Table 1.

Field measurements and UrbanCrowns analyses of sugar maple (Acer saccharum) sampled in urban areas of Blacksburg, VA, U.S. For UrbanCrowns analyses, trees were photographed at four horizontal distances equal to multiples (1.5×, 2.0×, 2.5×, 3.0×) of their individual heights. For each mean value, n = 10 (standard error in parentheses).

Tree Attribute	Trunk Diameter Class (cm)
Tree Attribute	1–15	16–30	31–45	46–60	>60
Trunk Diameter (cm)^z	11.2 (1.1) e ^y	27.2 (1.1) d	38.1 (1.3) c	54.6 (1.2) b	81.0 (5.7) a
Tree Height (m)^z	6.1 (0.5) c	11.4 (0.3) b	12.8 (0.4) b	16.2 (0.7) a	18.0 (0.7) a
Crown Diameter (m)^{^z^x}	3.8 (0.3) d	8.4 (0.4) c	9.0 (0.7) c	13.4 (0.3) b	17.4 (0.9) a
Crown Volume (m³)^w
1.5× tree height	22.8 (5.8) Ad	373.5 (44.4) Ac	555.7 (77.0) Ac	1487.7 (58.3) Ab	2933.1 (365.3) Aa
2.0× tree height	22.1 (5.6) Ad	346.9 (38.2) Ac	496.2 (65.9) Ac	1329.8 (45.8) Ab	2710.8 (361.0) Aa
2.5× tree height	22.1 (5.9) Ad	341.3 (37.6) Ac	491.4 (60.2) Ac	1281.6 (37.4) Ab	2672.6 (366.2) Aa
3.0× tree height	21.6 (5.8) Ad	336.8 (39.3) Ac	485.0 (61.7) Ac	1276.7 (52.5) Ab	2655.1 (366.1) Aa
Crown Density (%)^w
1.5× tree height	84.5 (1.0) Ab	89.9 (0.7) Aa	93.1 (0.7) Aa	92.7 (1.0) Aa	92.1 (1.1) Aa
2.0× tree height	83.0 (1.1) Ab	89.0 (0.7) Aa	92.5 (0.8) Aa	93.0 (0.6) Aa	92.1 (1.0) Aa
2.5× tree height	81.9 (1.1) Ac	88.5 (0.7) Ab	92.2 (0.7) Aab	92.9 (0.6) Aa	92.4 (0.9) Aab
3.0× tree height	81.7 (1.3) Ad	87.4 (1.1) Ac	91.9 (0.9) Abc	92.6 (0.6) Aab	92.1 (1.1) Aab

↵^zMeasured in the field using conventional techniques.
↵^yWithin a row, means with different lowercase letters are significantly different at α = 0.05 using Tukey’s HSD. Uppercase letters denote significant differences within a column for specific attributes.
↵^xMaximum width measured perpendicular to photograph line of sight.
↵^wComputed using UrbanCrowns software.