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Living and Writing in the Natural World

Heart on course, Head wandering

On Earth Day early last week, California redwood cloned saplings supplied by an outfit called Archangel Ancient Tree Archive were planted in California, Australia, New Zealand, Great Britain, Iceland, Canada, and Germany. Five months earlier, the group planted California redwoods and giant sequoias on the coast in southern Oregon. Their goal is to reforest the planet with redwoods and sequoias to preserve the ancient trees, soak up carbon as they grow, and save the planet from global warming. What could possibly go wrong with such a noble project?
Plenty, as it turns out.

To begin, I will admit wariness concerning projects whose founder (Michigan nurseryman David Milarch) describes getting the idea from an Archangel while in the throes of withdrawal from a lifetime of “formidable drinking.” That aside, and with no personal offense to the good gentleman, the idea of planting redwoods, sequoias, or any tree willy-nilly throughout the world flies in the face of a century of hard-won scientific findings on physiological and community ecology.

No single organism exists in a vacuum; it depends on a quantifiable range of environmental conditions to survive and prosper. For plants, these conditions include not just particular seasonable cycles of temperature, precipitation, and solar radiation, but also soil composition and processes involving soil fungi, soil bacteria, and animal vectors (for pollination and seed dispersal, among other services). The idea of plopping a sequoia sapling down in Iceland, Australia, or Germany, lacking all these necessary prerequisites for sequoia survival and growth, reflects a woeful ignorance of—well, of sequoias in particular, and the way the living world works, in general.

Readers of this blog can attest that I yield to none in my admiration of giant sequoias. But in my view, part of respecting and cherishing sequoias (or redwoods, or petunias, or chipmunks, for that matter) involves learning about the creatures, their traits and requirements. This means a certain amount of information transfer from science. Archangels simply don’t provide this sort of information, I would guess.

For example, giant sequoias thrive in their natural habitats on the western slope of the Sierra Nevada in California, mostly between 5,000 and 8,000 feet elevation, but when you try to grow one here in the Sacramento (or in the San Joaquin) Valley, they do terrible. The fungus Botryospheria in the valley infects the sequoia needles and kills much of the foliage. The trees don’t outright die, but they look miserable and clearly do not thrive.

On the other hand, some trees are “generalists,” able to survive and thrive in a relatively broad spectrum of temperature, precipitation, and solar radiation situations. The coastal redwood is one of these. Assuming conscientious watering for the first decade or so, they do fine in the Sacramento Valley here, and have been so widely planted as to become, to my mind, a weed tree.

Here’s the problem with planting redwoods in areas outside their natural coastal habitat, even in those other habitats in which they can survive: they replace the native trees that could have been planted instead in those habitats. And those native trees are connected in an ancient, finely-tuned web with the other living creatures of that habitat. Every redwood brought in and planted in the Sacramento valley is taking up space, water, nutrients, and solar radiation that could be used by a Valley oak, for example. A single Valley oak provides spatial habitat for many dozen species of co-evolved insects, mammals, and birds; and provides food in the form of acorns to bear, deer, turkey, scrub jays, acorn woodpeckers, squirrels (both tree and ground), and mice, not to mention “gall” tissue provided to dozens of species of Cynipid wasps. Redwoods provide none of this.

So when you plant redwoods in the valley, you are displacing many dozens of other living species—thousands of individual creatures—that depend on the native vegetation that the redwood is taking the place of.

Can you imagine the havoc if redwoods and sequoias were planted worldwide in the dense clusters that the Archangel Archive folks envision? The many thousands of creatures deprived of the spatial habitat and food they’ve evolved to depend on from the native trees that the alien invaders are taking the place of?

Reforesting large areas of the earth is a great idea; kudos for that idea to Archangel Ancient Tree Archive (though they are hardly the first to propose it). Reforestation has multiple advantages: tree growth that soaks carbon dioxide out of the atmosphere and ameliorates global climate change, providing natural areas for humans to escape the stresses of urban life and recharge their spirits and bodies. And if instead of planting sequoias and redwoods, you plant trees native to their home regions, then you add a further advantage: sustaining and strengthening the entire web of ecological community that has co-evolved in that place over thousands of years, permitting the native plants, insects, birds, amphibians, and mammals to thrive and flourish again.

So in Great Britain, by all means let’s reforest, but not with the alien redwoods and sequoias. Rather, let’s plant the English oak (Quercus robur), silver birch (Betula pendula), and hawthorne (Crataegus monogyna)—that’ll make the blackcaps (Sylvia atricapilla), skylarks (Alauda arvensis), and crested tits (Lophophanes cristatus) happy, maybe even bring the red squirrels (Sciurus vulgaris) back from their last strongholds in northwest England and Scotland (particularly if you remove those pesky invasive grey squirrels from America). In Germany let’s re-invigorate the great old forests of Oak (Quercus), beeech (Fagus) and pines (Pinus) and help the white wagtails (Motacilla alba), cuckoos (Cuculus canorus), fat dormice (Glis gis), and common voles (Microtus arvalis) also hang on and prosper.

Let’s pour a lot of time and money into this reforestation of native trees in every country, and the planet will thank us, habitat by habitat, trees, birds, mammals, and insects. The archangels will probably also thank us. I can hear their Alleluias! now.
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