Morphology, Nurse Plants, and Minimum Apical Temperatures for Young Carnegiea gigantea

摘要: The northern limit of Carnegiea gigantea (Engelm) Britton and Rose apparently depends on minimum apical temperatures. Diameters, spine coverage, effects nurse plants incoming long-wave (infrared [IR]) radiation, all which affect temperatures, were therefore determined for stems C. up to 4 m tall at four sites along a north-south transect in Arizona A simulation model indicated that the increase diameter accompanying stem growth raised temperature more than 3 Thus, with shortest would be expected most vulnerable freezing damage; indeed, damage <0.5 without was fairly common colder Nurse obstructed greater portion sky sites; e g., effective environmental IR radiation such locations 10 C under 1 tall. If reflects wintertime survival ...