COMPARATIVE ANALYSIS OF URBAN TREE SUITABILITY USING DENDROCHRONOLOGY

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1 Institute of Forest Botany and Forest Zoology Faculty of Environmental Sciences COMPARATIVE ANALYSIS OF URBAN TREE SUITABILITY USING DENDROCHRONOLOGY Sten Gillner and Sandra Korn

2 Introduction 2. Ziele 3. Material und Methoden 4. Ergebnisse 5. Zusammenfassung 6. Ausblick Urban trees are an essential part of urban infrastructure! Benefits of urban trees air pollution removal reduction of the urban heat island effect shading and evaporative cooling dust and noise reduction places for physical recreation positive effects on human health 1

3 Introduction 2. Ziele 3. Material und Methoden 4. Ergebnisse 5. Zusammenfassung 6. Ausblick Urban tree sites urban heat island effect (heat, low air humidity) soil compaction soil sealing de-icing salt.. heat and drought stress surface temperature (Dresden) hot summer day (30 C) reference: REGKLAM, IÖR Climate change precipitation decrease temperature increase from 2.5 to 4.0 (6.0) K increase of heat and drought increasing heat and drought stress 2

4 1. Introduction Einleitung Aims 3. Material und Methoden 4. Ergebnisse 5. Zusammenfassung 6. Ausblick Identification of drought tolerant tree-species at highly sealed urban sites assessment of vitality using growth pattern Analyzing of species-specific growth reactions climate sensitivity above-average/below-average radial growth impact of drought years 3

5 1. Introduction und Methoden 4. Ergebnisse 5. Zusammenfassung 6. Ausblick Sites (n=9) highly sealed street tree sites in the city of Dresden comparable sealed surface comparable age of the trees (70 to 100 yrs) Tree species (n=9) Acer platanoides Norway maple n= 31 Acer pseudoplatanus Sycamore maple n= 27 Fagus sylvatica Common beech n= 10 Pyrus communis Common pear n= 56 Platanus x hispanica London plane n= 14 Quercus petraea Sessile oak n= 14 Quercus rubra Northern red oak n= 32 Tilia cordata Winter-leaved linden n= 28 Tilia platyphyllos Large-leaf lime n= 24 4

6 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick Parameter for evaluating tree suitability 1. Changing radial growth rates 2. Changing climate-growth relationship 3. Pointer year analyzes 4. Superposed epoch analyzes 5

7 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 1. Changing radial growth rates Computing the ratio of average growth-rates for the periods and declining growth rates stable growth rates 6

8 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 2. Changing climate-growth relationship Is there an impact on growth of the decreasing precipitation sums and the increasing temperatures? Dresden [110 m a.s.l.] year April to June 7

9 Correlation coefficient 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 2. Changing climate-growth relationship Computing climate-growth correlations by moving correlations over 60 years Acer pseudoplatanus June major alterations Fagus sylvatica Acer platanoides Acer pseudoplatanus temperature precipitation 8

10 Correlation coefficient 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 2. Changing climate-growth relationship Computing climate-growth correlations by moving correlations over 60 years Quercus petraea June minor alterations Platanus x hispanica Pyrus communis Quercus petraea temperature precipitation 9

11 radial growth [mm] 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 3. Pointer year analyzes above-average growth = positive pointer years below-average growth = negative pointer years year N= 6 N= 7 Calculating the ratio of positive to negative pointer years in the common period 1920 to 2000 = 6/7 10

12 departure of mean radial growth (index) 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 4. Superposed epoch analyzes (sea) Do drought years have an impact on growth? drought years Drought years pre-years post-years 11

13 departure of mean radial growth (index) 1. Introduction und Methoden Methods 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 4. Superposed epoch analyzes (sea) Do drought years have an impact on growth? drought years Drought years petraea pre-years post-years 12

14 1. Introduction und Methoden Methods Results 4. Ergebnisse 5. Zusammenfassung 6. Ausblick 13

15 1. Introduction und Methoden Methods Results 4. Ergebnisse 5. Zusammenfassung 6. Ausblick stability Minor suitability Mean suitability Excellent suitability 14

16 1. Introduction und Methoden Methods Results 4. Ergebnisse 5. Conclusion Zusammenfassung 6. Ausblick Minor suitability Acer platanoides Acer pseudoplatanus Fagus sylvatica areas with balanced water supply and only minor heat stress (parks, gardens) Mean suitability Pyrus communis Tilia cordata Tilia platyphyllos areas with balanced water supply (street tree sites with minor soil sealing) Excellent suitability Platanus x hispanica Quercus petraea Quercus rubra areas with drought and heat stress (street tree sites with highly sealed soil 15