Managing NYC s Urban Forest and Natural Resources with Geospatial Data

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1 Managing NYC s Urban Forest and Natural Resources with Geospatial Data 2014 ESRI User Conference Jacqueline Lu, Director of GIS & Analytics Forestry, Horticulture NYC Department of Parks & Recreation

2 NYC Parks NYC is 14% Parkland (29,000 acres) 5,000+ individual properties 800 athletic fields nearly 1,000 playgrounds 550 tennis courts 66 public pools 48 recreational facilities 23 historic house museums 17 nature centers 13 golf courses 14 miles of beaches 5 stadia 1,200 monuments 2

3 593,132 street trees 1,651 acres of freshwater wetland 1,498 acres of salt marsh 1,444 acres of grasslands 5,136 acres of forest 2,383 greenstreets Estimated 2 million trees in landscaped parks

4 Operational Support 4

5 Street Tree Emergencies Typical Day Nor easter March 13, 2010 Tornados Sept 16, 2010 Hurricane Sandy Oct 28, 2012 Data Source: 311 Requests, NYC Parks Forestry Management System 5

6 014 Late Leaf Out Resurvey 6

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10 Late Leaf Out Affected Species 10

11 Comparing Salt Impacts to Routine Removals We compared the Late Leaf Out salt impacted trees data with the average annual dead tree removals in the Sandy inundation zone from fiscal year 2011 to fiscal year

12 Post-Sandy Late Leaf Out Survey 12

13 Data Collection and Development 13

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15 LiDAR Derived High Resolution Land Cover The 2010 land cover dataset is 97% accurate at a 6-inch pixel resolution. These can be combined with park property features to answer questions like which park features are currently shaded by trees, and which would benefit from additional plantings. 15

16 NYC s Tree Canopy Cover Landcover-Raster-Data-2010-/9auy-76zt

17 Mapping Trails in Natural Areas There is no citywide dataset of trails in NYC Parks natural areas Trails data of different sources exist for various Parks properties Most existing trails data have not been verified Trails data is important base layer for maintenance and operations Fall 2013 initiated citywide trail mapping effort with a member of Parks Conservation Corps More than 233 miles mapped to date Natural Resources Group unconfirmed trails data, Hunter Island and Orchard Beach, Pelham Bay Park, Bronx. 17

18 Citywide Trails Geodatabase 18

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20 Planning and Analytics 20

21 Possible Tree Canopy The 2010 LiDAR-derived land cover layer allows us to analyze the available space for greening projects across the five boroughs. Source: NYC 2010 Tree Canopy Assessment 21

22 Street Tree Block Planting Prioritization Site Suitability Need for Trees 22

23 Analytics Collaborations Volunteers at NYC Parks DataDive, September

24 Storm events in NYC are increasing in severity Forestry Storm Events *Events with more than 100 storm-related SR 25,000 26,011 WORK ORDERS GENERATED 20,000 15,000 10,000 5, , ,459 1,0311, ,563 1,115 1,853 1, , ,5452, ,792 2, ,860 1, /6/1997 8/16/1997 6/30/1998 9/6/1998 (Labor Day) 3/13/1999 8/5/1999 9/17/1999 (Floyd) 11/2/ /12&16/2000 4/19/2002 9/11/2002 (Gustav) 7/21/2003 9/18/2003 (Isabel) 10/15/ /13/2003 9/18/04 (Ivan) 8/14/ /24/2005 1/18/2006 9/2/2006 (Ernesto) 10/20/ /28/2006 6/28/2007 8/8/2007 (Bk tornado) 6/10-16/2008 6/29/2008 9/6/2008 (Hanna) 10/25/2008 2/12/2009 8/18/ /7/ /29/2009 1/25/2010 2/11/2010 2/25/2010 3/13/2010 (Nor'easter) 5/8/2010 6/24/2010 7/23-7/25/2010 8/22/2010 9/16/2010 (tornadoes) 9/30/ /1/2010 1/27/2011 2/1/2011 8/27/11 (Irene) 10/29/11 (Nor'Easter) 9/18/ /29/2012 (Sandy) F97 F98 F99 F00 F01 F02 F03 F04 F05 F06 F07 F08 FY09 F10 F11 F12 F13 STORM EVENTS, by fiscal year 10,030 2, Trees Down Hanging Limbs Limbs Down Requests Received 24

25 Can we quantify the effects of tree pruning on the occurrence of future tree hazards? 25

26 Determining Cause and Effect Prune Today Future NYC Parks has more than a decade of observational data in the form of treelevel hazard work orders and block-level pruning history. Not Pruned Controlled experimentation is not feasible with historical data. You can t A/ B test the past. Observational methods allow us to statistically recreate an A/B test and elucidate cause and effect. 26

27 Results Pruning on average reduced following year hazardous work orders on the blocks pruned by 22% Pruning Effect on Blocks Treated Effect on Treated Effect on Population % % Not Pruned Is Pruned *These are estimates made from 1000 bootstrapped samples of the data. Both estimates have p-values <0.001 in a standard two-way t-test. 27

28 Thanks! Jacqueline Lu Director of GIS & Analytics Division of Forestry, Horticulture New York City Department of Parks & Recreation