HomeMy WebLinkAbout23, 24 - Tree Retention Plan, Worksheet, and ReportFORESTRY AND VEGETATION MANAGEMENT SPECIALISTS
WFCI
3601943-1 723
FAX 3601943-4 1 28
1919 Yelm Hwy SE, Suite C
Olympia, WA 98501
URBANIRURAL FORESTRY TREE APPRAISAL HAZARD TREE ANALYSIS
RIGHT-OF-WAYS VEGETATION MANAGEMENT ENVIRONMENTAL STUDIES CONTRACT FORESTERS
Member of International Society of Arboriculture and Society of American Foresters
-Tree Protection Plan-
RENTON FIRESTONE
17808 108th Ave. SE Renton, WA
Prepared for: PACLAND
Prepared by: Washington Forestry Consultants, Inc. Date: September 23, 2016
Introduction
The project proponent is planning to build a new Firestone auto care center on 0.88 acres at 17808 108th Ave. SE in Renton, WA. The proponent has retained WFCI to:
• Evaluate and inventory all trees on the site pursuant to the requirements of the City of Renton Tree Protection Ordinance.
• Make recommendations for retention of significant trees, along with required protection and cultural measures.
Observations
Methodology In accordance with Renton Municipal Code 4-4-130, WFCI has evaluated all significant trees on
site. This includes cottonwood and red alder trees 8 inches diameter at breast height (DBH) and
larger, and all other trees 6 inches DBH and larger, and assessed their potential to be incorporated into the new project. Trees were numbered on a map, but not marked in the field. The tree evaluation phase used methodology developed by Nelda Matheny and Dr. James Clark
in their 1998 publication Trees and Development: A Technical Guide to Preservation of Trees
during Land Development.
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Site Description The site has an existing restaurant, with associated parking lot surrounding the building. The eastern portion of the lot includes a grass lawn and trees. There are 26 native and planted trees on site. Overall, tree quality is very poor to fair. The trees on site range between approximately
15 and 40 years old. The site is generally flat, except a short treed slope along the southern
boundary exist. Soil Description According to the USDA Web Soil Survey there is one soil type on this parcel (see soils map
below). Alderwood gravelly sandy loam, a moderately deep, moderately well drained soil found on glacial till plains. It is formed in ablation till overlying basal till. A weakly cemented hardpan is at a depth of 20 to 40 inches. Permeability is moderately rapid above the hardpan and very slow in the pan. Available water capacity is low. The effective rooting depth for trees is
20-40 inches. A perched seasonal high water table is at a depth of 18-36 inches from November
to March. The potential for windthrow of trees is moderate under normal conditions. New trees require irrigation for establishment. In areas where grading brings the hardpan nearer to the surface, the hardpan must be fractured under new trees to provide soil volume for root development and to improve drainage around the tree.
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Tree Conditions The project area consists of one conifer forest cover type with scattered deciduous trees. An inventory of the trees was conducted to determine the composition and health of the forest.
Type I. -- The majority of the trees in this type are Scotch pine (Pinus sylvestris). Other species
include Sitka spruce (Picea sitchensis), grand fir (Abies grandis), and red alder (Alnus rubra).
There is also one Douglas-fir (Pseudotsuga menziesii), one Alaska yellow cedar (Chamaecyparis
nootkatensis), and one flowering plum (Prunus spp.). There are a total of 26 significant trees in this type, ranging in diameter from 6 to 26 inches DBH. Seventeen (17) of the trees were classified as sound, healthy, long-term trees in the
dominant and co-dominant crown class. The other nine trees are not long-term trees due to structural defects and/or poor health. Table 1. Summary of Significant Trees in Type I.
Species DBH Range (in.) Total # of Trees # of Healthy Trees
# of Trees in Poor Health*
Species Composition of Stand
Alaska Yellow Cedar 16-17 1 1 0 3.85%
Douglas-fir 20 1 1 0 3.85%
Flowering Plum 6 1 0 1 3.85%
Grand Fir 12-13 2 2 0 7.7%
Red Alder 8-24 3 0 3 11.55%
Scotch Pine 10-17 11 6 5 42.3%
Sitka Spruce 10-26 7 7 0 26.9%
Total 6-26 26 17 9 100%
*Dead, diseased, or hazardous.
Off-Site Impacts There is one 16-inch DBH red alder tree just north of the parcel boundary that is in poor condition. Tree removal on this parcel will not impact this tree.
Discussion
Potential for Tree Retention There are 9 trees that were evaluated as unhealthy. Therefore 17 significant trees in Type I are available for retention. From the site plan provided, it appears that 1 tree can be saved. The
remaining 25 trees will need to be removed due to construction, and retaining wall installation. The proposed ‘save’ trees are illustrated on the aerial photo in Attachment #1. A detailed list of all trees (over 6 inches DBH) by species, DBH, condition, root protection zone (RPZ), save/remove potential, and retention availability is provided in Attachment #3.
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Tree Density Calculations Title 4-4-130 of the Renton Municipal Code requires that a minimum of 10% of all healthy significant trees in buildable areas be retained on the project in a 'commercial' zone. The following is a summary of the required and planned tree retention:
Total Project Area 0.88 acres Critical Areas and Buffers 0 acres Buildable Area 0.88 acres Total Number of Trees on Site 26 trees
Trees Excluded from Retention Calculation: Trees that are Dead, Diseased, or Dangerous 9 trees Number of Healthy, Significant Trees in Buildable Area: 17 trees Required Tree Retention (‘Protected Trees’):
10% of healthy significant trees in buildable area: 2 trees Planned Tree Retention 1 tree Shortfall of Required Tree Retention 1 tree
There are 17 healthy significant trees in the buildable area of the site. At least 2 of these trees need to be retained to meet the 10% requirement of the City of Renton Code. These trees are considered ‘Protected Trees’. The proposed plan retains 1 tree which is below the minimum retention requirement. Therefore replacement trees will be required for the one ‘protected’ tree
to be removed.
The Renton Municipal Code requires that “replacement trees, with at least a two-inch (2") caliper or an evergreen at least six feet (6') tall, shall be planted at a rate of twelve (12) caliper inches of new trees to replace each protected tree removed. See the Tree Retention Worksheet in
Attachment #4.
Replacement Trees Required 6 Number of Landscaping Trees to Count Toward Replacement Requirement (50% of total requirement) 3
Total Tree Replacement Necessary 3
Up to fifty percent (50%) of trees required pursuant to RMC 4-4-070, Landscaping, may contribute to replacement trees.” Therefore, at least three 2-inch caliper deciduous trees or three 6 ft. tall conifers will need to be planted in addition to the Landscaping requirements.The
landscape plan (prepared by others) should incorporate native conifer trees along with deciduous
accent and shade trees to provide a mix of color, texture, and size.
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Recommendations
Tree Protection Measures
Trees to be saved must be protected during construction by six foot high chain link fencing (Attachment #7), located at the edge of the critical root zone (CRZ). Placards shall be placed on the fencing every 50 feet indicating the words, "NO TRESPASSING - Protected Trees". The
individual CRZ are a radius of one foot for each one inch of DBH (6 feet minimum), unless
otherwise delineated by WFCI (see Attachment #3). Tree protection fences should be placed around the edge of the critical root zone (CRZ). The fence should be erected after logging but prior to the start of clearing. The fences should be
maintained until the start of the landscape installation.
There should be no equipment activity (including rototilling) within the critical root zone. No irrigation lines, trenches, or other utilities should be installed within the CRZ. Cuts or fills should impact no more than 20% of a tree’s root system. If topsoil is added to the root zone of a
protected tree, the depth should not exceed 2 inches of a sandy loam or loamy fine sand topsoil
and should not cover more than 20% of the root system. If roots are encountered outside the CRZ during construction, they should be cut cleanly with a saw and covered immediately with moist soil. Noxious vegetation within the critical root zone
should be removed by hand. If a proposed save-tree must be impacted by grading or fills, then the tree should be re-evaluated by WFCI to determine if the tree can be saved with mitigating measures, or if the tree should be removed. Pruning and Thinning All individual trees to be saved near or within developed areas should have their crowns raised to provide a minimum of 8 feet of ground clearance over sidewalks and landscape areas, 15 feet over parking lots or streets, and at least 10 feet of building clearance.
All pruning should be done according to the ANSI A300 standards for proper pruning, and be completed by an International Society of Arboriculture Certified Arborist®, or be supervised by a Certified Arborist®. Conclusions and Timeline for Activity
1. One tree is proposed to be retained on the site in the buildable area.
2. The final, approved tree protection plan map should be included in the construction drawings for bid and construction of the project and should be labeled as such. 3. Contact WFCI to attend pre-job conference and discuss tree protection issues with contractors. WFCI can verify all trees to be saved and/or removed are adequately marked for
retention.
4. Complete necessary hazard tree removals and invasive plant removals from the tree protection areas. No equipment should enter the tree protection areas during logging.
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5. Install tree protection fences along the 'limits of construction'. The fences should be located
at the limits of construction or 5 feet outside of the dripline of the save tree or as otherwise specified by WFCI. Maintain fences throughout construction. 6. Complete clearing of the project. 7. Do not excavate stumps within 10’ of trees to be saved. These should be individually
evaluated by WFCI to determine the method of removal.
8. Complete all necessary pruning on save trees or stand edges to provide at least 8’ of ground clearance near sidewalks and trails, and 15’ above all driveways or access roads. 9. Complete grading and construction of the project. Summary The City of Renton Municipal Code requires 2 of the 17 significant trees be retained on the
buildable area of the site. This plan retains 1 tree, which is 1 short of the minimum tree retention
requirement. Therefore, at least 6 two inch caliper deciduous trees or 6 six foot tall conifers need to be planted as replacement trees to meet the minimum density requirements. Credit for 3 of these trees can be taken from trees planted as a requirement of the landscaping code.
Please give me a call if you have further questions.
Respectfully submitted,
Galen M. Wright, ACF, ASCA Ben MacColl, ISA, SAF ISA Bd. Certified Master Arborist PN-129BU ISA Certified Arborist® -Certified Forester No. 44 No. PN-7972A ISA Tree Risk Assessor Qualified Professional Forester
attachments
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Attachment #1: Aerial Photo of Firestone Site
with Forest Cover Types (King County Parcel Viewer 2.0)
Approximate Site Boundary Planned Save Trees Planned Removals
X
X X X X
X
X
X X
X X X X
X X
X X
X
X
25
12
11
10
9 8 7 6 5 4 3 2 1
13
24 23 22
21
20
19 18
17 16
15 14
Off-site edge tree: 16” RA (Poor)
X 26 X
X X X X X
X
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Attachment #2: Current Site Conditions/Tree Survey Map (1)
& Site Plan with Approximate Tree Locations (2)
Planned Save Tree Planned Removals X
X X
X
X
X
X
X X X X X
X X X X
X
X
Current Site Conditions/Tree Survey Map
Site Plan with Approximate Tree Locations
11
25
18
17
16 15 14 13
12 10
1
X
2 3 4 5 6 7 8 9
24 26 23 22
21
20 19
X
X X X X X
X
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Attachment #3: Inventory list of project area trees
Tree # Species DBH (in) Condition
Crown
Radius (ft)
Root
Protection Radius (ft)
Savable
based on Tree Health?
Tree to be
Saved in Project?
1 Scotch Pine 10 Fair 12 6 Yes No
2 Scotch Pine 12 Poor 12 6 Yes No
3 Scotch Pine 12 Poor 12 6 Yes No
4 Scotch Pine 12 Fair 10 6 Yes No
5 Scotch Pine 10 Fair 10 6 Yes No
6 Scotch Pine 10 Poor 10 6 No No
7 Scotch Pine 14 Fair 10 6 Yes No
8 Scotch Pine 12 Poor 10 6 Yes No
9 Scotch Pine 17 Poor 12 10 Yes No
10 Sitka Spruce 18 Fair 15 12 Yes No
11 Alaska Yellow Cedar 17,16 Fair 10 12 Yes No
12 Grand Fir 13 Fair 10 12 Yes No
13 Grand Fir 12 Fair 10 8 Yes Yes
14
Flowering
Plum 6 Very Poor 5 4 No No
15 Sitka Spruce 13 Fair 15 10 Yes No
16 Sitka Spruce 15 Fair 12 10 Yes No
17 Sitka Spruce 16 Fair 12 10 Yes No
18 Red Alder 24 Very Poor 15 16 No No
19 Sitka Spruce 10 Fair 10 10 Yes No
20 Red Alder 14 Very Poor 12 10 No No
21 Sitka Spruce 14 Fair 10 12 Yes No
22 Sitka Spruce 26 Fair 15 14 Yes No
23 Douglas-fir 20 Good 18 15 Yes No
24 Scotch Pine 13 Fair 12 4 Yes No
25 Scotch Pine 14 Fair 10 4 Yes No
26 Red Alder 8 Poor 8 6 No No
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Attachment #4: Tree Retention Worksheet
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Attachment #5. Individual Tree Rating Key for Tree Condition
RATING SYMBOL DEFINITION
Very Good VG • Balanced crown that is characteristic of the species
• Normal lateral and terminal branch growth rates for the species and soil type
• Stem sound, normal bark vigor
• No root problems
• No insect or disease problems
• Long-term, attractive tree Good G • Crown lacking symmetry but nearly balanced
• Normal lateral and terminal branch growth rates for the species and soil type
• Minor twig dieback O.K.
• Stem sound, normal bark vigor
• No root problems
• No or minor insect or disease problems – insignificant
• Long-term tree Fair F • Crown lacking symmetry due to branch loss
• Slow lateral and terminal branch growth rates for the species and soil type
• Minor and major twig dieback – starting to decline
• Stem partly unsound, slow diameter growth and low bark vigor
• Minor root problems
• Minor insect or disease problems
• Short-term tree 10-30 years
Poor P • Major branch loss – unsymmetrical crown
• Greatly reduced growth
• Several structurally import dead or branch scaffold branches
• Stem has bark loss and significant decay with poor bark vigor
• Root damage
• Insect or disease problems – remedy required
• Short-term tree 1-10 years
Very Poor VP • Lacking adequate live crown for survival and growth
• Severe decline
• Minor and major twig dieback
• Stem unsound, bark sloughing, previous stem or large branch failures, very poor bark vigor
• Severe root problems or disease
• No or minor insect or disease problems
• Mortality expected within the next few years Dead DEAD • Dead
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Cultural Care Needs:
ABBRV. ACTIVITY DESCRIPTION
CC Crown Cleaning
Pruning of dead, dying, diseased, damaged, or defective branches over 1/2 inch in diameter –includes removal of dead tops
CT Crown Thinning
Pruning of branches described in crown cleaning, plus thinning of up to 20% of the live branches over ½ inch diameter. Branch should be 1/3 to ½ the diameter of the lateral branch. Thinning should be well distributed throughout crown of tree, and should release healthy, long-term branches.
RC Crown
Reduction
Reduction of the crown of a tree by pruning to lateral branches. Generally used to
remove declining branches or to lighten end weight on long branches.
CR Crown
Raising
Pruning of lower branches to remove deadwood or to provide ground or building
clearances.
RMV Remove Remove tree due to decline or hazardous conditions that cannot be mitigated by
pruning. RS Remove Sprouts
Remove basal sprouts from stem of tree.
Rep Replace Tree is small – is in decline or dead. Replace with suitable tree species.
HT Hazard Tree Tree is hazardous and cannot be mitigated by pruning. Recommendation is to
remove tree. None No Work No work necessary at this time.
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Attachment #6: Description of Tree Evaluation Methodology
The evaluation of the tree condition on this site included the visual assessment of:
1. Live-crown ratio, 2. Lateral and terminal branch growth rates, 3. Presence of dieback in minor and major scaffold branches and twigs,
4. Foliage color,
5. Stem soundness and other structural defects, 6. Visual root collar examination, 7. Presence of insect or disease problems. 8. Windfirmness if tree removal will expose this tree to failure.
In cases where signs of internal defect or disease were suspected, a core sample was taken to look for stain, decay, and diameter growth rates. Also, root collars were exposed to look for the presence of root disease.
In all cases, the overall appearance of the tree was considered relative to its ability to add value
to either an individual lot or the entire subdivision. Also, the scale of the tree and its proximity to both proposed and existing houses was considered.
Lastly, the potential for incorporation into the project design is evaluated, as well as potential site
plan modifications that may allow otherwise removed tree(s) to be both saved and protected in the development. Trees that are preserved in a development must be carefully selected to make sure that they can survive construction impacts, adapt to a new environment, and perform well in the landscape.
Healthy, vigorous trees are better able to tolerate impacts such as root injury, changes in soils moisture regimes, and soil compaction than are low vigor trees. Structural characteristics are also important in assessing suitability. Trees with significant decay and other structural defects that cannot be treated are likely to fail. Such trees should not be
preserved in areas where damage to people or property could occur. Trees that have developed in a forest stand are adapted to the close, dense conditions found in such stands. When surrounding trees are removed during clearing and grading, the remaining trees are exposed to extremes in wind, temperature, solar radiation, which causes sunscald, and
other influences. Young, vigorous trees with well-developed crowns are best able to adapt to these changing site conditions.
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Attachment #7: Glossary of Forestry and Arboricultural Terminology
DBH: Diameter at Breast Height (measured 4.5 ft. above the ground line on the high side of the
tree).
Caliper: In the City of Renton - Caliper is referring to diameter measurement at DBH. Live Crown Ratio: Ratio of live foliage on the stem of the tree. Example: A 100’ tall tree with
40 feet of live crown would have a 40% live crown ratio. Conifers with less than 30%
live crown ratio are generally not considered to be long-term trees in forestry. Crown: Portion of a trees stem covered by live foliage.
Crown Position: Position of the crown with respect to other trees in the stand.
Dominant Crown Position: Receives light from above and from the sides. Codominant Crown Position: Receives light from above and some from the sides.
Intermediate Crown Position: Receives little light from above and none from the sides. Trees tend to be slender with poor live crown ratios. Suppressed Crown Position: Receives no light from above and none from the sides. Trees
tend to be slender with poor live crown ratios.
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Attachment #8: Tree Protection Fence Detail
Temporary Chain Link on Driven Posts
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Attachment #9: Assumptions and Limiting Conditions
1) Any legal description provided to the Washington Forestry Consultants, Inc. is assumed to be correct. Any titles and ownership's to any property are assumed to be good and marketable. No responsibility is assumed for matters legal in character. Any and all property is appraised or evaluated as though free and clear, under responsible ownership and competent management. 2) It is assumed that any property is not in violation of any applicable codes, ordinances, statutes, or other governmental regulations, unless otherwise stated. 3) Care has been taken to obtain all information from reliable sources. All data has been verified insofar as possible; however, Washington Forestry Consultants, Inc. can neither guarantee nor be responsible for the accuracy of information. 4) Washington Forestry Consultants, Inc. shall not be required to give testimony or to attend court by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services as described in the fee schedule and contract of engagement. 5) Loss or alteration of any part of this report invalidated the entire report. 6) Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person to whom it is addressed, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. 7) Neither all or any part of the contents of this report, nor copy thereof, shall be conveyed by anyone, including the client, to the public through advertising, public relations, news, sales or other media, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. -- particularly as to value conclusions, identity of Washington Forestry Consultants, Inc., or any reference to any professional society or to any initialed designation conferred upon Washington Forestry Consultants, Inc. as stated in its qualifications. 8) This report and any values expressed herein represent the opinion of Washington Forestry Consultants, Inc., and the fee is in no way contingent upon the reporting of a specified value, a stipulated result, the occurrence neither of a subsequent event, nor upon any finding in to reported. 9) Sketches, diagrams, graphs, and photographs in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering or architectural reports or surveys. 10) Unless expressed otherwise: 1) information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection; and 2) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the tree or other plant or property in question may not arise in the future.
Note: Even healthy trees can fail under normal or storm conditions. The only way to eliminate all risk is to remove all trees within reach of all targets. Annual monitoring by an ISA Certified Arborist or Certified Forester will reduce the potential of tree failures. It is impossible to predict with certainty that a tree will stand or fail, or the
timing of the failure. It is considered an ‘Act of God’ when a tree fails, unless it is directly felled or pushed over by man’s actions.