We're dabbling in eugenics all the time, breeding ideal crops to replace less aesthetic or nutritious or hardy varieties; leveling forests to graze cattle or erect shopping malls and condos; planting groves of a few familiar trees that homeowners and industries prefer.
"They're perfectly hardy," Mr. Woods said.
An impoverished forest of hardy oaks well within the normal range of variability of the oak-pine forest of the region occurred down the gradient of exposure and beyond that zone; at exposures of one roentgen or less daily, the pines survived and the forest appeared intact and normal.
Over time, however, the better-quality ponies were sold off, leaving the poorer-quality and less hardy animals as the Forest breeding stock.
Past studies have tended to assume all trees react equally to ozone, but the new research suggests prolonged ozone exposure creates winners and losers in forests, tilting the balance toward smog-hardy species without hurting the forest's CO2-trapping abilities.
As elevation continues to increase, only the hardiest trees remain in the forest, which is composed almost exclusively of balsam fir.
Bygone era The Knysna forests were once felled by hardy lumberjacks, who lived deep in the woods and avoided the now-vanished elephants – as represented in the four Forest Novels of South African author Dalene Matthee.
The mist thins on the drive down: in place of rolling green there is bleak, sheer grey; the forests beneath are of hardy, pointed pine.
During the Forest match, many of the 7,453 hardy souls who parted with their money to watch yet another Stoke defeat voiced their disapproval towards chairman Frank Edwards and the rest of the board.
Shielded underground, the hardy rhizomorph can withstand extremes of temperature, including aboveground forest fires.
