binomials given in this right-hand column may be unfamiliar 

 ones, but they are the names that are given to the fossil counter- 

 parts of the species listed on the left. That is, Sequoia langsdorfii 

 is the Bridge Creek counterpart of 5*. sempervirens; Quercus con- 

 similis is the counterpart of the modern Lithocarpus densiflora. 

 The figures for each of the four species are somewhat different 

 between the Miocene representatives and the modern Redwood 

 Forest counterparts, although the total figures for the four spe- 

 cies at each time period are similar (84 percent vs. 87 percent). 

 Since we are dealing with the representation of plants that grew 

 in two widely separated areas at time periods that are separated 

 by fifteen or twenty million years, it is remarkable that there is 

 so strong a similarity between the species composition of the 

 Miocene redwood forest and the modern one. It would seem that 

 Coast Redwood and its woody associates have had an amazingly 

 long and relatively consistent association over a period of many 

 millions of years. It is probable that this is also the case for a 

 number of other plant communities in California. Some plant 

 communities of the state — such as the Closed-Cone Pine Forest 

 or segments of the North Coastal Forest (as exemplified by the 

 Coast Redwood forest) — are very "old" and conservative 

 plant communities. Other California plant communities, to be 

 discussed later, are probably relatively recent newcomers that 

 have evolved within the past million years or so. 



Ecological Characteristics of Coast Redwood 



There are a few other tree species that occur with Coast Red- 

 wood, although perhaps with only a modest degree of success. 

 Some of the ecological requirements of Coast Redwood have been 

 mentioned above. Obviously, areas in California with a "redwood 

 climate" generally support a Coast Redwood forest. But what is 

 it about Coast Redwood that aUows it to be so successful in 

 these areas, almost to the exclusion of other species of herbs, 

 shrubs, or trees? Coast Redwood casts considerable shade and its 

 roots pervade the ground under the trees. In addition, the ground 

 under the trees is covered with a layer of needles, branches, and 

 other plant debris that may be several centimeters deep. This 

 combination of shade, root competition, and a deep organic 



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