 8002, 8003

• Recommend retaining these trees as potentially contributing specimens to the cultural landscape.

https://trees.stanford.edu/ENCYC/EUCfic.htm

Southern magnolia (Magnolia grandiflora)

• Typically a large tree living up to 80 years or longer

• Specimens at Point Reyes Rx Station are quite small and not well suited for this environment, evidenced by their poor to fair condition.

• Trees size indicates they are not contributing to the cultural landscape, and probably not compatible based on the overall design scheme of native/coast tolerant conifers, but they pose no negative impact and may be retained and maintained if desired.

• Magnolia grandiflora, southern magnolia | Trees of Stanford & Environs https://trees.stanford.edu/ENCYC/MAGgr.htm

Mousehole tree, aka Myoporum (Myoporum laeteum)

• Species is suited to coastal California and can live from 50-150 years

• Specimens at Point Reyes Rx Station are likely contributing and compatible with the cultural landscape based on size, condition, and location.

• It is recommended that a renovation pruning effort be enacted on these trees to restore their intended effect as a screen between the entry turnaround and the utility buildings to the south-east. Begin renovation pruning by lowering mousehole tree heights to at or below the roof height of adjacent buildings.

• Also recommended is replacement planting mousehole trees in vacancies in-between existing mature trees at appropriate spacing, to restore the integrity of the hedge effect.

• Renovation pruning takes some years to accomplish depending on the vigor of the vegetation, but these myoporum trees appear healthy enough to be renovated, and this species is capable of basal sprouting once large heading cuts are made, from which the new foliage can be pruned to restore the hedge effect.

• Note: the common name is usually just Myoporum, as I learned it, but mousehole works too.

• https://selectree.calpoly.edu/tree-detail/myoporum-laetum

• https://www.cal-ipc.org/plants/profile/myoporum-laetum-profile/

(Recommended renovation pruning height illustrated by yellow lines, infill planting by blue line) https://selectree.calpoly.edu/tree-detail/myoporum-laetum https://www.cal-ipc.org/plants/profile/myoporum-laetum-profile/

Spruce (Picea sp.)

• Spruce tree species at Point Reyes Rx Station is undetermined, possibly a Sitka spruce.

• Spruce are long-lived conifers, up to several hundred years depending on the species.

• The single specimen at Point Reyes Rx Station is a potentially contributing and compatible resource, based on size, diameter, and location.

• This tree appears healthy with no immediate need for pruning, with the exception of the lichen that has accumulated on it’s lower branch tips. Lichen is not necessarily injurious to trees, at least it is not parasitic, however anecdotal evidence suggests that too much lichen accumulation can hasten the decline of susceptible ornamental trees, but this is not a fact.

• The profusion of new growth emerging from the trunk of this spruce tree is interesting, but not necessarily cause for concern. Recommend monitoring the tree for signs of decline in the canopy, as some species of plants will respond to health issues in the canopy with new growth below.

Appendix: Supplemental Images

Figure 1 - Examples of volunteer Monterey pine trees throughout the site that should be removed.

Note: Leptospermum shrubs can be seen in background beneath bough of pine tree.

Figure 2 - One of two leptospermum shrubs on north side of main Point Reyes Rx Station, flanking cypress tree # 5003. While they appear reasonably healthy, they would benefit from more light by removing encroaching non-contributing vegetation and raising of the canopies of the cypress and neighboring pine tree canopies by selective removal of some lower limbs.

Figure 3 - Black acacia vegetation located at north corner of Point Reyes Rx Station should be evaluated for historic significance. If found contributing and compatible maintain as hedgerow, if found to be non-contributing and/or incompatible remove and treat cut stumps with herbicide to prevent reproduction.

Appendix: Additional Pruning Notes

Figure 4 - The Three “D” of Stabilization Pruning: Dead, Damaged, and Diseased wood should be removed.

Figure 5 - Thinning vs. Heading Cuts: make thinning cuts whenever possible to retain tree structure, unless renovation pruning in which case heading cuts are permissible.

Figures 6 (Left) - Target Pruning Method: Undercut, Top Cut, Final Cut.

Figure 7 (Right) - Detail of branch collar and where to make final cut

Figure 8 - Example of dead trees retained as stable snags for wildlife habitat purposes (photo by author, Stanley Park, Vancouver BC)

Figure 9 – example of renovation pruning technique to lower height and spread of mousehole trees.