@article {812, title = {Demography and regeneration of oaks in the foothill woodlands of central California: a review of the scientific literature}, journal = {Quarterly Review of Biology}, volume = {81}, year = {2006}, month = {2006}, pages = {127-152}, abstract = {We review published studies on the demography and recruitment of California oak trees and focus on the widespread dominant species of the foothill woodlands, Quercus douglasii, Q. lobata, and Q. agrifolia, to ascertain the nature and strength of evidence for a decline in populations of these species. The vast majority of studies have been of short duration (less than three years), focused on the acorn and seedling life stages, and conducted at few locations within each species{\textquoteright} geographic range. We summarize the extensive body of research that has been conducted on the biological and physical factors that limit natural seedling recruitment of oaks. The oak {\textquotedblleft}regeneration problem{\textquotedblright} has largely been inferred from current stand structure rather than by demographic analyses, which in part reflects the short-term nature of most oak research. When viewed over longer periods of time using field surveys or historical photos, the evidence for a regeneration problem in foothill oaks is mixed. Q. douglasii shows very limited seedling or sapling recruitment at present, but longer term studies do not suggest a decline in tree density, presumably because rare recruitment is sufficient to offset low rates of mortality of overstory individuals. Q. agrifolia appears to be stable or increasing in some areas, but decreasing in areas recently impacted by the disease Phytophthora ramorum. Evidence from the few available studies is more consistent in suggesting long-term declines in foothill populations of Q. lobata. Longterm monitoring, age structure analysis, and population models are needed to resolve the current uncertainty over the sustainability of oak woodlands in California.}, keywords = {oak woodland, Quercus, seedling establishment}, url = {http://www.journals.uchicago.edu/QRB/journal/issues/v81n2/810202/810202.web.pdf}, author = {Tyler, C. M. and Kuhn, W. and Davis, F. W.} } @article {814, title = {Reproduction and growth of the chaparral geophyte, Zigadenus fremontii (Liliaceae), in relation to fire}, journal = {Plant Ecology}, volume = {165}, year = {2003}, month = {2003}, pages = {11-20}, abstract = {Zigadenus fremontii is often a striking component of the flora following fire in the chaparral. Like other geophytes, it produces large numbers of flowers in the first spring after a burn. Although these plants are most conspicuous in the early postfire environment, the question that remains is, how do they persist in the interval between fires? To address this we investigated differences in the growth and reproduction of Z. fremontii in burned and unburned chaparral. We monitored marked individuals for nine years at three sites: two that were burned in 1990 and one in the same area that was in unburned mature chaparral. We measured leaf area, and production of flowers and fruits. We also conducted seed experiments in the field to determine the rates and timing of germination. We found that reproduction occurs only in the immediate postfire period: flowering and production of fruits and seeds in the first year following fire, and seedling establishment by year 3. There was a cost of reproduction; plants that flowered (in the burn area) had negative growth rates the following year. In contrast, plants in unburned chaparral, which did not flower, had positive growth rates over the same period. Moreover, plants that produced the most flowers had the lowest growth rates. In the unburned chaparral site, plants were not dormant as predicted from previous literature; instead they produced leaves nearly every year. In most years the average leaf area per plant was greater than that in the burned sites. Our results indicate that postfire reproduction depends on growth and carbohydrate storage in the inter-fire period. We also suggest that this species is relatively long-lived for a herbaceous perennial.}, keywords = {bulb, California, fire-dependent reproduction, fire-induced flowering, germination, life-history, long-lived, pityopsis-graminifolia, populations, postfire, seedling establishment, soil fertility}, url = {://000179659700002}, author = {Tyler, C. and Borchert, M.} }