184 A, Gray—Forest Geography and Archeology. 
pai is a California Laurel instead of our southern Red Bay 
in any of the genera common to the two does the 
Pacific ae oe the Atlantic in species. It has not half as 
ity; it has not half as many Oaks; and these and the Ashes 
are of so inferior economical value, ‘that (as we are told) a pass- 
able wagon-wheel cannot be made of California wood, nor a 
really ae oe in Oregon. 
This of the western forest in species and types may 
be exhibited gpa in a way which cannot fail to strike 
the eye more impressively than when we say that, whereas the 
Atlantic forest is composed of 66 genera and 155 species, the 
Pacific forest has only 31 genera and 78 species.* In the 
appended diagrams, the short side of the rectangle is propor- 
tional to the number of genera, the long side to the number of 
species 
a es ow the geographical areas of the two forests are not very 
different. From the Gulf of Mexico to the Gulf of St. Lawrence 
about twenty degrees of latitude intervene. From the southern 
end of California to the peninsula of Alaska there are twenty- 
eight degrees, and the forest on the coast runs some degrees 
north of this; the jenuath may therefore make up for ‘the com- 
parative narrowness of the Pacific forest region. How can so 
meagre a forest make so imposing a show? Surely not by the 
(or more correctly non-coniferous) trees are concerned ; for on 
the whole they are inferior to their eastern Ede in size if 
not in number of individuals. e reason is, that a larger Bro: 
ortion of the genera and species are son anes trees; and thes 
ing evergreen (except the Larches), of espiring, pent a, 
eminently gregarious habit, usually dominate where 
k laging the et _ almost three times as many sg aos four 
mes ies of non-coniferous trees as the west, it 
es slightly ion genera and almost one-half fewer species 
of coniferous trees than the west. That is, the Atlantic conif- 
ponderance may also be expressed by the diagrams, in which 
the smaller enclosed rectangles, drawn on t e e, 
represent the coniferous portions of these forests. 
* We take in only timber trees, or such as attain in th t fi ble localities 
to a size which gives them a clear title to the arboreous rank. The subtropical 
southern pared es ae aad Keys of Florida are excluded. So also are one or two 
trees of the Ariz t southern borders of 
the Californian tienes In counting the Coniferous genera, Pinus, Larix, Picea, 
Abies and Tsuga are ae ere ee Chamecyparis are 
taken as one genus. 
| 
j 
oe 
' 
: 
