Species area effect: two trees exponentially more awesome than one

Why are two trees more than twice as good as one?  Because they’ll support exponentially more species.

“So, you got zero area, you got zero species,” said the scientist known as The Machete Man pointing to the origin of the X & Y axes he helpfully drew:

But as forest area increases … follow that upper curve from left to right … the number of species also increases, exponentially!

This graph is a simplified, generalized illustration of the fact that as a forest grows in area (or savannah or swamp or other healthy biome), the number of species that can live there makes a steep jump before leveling off.

The scale here starts at zero, growing, like to continent  size at the far right.  You have a North America-sized forest and it can support even the big animals:  lion, godzilla, panther, yeti, etc.

And if you cut that forest size in half, you’ll get a lot of animal corpses and the top mammals will go extinct, though interestingly, you’ll still have a fairly high number of species.

To get mucho species, the forest must be contiguous — If Gwinnett County was an intact forest and Cobb County was too, great … but you’d get healthier effect by Gwinnett and Walton both being forest, b/c they touch.

However, the Machete Man optimistically emphasized, research shows that good biological corridors have the same effect:  Gwinnett is a forest, Cobb is a forest and I-285 from Buford Highway to Smyrna is a forest, bam, you just made one big forest instead of two little ones and you could reintroduce some disappeared species.

Illustrated here:

Each square is a little patch of forest; they’ve been helpfully connected by creeks.  Law requires those creeks to be forested -> they’re buffer zones & biological corridors.  A fox will slip down the creek from one forest to another and spread her genes.  No buffer -> her forest is small, she gets tired of mating with her own family or she’s hit by a car, whatever.  No more foxes.

Exponentially awesome: a citrus allegedly hardy to 10F, now planted in my neighborhood

The other way to not kill off species

Keep your forests contiguous, make the forest area far on out the X axis.  That’s one way to support more species.

The other is to keep that curve as big as you can, make it roomy underneath, let it reach high on the Y axis.

Machete man drew another curved line, under the first.  That’s the shrunken number of species supported by a forest choked with invasive, non-native species.

Invasive species here include things like kudzu, ivy and wisteria.   For example, when kudzu’s taken over a patch of forest, you know it only supports two species:  kudzu and mosquito.  Even if you have 50 acres of kudzu, all you get are those two species.

Removing invasives makes the curve arch high and healthy again.  Machete Man’s website shows some ATL examples, explains biology, organic healthification methods, etc.

Planting two trees

Here’s the outside of our neighborhood common house, a typically bleak patch of concrete, bare wall and crunchy dry bermuda grass.

Bleak concrete, wall and crunchy bermuda grass

Yesterday I installed two trees, so that means I added a few species already: 2x Sapindales Rutaceae Citrus unshiu, var. owari (satsuma mandarin) & all the bacteria in the homemade compost.  As the trees grow, they’ll attract spiders, soil fungi and/or bacteria, butterflies and birds.  Maybe one day, even an H. sapiens sitting in the branches.

It’s time to plant trees now.  They’re at all the garden stores and Trees Atlanta is having a tree sale Oct. 9.

Be the first to comment on "Species area effect: two trees exponentially more awesome than one"

Leave a comment

Your email address will not be published.