Fall color at The Arnold Arboretum of Harvard University, Boston, Mass.(Courtesy Arnold Arboretum Archives)

"All the trees and shrubs…which can be raised in open air.”

I'm confident Joni Mitchell wasn't contemplating the nation's arboreta when she penned the lyrics to "Big Yellow Taxi," though she was rightly worried that America was becoming a "paved paradise" more content to build malls than parks. Still, arboreta are in a sense "tree museums," organized collections of trees and shrubs where specialists study their growth and development.

"They took all the trees,

Put 'em in a tree museum."

Joni Mitchell, Big Yellow Taxi.

For us laypeople -- free to enter an arboretum to duck under branches, wander a secret brook or discover a grandfather oak -- autumn calls loudest. There's simply no better time to hide beneath the branches as the tree's leaves and subsequent shadows fall away toward winter.

Harvard's Arnold Arboretum, established in 1872, is thought to be America's first "botanic garden of trees." Today, American tree museums span from Hawaii's Pua Mau Place Arboretum and Botanical Gardens on the Big Island to the Ecotat Gardens and Arboretum in Harmon, Maine. U.S. arboreta might encompass the 10 acres of Simmons Arboretum in Madison, Miss. or fill 1,260 acres in Madison, Wis. Regardless of size or locale, taking time to delve into our inner wood nymph within the boundaries of America's arboreta is a mid-autumn dream well spent.

The Arnold Arboretum of Harvard University
, Boston, Mass.

James Arnold's vision to contain "all the trees and shrubs ... which can be raised in open air" was as ambitious as the university to which he deeded his land in 1872 to establish the Arnold Arboretum. An integral component of Frederick Law Olmsted's 7-mile long Emerald Necklace, the 265-acre arboretum offers a dynamic range of programs including the Landscape Institute, Field Studies for Children and art exhibitions.