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Pine. What the apple is among the fruits, what the oak is among the broad- leaved trees of the temperate zone, the pines represent among the conifers, excelling all other genera in this most important family in number of species, in fields of distribution, in extent of area occupied, in usefulness and importance to the human race. No other trees of the temperate zone have contributed so much to the building up of civilization, and no other, it may be predicted, will continue longer to fill
the important place in the household of civilized men; for not only do they furnish in a number of species the most satisfactory qualities of wood for structural purposes, but their frugality in regard to soil conditions will preserve them a place as wood-producers in many of the poor sites, when the lands fit for agricultural use have all been turned over to food-production.
Among the seventy or more well-distinguished species —over 600 species and varieties of Pinus have been described—all inhabitants of the northern hemisphere, ranging from the arctics through plains and mountains to near the equator, occurring in the tropics at least on high mountains, a variety of adaptation, of form, of usefulness, may be found to satisfy every requirement; and since more than half the number of species (about forty) are indigenous to North America or the United States, it is hardly necessary to go out of this general region for plant material.
For economic importance, as well as for a combination of points of excellence in all directions, ornamental as well as useful, rapidity and quantity of production and adaptability to climate and soil, the chief place belongs to the white pine (P.Strobus), and next in importance stands the longleaf pine (P.palustris) of the southern states. The red pine (P. resinosa), the shortleaf (P. echinata), the Loblolly (P. Taeda), with the Cuban pine (P. caribaea), add their stores to the enormous quantities furnished annually by the first and second. In the western mountains the bull pine (P. ponderosa), the sugar pine (P. Lambertiana), and the silver pine (P. monticola) are very large timber pines; and in Mexico P. Ayacahuite replaces the white pine, and P. arizonica and P. montezumae are the important yellow pines. In the Philippine Archipelago one species, P. insularis, forms important mountain forests. In Europe the Scotch pine (P. sylvestris) furnishes the bulk of supplies, with P. nigra in the more southern countries. In Japan and northern China P. densiflora and P. Thunbergii and in the Himalayas P. excelsa and P. longifolia are the important species.
Besides the timber, several of the species furnish from their resinous contents naval stores, turpentine, tar, and pitch, the bulk of which is now still derived from the native longleaf pine. Pine wool is made from the leaves of this and other species, essential oils are distilled from leaves and young shoots and used medicinally, and the seeds of the nut pines are used for food and flavors. While the economic importance of the genus can hardly be overrated, the ornamental value is undoubtedly less than that of other genera like the spruces and firs. Nevertheless, at least interest and picturesqueness, if not beauty and symmetry of form, attach to a large number of species.
Choice of material for planting with such a wealth of species is difficult; yet climatic limitations reduce the number that may be grown within each climatic zone, and further assistance in the choice may be found in the fact that the botanical division of the species into three groups; viz., white pines, yellow pines (so called from the color of the wood), and nut pines, denotes at the same time differences of habit and form.
In no other group, perhaps, is it Bo necessary to keep in mind that form and habit change through the different periods of life from the juvenile through the adolescent to the virile and senile stages of development: while symmetrical and pleasing in their youth and grand or picturesque in their age, in their intermediate stages the trees may be straggling and unsightly. Starting in its youth with the pyramidal aspiring habit of all the conifers, the shaft dominating over the branch system and the latter surrounding the former in regular whorls, later on the symmetry is disturbed and finally the towering old pine may have its bole split up into many stout branches and the crown may have broadened and flattened or rounded off in the umbrella-like fashion which the stone pine (P. Pinea) exhibits so strikingly
in the Italian landscape. This flattening of crown is characteristic of most yellow pines, while the pinons or nut pines have a tendency to the broom-like or apple- tree appearance. Of the eastern species, the white pines alone preserve to some extent the conical habit of the crown in imitation of the spruces with more or less symmetrical horizontally spreading branches, which render them pleasing objects throughout all periods of life. On the Pacific Coast a number of species preserve the conical form.
In the choice and combination of plant material it should be kept in mind that the pines are essentially light-needing species, hence do not bear overtopping or crowding unless they have a chance by their rapid growth in height to escape from the pressure of their shade-making neighbors; the white pines, especially P. Strobus with its denser foliage, are more tolerant of shade than others; the dwarf P. montana is also tolerably shade-enduring.
In each of the three groups there are rapid growers (in height) and slow growers, although all are slow during the first two to seven years.
The common white pine (P. Strobus) and the Cuban pine (P. caribaea), with the European, Scotch, and Austrian pines, are good examples of the first class, making under favorable conditions annual shoots of 1 to 2 feet for a number of years; while the Swiss stone pine (P. Cembra) and other pines of high altitudes, like P. flexilis and P. albicaulis, are examples of slow growers. There are persistent growers reaching great heights, and laggards, remaining dwarfs or medium- sized trees; again the king of pines, the common white pine, and its giant congener the sugar pine, with the bull pine in favorable situations, take first rank, the first with a maximum height of 160 feet and more, the last with over 200 feet, while many of thp so-called scrub pines, like P. virginiana, P. serotina,P. Banksiana, the Alpine white pines, P. flexilis, P. aristata, P. Peace, P. pungens, P. densiflora, and most nut pines reach rarely over 40 feet; some, like P. koraiensis, P. Bungeana, P. montana, with several of the nurserymen's varieties, remain actually dwarfs and maintain a compact bush-like appearance for a long time.
In regard to foliage, quite a large variety can be secured. For grace and elegance nothing better again than the five-needled silver-lined white pine can be suggested, although P. excelsa from the Himalayas, with its slenderer and longer branches and more drooping foliage, and the dwarfs P. Peace from Macedonia and P. koraiensis, with their denser and more compact crowns, and some others of the white pine tribe, may vie with it. Among the yellow pines, the native almost entirely overlooked, P. glabra, deserves mention in this connection, where the climate permits its use, as well as the interesting sand pine, P. clausa.
For richness, fulness, and vigor of foliage, the red pine (P. resinosa) outranks even the much-planted more somber Austrian pine, and for interest in development nothing can compete with the longleaf pine (P. palustris). With its needles, which in young specimens exceed a foot in length, surrounding in dense graceful tufts the big silvery buds at the tip of the candelabra-like branches. P. palustris offers a most striking appearance. Unfortunately, it is not adapted for planting north of 32°.
The thin, grayish, short foliage of the frugal Bank- sian pine and of several other of the scrub pines, and the stouter, also grayish, foliage of the Scotch pine, make a pleasing color contrast against the somber dark background of spruces and firs, while the short stiff needles of the nut pine, P. edulis, and the interesting one-needle pine (P. monophylla) resemble the spruce foliage. Color of bark varying in species from silvery gray through red and yellow tints to almost black, and character or size of cones from the diminutive globose forms of P. contorta to the long pendulous cones of the sugar
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pine, 2 feet in length, and the hooked, ponderous cones of P. Torreyana and P. Sabiniana, may also influence choice of material.
With wide range of distribution and hence adaptiveness as far as climate is concerned, we have the short- leaf pine (P. echinata), which is found from Massachusetts to Texas, and in the West the bull pine (P. ponderosa), which ranges from the moist Pacific Coast in Washington to the dry slopes of Arizona. In Europe, the Scotch pine comes nearest to such wide distribution. Besides the native northern species, there have been found hardy in the northeastern states the Scotch and Austrian pines, P. Bungeana, P. Cembra, P. koraiensis, P. montana, P. Thunbergii, while the Mexican pines and those of southern Asia will endure only the light frosts of the southern states. Yet in the parks of Washington, D. C., the following pines are to be found: P. Strobus, P. Cembra, P. excelsa, P. Lambertiana, P. Ayacahuite, P. koraiensis, P. palustris, P. Taeda, P. ponderosa, P. rigida, P. nigra, P. glabra, P. virginiana, P. echinata, P. montana, P. Pinaster, P. edulis, P. pungens, P. sylveslris, P. Massoniana; and the probability is that most of the other species could find a place there to live if not to thrive.
The list of species hardy in the Arnold Arboretum (Boston) comprises the following:
1. Thriving wett.
Banksiana. Lambertiana. resinosa.
Bungeana. montana. rigida.
Cembra. monticola. Strobus.
donsiflora. nigra. sylvestris.
echinata. parviflora. Thunbergii.
Jeffreyi. Peuce. virginiana.
koraiensis. pungens.
P. excelsa and P. ponderosa pendula thrive well in a sheltered place, but are probably not quite hardy here.
2. Hardy, but not of promising growth.
aristata. flexilis.
contorta var. Murrayana. monophylla.
edulis.
In the interior middle states the number which would stand the extremes of drought and cold would probably be reduced; a partial list found in the Missouri Botanical Garden is given below:
The best are given first. All of the later ones on the list die out sooner or later, as the city smoke is very detrimental to conifers. None does very well on that account.
Mughus (Pumilio). Virginiana.
austriaca. } best three. resinosa.
Strobus. nigra.
Cembra. sylvestris.
rigida. ponderosa.
For seaside planting, P. rigida has shown itself most fit, and of foreigners in proper climate, P. Pinaster and P. halepensis, while P. contorta on the northwest coast and the frugal P. radiata on the southwest coast are the seacoast trees par excellence.
The pines are essentially inhabitants of the poor sandy soils and dry situations, their stout root-system enabling them to seek the scanty water-supplies where other species find it difficult. Some, like the white pine, are adapted to a variety of soil conditions, but only a few can endure a surplus of water: P. resinosa will follow the white cedar into the swamp and thrive there as well as with the Banksian pine on the poorest gravels; P. rigida is at home both in wet and dry places; the Scotch pine of the Baltic sand plains may be found in the peat-bogs, but only eking out a miserable existence, while P. Taeda, the old field pine, makes magnificent trees in the southern swamp, and with its slow growth under such conditions an excellent timber. P. contorta and P. serotina also are indifferent to water conditions at the root; so is the Cuban pine, but P. palustris belies its name, for it is only very rarely found in poorly drained places and does not thrive there.
The propagation of pines does not offer any difficulties. The seed usually has a high germination percentage in most species if kept dry and cool, and it retains vitality for several years, deteriorating of course somewhat from year to year. To avoid deterioration hi transoceanic shipments, packing in charcoal dust has been found very serviceable. While most of the pine seeds sprout readily, the white pine, with some others, has the bad habit of lying over for one year in part, unless treated to a hot-water bath for twenty-four hours before sowing; or perhaps by sowing in autumn immediately after coming out of the cone, which is during the first two weeks of September. The seeds should be sown in light mold early, rather thinly to permit a good root-system to develop, covering them thinly according to size of seed, not over 1/4 inch, which is best done by sifting sand over the seed with a sieve. During the first year special care is necessary to regulate the water-supply and transpiration for the young seedlings; they need to be kept humid, not wet, but resent drought as much as a surfeit; and especially sudden changes from drought to wet are likely to produce "damping-off." To prevent too rapid transpiration, the familiar lath screens should be applied.
To prevent the formation of excessively long taproots which some species form, mechanical means may be adopted; but the best plan is to manure near the surface, so that fibrous roots will be formed. Such manure consists of one-third steamed bone-meal and two-thirds ammonia superphosphate. Root- pruning and transplanting in nursery rows when one or two years old is practised to secure a stocky root-system. In Germany one-year-old Scotch pines are planted by the million for forest purposes, but for ornamental purposes older plants are to be used; yet it is safest not to use them older than three or four years for permanent situations. In the third year usually the first branching occurs, indicating that the root-system is now well established.
In transplanting, the utmost care must be taken not to expose the roots to drying influences, a thin loam puddle answering best to keep them moist. While transplanting can be done at any time of the year, it is safest to do so in early spring, except when a droughty season is likely to follow, in which case fall planting is to be preferred.
A large number of nurserymen's varieties, dwarf and pendulous, varicolored, and the like, have been developed, especially from P. sylvestris and P. Strobus. The most interesting freaks perhaps are those bushy forms derived from P. canariensis and P. Pinea produced by layering, in which single needles instead of the usual bundles of two in one sheath are produced, imitating the primary single needles of seedlings. The manner in which nurserymen's varieties are propagated by grafts or cuttings is discussed under Pinus.
According to the nature of the pines, if there is choice of location possible, the well-drained situations, even dry ones, should be reserved for them. They belong, with few exceptions, to the hilltops not the bottoms, to the sands not clay soils, and will stand southern exposures better than the spruces.
Pines are frugal by nature, and can stand poverty better than surfeit,—nevertheless they respond best to medium conditions, namely, a mellow surface and well- drained deep loamy sand, not too rich in organic matter and loose enough to permit the natural development of the heavy tap-root system. Under such conditions, the peculiar rich foliage gives most satisfaction and the rank luxuriant growth which leads to poor form is checked; disease from fungi is obviated; the cottony scale (almost the only enemy of the white pine) is more readily fought, and injuries from caterpillars and beetles are more easily repaired. Lately,
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two enemies of the white pine have developed which require attention. The one, a fungous disease, seems to be an importation from Germany, the white pine blister rust (Peridermium strobi), which attacks young trees and young foliage of the white pine tribe. It needs gooseberry and currant as intermediary host plants. The other pest is the white pine weevil, which works in the young shoots and disfigures the tree by inducing repeatedly new leaders to develop.
To prune evergreens, and especially pines, requires an artist, or else the result will be malformation: the best plan is to correct form by breaking out the center bud from such shoots as project beyond proper limits; thereby also a more compact growth is induced, which in the pines with their open habit is desirable. If it becomes necessary to prune the branches, the cut must remove also the bolster at the base of the branch; the resinous exudation will prevent decay, and the cambium soon covers the scar if the cut has been made properly. For hedge planting the pines furnish no specially desirable material, being' light-needing and therefore thinning out soon in the interior; yet the white pine will stand as a hedge for a considerbale time and also the dwarf P. montana. Perhaps some others may answer the purpose.
For the botany of the pines, see Pinus.
B. E. FERNOW.
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