Letter from Donna P. Lopez, City Clerk transmitting a report from Councillor Zondervan and Vice Mayor Jan Devereux, Co-Chairs of the Health and Environment Committee for a public hearing held on on December 4, 2018 to discuss reviewing the preliminary LiDAR-based canopy study results from April 1, 2018 and to discuss potential reasons for the precipitous decline in our tree canopy and any other related matter

TUESDAY DECEMBER 4, 2018 SULLIVAN COUNCIL CHAMBER City of Cambridge Tree Canopy HEALTH AND ENVIRONMENTAL COMMITTEE: PUBLIC HEARING b0 o ATTACHMENT A WORKS

CAMBRIDGE OUR URBAN FOREST gov/adoptatred MASSACHUSETTS LIDAR Canopy Loss Introduction agenda Current Tree Regulations Overview of Urban Forest Master Plan ORKS

Existing and Possible Tree Canopy A Report on the City of Cambridge's 30% Canopy 2009 introduction Tree Canopy in Cambridge, MA. 2009-2014 28% Canopy 2014 Since then: Initial Assessment: 25% Canopy for the 3 flyovers based on raw data. Numberous revisions. ?% Canopy 2018 based on consistent methodology February 2019: Expected completion City GIS Dept. & UVM: Completing Independent Assessment RUDG ORKS

plane LIDAR Basics Pulse LiDAR on the last return. Unit LiDAR • Millions of pulses are collected with 4 separate returns 4 Returns La Return 2nd Retur Return Return Laser Pulse Number of Returns LiDAR: Light Detection and Ranging • A LiDAR system sends a pulse of light to the ground and waits for the pulse to return • The type of LiDAR we are using for tree canopy is collected from a unit mounted on a • The LiDAR unit scans the ground from side to side as the plane flies to cover a large area • Treetops are collected on the 15t return, lower vegetation on the 2nd & 3rd, and bare earth CAMORIOO ARTMEN ORKS

• Sometimes errors can result in this cleanup • Our vendors remove points which are thought to be 'noise' • Points are given a classification depending on what they represent • In our 2018 data set we noticed City Hall tower was missing on the first deliverable Determining Tree Canopy trom LiDAR • Points are collected and various factors can affect the light intensity of the LiDAR returns CAMBRIDGE VORKS

• 2018 LIDAR • 2014 LIDAR • 2009 LIDAR • April flight. • April flight. • November flight. • 0.7 meter point spacing. • 8 classifications for points • 3 classifications for points • Still fine tuning this data set • Basic classifications for points. • Higher resolution point spacing • 1 meter resolution point spacing. • Flown for UASI (Homeland Security funded) project. • Flown for the City of Cambridge to meet USGS Specifications • Flown for City of Boston. Cambridge joined in for minimal cost. Our LIDAR Data is trom Various Sources CANBRIDOE EPARTMENT TORKS

flights, but still a good data set • LiDAR is only one tool for representing tree canopy photo review, City arborist data, and field work. • Misclassified points or lack of classification can skew the loss vs. gain numbers • An excellent data set but interpretation of points needs to be combined with aerial LiDAR is an Analysis Tool for Tree Canopy • Our data is getting more refined. The 2009 fall flight is lower quality than subsequent WORKS

important than ever before. Overview of Urban Forest Master Plan a healthy, connective urban forest at a time when the urban forest is more To maintain, plan, build, and sustain ORKS

Outreach. • Data Driven. • Scientifically Based. • Community Engagement & Scope of Work for UFMP: PRACTICE AES BARTLETT FR ENVIRONMENTAL RH V ASSOCIATES CLF ANALYTICS KLEINFELDER OVER/UNDER ADVOCACY ORKS

community. 18 members. www.cambridgema.gov/UFMP Meet monthly for 12 months. Urban Forestry Task Force: Representing broad spectrum of RKS

City Kobe Miami Boston London Durban Geneva New York Montreal Frankfurt Capetown Cambridge Los Angeles Amsterdam Johannesburg GVI 9.4% 12.7% 13.5% 25.5% 15.2% 23.6% 19.4% 21.4% 21.5% 20.6% 18.2% 23.7% 13.4% 25.3% 3,889 4,770 5,518 2,783 3,198 2,900 4,908 2,600 5,344 3,000 1,100 6,586 10,831 Source: MIT Senseable City Lab 12,000 Comparison of Cities Pop. Density Treepedia Green View Index - City Oslo Turin Paris Quito Tampa Seattle Sydney Tel Aviv Toronto Sao Paulo Singapore Vancouver Sacramento GVI 8.8% 19.5% 25.9% 25.9% 36.1% 17.5% 16.2% 23.6% 29.3% 20.0% 10.8% 11.7% 28.8% 400 8,353 6,900 5,249 4,150 3,151 1,283 7,913 7,797 4,421 7,200 1,800 21,000 Pop. Density Streetview based on Google seen from a location cover from street level Green View Index (GVI) represents% of canopy ORKS

2014 DRAFT PER YEAR Opens Areas 0.48% AVERAGELOSS -99 ACRES 2014 Canopy Cover Area of Canopy Less 303K COVER 2.5% (101ACRES) 49% (200 ACRES) OF PERCENT CANOPY COVER A TREND OF CANOPY LOSS Change Between 2009-2014 rom the UVM Study, 3017 LOSS GAN DRAFT PER YEAR NEED HILDERBRAND Open Areas 076% AVERAGE LOSS 2018 Canopy Cover I Areaof Canopy Loss (1,027 ACRES) 28.3% COVER 25.3% COVER 5% (206 ACRES) 8.1% (330 ACRES) OF PERCENT CANOPY COVER Source: Prepared by RH Team fo Change Between 2014-2018 A TREND OF CANOPY LOSS the 2018 AES classification data. Canopy Loss across the city - 220 acres in 10 years. WORKS

DRAFT 8 150 100 200 450 300 [phone removed] 400 2018 RESIDENTIAL 179% -171AC +82 AC INSTITUTIONAL -11.9% -34 AC +20AC COMMERCIAL 8.7% -17 AC +13AC INDUSTRIAL Source: Prepared by RH Team from the 2018 AES classification data and City GIS data. 18.3% 9 AC +5AC PUBLIC -4.1% +9AC -11 AC Canopy losses - where are the losses occurring OPEN SPACE 43/AC -45 AC +53AC -60 AC I. 2014-2018 GAIN • CAMBRIDOE - PUBLIC DEPARTMENT TORKS

• 63858338 OBSERVATION| CANOPY COVER Plantable area by neighborhood Mantable area by neighborhood Agassiz Cambridgeport •Plantable - Not Canopy Covered Institutional Open Space Not Plantable 8 Plantabic area by neighborhood Area 2/MIT East Cambridge 1 OpenSpace / Canopy Loss per land use category for each Community area. PASS CAMBRIDGE RKS

DRAFT Source: Prepared by RH Team according to the 2018 AES classification data. WHAT IS THE MAKEUP OF THE CURRENT CAMBRIDGE FOREST? Ash Other Pin Oak Red Oak Crabapple Red Maple Callery Pear Honey locust Norway Maple Littleaf Linden London Planetree What makes up the canopy? 6% 2.5% 11% 6.8% 9.2% 3-9% 4.2% 3-4% 3-6% 12.5% 36.4% of the Cambridge forest. Today, 3 species make up over 30% Catastrophic loss of those 3 species would result in 17% remaining total canopy cover.

82-84 92 - 94 90 - 92 86 - 88 80-82 84 - 86 96-98 88-90 94 - 96 98 - 100 Source: CCVA REED HILDERBRAND 80 or Below OF A 90 °F DAY TEMPERATURE ESTIMATED AMBIENT AIR Heat island + bus routes (cool corridors) CRITICAL URBAN CORRIDORS LACK SHADE CAMBRIDGE URBAN FOREST MASTER PLAN PUBLIC MEETING 1 (OCTOBER 3, 2018

82 - 84 80-82 94 - 96 90 - 92 84-86 86-88 92 - 94 88-90 96 - 98 98 - 100 REED HILDERBRAND Source: CCVA 80 or Below TEMPERATURE OF A 90 °F DAY ESTIMATED AMBIENT AIR Heat island + bus routes (cool corridors) CRITICAL URBAN CORRIDORS LACK SHADE CAMBRIDGE URBAN FOREST MASTER PLAN PUBLIC MEETING 1 | OCTOBER 3, 2018

DRAFT causes of Area of Canopy Loss • Area of Canopy Gain Area with No Change canopy loss? What are the HURON AVENUE. ESERYOUR Source: Prepared by RH Team from the 2018 AES classification data and City GIS data. WALDEN ST

STEM LOSS 5 Existing Tree Canopy 8 g Land Area (sq fO) 30.027,800 $4,000,000 $2,000,000 56,000,000 $01,900 1/10 1730 0------300%9--- 10 000 1779 1700 1019 1830 Impacts of planting cycles in residential development Figure 8:% Existing Tree Canopy in relotion to year built, parcel value, and tond area for single family residential porcels. Source: UVM, "A Report on the City of Cambridge's Existing and Possible Tree Canopy", 6/1/12 1999 Development tapered off after 1930 so we can surmise that the residential canopy will also begin to taper off as those trees age. Properties with homes built around 1920 have unusually high percentage of tree canopy. These trees are now likely reaching maturity. tree lifespan ------ MA forest cover % Hypothetical 100 yr

Reversing the trend Canopy loss CAMBRIDGE URBAN FOREST MASTER PLAN TASK FORCE MEETING 6 [NOVEMBER 29,2018 Stem the loss of existing trees Grow Canopy by planting new trees current trend of urban forest contraction - There are two primary approaches to reversing the

CANOPY ACRES 1000 [phone removed] 2020 2022 2024 2026 2028 2030 2032 STEMMING LOSS AND GROWING CANOPY 2034 2036 2038 2040 2042 Mortality rate unchanged (6.5%/yr) + No new plantings § 2044 2046 2048 2050 2053 2055 2057 2059 2061 2063 2065 2067 2069 • Remaining Canopy Annual loss Tree Hardiness Year over Year Canopy Growth Pest and Diseases Mortality includes: Climate (flood/drought)

CANOPY ACRES 800 1000 1200 2018 2020 2022 2024 2026 2028 2030 2032 STEMMING LOSS AND GROWING CANOPY 2034 2036 2038 2040 Stem Loss (3%/yr) + Grow Canopy (2,500 trees/yr) 2042 § 2044 2046 2048 2050 2053 2055 2057 2059 2061 2063 2065 2067 2069 • New Planting • Remaining Canopy •Year over Year Canopy Growth •Cumulative Canopy Growth From New Planting

Ideal volume: 1250 cu ft per tree Change practices Strategies maximize soil volumes PLANTING DETAILS IMPACT LONG TERM SURVIVAL OF STREET TREES

200 1200 600 [phone removed] 1600 · 2000 ROW 157. BEYOND MUNICIPAL TREES Commercial • Canopy Covered 66. Industrial 115 Institutional City of Cambridge (sidewalks, parking lots, yards, • Plantable - Not Canopy Covered open space, impervious surfaces) The opportunities for planting are greatest on residential and open space land use types. 276 Open Space wetlands) Not Plantable Public (streets, buildings, athletic fields, 491 Residential

SURVEY OF ATTITUDES Feasibility Survey/Study particular policy or proposal — Why are things working or not working - Insights about what will be well-suited for Cambridge — Narrowing the world of possibilities - not supporting a U2 society/ ISSES https://nexusofchange.wordpress.com/2012/04/08/occupy-atlanta-surveys-public-opinion-for-better

Conservancy report PRACTICE | URBAN FORESTRY - Forestry division growing - Cartegraph, new Tree tracking system Cambridge has a strong and growing department - Today the average municipal expenditure on capita spending for other Tree Cities in MA) - 6 out of 8 forestry staff are certified arborists tree planting in U.S. is $5.83 per capita (Nature per capita 2017. (Compare with $7-30 average per - Forestry Budget: $18 per capita in 2016 and $19.75 TREE CITY USA®

consent public hearing hearing to be removed Establishes powers for tree wardens M.G.L. Chapter 87 Shade Trees Trees that pose immediate hazards do not require a feet of the public way with Tree Warden & Owner's Removal of healthy public shade trees requires advertised Applies to trees within the public right of way or within 20 current regulations: state

• Tree Study • Enforcement • Parkway Overlay • Tree Protection Plan • Prospect Street Overlay • Tree Replacement Fund City Zoning Articles 5 & 19 City Tree Removal Policy City Tree Protection Ordinance City Zoning Article 20 (Overlay Districts) current regulations: city

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