Arabia Mountain: Late January

 The winter storm has gone. Lows were in the 30s, but above freezing. Three deer were in the backyard. Goldfinches and cardinals were at the feeder.

Glad to get out of our den, we went to Arabia Mountain and took a trail that went over a long stretch of granite outcrop. The granite is pockmarked with holes, with the scientists call “depressions.” Small plants grow in them, die and decay, building up soil. Biologists call those pockets of soil in the rock face “islands.”

The kind of plant communities that grow in the islands depends on the depth of the soil. These four are common:

• Diamorpha communities — 2-6 cm.

• Lichen-annual herb communities, 7-15 cm.

• Annual-perennial herb communities, 16-39 cm.

• Herb-shrub communities, 40-50 cm.

We stopped to look at a large group of haircap moss, family Polytrichaceae, mixed with pixie cup lichens, genus Cladonia, in one of the islands. I will never get tired of that sight: green things, apparently growing out of solid rock.

• Sources: The four kinds of communities are described in M.P. Burbank and R.G. Platt, 1964. “Granite Outcrop Communities of the Piedmont Plateau in Georgia. Ecology, 42:2, 292-306. I found an excerpt on Scott Ranger’s Nature Notes:

http://www.scottranger.com/granite-outcrop-plants.html