Only in the thicker part of the analysed windfalls (first 10% section) the density of I. typographus maternal galleries was smaller (ANOVA: F 9,490 = 1.940, P = 0.0445; post hoc LSD procedure for α = 0.05 see Fig. 5). The average infestation densities in the remaining 10% sections were similar and had the values PS-341 manufacturer of 483.1 to 563.3 maternal galleries/m2 (Fig. 5). The observed, lower colonisation of the first 10% section is the result of low I.
typographus frequency in the zone with the nodules and thickest bark, within the first 0.5 m-section (ANOVA: F 3,196 = 14.3515, P < 0.001; post hoc LSD procedure for α = 0.05 see Fig. 6). An even distribution of I. typographus on the examined windfalls suggests the existence of a directly proportional relationship between the number of maternal galleries of this insect species in the selected sections and the number of maternal galleries on all stems. Fig. 5 Distribution of I. typographus on P. abies windfalls in 10% stem length sections (marked are means and 95.0% LSD intervals) Fig. 6 Distribution of I. typographus on P. abies windfalls in the first four 0.5 m-long stem sections (marked are Selleck 3 MA means and 95.0% LSD intervals) The relationships between the numbers of I. typographus maternal galleries found in 0.5 m-long stem sections and the total density of the Selleck Go6983 windfall infestation The
results of the correlation and regression analyses show that the most significant correlations were obtained for the 6, 7 and 17th 0.5 m-long stem sections (counting from the butt end) (Table 1). The coefficients of determination for these correlations were highly significant and their values ranged from 0.8459 to 0.8697. The distribution of the mean relative errors of estimation between the 6th and 23rd sections (with the exception of sections 10, 11, 12, and 21) did not exceed 30%. The mean relative error of estimation click here was lowest in sections 17 (18.49%), 7 (18.90%), and 6 (20.74%). These results suggest that
to estimate the total density of I. typographus infestation of the whole P. abies windfall, the linear regression equations obtained for the 6, 7 and 17th 0.5 m-long stem sections may be used. Estimation of I. typographus population density in area investigated—accuracy assessment of the proposed method On each of 50 windfalls distributed randomly in the area investigated, the total I. typographus infestation density (tree-level analyses) and then the mean total infestation density of the windfall were estimated—the unbiased estimator of the mean and confidence intervals were calculated (stand level analyses). The mean total infestation density of the windfall (\( \bar\barD_\textts \)) was 440.6 maternal galleries/m2. The confidence interval at α = 0.05 for the mean total infestation density of the windfall was from H l = 358.7 (the lower limit) to H u = 522.6 (the upper limit) maternal galleries/m2. The relative error of estimation (\( \hatd_\textB \)) was 18.6%.