Natural, potential and actual vegetation in North America

Human-vegetation interactions during the Holocene in North America

Predicting Pleistocene climate from vegetation in North America

Climates at the Last Glacial Maximum have been inferred from fossil pollen assemblages, but these inferred climates are colder for eastern North America than those produced by climate simulations. It has been suggested that low CO2 levels could account for this discrepancy. In this study biogeographic evidence is used to test the CO2 effect model. The recolonization of glaciated zones in easter...

Potential for Ribes Cultivation in North America

Fruit from black, red and white currants, and gooseberries (Ribes L.) were grown commercially in North America at the beginning of the 20th Century. However, when white pine blister rust (WPBR) (Cronartium ribicola J. C. Fisch.) was introduced into the new world, their cultivation was discontinued. About 825,000 t (908,000 tons) of Ribes fruit are produced worldwide, almost entirely in Europe. ...

Forest Health in North America: Some Perspectives on Actual and Potential Roles of Climate and Air Pollution

The perceived health of forest ecvqems over large temporal and spatial scalm can be strengly inlluenced by the frames of refmence chosen to e+aluate both forest condition and the timctional integrity of sustaining forsl processes. North American forests arc diverse in range, species compceiti~ past disturbance history, and current managementpracticcs.~~eforcthcimplikltionsofchangesinenvLonmenta...

Industrial Hemp in North America: Production, Politics and Potential

Most of the Western World banned the cultivation of Cannabis sativa in the early 20th century because biotypes high in ∆9-tetrahydrocannabinol (THC, the principal intoxicant cannabinoid) are the source of marijuana. Nevertheless, since 1990, dozens of countries have authorized the licensed growth and processing of “industrial hemp” (cultivars with quite low levels of THC). Canada has concentrat...