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HomeMy WebLinkAboutDRAFT_Bio and Tree Peer Review_12.29.2020 2121 Alton Parkway Suite 100 Irvine, CA 92606 949.753.7001 phone 949.753.7002 fax esassoc.com December 28, 2020 City of Diamond Bar Planning Division Contact: Ms. Mayuko Nakajima, Associate Planner 21810 Copley Drive Diamond Bar, CA 91765 909.839.7033 Subject: Peer Review of Crooked Creek Residential Development Biological Resources Assessment and the Crooked Creek (Vesting Tentative Tract Map No. 54081) Arborist Report Dear Ms. Mayuko Nakajima: As requested, Environmental Science Associates (ESA) has conducted a peer review of the Biological Resources Assessment for the proposed Crooked Creek Residential Development Project prepared by LSA and dated July 2019. ESA has also conducted updated measurements for the native trees documented within the Crooked Creek (Vesting Tentative Tract Map No. 54081) Arborist Report prepared by Dudek and dated January, 2017. The purpose of our peer review is to provide our best professional judgment regarding biological resources associated with the proposed Crooked Creek Residential Development Project (herein referred to as the Project) by supplementing information in the LSA report with observations made by ESA biologists and, where our best professional judgment differs with the contents of the LSA report, indicating the reasons for the variance. The City of Diamond Bar may use both the LSA report and this ESA letter report as the technical basis on which to prepare the biological resources section of the California Environmental Quality Act (CEQA) document for the Project. Project site in this letter report refers to all areas within the Project parcel boundary (12.9 acres). Grading limit refers to all areas within the Project site where temporary and permanent ground disturbance would occur under the current site plans. Fuel modification is the area within 100 feet or 200 feet of the proposed residential structures within the separate lots. Project vicinity refers to the Project site plus an approximately five-mile buffer. ESA biologists reviewed existing information and conducted three site visits. Because the City of Diamond Bar indicated that the LSA report would form the basis of the CEQA evaluation, ESA considered the LSA report as a baseline for the Project site biological resources. ESA also included the Dudek Arborist Report as a baseline for the status of the native trees onsite. After reviewing the LSA and Dudek reports, ESA biologists conducted a biological reconnaissance survey of the Project site on May 26, 2020, and subsequently conducted native tree surveys on the Project site on August 18 and September 11, 2020. During the biological reconnaissance survey, the ESA biologists walked the entire project site making observations of existing habitat conditions, presence of suitable habitat for special-status species, and presence of potentially regulated jurisdictional resources, and comparing these observation with the information in the LSA report, noting where professional judgment differed from the LSA report determinations. DRAFT Ms. Mayuko Nakajima December 28, 2020 Page 2 The May site visit was also conducted to determine the presence of special-status plant species. A primary objective was the assessment for special status plant species to occur onsite, ESA biologists also included a survey of the reference populations of intermediate mariposa lily (Calochortus weedii var. intemedius) mentioned in the LSA report. Intermediate mariposa lily is the only special-status plant species known to occur within the immediate vicinity of the Project site. Surveys were timed to conduct observations during the peak blooming period of intermediate mariposa lily, and the reference site population (located 0.10 miles to the southeast). During the native tree surveys, an ESA arborist conducted assessments of each tree recorded by Dudek located within the most current proposed grading limits, the 100-foot Fuel Modification and the 200-foot Fuel Modification. Trunk location, trunk diameter, height, and notes about tree condition were recorded. The Dudek report did not document tree canopy diameters in multiple cardinal directions, so those measurements were also recorded by ESA. In addition, ESA biologists reviewed relevant background information on biological resources in the vicinity of the Project site, including previous reports prepared for other projects in the area. These included reports for the Canyon Loop Trail Improvement Project, the Brea Canyon Business Park Project, and others. As a result of our review, the following comments are provided, in the same order as in the LSA report. Biological Assessment Report Project Location The Project site consists of Assessor’s Parcel Number (APN) 8714-028-003 in the northwestern quarter of the United States Geological Survey (USGS) Yorba Linda, California, 7.5-minute topographic quadrangle map within Section 29, Township 2 South, Range 9 West. Regional access to the Project Site is via SR-57; refer to Figure 1, Regional Map and Figure 2, Local Vicinity Map. Local access to the Project Site is from the existing Crooked Creek Drive within the city of Diamond Bar. Environmental Setting The Project site consists of approximately 12.9 acres of undeveloped area, which supports nonnative grassland (categorized in this letter report as either Avena-Bromus herbaceous semi-natural alliance or Brassica-Forb ruderal area; described as annual brome grassland in the LSA report) as well as coast live oak (Quercus agrifolia) and southern California black walnut (Juglans californica) woodland. Elevations within the Project site range from approximately 645 feet in the southwest corner to 835 feet above mean sea level in the southeast corner. The eastern portion of the Project site consists of natural steep hillside terrain with gently rolling terrain on the northern portion. The western portion of the Project Site, including much of the proposed grading limit, are relatively flat and have elevations ranging from 645 feet to 720 feet above mean sea level. 60 39 210 210 Monrovia Wilderness Preserve WalnutCity Parkland Vincent GlendoraArcadia BaldwinPark Montebello Rosemead Covina Azusa SanGabriel West CovinaElMonte 39 57 91 19 60 405 405 FirestoneBoy Scout Reservation Cerritos Westminster Whittier BuenaPark Bellflower YorbaLinda Tustin Orange Norwalk Fullerton GardenGrove SantaAna Anaheim Sunset Beach Fountain Valley 60 210 Upland Montclair Claremont LaVerne Ontario Rancho Cucamonga Pomona 241 83 91 ChinoHillsState Park ChinoHills Chino OrangePath: U:\GIS\GIS\Projects\18xxxx\D180195_Diamond_Bar_Crooked_Creek\03_MXDs_Projects\IS_MND.aprx, dkaneshiro 10/6/2020SOURCE: ESRI N 0 4 Miles Ø Project Area Figure 1 Regional Map Crooked Creek Residential Subdivision Project Project Location CastleRockRdBreaCanyonRdO ran g eFw yOrangeFwyO ran geFw yOrangeFwyCastl e Ro c k R d Bre a C a n y o n R d R unn in g B ran c h R dCrookedCreekDrCastleRockRd GoldRun Dr Fl apjackDr Path: U:\GIS\GIS\Projects\18xxxx\D180195_Diamond_Bar_Crooked_Creek\03_MXDs_Projects\IS_MND.aprx, dkaneshiro 10/6/2020SOURCE: Mapbox, 2020. Figure 2 Local Vicinity Map Crooked Creek Residential Subdivision Project N 0 300 Feet Project Site Ms. Mayuko Nakajima December 28, 2020 Page 5 Project Description The proposed Project includes the development of seven single-family residences and associated infrastructure including a southward extension of the existing Crooked Creek Drive within the proposed grading limit of the undeveloped Project site. The Project proposes a total of nine lots: seven residential lots, one private roadway lot (i.e., southward expansion of Crooked Creek Drive); and one open space lot of approximately 10.4 acres to be retained as an undeveloped area; refer to Figure 3, Site Plan and Figure 4, Vesting Tentative Tract Map. Figure 5, Vesting Tentative Tract Map Cross Sections, depicts five cross sections throughout the proposed residential development area and a cross section of the proposed southward expansion of Crooked Creek Drive. Approximately 2.9 acres of the Project site will be disturbed for residential development and associated infrastructure. Of the 2.9 acres, approximately 2.5 acres (the Proposed Development Area) includes grading for the proposed individual seven parcels, and the southward expansion of the existing Crooked Creek Drive. The remaining 0.4 acre of the 2.9 acres of grading will include hillside grading with 8-foot terrace drains and retaining walls. The remaining 10.0 acres would be retained as undeveloped area located within the eastern portion of the Project site. Regulatory Setting Federal and State Endangered Species Acts The Federal Endangered Species Act (FESA) provides guidance for conserving federally listed species and the ecosystems upon which they depend. Section 9 of the FESA and its implementing regulations prohibit the “take” of any federally-listed endangered or threatened plant or animal species, unless otherwise authorized by federal regulations. “Take” includes the destruction of a listed species’ habitat. Section 9 also prohibits a number of specified activities with respect to endangered and threatened plants. The California Endangered Species Act (CESA) mandates that state agencies not approve a project that would jeopardize the continued existence of species if reasonable and prudent alternatives are available that would avoid a jeopardy finding. CESA also prohibits the take of any fish, wildlife, or plant species listed as endangered or threatened, or designated as candidates for listing, under CESA. Similar to the FESA, CESA contains a procedure for the California Department of Fish and Wildlife (CDFW) to issue an incidental take permit authorizing the take of listed and candidate species incidental to an otherwise lawful activity, subject to specified conditions. Migratory Bird Treaty Act The Migratory Bird Treaty Act (MBTA) prohibits the take of native birds “by any means or manner to pursue, hunt, take, capture (or) kill” any migratory birds except as permitted by regulations issued by the U.S. Fish and Wildlife Service (USFWS). The term “take” is defined by USFWS regulation to mean to “pursue, hunt, shoot, wound, kill, trap, capture or collect” any migratory bird or any part, nest or egg of any migratory bird covered by the conventions, or to attempt those activities. Crooked Creek Residential Subdivision ProjectFigure 3Site PlanSOURCE: Michael Baker International, 2020D180195.00 - Diamond Bar Crooked Creek Residential\05 Graphics-GIS-Modeling\Initial StudyN0160Feet LEGENDSSDWCrooked Creek Residential Subdivision ProjectFigure 4Vesting Tentative Tract MapSOURCE: Michael Baker International, 2020D180195.00 - Diamond Bar Crooked Creek Residential\05 Graphics-GIS-Modeling\Initial Study Crooked Creek Residential Subdivision Project Figure 5 Vesting Tentative Tract Map Cross Sections SOURCE: Michael Baker International, 2020D180195.00 - Diamond Bar Crooked Creek Residential\05 Graphics-GIS-Modeling\Initial Study5 S P M SECTION B-B SECTION C-C XXXSECTION D-D SECTION E-E SECTION A-A FUTURE CROOKED CREEK DRIVE - LOT A Ms. Mayuko Nakajima December 28, 2020 Page 9 Sections 3503, 3503.5 and 3513 of the California Fish and Game Code Section 3503 of the California Fish and Game Code (CFGC) prohibits the killing of birds or the destruction of bird nests. Birds of prey are protected under Section 3503.5 of the CFGC, which provides that it is “unlawful to take, possess, or destroy any birds in the order Falconiformes or Strigiformes (birds of prey) or to take, possess, or destroy the nest or eggs of any such bird except as otherwise provided by this code or any regulation adopted pursuant thereto.” Section 3513 of the CFGC prohibits any take or possession of birds that are designated by the MBTA as migratory nongame birds except as allowed by federal rules and regulations promulgated pursuant to the MBTA. Migratory birds include all native birds in the United States, except those non-migratory game species such as quail and turkey that are managed by individual states. Clean Water Act In accordance with Section 404 of the Clean Water Act (CWA), the US Army Corps of Engineers (USACE) regulates discharge of dredged or fill material into waters of the U.S. Waters of the U.S. and their lateral limits are defined in 33 CFR 328.3(a) and includes navigable waters of the U.S., interstate waters, all other waters where the use or degradation or destruction of the waters could affect interstate or foreign commerce, tributaries to any of these waters, and wetlands that meet any of these criteria or that are adjacent to any of these waters or their tributaries. Waters of the U.S. are often categorized as “jurisdictional wetlands” (i.e., wetlands over which the USACE exercises jurisdiction under Section 404) and “other waters of the United States” when habitat values and characteristics are being described. “Fill” is defined as any material that replaces any portion of a water of the U.S. with dry land or that changes the bottom elevation of any portion of a water of the U.S. Any activity resulting in the placement of dredged or fill material within waters of the United States requires a permit from USACE. In accordance with Section 401 of the CWA, projects that apply for a Section 404 permit for discharge of dredged or fill material must obtain water quality certification from the appropriate Regional Water Quality Control Board (RWQCB) indicating that the proposed project would uphold State of California water quality standards. Section 1602 of the California Fish and Game Code Section 1602 of the CFGC requires a Streambed Alteration Agreement for any activity that may alter the bed and/or bank of a lake, stream, river, or channel. Typical activities that require a Streambed Alteration Agreement include, but are not limited to, excavation or fill placed within a channel, vegetation clearing, installation of culverts and bridge supports, and bank reinforcement. As part of the notification process, the CDFW requires documentation of any trees to be removed as part of the project. Trees that have a trunk diameter at breast height (dbh) of greater than two inches are subject to regulation by the CDFW via the Streambed Alteration Agreement. Ms. Mayuko Nakajima December 28, 2020 Page 10 City of Diamond Bar Tree Protection Ordinance The City of Diamond Bar’s Tree Preservation and Protection Ordinance under Title 22, Article III, Chapter 22.38 of the City’s Municipal Code provides protection for the following trees, broadly defined as “protected tree(s)”: 1. Native Oak, walnut, sycamore and willow trees with a diameter at breast height (DBH) of eight inches or greater; 2. Trees of significant historical or value as designated by the council; 3. Any tree required to be preserved or relocated as a condition of approval for a discretionary permit; 4. Any tree required to be planted as a condition of approval for a discretionary permit; and 5. A stand of trees, the nature of which makes each tree dependent on the others for survival. The City’s tree ordinance requires an arborist report to be prepared for the removal of protected tree species. In the section Dudek Tree Report and Updated ESA Findings, below, total quantities of impacted trees as compared to the 2017 Dudek report are included. After project discretionary approval, a comprehensive tree report will need to be prepared that will describe methodology for replacement plantings, and tree protection for established and mitigation trees (before, during, and after planting). Impact Analysis and Thresholds of Significance The following Appendix G of the State CEQA Guidelines serve as thresholds of significance for determining the potential impacts to the biological resources identified in the LSA report and ESA’s findings: Would the project: a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? The literature review conducted by LSA identified 34 special-status plants species and 42 special-status wildlife species with the potential to occur within the project area. LSA determined only one special- status wildlife species with a moderate potential to occur in the project area, red diamond rattlesnake (Crotalus ruber). As noted in Appendix C-1 of the LSA report, this species has been observed in the immediate project vicinity. LSA also found one special-status plant species with a high potential to occur in the project area, intermediate mariposa lily (Calochortus weedii var. intermedius). During the three site Ms. Mayuko Nakajima December 28, 2020 Page 11 visits conducted by ESA in May, August and September of 2020, no observation of either special-status species or suitable habitat was observed to be present within the Project site. b) Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? Habitat mapping conducted by LSA and ESA did not identify any riparian habitat within the proposed grading limit. LSA determined that both the coast live oak woodland and the California walnut groves are considered sensitive natural communities. LSA explained that CDFW often considered coast live oak woodland as a special-status plant community due to the historical loss of oak trees throughout southern California. However, a strict assessment of sensitive natural communities as having a conservation rank of S3 or lower, coast live oak woodland would not be designated as a sensitive natural community because CDFW has designated nearly all coast live oak woodland associations with a conservation rank of S4. ESA concurs with LSA in identifying both coast live oak woodland and California walnut groves (walnut woodland) and determined that 4.6 acres of coast live oak woodland and 3.4 acres of California walnut groves (walnut woodland) are present on the Project site. ESA found that the proposed Project, inclusive of the 100-foot fuel modification area, would remove up to 1.1 acres of coast live oak woodland and 0.01 acre of California walnut groves; refer to Figure 6, Vegetation Maps and Table 1, Vegetation Impacts. LSA recommended MM BIO-1 - Tree preservation and protection to provide mitigation for impacts to sensitive natural communities, however, MM BIO-1 includes provision only for the replacement of removed trees and is not specific to habitat mitigation. ESA recommends that the impact to 0.01 acre of California walnut groves be mitigated through implementation of MM BIO-1 but require the replacement walnut trees to be planted within the non-native herbaceous areas within the remaining on-site California walnut groves with the provision that non-native invasive species be controlled within the preserved on-site habitat. GeoEye, Maxar Path: U:\GIS\GIS\Projects\18xxxx\D180195_Diamond_Bar_Crooked_Creek\03_MXDs_Projects\2020_Bio.aprx, sgeissler 12/15/2020SOURCE: ESA, 2019.Diamond Bar, Crooked Creek Figure 6 Vegetation Map N 0 125 Feet Project Site Vegetation Community Avena - Bromus Herbaceous Semi-Natural Alliance Brassica-Forb Ruderal Area Coast Live Oak Woodland Juglans californica Stand Walnut Woodland Ms. Mayuko Nakajima December 28, 2020 Page 13 TABLE 1 VEGETATION IMPACTS Vegetation Community Total within Project Site (acres) Within Grading Limit 100-ft Fuel Modification beyond Grading Limit 200-ft Fuel Modification beyond Grading Limit Avena - Bromus Herbaceous Semi- Natural Alliance 3.3 1.3 0.1 0.2 Coast Live Oak Woodland 4.7 0.8 0.3 0.9 Juglans californica Stand 0.4 0.0 0.0 0.0 Brassica-Forb Ruderal Area 1.4 0.8 0.2 0.3 Walnut Woodland 3.0 0.0 0.01 0.3 Totals 12.8 2.9 0.61 1.7 c) Have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? LSA and ESA found no state or federally protected wetlands within the proposed grading limit. The project site is located adjacent to the Brea Canyon Channel, a concrete lined riverine feature, however, project site storm water drainage will connect to the Brea Canyon Channel, which would be a direct impact to the channel wall. A jurisdictional drainage feature occurs within the Project site but possess no direct connection to the Brea Canyon Channel. No direct impacts will occur to the drainage feature as a result of the project, as the jurisdictional area is not within the proposed grading limit. Indirect project impacts associated with Brea Canyon Channel are possible through attraction of predators and increased levels of noise, vibration, lighting, and dust during construction activities. LSA recommends MM BIO-2 – Construction Site Housekeeping and MM BIO-3, which is not described in the LSA recommended mitigation and minimization measures. Page 12 of the LSA report discusses MM BIO-3 as a water quality management plan (WQMP) and/or a storm water pollution and prevention plan (SWPPP). ESA recommends implementation of a WQMP/SWPPP, because construction would occur adjacent to the Brea Canyon Channel. A CDFW streambed alteration agreement will be required for direct connection of the project storm drain system to the Brea Canyon Channel. d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? Ms. Mayuko Nakajima December 28, 2020 Page 14 As noted within the LSA report, the proposed grading limit is located entirely outside of jurisdictional aquatic resources and any regional or local wildlife movement corridor. ESA concurs with LSA’s findings that it is “unlikely that the site serves as an important corridor for animals moving locally, regionally, or in broader migrations”. The city of Diamond Bar recognizes the Puente-Chino Hills Wildlife Corridor to the south of the Project site. The project site is restricted to movement through fencing and barbed wire associated with the adjacent ranching activities that may hinder large mammal movement throughout the area. However, evidence of large mammals (such as mule deer and coyote) were included within the faunal compendium within Appendix D of the LSA report, and ESA also observed evidence of coyote presence within the project site. No increase or decrease in the potential for movement across the site is anticipated as a result of the Project, as existing boundaries will remain in place throughout the duration of the project. The proposed project has the potential for the disruption of migratory birds nesting on the project site. LSA states that avoidance of direct and indirect disturbance to nesting birds during construction would ensure compliance with applicable provisions of the California Fish and Game Code and the Migratory Bird Treaty Act with implementation of MM-BIO 4. With successful mitigation implementation, impacts associated with migratory and nesting birds would be considered to be less than significant. ESA recommends inclusion of the MM-BIO 4 to prevent harm to nesting birds. e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? City of Diamond Bar Municipal Tree Code states that replacement ratios for tree removals on residential lots greater than 20,000 square feet be replaced at a 3:1 ratio, and that tree sizes and planting location will be determined by the director (of Public Works). LSA recommended MM BIO-1 - Tree preservation and protection, which states: A minimum 1-to-1 planting-to-impact ratio is recommended for all native trees greater than or equal to 8 inches DBH, or as otherwise required by the City. A 3-to-1 planting-to impact ratio is recommended for protected trees greater than or equal to 36 inches DBH. Compensatory planting should be conducted within the portion of the project area that would remain undeveloped under the approved plans, or at an off-site location as approved by the City. Existing oak and walnut woodland habitat located within the undeveloped portions of the project area should be preserved. LSA states that with implementation of MM-BIO 1, impacts associated with the removal of walnut woodland and coast live oak woodland trees would be considered less than significant under CEQA with the replanting of walnut and oak trees within the Project area. However, the City of Diamond Bar Municipal Tree Code requires replacement ratios for tree removals at a 3:1 ratio, with tree sizes and planting location determined by the director (of Public Works). ESA recommends adherence to this Ms. Mayuko Nakajima December 28, 2020 Page 15 policy and recommends that smaller replacement tress be considered because smaller-sized trees have a better chance for quicker establishment after planting. Further discussion of the tree resources on site is included below in the Tree Report and updated Findings section. f) Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? As noted within the LSA report, the Project Area is not located within lands covered under an existing Natural Communities Conservation Plan, Habitat Conservation Plan, or any areas mapped as Critical Habitats by the USFWS. Peer Review Comments on the LSA Biological Resources Assessment After review of the LSA Biological Assessment Report, ESA offers the following comments on the LSA report. Critical Habitat  Page 9: No mention of nearest critical habitat is included. The nearest critical habitat is coastal Californica gnatcatcher critical habitat 0.8 miles to the south-southwest of the project site, and associated with the ridgelines above Brea and Tonner Canyons. No coastal California gnatcatcher suitable habitat is present within the project area. Wildlife Movement and Habitat Connectivity  Page 10: Although ESA concurs with LSA’s findings that it is “unlikely that the site serves as an important corridor for animals moving locally, regionally, or in broader migrations”, the Puente-Chino Hills Wildlife Corridor is a nearby regional wildlife corridor and regional movement of wildlife species through Tonner and Brea Canyons is possible. Furthermore, barbed wire fences associated with the adjacent ranching activities hinder large mammal movement throughout the area, even though evidence of large mammals (such as mule deer and coyote) was observed by both LSA and ESA. Regional Habitat Conservation Plans and Local Policies  Page 10: The Diamond Bar General Plan (DBGP) goals and policies should be adhered to with any project application approval. Impact Findings and Recommended Avoidance and Mitigation Measures  Page 12-13, 15: MM BIO-3 is mentioned several times in the LSA but no discussion or mitigation details are included. As discussed on Page 12 and within the summary of impacts on Page 13, MM BIO-3 was intended to be a WQMP/SWPPP measure to be included at the discretion of the lead agency. ESA recommends a WQMP/SWPPP measure to mitigate indirect impacts to the Brea Canyon Channel because project construction would occur adjacent to that channel. Ms. Mayuko Nakajima December 28, 2020 Page 16 Dudek Tree Report and Updated ESA Findings ESA Arborist Douglas Gordon-Blackwood and Biologist Karl Fairchild conducted the initial update native tree survey on August 8 and Douglas Gordon-Blackwood conducted a follow up native tree survey on September 11, 2020. During the field survey, the area identified as the grading limits, the 100-foot and 200-foot fuel modification areas were walked and a Global Positioning System (Bad Elf GNSS GPS) unit used in conjunction with ESRI’s Collector for Arc GIS (Classic) application to collect location and tree survey data; refer to Figure 7, Tree Survey and Table 2, Tree Impacts Summary. To maintain consistency and maintain ease of tree reference, previously affixed tree tags and numbering were utilized in order to remain consistent with previous tree inventories conducted by Dudek (2017). A total of 457 trees occur within the Project site. Fifty-one (51) trees (50 southern California black walnut and 1 coast live oak) were recorded within the proposed grading limits. Fifteen (15) trees (3 coast live oaks and 12 southern California black walnuts) occur within the 100-foot fuel modification area, but outside the grading limit, and would be potentially removed as a result of the project. Thirty-three (33) coast live oaks and thirty-four (34) southern California black walnuts were observed within 100-feet to 200-feet of the fuel modification, and although they will not be removed because they occur within the fuel modification thinning zone, they will be subject to indirect impacts associated with possible lower limb removal and routine fuel modification. Twenty- one dead trees were observed, either previously recorded in the Dudek report or during the most recent ESA update survey. Also of note are several large non-native Persian walnut trees that were incorrectly identified as southern California black walnuts in the Dudek report. These non-native trees are not provided the same protections as native walnuts and their presence should be considered deleterious to the health of the walnut woodlands on the Project site because of the potential for hybridization. Previous Dudek measurements were utilized for 15 closely grouped walnut trees because the arborist was unable to access these trees during the site visits. The Dudek report calculated a total of 297 native trees as being encroached or removed, based on an earlier project design. The current proposed grading limits and associated fuel modifications would require the removal of 4 coast live oak trees and 62 southern California black walnut trees. The removal of these native trees would require 12 replacement coast live oak trees and 186 replacement southern California black walnut trees. A total of 67 trees will be encroached upon (as indirect impacts) within the 100 to 200-foot fuel modification. In the Dudek report, replacement native trees were included within the proposed landscaping plan. The most current version of a proposed landscape plan, Figure 8 - Preliminary Landscape Plan, incorporates 25 15-gallon size coast live oak trees but no southern California black walnut trees into the landscape plan. Planting 186 walnut and 12 oak 24” box trees within the landscape and appropriate woodland enhancement areas would not be possible nor ecologically sustainable. GeoEye, Maxar Path: U:\GIS\GIS\Projects\18xxxx\D180195_Diamond_Bar_Crooked_Creek\03_MXDs_Projects\2020_Bio.aprx, sgeissler 12/15/2020SOURCE: ESA, 2019.Diamond Bar, Crooked Creek Figure 7 Tree Survey N 0 125 Feet Project Site Grading Limit 100-foot Fuel Modification 200-foot Fuel Modification Species - Impact Type Juglans - Development Footprint (52) Juglans - Fuel Mod Zone - 0-100 ft (12) Juglans - Fuel Mod Zone - 100-200 ft (36) Quercus agrifolia - Development Footprint (1) Quercus agrifolia - Fuel Mod Zone - 0-100 ft (3) Quercus agrifolia - Fuel Mod Zone - 100-200 ft (33) Avoided Trees Non-Impacted Native Trees (299) 670669668667666665R=100'R=175'660670650650669670668 667 666 665 664662660LOT 5LOT 6LOT 7LOT 4LOT 3LOT 2LOT 16606506505(48,5('0,;2)3/$170$7(5,$/63/$170$7(5,$/ +6721(3,/$67(5:,7+&21&5(7(&$3$1'9(57,&$/67((/3,16,*1$*((1+$1&('7(;785('9(+,&8/$53$9(5$7(175<&211(&7216,7(6,'(:$/.:,7+$'-$&(17(;,67,1*6,'(:$/.),(/'*52:12/,9(6$7(175<:,7+,7$/,$1&<35(66$76,'(6PRELIMINARY PLANT PALETTE:2/($(8523$($2/,9(&835(66866(03(59,5(16,7$/,$1&<35(6675((675,67$1,$&21)(57$%5,6%$1(%2;%27$1,&$/1$0(&200211$0(&217$,1(56,=(&200(176 :8&2/65(*,21$5%8786µ0$5,1$¶0$5,1$675$:%(55<75((+(,*+7[:,'7+*52:7+ [ 0(',8067'*$/ 0(' [ 0(',80/2:%5$1&+,1*%2; 0(' [ 6/2:08/7,7581./2:%5$1&+,1*),(/'*52:1/2: [ 6/2:08/7,7581./2:%5$1&+,1**$//2:48(5&86$*5,)2/,$&2$67/,9(2$. [ 6/2:67'08/7,*$/ 9(5</2:3/$7$1865$&(026$&$/,)251,$6<&$025( [ 6/2:67'08/7,*$/ 0('358186,/,&,)2/,$+2//</($)&+(55< [ 0(',80/2:%5$1&+,1**$/ /2:LARGE SHRUBS:&($127+86633:,/'/,/$& [ 0(',806+58%*$//2:$5%8786 &203$&7$ ':$5)675$:%(55<75(( [ 0(',80/2:%5$1&+,1**$/ /2:5+$0186&$/,)251,&$&2))((%(55< [ 0(',80*$/ /2:6$0%8&861,*5$0(;,&$1(/'(5%(55< [ 0(',80*$/ /2:MEDIUM SHRUBS:%$&&+$5,63,/µ3,*(2132,17¶':$5)&2<27(%586+ [ 0(',80635($',1**$//2:SPREADING SHRUBS / GROUNDCOVER:%$&&+$5,63,/µ3,*(2132,17¶':$5)&2<27(%586+ [ 0(',80635($',1**$//2:&$5,66$0$&52µ*5((1&$53(7¶/2:*52:,1*1$7$/3/80 [ 0(',80635($',1**$//2:&($127+86633:,/'/,/$& [ 0(',80635($',1**$//2:,%(6$85(80*5$&,//,080*2/'(1&855$17 [ 0(',80635($',1**$//2:5+86,17(*5,)2/,$/(021$'(%(55< [ 6/2:*$/ 9(5</2:526(0$5<2)),&,$/1,675$,/,1*526(0$5< [ 0(',80635($',1**$//2:6$/9,$6336$*( [ 0(',806+58% 9(5</2:*$/$*$9($77(187$)2;7$,/$*$9( [ 6/2:*$/9(5</2:ACCENT SHRUBS:$*$9(*(0,1,)/25$7:,1)/2:(5('$*$9( [ 6/2:*$/9(5</2:$*$9(µ%/8()/$0(¶%/8()/$0($*$9( [ 6/2:*$/9(5</2:$/<2*<1(+8(*(/,,%/8(+,%,6&86 [ 0(',80*$/ /2:$5&7267$3+</2663(&,(6&$53(70$1=$1,7$ [ 0(',80635($',1**$//2:),&86380,/$ [ 0(',80&/,0%,1**$//2:CLIMBING VINE ON RETAINING WALLS:5(48,5('3(5&(17$*(2)0,;TREES:%2;*$//21SHRUBS:*$//21*$//21GROUNDCOVER:&29(5$*(:,7+,1<($56        75((5(3/$&(0(1775((5(3/$&(0(175$7,2 75((65(029('2$.672%(5(029(' &$/,)251,$%/$&.:$/187 727$/75((65(029(' 727$/75((65(48,5(' 727$/75((63529,'(' 5()(572(;,67,1*75((6859(<35(3$5('E\DUDEKInc.)25025(,1)250$7,21'($'75((65(029(' Crooked Creek Residential Subdivision ProjectFigure 8Preliminary Landscape PlanSOURCE: Daydreams Designed Environments, 2020D180195.00 - Diamond Bar Crooked Creek Residential\05 Graphics-GIS-Modeling\Initial StudyN Ms. Mayuko Nakajima December 28, 2020 Page 19 TABLE 2 TREE IMPACT SUMMARY Species Trees within the proposed grading limit (Tree ID’s) Trees within 100 feet of residential structures but outside the proposed grading limit (100- foot fuel modification) Trees within the 100 to 200-foot fuel modification area Avoided (Within Previous Development Footprint) Total Required Replacement Tree Plantings Coast live oak 1 (Tree 2) 3 (Trees 144, 145, 188) 33 (Trees 98, 99, 100, 101, 103, 104, 107, 108, 139, 141, 192, 193, 194, 195, 196, 197, 199, 200, 201, 202, 207, 208, 209, 211, 212, 213, 214, 215, 217, 218, 219, 220, and 221) 38 (Trees 39, 41, 51, 52, 53, 54, 57, 58, 59, 81, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 96, 97, 111, 112, 113, 114, 116, 118, 119, 120, 121, 130, 131, 132, 133, 134, 135, and 136) 12 24” box (or smaller) trees Southern California black Walnut 50 (Trees 1, 3, 5, 6, 16, 17, 18, 19, 20, 21, 27, 28, 149, 150, 151, 152, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 234, 235, and 236) 12 (Trees 4, 29, 146, 147, 148, 198, 227, 228, 230, 231, 232, and 233) 34 (Trees 30, 31, 32, 142, 143, 166, 187, 189, 190, 191, 210, 223, 224, 242, 251, 252, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 280, 283, 285, 286, 287, 288, 351, and 355) 19 (Trees 7, 203, 281, 292, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 372, 497, 498, and 499) 186 24” box (or smaller) trees As noted in the Dudek report, planting seeds and seedlings has long been considered the simplest, economical, and successful way to establish healthy trees. Trees in 24” boxes are more likely to be root bound and tend to do poorly when compared to acorns, walnuts or seedlings planted in the ground. ESA recommends the combination of some boxed trees within the landscaped areas, and seedlings and smaller sized container trees in the undisturbed woodland areas of the remaining Project undeveloped area, as recommended within the Dudek report. ESA also concurs with Dudek on the recommendations for tree mitigation, tree protection measures, tree maintenance and follow-up monitoring contained in that report. ESA also recommends the control of non-native species within the preserved coast live oak woodland and the California walnut groves, which will improve the quality of these retained natural communities. Sincerely, Douglas Gordon-Blackwood, Senior Biologist and Arborist Ms. Mayuko Nakajima December 28, 2020 Page 20 REFERENCES Baldwin, B. G. 2012. The Jepson Manual: Vascular Plants of California, Second Edition. Berkeley, CA: University of California Press. California Native Plant Society, Rare Plant Program. 2020. Inventory of Rare and Endangered Plants of California. Vers. online edition, v8-03 0.39. December. Accessed December 14, 2020. http://www.rareplants.cnps.org/result.html?adv=t&quad=3411921:3411828:3411827:3411911:3411818:3 411817. CDFW. 2020. California Natural Communities List. December 14. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=153609&inline. CDFW. 2020. California Natural Diversity Database and Rarefind. Sacramento, CA, December 14. CNDDB. 2020. "RareFind 5." Vers. 5.2.14 . California Department of Fish and Wildlife (CDFW). November 29. Accessed December 14, 2020. https://apps.wildlife.ca.gov/rarefind/view/RareFind.aspx. CNPS. 2020 Inventory of Rare and Endangered Plants and Natural Communities. Accessed December 14, 2020. http://cnps.web.aplus.net/cgi-bin/inv/inventory.cgi. Holland, R. F. 1986. "Preliminary descriptions of the terrestrial natural communities of California." Berkeley, California: California Department of Fish and Game Natural Heritage Division. Judi Tamasi. 2013. The Puente - Chino Hills Wildlife Corridor. January 23. Accessed December 14, 2020. https://habitatauthority.org/newsite/wp-content/uploads/2012/04/pg1-12v2b.pdf. Dudek. 2017. Crooked Creek (Vesting Tentative Tract Map No. 54081) Arborist Report. Arborist Report, Diamond Bar. Christopher J. Kallstrand, preparer. LSA. 2019. "Crooked Creek Residential Development Project Biological Resources Assessment." Biological Resources Assessment, Diamond Bar. Lycoming, LLC. 2019. Brea Canyon Business Park Initial Study and Draft Mitigated Negative Declaration. Initial Study and Mitigated Negative Declaration, Diamond Bar: Lycoming, LLC. Michael Baker International. 2020. Canyon Loop Trail Improvement Project . Initial Study / Mitigated Negative Declaration, Diamond Bar: Michael Baker International. NRCS. 2020. Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Vers. 7. May 27. Accessed December 14, 2020. https://websoilsurvey.sc.egov.usda.gov/. Ms. Mayuko Nakajima December 28, 2020 Page 21 Sawyer, John O., T. Keeler-Wolf, and J. Evans. 2009. A Manual of California Vegetation, Second Edition. Sacramento: California Native Plant Society. USFWS. 2020. Critical Habitat for Threatened & Endangered Species (USFWS). June 4. Accessed December 14, 2020. https://fws.maps.arcgis.com/home/webmap/viewer.html?webmap=9d8de5e265ad4fe09893cf75b8dbfb77. —. 2020. USFWS ECOS IPaC Resource List. December 14. Accessed December 14, 2020. https://ecos.fws.gov/ipac/location/5RG4GRAOU5EJXJ34ZHDGB3LK.