The Changing Urban Landscape. David J. Nowak US Forest Service Northern Research Station Syracuse, NY

Transcription

1 The Changing Urban Landscape David J. Nowak US Forest Service Northern Research Station Syracuse, NY

2 Overview Factors of Change Changing Tree Cover Changing Species Composition Steps to Sustainability

3 Drivers of urban forest change Humans Nature

4 Directions of urban forest change Increased tree cover Decreased tree cover

5 Manage or utilize all factors All combine to affect current and future tree cover Tree cover Tree cover Human Tree planting Facilitate regeneration* Species selection (invasive species)* Maintenance* Climate change* Tree removals Mowing Pruning Development Vandalism Pollution* Transporting insects/diseases* Climate change* Nature Natural regeneration Insects/disease Old age Fire Storms Drought

6 Manage or utilize all factors All combine to affect current and future tree cover Tree cover Tree cover Human Tree planting Facilitate regeneration* Species selection (invasive species)* Maintenance* Climate change* Tree removals Mowing Pruning Development Vandalism Pollution* Transporting insects/diseases* Climate change* Nature Natural regeneration Insects/disease Old age Fire Storms Drought

7 Manage or utilize all factors All combine to affect current and future tree cover Tree cover Tree cover * Indirect human effects Human Tree planting Facilitate regeneration* Species selection (invasive species)* Maintenance* Climate change* Tree removals Mowing Pruning Development Vandalism Pollution* Transporting insects/diseases* Climate change* Nature Natural regeneration Insects/disease Old age Fire Storms Drought

8 Manage or utilize all factors All combine to affect current and future tree cover Tree cover Tree cover * Indirect human effects Human Tree planting Facilitate regeneration* Species selection (invasive species)* Maintenance* Climate change* Tree removals Mowing Pruning Development Vandalism Pollution* Transporting insects/diseases* Climate change* Nature Natural regeneration Insects/disease Old age Fire Storms Drought

9 Manage or utilize all factors All combine to affect current and future tree cover Tree cover Tree cover * Indirect human effects Human Tree planting Facilitate regeneration* Species selection (invasive species)* Maintenance* Climate change* Tree removals Mowing Pruning Development Vandalism Pollution* Transporting insects/diseases* Climate change* Nature Natural regeneration Insects/disease Old age Fire Storms Drought

10 Manage or utilize all factors All combine to affect current and future tree cover Tree cover Tree cover * Indirect human effects Human Tree planting Facilitate regeneration* Species selection (invasive species)* Maintenance* Climate change* Tree removals Mowing Pruning Development Vandalism Pollution* Transporting insects/diseases* Climate change* Nature Natural regeneration Insects/disease Old age Fire Storms Drought

11 Nature and Humans - Nationally Urban/Community Land Average US imp. cover = 2.4% US Impervious Cover Urban/community land = 5.3%

12 Nature and Humans - Nationally Urban/Community Land Average US tree cover = 34.2% US Tree Cover Urban/community land = 5.3%

13 Nature and Humans - Nationally Urban/Community Tree Cover Region and population density influence tree cover Average US tree cover = 34.2% US Tree Cover Urban/comm. tree cover = 35.1% Rural tree cover = 34.1% Urban/comm. imp. cover = 17.5% Rural impervious cover = 1.5%

14 Nature and Humans - Nationally Difference in Tree Cover between Urban / Community Land and Rural Land

15 Nature and Humans - Locally What percent of trees in cities are planted?

16 Nature and Humans - Locally What percent of trees in cities are planted?

17 Planting varies by city population density and region

18 Percent planting varies by land use

19 Species differences Humandominated Naturedominated

20 Change Analysis

21 Tree Cover Change

22 Tree Cover Change

23 Tree Cover Change 17 of 20 cities had a significant decrease in tree cover Average tree cover change: -0.27% of city area per year* Nationally, urban tree cover dropping: 0.033% of urban area per year 20,000 acres per year 4.0 million trees per year 16 of 20 cities had a significant increase in impervious cover (e.g., buildings, roads) Average impervious cover change: +0.31% of city area per year* * Excluding New Orleans and Detroit

24 Field Data Assessments of Change Random plots

25 Change in Baltimore and Syracuse ( )

26 Baltimore, MD * Invasive species

27 Ratio of Small vs. Large Trees: Baltimore Small: < 3 in DBH; Large: > 18 in DBH Most common large trees * Invasive species

28 Syracuse, NY * * Invasive species

29 Ratio of Small vs. Large Trees: Syracuse Small: < 3 in DBH; Large: > 18 in DBH Most common large trees * Invasive species

30 Other cities no field data on change, but

31 Ratio of Small vs. Large Trees: Chicago Small: < 3 in DBH; Large: > 18 in DBH Most common large trees * Invasive species

32 Ratio of Small vs. Large Trees: San Francisco Small: < 3 in DBH; Large: > 18 in DBH Most common large trees * Invasive species

33 Ratio of Small vs. Large Trees: Los Angeles Small: < 3 in DBH; Large: > 18 in DBH Most common large trees

34 Invasive Species

35 Emerald Ash Borer

36 Steps to Sustainability Data Collection (Ground, Aerial) FUTURE STATE CURRENT STATE Specific Management Plan Management Goals Canopy cover Species, location, time Tie to services / regulations

37 Summary Urban forests are changing Understanding urban forest change can guide management to sustain healthy urban forests nrs.fs.fed.us/units/urban