The spring-fed Sabinal River and the limestone canyon — the clear pools, the bald cypress, and the cool, moist microclimate that lets the maples survive here.
Stop a moment by the water. This is the Sabinal River, and it is the whole secret to this place. It rises from springs up in these hills and runs clear and cool and green over pale limestone, pooling in quiet green holes shaded by big bald cypress trees — those tall trees right at the water's edge with the fluted trunks and the feathery needles, their knobby 'knees' poking up out of the mud.
Now here's why the river matters so much to those maples. Feel how it's cooler and damper down here on the canyon floor than up on the open hills? That's the river's doing, and the high canyon walls': they trap cool, moist air down here in the shade, and they hold water in the ground year-round. Up on the dry Edwards Plateau above us, it's hot, thin-soiled, and harsh — no place for a maple. But down in these sheltered, spring-fed canyons, it stays just cool and wet enough, all year, for those Ice-Age trees to hang on. The river is the maples' life-support, and has been for ten thousand years.
The rock itself is worth a look too — this whole country is limestone, laid down as the mud of a shallow tropical sea about a hundred million years ago, back in the age of the dinosaurs. Look for the fossils of little sea creatures in the pale stone. Then the whole Edwards Plateau lifted up, and rivers like this Sabinal carved down into it, cutting these canyons — and making, without meaning to, the one cool refuge where the maples could survive. Keep following the water; the canyon deepens ahead.
Photo: G. Lamar · CC BY 2.0
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