2.4 Data Analyses
To meet the criteria for a dry-down event, the LWD sensor had to register 100% saturated and decline to the threshold dry level of 15% without an increase of at least 2% wetness over ten minutes. This stipulation ensured that an errant water droplet did not discount a dry-down event but eliminated breaks in precipitation during long storm events. These inclusion criteria were applied across sites and years, and a total of at least nine dry-down events that were representative of each vegetation type were used in the analysis. The data below the dryness threshold were rescaled as 0% wet.
We also compared the rate of leaf drying between crop sites and forested conditions. For each 10-minute time point throughout the dry-down event, the differences in leaf wetness between sites were compared across all replicate events using a paired t-test (α-value of 95%). Dry-down curves were best-fit with logarithmic trend lines using the format y = –m(ln)x + b where m is the slope and b is the y-intercept. We compared mean least squared differences in dry-down slopes to canopy height using a back-transformed linearized equation derived from the logarithmic trends. To allow transformation, we first increased all the data by two orders of magnitude and converted the dry-down rates to positive values. Analysis of transformed data reduced variance and kept the resulting data within the same order of magnitude.
To compare drying times between vegetation types, an analysis of variance (ANOVA) model was applied for all paired treatment combinations. Afterwards we applied a Tukey’s post-hoc test to separate the conditions into like groups by comparing their means. Drying times were considered different between groups at p < 0.05, and coefficient of determination (R2) was used to indicate model fit.

Results