Magazine
September-October 2004
September-October 2004
Volume: 92 Number: 5
Polylepis, a genus that includes 20 species of trees superbly adapted to survive at high altitude in the Andes, was once thought to be naturally restricted to boulder fields and steep mountainsides. Since about 1990, however, investigators have realized that Polylepis forests once dominated the cordilleras. Cutting and burning have reduced these woodlands to only 1 percent of their former extent in the eastern Bolivian Andes, making the Polylepis ecosysetm one of the planet's most threatened. In "The World's Higest Forest," Jessica Purcell, Alan Brelsford and Michael Kessler describe the threat to the remaining woodlands and discuss measures that may stem the losses. (Photograph by R. Bode.)
In This Issue
- Art
- Astronomy
- Biology
- Communications
- Computer
- Engineering
- Environment
- Evolution
- Mathematics
- Physics
- Policy
- Psychology
- Sociology
- Technology
The Design and Function of Cochlear Implants
Blake Wilson, Michael Dorman
Biology Engineering
Fusing medicine, neural science and engineering, these devices transform human speech into an electrical code that deafened ears can understand
Cell Fusion
Brenda Ogle, Jeffrey Platt
Biology Evolution
Cells of different types and from different species can fuse, potentially transferring disease, repairing tissues and taking part in development
The Lifestyles of the Trilobites
Richard Fortey
Biology Evolution
These denizens of the Paleozoic Era seas were surprisingly diverse
The World's Highest Forest
Jessica Purcell, Alan Brelsford, Michael Kessler
Environment
A better understanding of the properties of Andean queñua woodlands has major implications for their conservation
