Table 2.

Variables that described the veteran oak and its surrounding landscape and were used to predict species richness and functional diversity of beetles captured around the tree

Variable	Type	Measurement	Reference
Tree circumference	Continuous	Tree circumference at breast height in cm. Natural logarithm taken	Sverdrup‐Thygeson et al. (2010)
Light availability	Continuous	Slope*cos(Aspect−45)	Stage (1976), Stage and Salas (2006)
Vitality	Categorical (2 levels)	Healthy: 20% or more living canopy Senescent: <20% living canopy	Sverdrup‐Thygeson et al. (2017)
Regrowth	Categorical (3 levels)	Open: no regrowth around oak Shrubs: low vegetation, shrubs or small trees Trees: trees with height similar to the focal tree	Sverdrup‐Thygeson et al. (2017)
Connectivity (8 variables)	Continuous	Predicted number of hollow oaks within 0.5 km, 1 km, 2 km, 3 km, 4 km, 5 km, 10 km, and 25 km of focal tree	Skarpaas et al. (2017)
Habitat class	Categorical (2 levels)	Forest: tree situated in a forest Open landscape: tree in either a park or agricultural landscape	Sverdrup‐Thygeson et al. (2010)
Tree cover density (3 variables)	Continuous	20 m: the percent of the 20 m pixel where focal tree is located that is covered by forest. 100 m: the percent of 20 m pixels covered by forests within 100 m radius of focal tree. Standard deviation: the standard deviation of the percent of 20 m pixels covered by forests within 100 m radius of focal tree	CLMS (2012 & 15)

Trees were either located in forest (n = 38) or open landscapes (n = 23).