ARBORICULTURE 



ARBORICULTURE 



359 



celsa, Fig. 356) recommends itself by its elegant gothic 

 form, often with pendulous branchlets, its very rapid 

 growth, and its wide adaptation to soils and climates, 

 together with its ease of propagation and cheapness. It 

 excels most of the American spruces in form and rapidity 

 of growth. Like all conifers, after the twenty-fifth to 

 fortieth year it must pass through a period of change in 

 form, during which it loses, for a time, its shapeliness. 

 The Scotch pine (Pinu^ sytvestris) has nothing to recom- 

 mend it which may not be found in native species, 

 except, perhaps, adaptation to the dry climate of the 

 \\'est, and cheapness. The Austrian pine, on the other 

 hand, is an acquisition by its stout growth in its youth, 

 although the red pine (Pinus resinosa) would probalily 

 do as well; so far, its small cones and seed have made 

 the latter expensive. The European larch outgrows the 

 native northern one easily, but Larix occidentalia, from 

 the interior basin, will probably do as well or better. 

 There is no particular commendation for the European 

 fir, but the Nordmann fir, from the Caucasus, is a most 

 decided aquisition, by its beauty and adaptation; so is 

 the most graceful of all spruces, Picea orienUdis, while 

 the Spanish Abies Pinsapo (Fig. 318) will always attract 

 attention by its pecuUar shape and foliage. 



Of other ornamental forms that are without repre- 

 tatives in the United States and hence fill vacancies, 

 may be mentioned as capable of adaptation and more 

 or less in use, from South America, the araucarias; from 

 Africa and eastern Asia, Cedrus Deodara, libani, at- 

 lantica, Abies Apollinis and cilicica; from Korea, the 

 promising, more densely foUaged white pine, P. koraien- 

 sis; from China, Cunninghamia, Biota, Glyptostrobus, 

 Cephalotaxus, Podocarpus, Pseudolarix, and, above all, 

 that interesting remnant of former ages, the maiden- 

 hair-tree, Gingko biloba, which will maintain itself any- 

 where along the Atlantic coast if propagated from seed 

 of the proper localities. Japan has furnished a number 

 of additions, especially retinosporas, torreyas, taxus, 

 various pinus, piceas and tsugas, with the peculiar 

 Sciadopilys verticillata, the umbrella pine, and, the most 

 acceptable of all, the graceful Cryptomeria japonicn. 



As with all introductions from one country to another, 

 nay, from one cUmatic region to another, caution is ad- 

 vised, so it may be laid down as a rule, that exotics 

 should be used with great discretion, and, until their 

 adaptation is amply demonstrated, only in a subor- 

 dinate way. If it is in general true that perennial plants 

 can be transplanted with permanent success only into 

 similar climatic conditions, it must be especially true 

 with the conifers, which do not lose their foliage, and 

 hence must be able to bear svimmer as well as winter 

 conditions. The long-leaf pine of the South, most 

 striking of our pines, may, therefore, not be trans- 

 planted far beyond its northern Umit, and, if one desires 

 to utilize any of the Pacific coast species in the East, 

 one will have to secure them at least from the highest 

 and driest altitudes and exposures, or if, as in the case 

 of some species, hke the Douglas fir and Engelmann 

 spruce, their field of distribution covers the dry slopes 

 of the Rocky Mountains as well as the moist slopes of 

 the coast ranges, one may be successful if one chooses 

 the plant material from these drier slopes. 



Of the many native species, a number that are not 

 of any particular value may be discarded, although the 

 distinction could be more readily accomplished from 

 the economic point of view than from the standpoint of 

 the horticulturist and landscape gardener, for almost 

 every one has a distinctive feature of either form or 

 ailaptation to soil or other interest. For each climatic 

 region the choice must be different; hence it would be 

 imi)Ossible to give, in the brief space of an article, 

 intelligent advice as to best selections. In general, be- 

 sides climatic limitations, the following consi<lerations 

 may serve in the choice of native species: 



The pines, as a rule, are not to be placed on compact 

 clay soU, and on account of their taproot, not on shal- 



low soils, on which they soon become spindly; they thrive 

 best on loose, sandy soils, and can endure dry soils, the 

 white pine adapting itself perhaps best to the clay soils 

 without detriment to its development. On wet soils pines 

 are, as a rule, decidedly out of place, although the red 

 pine (P. resinosa), of the North, and the loblolly (P. 

 Tseda), and some other southern species are capable of 

 supporting such conditions. For such situations here, 

 however, the cedar tribe furnishes better material,^the 

 chamaecyparis, thuyas and taxodium. These trees of 

 the bog and swamp are, however, — it should not be 

 overlooked, — capable of thriving even better on drier 

 soils. They are merely indifferent to moisture condi- 

 tions at the foot. 



The shallow-rooted spruces are trees of the higher 

 mountain ranges, and are, therefore, more adapted to 

 moist and cool situations, although some of them, the 



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319. A well clothed conifer.— Abies venusta. 



Norway spruce, the blue spruce of Colorado and the 

 northern white spruce will — the former, at least, during 

 its juvenile period — endure more droughty situations. 

 The firs, too, are rather more species of northern 

 climates and high altitudes, the red fir, so-called 

 {Pseudotsuga laxtfolia), which is not a fir proper, be- 

 ing, perhaps, best capable of supporting drier and hot- 

 ter situations. The most ornamental, and, in many 

 respects, most serviceable of the firs, Abies Nordmanni- 

 ana, from the Caucasus, develops its magnificent dense 

 and dark green foliage in the warm but moist climate of 

 Washington, while our most ornamental Abies concolor 

 from Colorado will thrive even in the drier atmos- 

 pheres of the middle states. The fine firs of the Pacific 

 coast will probably not thrive anywhere in our drier and 

 hotter eastern climates for any length of time, unless 

 placed in cool and shady situations. 



The Douglas fir (Pseudotsuga laxifolia) is, perhaps, 



