Università degli Studi di Firenze

Dipartimento di Scienze delle Produzioni Agroalimentari e dell’Ambiente (DISPAA)

Sezione di Patologia vegetale ed Entomologia

Beatrice Ginetti, Alessandro Ragazzi, Salvatore Moricca

Action 16 & Action 17

Establishing a monitoring network to assess

lowland forest and urban plantation in Lombardy

and urban forest in Slovenia

Phytopathology Unit

Report of the activities

May 2014

Observations and data collection were during the months of July and September 2012 and June and September 2013 For each individual tree the following parameters were recorded: species; social position; height; age; diameter; percentage of chlorosis; percentage of defoliation Data were processed following each sampling, and the averages for estimated defoliation percentages were calculated Data on chlorosis percentage were excluded due to their numerical inconsistency (just few trees in the 14 investigated plots showed chlorosis)

Defoliation percentage 2012 Defoliation percentage 2013

July September June September

Carpaneta 11 - 21,4 22,9

Boscofontana 13,3 - 27,5 37,5

Maristella 11,4 - 14,7 26,9

Boscoincittà 48 60 61,2 63,8

PN1a 9,3 43,2 28,2 19,6

PN1d 23 74,5 42,9 45

PN2a thinned 24 41,5 47,5 40

PN2a

unthinned 21 61,9 61,7 50,7

PN9a 15 45,4 43,4 40,5

PN14a 14 71,8 41,6 41

PN18c 67,6 39,2 49,4 67,6

PN23b 15 65 46,7 41

PN25a 7,5 61,6 16,2 14,8

PN28c 18 69 25,5 37,4

21,29286 57,55455 37,70714 39,19286

Defoliation trend observed through the years 2012-2013. (*): The precise month of the monitoring, e.g. July (beginning) / June (end), depended on tree phenology in relation to the ongoing season (vegetation status).

Statistical analisys

Comparisons among plots during the same month

Parametric t-test or a nonparametric rank sum test

Wilcoxon rank sum (Mann Whitney) test

Comparison among groups with paired data (e.g. before/after) to correlate data obtained at

different sampling dates Parametric t-test or nonparametric rank sum with sign test

Wilcoxon signed-rank test

Pr(T < t) = 0.0000 Pr(|T| > |t|) = 0.0000 Pr(T > t) = 1.0000 Ha: diff < 0 Ha: diff != 0 Ha: diff > 0

Ho: diff = 0 Satterthwaite's degrees of freedom = 53.7232 diff = mean(1) - mean(2) t = -4.5602 diff -17.56131 3.851031 -25.28307 -9.839546 combined 201 38.20398 2.14889 30.46577 33.96659 42.44137 2 178 40.21348 2.354453 31.41232 35.56707 44.8599 1 23 22.65217 3.047456 14.61509 16.33214 28.97221 Group Obs Mean Std. Err. Std. Dev. [95% Conf. Interval] Two-sample t test with unequal variances

Milan statistically higher defoliation than

Mantova-Cremona (40% vs 22,5%)

…data gathered until June 2013…

MILANO (Boscoincittà+Parco Nord) VS MANTOVA-

CREMONA (Bosco Fontana+Maristella+Carpaneta)

Milano Parco Nord Boscoincittà Mantova Cremona

Milano - - = >*

Parco Nord - <*** = =

Boscoincittà - - >*** >***

Mantova - - - =

Cremona - - - -

Defoliation percentages

Prob > |z| = 0.0047 z = 2.824Ho: var7(var8==1) = var7(var8==2)

adjusted variance 28589.96 adjustment for ties -140.04unadjusted variance 28730.00

combined 169 14365 14365 2 156 12782.5 13260 1 13 1582.5 1105 var8 obs rank sum expected

Two-sample Wilcoxon rank-sum (Mann-Whitney) test

Boscoincittà VS Parco Nord

Boscoincittà Vs

Mantova-Cremona

Prob > |z| = 0.0368 z = -2.088Ho: var1(var2==1) = var1(var2==2)

adjusted variance 101.11 adjustment for ties -1.81unadjusted variance 102.92

combined 18 171 171 2 13 144.5 123.5 1 5 26.5 47.5 var2 obs rank sum expected

Two-sample Wilcoxon rank-sum (Mann-Whitney) test

Prob > |z| = 0.0001 z = -3.829Ho: var1(var2==1) = var1(var2==2)

adjusted variance 909.70 adjustment for ties -12.22unadjusted variance 921.92

combined 36 666 666 2 13 356 240.5 1 23 310 425.5 var2 obs rank sum expected

Two-sample Wilcoxon rank-sum (Mann-Whitney) test

Boscoincittà, statistically

higher defoliation…

Boscoincittà Vs Bosco Fontana

Pr(T < t) = 0.0878 Pr(|T| > |t|) = 0.1756 Pr(T > t) = 0.9122 Ha: diff < 0 Ha: diff != 0 Ha: diff > 0

Ho: diff = 0 degrees of freedom = 32 diff = mean(1) - mean(2) t = -1.3852 diff -15.75 11.36993 -38.90979 7.409785 combined 34 58.61765 5.252283 30.62581 47.9318 69.3035 2 24 63.25 6.180923 30.28021 50.46379 76.03621 1 10 47.5 9.49415 30.02314 26.02274 68.97726 Group Obs Mean Std. Err. Std. Dev. [95% Conf. Interval] Two-sample t test with equal variances

. ttest var9, by(var10)PN 2a thinned VS PN 2a unthinned plot

Defoliation percentage 2012 Defoliation percentage 2013

July September June September

PN2a unthinned 21 61,9 61,7 50,7

PN2a thinned 24 41,5 47,5 40

No statistical

differences

between plots

but…

PN 2a unthinned plot is slightly more defoliated than 2a thinned one

June ‘13 September ‘13

BiC = =

PN1A <** >**

PN1D = =

PN2Ad = =

PN2And = =

PN9A = =

PN14A = =

PN18C = =

PN23B = =

PN25A = =

PN28C = =

Carpaneta = =

Boscofontana = =

Maristella <** >**

September ‘12 September ’13

BiC = =

PN1A >* <*

PN1D >** <**

PN2Ad = =

PN2And = =

PN9A = =

PN14A >*** <***

PN18C >* <*

PN23B >* <*

PN25A >*** <***

PN28C >*** <***

…September 2013…

No statistical differences September 2013: lower loss of

foliage mass than September 2012

1. Milan statistically higher defoliation than Mantova-Cremona

effect of urbanization

city as a urban heat island

Pollution

Soil conditions (structure and compaction)

2. Boscoincittà, statistically higher defoliation…

CONCLUSIONS…

Occurrence of harmful pathogens species

Role of management practices

3. PN 2a unthinned plot slightly more defoliated than 2a thinned

plot… even if no statistical difference between plots was found

the data is not statistically supported due to the

low number of individuals (N) per plot

Why defoliation is higher in the

unthinned plot, especially in coincidence

with drought periods?

Higher competitiveness among tree individuals in

unthinned plot (e.g. for water resources) -> tree

physiology impairment in unthinned plots

The overall average shows that in June 2013 survey, plant defoliation was

statistically higher than in July 2012, but significantly lower than in September

2012

Severe drought of 2012! Plants partially recovered but they couldn’t reach the

health conditions of the previous year (July 2012)

Repeated summers with extended drought can in a long time can become

lethal to trees

The defoliation percentage of September 2013 was not statistically different from the

one recorded in June 2013

A higher number of plots per town (at least 3) would probably be more

appropriate to get a greater statistical strength.

Furthermore, plots had quite different species composition, a fact that makes

statistical analyses to species level unreliable

2014: it will be of particular interest to observe the trend of stand resilience

Summer of 2013: it can be considered a cool and rainy season