116 



SCIENCE. 



[Vol. V., No. 105. 



THE FORESTS OF THE UNITED 

 STATES. 



Many essays and some books there are to 

 tell us what should be done with our forests, 

 or with their remains. This ninth volume of 

 the reports of the census taken in 1880, now 

 before us, tells us what these forests are. 

 First and briefly as to their general distribu- 

 tion in accordance with the climate and con- 

 figuration of the country. There is, in the 

 most general terms, a forest of the Atlantic, and 

 another of the Pacific region, widely separated 

 through a long stretch of the continent, more 

 approximate at their northern extremities, and 

 essentially but loosely joined along the Mexican 

 borders from Texas to southern California 

 hy a very peculiar arboreal vegetation. And 

 even where the Atlantic and Pacific woods are 

 most widely severed, as in about latitude 40°, 

 the western own to a near relationship with 

 the eastern along the line where the Rocky 

 Mountains flank the plains. Together, the two 

 compose one large whole, — a temperate North- 

 American sylva, the harmony of which is not 

 greatly disturbed by the intrusion of Mexi- 

 can types into its southern borders. A more 

 seriously discordant element, however insig- 

 nificant geographically, but figuring rather 

 prominently in the catalogue, comes as a con- 

 sequence of the southward extension of the 

 peninsula of Florida, upon which a good num- 

 ber of tropical West-Indian trees have effected 

 a lodgment. Like other immigrants, these 

 denizens must be received upon the same foot- 

 ing with those more truly to the manner born, 

 although they sensibly impair the homogeneity 

 of the United States sylva. 



Next as to the genera and species of which 

 our forests are composed, amounting, it ap- 

 pears, to a hundred and fifty-eight genera 

 and four hundred and twelve species. A con- 

 siderable number of these, however, are only 

 arborescent at their best, never attaining the 

 magnitude of timber-trees ; and forty-eight of 

 the genera, and nearly sixty species, occur 

 only in semi-tropical Florida. The systematic 

 account of the trees fills two hundred and 

 twenty pages of the volume. It is wonderfully 

 full, not to say exhaustive, in the bibliography 

 and S3 T nonynry, is comprehensive as to geo- 

 graphical ranges, particular in its statement of 

 the character of the wood (the specific gravity 

 and the amount of ashes being specified under 



Report on the forests of North America {exclusive of Mexico). 

 By Charles S. Sargent, Arnold professor of arboriculture in 

 Harvard college, special agent tenth census. Washington, Gov- 

 ernment, 1884. 612 p., 4°; 39 colored maps, 4° and f° ; with port- 

 folio of 16 maps, eleph. f °. 



each species), and also its economical uses. 

 But descriptive matters and all botanical 

 details, be} r ond a mention of the height at- 

 tained by the tree, are scrupulously omitted. 

 Even the nature and appearance of the bark, 

 characteristic as it generally is, and sometimes 

 very important in its practical applications, is 

 nowhere mentioned, except in a single line in 

 a single case, that of the canoe birch. Even 

 the difference between the cherry birch and 

 the yellow birch, so striking in the bark and 

 so slight in every other respect, is not alluded 

 to. This is evidently done on principle. It 

 was necessary to draw the line somewhere, and 

 Professor Sargent has drawn it very taught. 

 We should grieve inconsolably over the ex- 

 clusion, except for our expectation that the 

 author means to make amends in another work, 

 in which the tree will stand for more than its 

 timber. Let us note, in passing, that in any 

 future publication ' Palmaceae ' should give 

 place to ' Palmae.' It was a good thought to 

 supply a separate and full index to the ' Cata- 

 logue of forest- trees,' as this part of the vol- 

 ume is modestly entitled. The addition of as 

 much descriptive botanical matter as there is 

 of bibliography would have made of it a com- 

 pendious treatise. 



We will not complain that practical matters 

 predominate in a census report. Part ii., ' The 

 woods of the United States,' fills two hundred 

 and forty pages, most of it tabular matter. 

 ' Woods ' are here used in the sense of timbers ; 

 and this portion of the volume records with 

 much completeness the result of an exhaustive 

 determination of the specific gravit} T , the amount 

 of ash, the weight per cubic foot, the tensile 

 strength, the behavior under compression, and 

 the fuel value of the wood of all the species. 

 This great piece of work was done by, or 

 under the direction of, Mr. S. P. Sharpies. 

 The wood specimens are preserved in two full 

 series, — one in the National museum at Wash- 

 ington, one in that of the arboretum of Har- 

 vard university ; and the surplus material, 

 worked into 12,961 museum specimens, has 

 been made into sixty sets, and distributed to 

 nearly as many educational institutions. 



Any one wishing to know the relative specific 

 gravity of the wood of our trees has only to 

 consult the table beginning on p. 249. He 

 will learn that all those which are heavier than 

 water are of semi-tropical species, or of the 

 arid south-western interior region ; that the 

 Floridian Condalia ferrea leads the list (spe- 

 cific gravity, 1.3020) ; that Cercocarpus ledi- 

 folius, the mountain mahogany of Utah, etc., 

 comes up to 1.0731 ; that the lightest conifer- 



