Table 3. Estimates of treatment effects on melt-out dates.
Melt-out dates | TDD | |||||
Effect ± sd | t-value | p-value | Effect ± sd | t-value | p-value | |
Intercept (Normal) | 155±1.0 | 272.7±6.7 | ||||
Removed | −34±0.9 | −39.9 | <0.001 | 45.7±11.6 | 3.95 | 0.003 |
Shallow | −5±0.7 | −6.9 | <0.001 | 10.7±9.3 | 1.16 | 0.253 |
Medium | 8±0.6 | 14.1 | <0.001 | −26.4±9.6 | −2.74 | 0.009 |
Deep | 12±0.5 | 26.2 | <0.001 | −38.9±9.0 | −4.35 | <0.001 |
df | 182 | 6180 |
Melt-out dates in days of year (doy) and on TDD (thawing degree days, i.e. positive air temperature sums in °C). Effect values other than the intercept (here: Normal treatment) are deviations from the latter. Normal = unmanipulated snow cover; Removed = snow removal on 1. May; Shallow = naturally early snowmelt; Medium = intermediately increased snow; Deep = maximally increased snow. Given are standard deviation (sd), t- and p-values and degrees of freedom (df) of the model.