1. Ground-level ozone is produced by chemical reactions between volatile organic compounds and nitrogen oxides in the presence of sunlight. It can adversely affect crop yields, tree health and growth. 2. The Slovenian Forestry Institute has monitored ozone levels and visible injury on forest trees for over 10 years. Studies in 2013 and 2014 found no visible ozone symptoms in urban forests in Ljubljana, though symptoms have been observed in other years. 3. Global models predict that ground-level ozone concentrations will increase in the future without measures to reduce precursor emissions. Urban areas can help by planting native, ozone-resistant tree species and increasing education about trees and air pollution.

1. OZONE in Urban Forests
EMoNFUr Project - LIFE+ 10 ENV/IT/399
Urban Forests the lungs of the city
FINAL CONFERENCE
MILAN, Tuesday, June 17thth, 2014
OZONE in Urban Forests
Matej Rupel, Department of Forest Ecology,
Slovenian Forestry Institute, Večna pot 2, SI – 1000 LJUBLJANA, Slovenia
matej.rupel@gozdis.si

2. Today is OZONE very popular! Realy?
BAR

3. Is O3 good or
bad?
Statement: OZONE is a
serious air pollution
problem, adversely
affecting crop yield
(quality and
quantity), tree health
and growth.
Both ozone in the stratosphere
(90%) and ground-level ozone in
the troposphere (10%) occur
naturally.
and growth.

4. Elevated OZONE effects on
trees
O3 LEAVES
• Symtoms
• Respiration
• Photosynthesis
• Lipid peroxidation
• Growth
Good quality of life
of citizens
ROOTS
SOIL
INDIVIDUAL
Growth
• Quality
• Biomass
• Yeild
• Biomass
• Physiology
• Exudate
• Respiration
• Humidity
• Soil microbes
• Methane emissions

5. What's going on?
VOCNOx + +
Ground level or
tropospheric
ozone is
produced in the
reaction of
Volatile Organic
Compounds -
VOC with NOx
and sunlight.

6. Fraxinus ornus Ulmus glabra
What happens?
Acer platanoidesCorylus avellana
Fagus sylvatica
Ozone visible injury
• bronzing,
• intercostal stippling…

7. And what does it mean in urban
forest? •• AlsoAlso SlovenianSlovenian forests, urbanforests, urban
forests andforests and periurbanperiurban forests areforests are
endangeredendangered from pollution by airfrom pollution by air
(ozone).(ozone).
1. Injury leaves on the forest trees and shrubs,
2. Smaller surface area for photosynthesis,
3. Worse growth and health of trees…
and cyclically;
a) less oxygen,
b) wasting trees,
c) less water retention,
d) more dry
and warmer air…
e) worse health
of citizen…

8. Changes of O3 concentration in future
AOT40 Ozone Levels in Europe. High AOT40 levels are harmful for
crops. In the light green areas, the pollution levels are under the
critical value of 3000 ppb.hours. In the dark green areas the critical
level is exceeded up to two times. In the yellow areas the critical level is
exceeded from two to three times. In the orange areas the critical level
is exceeded from three to four times. In the most polluted areas of
Europe, the red areas, the critical level is exceeded by more than four
times. The results are obtained by running the Danish Eulerian Model
(DEM), discretized on a (96x96) grid, i.e. by using (50 km x 50 km)
grid-squares, over a space domain covering the whole of Europe
together with parts of Africa, Asia and the Atlantic Ocean.
Modeling prediction on geographical
distribution of ground-level ozone
concentrations in 1993 above (average
from May to August) and 2025 below.
(Lelieveldand
Dentener
2000)

9. The forecasts are global increase of
ozone!!!
What we done?
The Slovenian Forestry Institute have more than
ten year study period (2004 – 2013), assessing
ozone visible injury on forest vegetation in
Slovenia, observed as foliage damage on the
forest trees and shrubs species.
The Slovenian Forestry
Institute has been
performing passive
sampling of ozone for more
than 10 years. In 2013, we
embarked on measuringforest trees and shrubs species.
Our first observations of negative impacts of
ozone on forest tress were in year 2003. During
these years the visible ozone demages were
observing at 5 to 11 intensive monitoring plots
(ICP-Forest Level II)
and in the years 2013 and 2014 with
Project - LIFE+ 10 ENV/IT/399
also in Ljubljana urban and peri-urban forests.
embarked on measuring
sulphur dioxide, nitrogen
dioxide and ammonia. We
monitor air pollution with
passive samplers also in
the capital of Slovenia –
Ljubljana. We perform
measurements in urban
areas and urban and peri-
urban forests (city parks,
nature park Tivoli, Rožnik,
Šišenski hrib, forest

10. No Plot
Year
2006 2007 2008 2009 2010 2011 2012 2013
99 Ljubljana GIS ¤ ¤ ¤ ¤ ¤ ¤ ¤ ¤
99 a Ljubljana Tivoli ¤
99 b Ljubljana Debeli
hrib
¤
Identification of visible ozone or visible ozone like symptoms
in small trees and shrubs in Ljubljana urban forests
Visible foliar injury by ozone we survey on off-plots,
on light-exposed sampling sites at urban forest edge.
hrib
Tropospheric ozone increases during summer –
during the growth of vegetation.
Long dry season and high air temperatures in the second half
of July, are dried approximately 20% of the leaves on trees
and shrubs, so that they turn yellow and fall off in early August 2013.
11stst observationobservation betweenbetween 1818thth andand 1717thth JulyJuly 20132013 -- NONO VISIBLE OZONEVISIBLE OZONE
SYMPTOMS.SYMPTOMS.
22ndnd observationobservation betweenbetween 2121stst andand 2828thth September 2013September 2013 -- NO VISIBLE OZONENO VISIBLE OZONE

11. Foliage ozone
damages are diferent
each year. Typical
Nature park Tivoli, Rožnik and
Šišenski hrib
in LjubljanaTree species and shrubs observed on plot Ljubljana
TIVOLIFagus sylvatica
Tilia cordata
Corylus avellana
Juglans regia
Tilia sp.
Sorbus aria
Acer
pseudoplatanus
Acer platanoides
Quercus rubra
Quercus sessiliflora
Salix sp.
Carpinus betulus
Populus nigra
Sambucus nigra
Sorbus aucuparia
Viburnum lantana
Viburnum opuluseach year. Typical
ozone visible damages
were in the year 2013
in Ljubljana urban
forests not found.
Tree species and shrubs observed on plot Ljubljana
- DEBELI HRIB
Fagus sylvatica
Picea abies
Abies alba
Populus tremula
Cornus mas
Castanea sativa
Acer pseudoplatanus
Acer platanoides
Corylus avellana
Fraxinus excelsior
Laburnum sp.
Robinia pseudoacacia
Prunus avium
Crataegus oxyacantha
Crataegus leavigata
Cornus sanguinea
Malus domestica
Acer platanoides
Cornus sp.
Viburnum opulus

12. What we can do in Ljubljana,
Milan…?
Different species show different sensibility to the same ozone dose.
Planting native species that are not on LIST OF EUROPEAN OZONE
SENSITIVE SPECIES.
Strong street and park tree programme.
RIGHT TREE to RIGHT PLACE (“Managing Trees in one American city — Charlotte, North

13. Educating of the importance of trees, forest, tree
care…
Photo: Andrej Verlič

14. Due to the environment pollution and impacts on the forest
vegetation, we present the acquired conclusions to the wider
public.

15. Typical ozone visible injury on a Populus nigra L. leaf.
Thank you for your attention!