Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/338

Rh 318 ARBORICULTURE tions, especially as coppice-wood. The spray, in some parts of the country, is sold to the besom-maker, and gives a fair return. The tree seeds freely, and is easy of manage ment. It is often planted in poor soil as a nurse for oak and sweet chestnut. It yields excellent fuel. The wood is used for carving, furniture, and agricultural implements, and in the Highlands of Scotland and Sweden for building material. The bark, covered with a layer of earth, is used in roofing, and baskets and boxes are made of it. The weeping birch forms one of the most beautiful features in Highland scenery. None of the American or Himalayan birches have yet been planted with a view to profit as timber-trees, though cultivated for many years. The COMMON WALNUT (Juglans regia, L.), is mentioned in the earliest British botanical writings, and is supposed to have been introduced by the Romans. It grows well, and ripens its fruit in the southern and midland counties of England; but large trees may be seen as far north as Ross-shire in sheltered places. The fruit is in some years plentiful, but ripens only in the hottest summers. The timber is excellent, and held the first place for the manu facture of furniture till the introduction of mahogany, and on this account the tree merits more attention. It is raised from the nuts, like horse chestnuts ; the seedlings should be protected from frost during the first winter. The rate of growth is not rapid, and a deep soil is essential to success. If cultivated for the fruit, the seedlings should be transplanted once or twice. The ROBINIA or false acacia (Robinia Pseud-Acacia, L.) is a tree of unquestionable beauty, and much has been written of the value of its timber. It was introduced from North America in the 17th century, and has been extensively cultivated as an ornamental tree. In 1 825 Cobbett strongly recommended the planting of it for its timber. It has been used largely in England for hop-poles, and in France for vine-props. In America it is much used for trenails or wooden pins for bolting ship timbers. It is now planted sparingly, the English summer not being sufficiently long and warm to ripen the shoots. The tree is readily produced from imported seeds, and occasionally from suckers, which are abundant. It should be planted in sheltered situations in dry friable loam. It grows rapidly the first few years, but the trunk in Britain rarely exceeds 1 foot in diameter. Amongst hard-wooded trees of the third rank, the timber of which is useful, are Cerasus sylvestris, the wild cherry or gean ; Cratcegus Oxyacantha, whitethorn ; Pyrus aucu- paria, mountain ash or rowan ; P. Aria, white beam tree; P. Mains, crab-tree ; P. communis, wild pear ; Ilex Aqiti- folium, holly; and Cytisus Laburnum, laburnum. A plantation formed solely of any of these trees is not to be recommended, but when jthey are self-sown or introduced by way of variety or ornament, it is well to know that their timber is of some value ; the laburnum, yew, and holly are the most valuable of the trees of the third rank. 3. Soft-wood Trees. The soft-wood trees are remarkable for the rapidity of their growth, the lightness and whiteness of the wood, and often for their early decay. Among those worthy of culti vation in Britain for timber, are the poplar, willow, alder, lime, and horse chestnut ; the two first being those that are generally recommended with a view to profit. Of the POPLAR (Populus, L.) there are numerous species, and several deserve culture for their timber in situations where the soil is good and deep, and where the roots can reach running water ; but they do not thrive in stagnant marshes. The following are the best adapted to our climate : P. alba, abele or white poplar, is widely distri buted over Europe, and is extensively cultivated in Britain. P. canescens, the grey poplar, is classed by Hooker as a sub-species. These trees attain a large size, giving long clean, straight timber, which induces planters to grow it, especially near factories, where the wood is used for flooring, machinery, &c., as it does not easily ignite. The timber is soft, white, and light. The root throws up strong suckers, which always replace trees cut down. P. tremula, the aspen, produces a white wood, which is much sought after for the manufacture of paper, and on that account it is rising in value. P. nigra, the black or Lombardy poplar, is much planted on the Continent in hedgerows, and also in Kashmir where the pyramidal variety is common. The wood, which is white, soft, and light, is used for sabots, but is not good for fuel. The bark is used by the tanner. The black Italian poplar (P. monilifera) ia always propagated by cuttings of the young wood. It pol lards well, and is a rapid grower. Poplars should not have large branches pruned off, and they do not coppice well, because moisture enters cracks in their wood. The WILLOW (Salix, L.) is an extensive genus, found in Europe, Asia, and North America, including all the shrubby osier species used for basket-work, as well as a few trees. The arborescent willows are most useful trees, and well merit the attention of planters. They are invaluable for fixing the banks of rivers and canals, and are successfully used for that purpose. As coppice woods with short rotation, they are grown in osier beds, and cut annually for basket- work, or when three or four years old, for hoops, &amp;lt;kc., and in this way they yield a good return. The laying down and treatment of osier beds may be seen in great perfection on the banks of the Thames. The w.ood is used for carving and other purposes. In North America, fishing nets and lines are made of the inner bark. All the species are easily propagated by cuttings, and require to be grown in damp soil. There are three species attaining the size of trees S. alba, the white or Huntingdon willow, reaches a larger size in twenty or thirty years than any other British tree except Populus alba, and often yields 1 foot of solid timber for every year of growth. S. caprea, the goat willow or sallow, occurs generally as a large shrub, but attains 40 or 50 feet in height. It forms a good protection in maritime situations, but often by its exuberant growth injures more valuable trees. The third tree is S. fragilis, the crack willow, and its sub-species S. Russelliana, the Bedford willow. Another tree willow, S. babylonica, or weeping willow, a native of Russia and China, is very ornamental on islands and river banks. The larvse of several nocturnal Lepidoptera feed upon the leaves of the willows, and the trunk of the sallow is often injured by the perforations of the Trochilium crabroniforme (Lunar Hornet Sphinx). The ALDER (Alnus glutinosa, D.C.) is an indigenous tree met with commonly on the banks of streams, but of smaller size than the poplars and tree willows; it often, however, attains to 40 or 50 feet. It is readily propagated by seeds, but throws up root suckers abundantly. The alder is important as coppice-wood on marshy ground. The wood is soft, white when first cut, and turning to pale red ; the knots are beautifully mottled. It is adapted for piles in embankments and bridges ; and charcoal of alderwood is valued in the manufacture of gunpowder. The LIME TREE (Tilia europcea, L.), is a beautiful leafy tree with wing-like bracts, much prized for ornament, and suitable for avenues. It is much planted along streets and promenades, affording a pleasant shade during summer; the blossoms are fragrant, and yield most delicate honey. The lime is generally propagated by layers. Its wood, which is very light and soft, is used by saddlers, shoemakers, glovers, and toy-makers ; and for carving and modelling purposes, it is superior to all other British trees. Several American lime trees have been introduced, and appear well deserving of a place in our arboriculture! collections.