It's cool to suggest that when Charles Darwin acknowledged that the simile of a great tree used to show the affinities of all the beings of the same class ... largely speaks the truth, he had a different truth in mind than many might suppose. Common descent is part of it, but he was more interested in the process of natural selection, which he saw illustrated by the way a tree grows. For Darwin a tree isn't a happy family...
At each period of growth all the growing twigs have tried to branch out on all sides, and to overtop and kill the surrounding twigs and branches, in the same manner as species and groups of species have tried to overmaster other species in the great battle for life. (On the Origin of Species [1859], 130)
While this fratricidal scene seems a little exaggerated, competition is the law of Darwinian life. (The second chapter of Origin is called "Struggle for Existence.") While he refers to vigorous and feebler buds, one might add that this refers not to anything about their nature - they're exactly the same plant - nor how hard each "tries." It's the accidents of light and position, wind and other life forms that make the selection, in turn shaping the environment which will determine who makes it in the next generation. Translated to the different beings of a class, there will be more variation among them than among a tree's buds and twigs, but the role of environment in determining who thrives remains central. And extinction. As we've seen, it was in realizing the role of extinction that Darwin sketched the famous "I think" tree/coral/seaweed drawing.
The environment is abstracted away in the sole diagram in On the Origin of Species, but then it's not a tree in the robust biological sense of the simile Darwin will countenance a few pages later. (Diagram and simile don't refer to each other. But the claiming of the tree simile comes as Darwin summarizes the chapter on "Natural Selection," emphasizing that natural selection can, as "the view that each species has been independently created" cannot, account for the "truly wonderful fact" that "all animals and plants throughout all time and space should be related to each other in group subordinate to group," as shown in the diagram. (129))
Each of the diagram's little starbursts represents a flurry of variation of which at most two variants survive... Only fifteen of the numberless variations make it to the present (fourteen thousand generations, though it could be ten times more), and they trace back to only three of the eleven starting lines! If this is a tree of life it's also a mausoleum. If translated back to an actual tree, each of those twigs that didn't make it is on or in the ground below.
Most references to Darwin's "tree of life" miss all these nuances, but it seems to me that enumerating the differences can be helpful, both for appreciating trees and for appreciating the contingent tangle of life which trees can seem particularly well to represent. But helpful for thinking about religion of trees? Yes - because this unnuanced view is widely held as part of "dark green religion." And because helping themselves to ancient religious notions of "cosmic trees," as such folks do, adds ideas of coherence, harmony, completeness and even progress to a story far more tragic and contingent - and sublime in a different way.
My purpose isn't to debunk but to complicate and enrich, but I find myself sounding a little shrill here. Ever the Weberian I don't see myself taking sides but rather pointing out "inconvenient facts" for all parties so readers can make up their own minds.
So for Darwin, the history of life isn't like a single-trunked tree, its growth all vertical out of a single source, but more like this diagram from an article about the implications of lateral gene transfer called "Uprooting the Tree of Life" - although it still maintains a more tree-like form than the latest representations below. And perhaps there is more cooperation within and among trees than he could imagine.
Still, I do have sympathies of my own of course! I guess I'm struggling to work out where to put them. Obviously my sympathies shape the kind of story I tell - what I include, what I let complicate and enrich what - but am I working toward a culminating all-encompassing insight? That unplanned use of the word "sublime" three paragraphs ago, for instance, and another word I didn't but was tempted to use: "tragic." And those ideals I've been problematizing - verticality, centrality, fullness, balance. Those are things many a tree-reverer sees in trees (and why fashionable thinkers prefer rhizomes). Am I saying they're not there, or there is some different profounder way?
And by what right do I favor some views over others? I'm no botanist, and spend more time thinking about trees than being with them. Still, my hope is that readers won't take my reflections as ungenerous attacks from a place of superiority but as insights from a place of grateful learning. My hoped response: you've given me ways to see more, to articulate what I've long known.
Back to the Darwin question. If Darwin's "tree of life" isn't what the deep green religionists think it is, and if it's been superseded by no longer tree-like diagrams among scientists anyway, why mention any of it? Because Darwin's tragic tree is truer than The Giving Tree, and Doolittle's swarm mangrove is truer still - truer in the sense that they let you see more of what really goes on among trees, and this is something profound. Like Darwin I'm complicating and enriching:
The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth. (130)
And because - here I'm stretching even more - this truer awareness brings us closer to elements of the non-modern religions of trees, too, which are formed and informed by relationships with trees more attuned to contingency and tragedy, to the realities of lateral intervention and to the wonder of their continued treeing forth.
