Article Figures & Data
Figures
- Figure 1.
Mean width of annual growth rings in the years 1973 to 1994 for DAPI-positive green ash (n=49) and DAPI-negative green ash (n=264) in nine Iowa and Wisconsin cities. Mean radial growth for the last 3 yr (1992-1994), 10 yr (1985-1994), and 20 yr (1975-1994) was significantly (Prob>F = 0.0001) less in DAPI-positive than DAPI-negative trees.
Tables
- Table 1.
Number of trees with phytoplasma (Ash Y) infection or associated decline symptoms in urban green ash populations classified by percent crown diebacka
Crown dieback category Symptom <10% 10 to 30% >30% Phytoplasma (AshY) infection 13 16 13 Epicormic sprouts 54 62 66 Deliquescent branching 10 12 11 Basal cracks 14 19 24 Basal shoots 6 5 11 ↵a Based on Chi-square tests (df=2) for contingency tables, frequencies of above symptoms are not associated with crown dieback.
- Table 2.
Number of phytoplasma-infected green ash identified in sample populationsa exhibiting or lacking specific decline symptoms.
Symptom Symptom present Symptom absent Pb Infected Total % Infected Infected Total % Infected Epicormic sprouts 29 193 15.0 18 137 13.1 0.750 Deliquescent branching 9 37 24.3 36 284 12.7 0.074 Basal cracks 8 56 14.2 41 277 14.8 1.0 Basal shoots 10 29 34.5 38 301 12.6 0.004 Witches’-brooms 7 13 53.9 40 313 12.8 0.001 ↵a N=334. Discrepancies in column totals are due to missing (nonreported) data.
↵b Based on Fisher’s exact test for 2 × 2 contingency tables. P = the probability of observing a table with equal or greater evidence for association, given the null hypothesis of equal proportions for symptomatic and asymptomatic trees (8).
- Table 3.
Analysis of variance in mean radial growth during 1992 to 1994 for green ash trees sampled in nine Iowa and Wisconsin cities. Analysis of mean radial growth for the past 10 years (1985 to 1994) and the past 20 years (1975-1994) indicated similar trends (unpublished data). Similar conclusions were obtained when the analysis was conducted using tree diameter as a covariate (continuous) variable.
Source df SS MS F P>F Phytoplasmas detecteda 1 293.50 293.50 22.77 0.0001 City 8 90.58 11.32 0.88 0.5409 Phytoplasmas detected X city 8 20.88 2.61 0.20 0.9892 Diameter classb 3 43.21 14.40 1.12 0.3507 Phytoplasmas detected X diameter class 3 4.39 1.46 0.11 0.9521 City x diameter class 20 222.58 11.13 0.86 0.6299 Phytoplasmas X city X diameter class (Error I)c 52 670.30 12.89 2.78d 0.0001 Error II (sample variation) 213 988.20 4.64 Corrected total 308 2333.64 ↵a Results of DAPI test for the presence of phytoplasmas in root sections.
↵b Tree diameter (at 1.4 m above the ground) classes of 0 to 30 cm, 31 to 50 cm, 51 to 70 cm, and 71 to 100 cm.
↵c In this survey, the number of DAPI-positive and DAPI-negative trees in each diameter class and city was not controlled (n=1 to 22). An analysis of the unweighted means for factors specified in the effects was conducted using the interaction mean square as the error term and locations (cities) as replications.
↵d The variance for individual observations (Error II) was used to test the significance of the interaction effect.
In this issue
Jump to section
Related Articles
Cited By...
- No citing articles found.