Spatial and Temporal Heterogeneity Creates a “Brown Tide” in Root Phenology and Nutrition

Table 5

Estimated coefficients, standard error (SE), 𝑡-value, and significance levels (P) of model variables used to predict crude protein content of alpine sweetvetch (Hedysarum alpinum) roots in west-central Alberta, Canada.

Variable	Coef.	SE	𝑡-value	P
JDAY	−0.702	0.124	−5.64	<0.001
JDAY2	0.592^†	0.105^†	5.65	<0.001
CTI	−12.91	3.522	−3.64	<0.001
GDD	−0.100	0.027	−3.64	<0.001
CTI : GDD	0.014	0.004	3.56	<0.001
JDAY : CTI	0.063	0.017	3.74	<0.001
JDAY : GDD	0.503^†	0.131^†	3.85	<0.001
JDAY : CTI : GDD	−0.682^‡	0.182^‡	−3.75	<0.001
Intercept	133.4	24.96	5.34	<0.001

†Estimated coefficients and standard errors are reported at 1,000-times their actual value.
‡Estimated coefficients and standard errors are reported at 10,000-times their actual value.