Technical Comments

Response to Comments on "Post-Wildfire Logging Hinders Regeneration and Increases Fire Risk"

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Science  04 Aug 2006:
Vol. 313, Issue 5787, pp. 615
DOI: 10.1126/science.1126583
  • Fig. 1.

    (A) Box-and-whisker plots of Biscuit Fire seedling data (seedlings per hectare) from (3) and (B) residuals from parametric test [analysis of variance (ANOVA)] on interannual changes in untransformed seedling data, as in (2). (A) shows tendency toward positive skewness (typical for ecological count data) for all groups and unequal variance, as well as marked difference between the 2005-logged sample compared with other samples. Dot within box is the median; box edges are the 25th and 75th percentiles; whiskers represent the data range; points beyond 1.5 times the interquartile range from the quartiles are drawn as horizontal lines across the whisker. Shapiro-Wilk normality test (32) indicates lack of normality: W = 0.7173, P = 0.0023 for 2005-logged plots. (B) shows that parametric ANOVA tests on untransformed data, as in (2), are prone to spurious results for the seedling data due to substantial departure from normality (Shapiro-Wilk normality test: W = 0.7226, P = 0.0026 for annual change in density between years in logged plots). Analyses after data transformations or nonparametric analyses are highly preferred (31).

  • Fig. 2.

    Changes in seedling densities between 2004 and 2005 for logged and unlogged plots, with logging occurring between measurement periods. Equivocal variation between years can be seen in the unlogged plots (no consistent trend), whereas logged plots all show marked declines.

Additional Files

  • Response to Comments on �Post-Wildfire Logging Hinders Regeneration and Increases Fire Risk�
    D. C. Donato, J. B. Fontaine, J. L. Campbell, W. D. Robinson, J. B. Kauffman, B. E. Law

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