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Biodiversity and pathology in
urban parks
Emilio Padoa-SchioppaUniversity of Milano-Bicocca
Alessandro RagazziUniversity of Firenze
Biodiversity in urban parks
Not only «urban» species
Biodiversity in urban parks
Biogeography rules confirmed
N°
of
spe
cie
s
Area of the park
N°
of
spe
cie
s
Distance of the park from
urban center
Biodiversity in urban parks
Far from natural systems
Biodiversity in urban parks
Invasive species
Forest ecosystem
Urban forest
Urban system
Pathosystem
Pathology in «urban forest»
1896, Vallombrosa (Florence), Royal Forest Institute: ForestPathology
1902, Rome, Experimental Institute of Plant Pathology: PlantPathology
2000, Florence, Padua, Viterbo, Sassari: Institutes of ForestPathology: Urban Forest Pathology
Timeline of discipline “Plant pathology" in Italy
Until the end of 1800 the phytopathological problems
were studied by botanists and mycologists
Forest ecosystem Urban forest (system)
Natural control of pathogens
Organic matter recycling
Mineral compounds
Well-structured and aerated soil Good microbial activity
Wounds
Compact soil Altered microbial activity
Antifreeze salt
Smog
Artificial light
Wounds
Freytet, 1990, modificato F. Bello
Ecosystem in balance
Good resistance to climatic
adversity and parasitic
diseases
H2O
Altered ecosystem
Exposure to climatic adversity
and parasitic diseases
The expression “urban forest” includes the concept of
“urbanity” and those of “forest” (Randrup et al., 2005)
……..and, adds the pathologist, the relative problems……
Change the “concept of disease” in urban forest??????
The relationship is with the population
and not with the single plant
Diffusion on vast territories
High probability of natural healing
No possibility of chemical treatments
Relationship also with the single plant
Damage threshold is lowered
Premature senescence
Altered physiological state
Deficiency of water and nutrients
Harder and slower natural healing
Possibility of chemical treatments
Forest ecosystem Urban forest (System)
The concept of disease does not change!!
Change the management
Prophylaxis is more difficult
Foliage diseases, which under general forest
conditions cause little damage and therefore require
minimal attention beyond a diagnosis, under
urban forestry conditions become "serious
diseases" requiring disease control application.
Foliage diseases
Defoliation can totally
destroy the landscape value
(Jorgensen. Modified)
Stem decays and cankers, which under forest
conditions contribute to natural succession, and
which in many cases can be eliminated through
regular silvicultural thinnings, become, under
urban forestry conditions, diseases worthy of
treatment in that hazardous to the citizens.
Stem decays and cankers
(Jorgensen. Modified)
Wilt and die-back diseases are, under urban
forestry conditions, major problems of concern.
These diseases appear readily to adapt to
introduced hosts or to the altered environmental
conditions of the urban area.
Wilt and die-back diseases
(Jorgensen. Modified)
Root disease problems are different under urban forestry
conditions where soil disturbances through earth
excavation work are commonplace.
Diseases like root rot (Armillaria mellea) which under
forestry conditions causes killing of young as well as
overmature trees (conifers and hardwood), under urban
conditions are often found associated with sudden death of
hardwoods.
Root rot diseases
(Jorgensen. Modified)
The "ecological" conditions of the urban environment are
favorable to the settlement and development of numerous
cryptogams and insects; however both are often found in
natural systems.
In the urban system however some associations fungi/insects
showed more incidences.
Associations fungi/insects
The disease management in
urban forest is discussed in
the next relation
