Only the coast redwood and the giant sequoia are clearly big enough.

If two-feet "walls" are enough to hold up the tree around a six-foot wide car, then the black willow, the coast Douglas fir, the sugar pine, and the white oak are big enough as well.

Complete Solution:
To find the diameter of a circle when you know the circumference, you divide the circumference by (pi, about 3.14). For example, the black willow has a girth of 400 inches and since 400 ÷ 3.14 is about 127, the black willow is about 127 inches wide, enough for a car to drive through and still leave at least 2 feet on each side.

 Tree Girth (4.5 ft above ground in inches) Diameter (girth ÷ ) Height (in feet) American Beech 279 89 115 Black Willow 400 127 76 Coast Douglas Fir 438 139 329 Coast Redwood 867 276 313 Giant Sequoia 998 318 275 Loblolly Pine 188 60 148 Pinyon Pine 213 68 69 Sugar Maple 274 87 65 Sugar Pine 442 141 232 White Oak 382 122 96

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