ARBORETUM

arboretum, the name given to that part of a garden or park which is reserved for the growth and display of trees. the term, in this restricted sense, was seemingly first so employed in 1838 by j.c. loudon, in his book upon arboreta and fruit trees. professor bayley balfour, f.r.s., the regius keeper of the royal botanic garden in edinburgh, has described an arboretum as a living collection of species and varieties of trees and shrubs arranged after some definite method--it may be properties, or uses, or some other principle--but usually after that of natural likeness. the plants are intended to be specimens showing the habit of the tree or shrub, and the collection is essentially an educational one. according to another point of view, an arboretum should be constructed with regard to picturesque beauty rather than systematically, although it is admitted that for scientific purposes a systematic arrangement is a _sine qua non_. in this more general respect, an arboretum or woodland affords shelter, improves local climate, renovates bad soils, conceals objects unpleasing to the eye, heightens the effect of what is agreeable and graceful, and adds value, artistic and other, to the landscape. what loudon called the "gardenesque" school of landscape naturally makes particular use of trees. by common consent the arboretum in the royal botanical gardens at kew is one of the finest in the world. its beginnings may be traced back to 1762, when, at the suggestion of lord bute, the duke of argyll's trees and shrubs were removed from whitton place, near hounslow, to adorn the princess of wales's garden at kew. the duke's collection was famous for its cedars, pines and firs. most of the trees of that date have perished, but the survivors embrace some of the finest of their kind in the gardens. the botanical gardens at kew were thrown open to the public in 1841 under the directorate of sir william hooker. including the arboretum, their total area did not then exceed 11 acres. four years later the pleasure grounds and gardens at kew occupied by the king of hanover were given to the nation and placed under the care of sir william for the express purpose of being converted into an arboretum. hooker rose to the occasion and, zealously reinforced by his son and successor, sir joseph, established a collection which rapidly grew in richness and importance. it is perhaps the largest collection of hardy trees and shrubs known, comprising some 4500 species and botanical varieties. a large proportion of the total acreage (288) of the gardens is monopolized by the arboretum. of the more specialized public arboreta in the united kingdom the next to kew are those in the royal botanic garden in edinburgh and the glasnevin garden in dublin. the collection of trees in the botanic garden at cambridge is also one of respectable proportions. there is a small but very select collection of trees at oxford, the oldest botanical garden in great britain, which was founded in 1632. in the united states the arnold arboretum at boston ranks with kew for size and completeness. it takes its name from its donor, the friend of emerson. it was originally a well-timbered park, which, by later additions, now covers 222 acres. practically, it forms part of the park system so characteristic of the city, being situated only 4 m. from the centre of population. there is a fine arboretum in the botanical gardens at ottawa, in canada (65 acres). on the continent of europe the classic example is still the _jardin des plantes_ in paris, where, however, system lends more of formality than of beauty to the general effect. the collection of trees and shrubs at schonbrunn, near vienna, is an extensive one. at dahlem near berlin the new _kgl. neuer botanischer garten_ has been laid out with a view to the accommodation of a very large collection of hardy trees and shrubs. there are now many large collections of hardy trees and shrubs in private parks and gardens throughout the british islands, the interest taken in them by their proprietors having largely increased in recent years. rich men collect trees, as they do paintings or books. they spare neither pains nor money in acquiring specimens, even from distant lands, to which they often send out expert collectors at their own expense. this, too, the royal horticultural society was once wont to do, with valuable results, as in the case of david douglas's remarkable expedition to north america in 1823-1824. it will be remembered that when the laird of dumbiedikes lay dying (scott's _heart of midlothian_, chap, viii.) he gave his son one bit of advice which bacon himself could not have bettered. "jock," said the old reprobate, "when ye hae naething else to do; ye may be aye sticking in a tree; it will be growing, jock, when ye're sleeping." sir walter assures us that a scots earl took this maxim so seriously to heart that he planted a large tract of country with trees, a practice which in these days is promoted by the english and royal scottish arboricultural societies. arboriculture (lat. _arbor_, a tree), the science and art of tree-cultivation. the culture of those plants which supply the food of man or nourish the domestic animals must have exclusively occupied his attention for many ages; whilst the timber employed in houses, ships and machines, or for fuel, was found in the native woods. hence, though the culture of fruit-trees, and occasionally of ornamental trees and shrubs, was practised by the egyptians, greeks and romans, the cultivation of timber-trees on a large scale only took place in modern times. in the days of charlemagne, the greater part of france and germany was covered with immense forests; and one of the benefits conferred on france by that prince was the rooting up of portions of these forests throughout the country, and substituting orchards or vineyards. artificial plantations appear to have been formed in germany sooner than in any other country, apparently as early as the 15th century. in britain planting was begun, though sparingly, a century later. after the extensive transfers of property on the seizure of the church lands by henry viii., much timber was sold by the new owners, and the quantity thus thrown into the market so lowered its price, as hollingshed informs us, that the builders of cottages, who had formerly employed willow and other cheap and common woods, now built them of the best oak. the demand for timber constantly increased, and the need of an extended surface of arable land arising at the same time, the natural forests became greatly circumscribed, till at last timber began to be imported, and the proprietors of land to think, first of protecting their native woods, afterwards of enclosing waste ground and allowing it to become covered with self-sown seedlings, and ultimately of sowing acorns and mast in such enclosures, or of filling them with young plants collected in the woods--a practice which exists in sussex and other parts of england even now. planting, however, was not general in england till the beginning of the 17th century, when the introduction of trees was facilitated by the interchange of plants by means of botanic gardens, which, in that century, were first established in different countries. evelyn's _sylva_, the first edition of which appeared in 1664, rendered an extremely important service to arboriculture; and there is no doubt that the ornamental plantations in which england surpasses all other countries are in some measure the result of his enthusiasm. in consequence of a scarcity of timber for naval purposes, and the increased expense during the napoleonic war of obtaining foreign supplies, planting received a great stimulus in britain in the early part of the 19th century. after the peace of 1815 the rage for planting with a view to profit subsided; but there was a growing taste for the introduction of trees and shrubs from foreign countries, and for their cultivation for ornament and use. the profusion of trees and shrubs planted around suburban villas and country mansions, as well as in town squares and public parks, shows how much arboriculture is an object of pleasure to the people. while isolated trees and old hedgerows are disappearing before steam cultivation, the advantages of shelter from well-arranged plantations are more fully appreciated; and more attention is paid to the principles of forest conservancy both at home and abroad. in all thickly peopled countries the forests have long ceased to supply the necessities of the inhabitants by natural reproduction; and it has become needful to form plantations either by government or by private enterprise, for the growth of timber, and in some cases for climatic amelioration. this subject is, however, dealt with more fully under forests and forestry (q.v.); and the separate articles on the various sorts of tree may be consulted for details as to each. arbor vitae (tree of life), a name given by clusius to species of _thuja_. the name _thuja_, which was adopted by linnaeus from the _thuya_ of tournefort, seems to be derived from the greek word [greek: thuos], signifying sacrifice, probably because the resin procured from the plant was used as incense. the plants belong to the natural order coniferae, tribe cupressineae (cypresses). _thuja occidentalis_ is the western or american arbor vitae, the _cupressus arbor vitae_ of old authors. it is a native of north america, and ranges from canada to the mountains of virginia and carolina. it is a moderate-sized tree, and was introduced into britain before 1597, when it was mentioned in gerard's _herbal_. in its native country it attains a height of about 50 ft. the leaves are small and imbricate, and are borne on flattened branches, which are apt to be mistaken for the leaves. when bruised the leaves give out an aromatic odour. the flowers appear early in spring, and the fruit is ripened about the end of september. in britain the plant is a hardy evergreen, and can only be looked upon as a large shrub or low tree. it is often cut so as to form hedges in gardens. the wood is very durable and useful for outdoor work, such as fencing, posts, etc. another species of arbor vitae is _thuja orientalis_, known also as _biota orientalis_. the latter generic name is derived from the greek adjective [greek: biotos], formed from [greek: bios], life, probably in connexion with the name "tree of life." this is the eastern or chinese arbor vitae. it is a native of china. it was cultivated in the chelsea physick garden in 1752, and was believed to have been sent to europe by french missionaries. it has roundish cones, with numerous scales and wingless seeds. the leaves, which have a pungent aromatic odour, are said to yield a yellow dye. there are numerous varieties of this plant in cultivation, one of the most remarkable of which is the variety _pendula_, with long, flexible, hanging, cord-like branches; it was discovered in japan about 1776 by carl peter thunberg, a pupil of linnaeus, who made valuable collections at the cape of good hope, in the dutch east indies and in japan. the variety _pygmaea_ forms a small bush a few inches high. _thuja gigantea_, the red or canoe cedar, a native of north-western america from southern alaska to north california, is the finest species, the trunk rising from a massive base to the height of 150 to 200 ft. it was not introduced to britain till 1853. it is one of the handsomest of conifers, forming an elongated cone of foliage, which in some gardens has already reached 70 or 80 ft. in height. it thrives in most kinds of soils. the timber is easily worked and used for construction, especially where exposed to the weather.