You don’t have to be Christian to love trees right about now, when this part of the world is mostly a black-and-white canvas, relieved by the occasional slash of blue. The Druids venerated trees’ mysterious power 1,500 years ago, dragging live evergreens indoors for midwinter festivals. The Christmas tree is just one of the many pagan rituals syncretized by those wily early Christians, along with the yule log and mistletoe.
The symbolism isn’t subtle. While so much of the natural world dies back into an ashen slumber, evergreens stay, well, green — resilient sentinels of the forest, representing hope for the sun’s return. Even today we hang the trees with our dreams: fruits and nuts for a bountiful harvest, gold and silver tinsel for prosperity, bells to waken the faerie spirits the Celts believed lived inside the wood. It’s no surprise that balsam and spruce were worshiped: Their scent alone is a religious experience.
In Boston’s Arnold Arboretum you can see 197 different species of conifer, whose common names — Japanese Red Pine, Serbian Spruce, Korean Plum Yew — nod to the 19th-century expeditions that the Arboretum’s founders embarked on to build the collection. Frederick Law Olmsted and Charles Sprague Sargent, the Arboretum’s first director, designed the conifer grove to be seen at a distance. It offers a mutable palette to the patient observer: not just green, but blue-green, grey-green, yellow-green all fusing together. The wax on each needle adds a chalky patina. Stand quietly on Hemlock Hill and just look. “There’s something almost lush about it, even when it’s 10 below zero,” said William (Ned) Friedman, the Arboretum’s director.
Because he doesn’t play favorites, Friedman also enthuses about deciduous trees in winter. “I love the sense of nakedness and architecture,” he said. “There’s a grandeur especially in the winter, when we’re not distracted by flowers.” In December, you can see the vestiges of last year’s growing season, the dried seed pods and last tenacious leaves rattling around. “The deciduous trees don’t fight the cold; they get rid of their tender parts and go to sleep,” Friedman said. Evergreens chose a different evolutionary path. “It’s a reminder that there are many ways of solving the same problem.”
The importance of trees to our health and the planet’s is well documented. A broad tree canopy can reduce urban temperatures by as much as 20 degrees, prevent stormwater runoff, aspirate humidity and, of course, oxygen, and sequester carbon in trunks and branches. Boston has fallen seriously short of its own goal to improve the city’s green roof, essentially abandoning a target that was set in 2007 to plant 100,000 new trees by 2020. The city’s overall tree canopy of 27 percent is well behind the national urban average of 35 percent. Some neighborhoods are particularly barren: East Boston’s tree coverage is only 7 percent. Boston is among the best cities for public access to greenery, according to the Trust for Public Lands. But some 3,400 Bostonians still live farther than 10 minutes away from a park.
In a way, praising trees for their health benefits is like supporting the arts only because they stimulate the economy or help children do better in math. Trees have their own inherent value, as mediators between earth and sky, as living spires that literally lift our eyes to heaven. Their roots form networks that alert one another to predators and other threats. Their fossils date back 50 million years. We should also celebrate trees for trees’ sake.
Unlike the ancient Druids, we can be pretty confident that spring will come again. But in the dying of the year, everyone can be uplifted by the promise in something evergreen.
Renée Loth's column appears regularly in the Globe.