1702

ARBORETUM AND FRUTICETUM.

PART III.

Though the birch may be propagated by layers, and even by cuttings, yetplants are not readily produced otherwise than by seed; and those of certainvarieties, which are procured from layers, or by inarching, never appear togrow with the same vigour as seedlings. Birch seed ripens in September andOctober; and may be either gathered and sown immediately, or preserved ina dry loft, and sown in spring. Sang directs particular attention to be paidto gathering the seeds only from weeping trees; and this we know to be thedirections given to the collectors employed by the nurserymen in the northof Scotland. If the seeds are to be sown immediately, the catkins may begathered wet; but, if they are to be kept till spring, they ought not to begathered except when quite dry; and every day’s gathering should be carriedto a dry loft and spread out thinly, as they are very apt to heat when keptin sacks, or laid up in heaps. The seeds should be sown in very fine, light,rich soil, in beds of the usual width, and very slightly covered. Boutchersays: — “ Sow the seeds and clap them into the ground with the back of thespade, without any earth spread over them, and throw a little peas haulm overthe beds for three or four weeks, till the seeds begin to vegetate. The peashaulm will keep the ground moist, exclude frost, and prevent the birds fromdestroying the seeds.” (Treat, on Forest Trees, p. 113.) “It is scarcelypossible,” Sang observes, “ to cover birch seeds too little, if they be coveredat all.” The plants, if sown in autumn, will come up in the March or Aprilfollowing. If sown in spring, they will come up in May or June; which, invery cold climates, is a preferable season. If any danger is apprehended frommoisture in the soil during winter, the alleys between the beds may bedeepened, so as to act as drains. In the nursery lines, the plants require verylittle pruning, and their after-care, when in plantations, is equally simple.

Wherever the birch abounds in woods or coppices, a great many seedlingplants spring up ; and these in various parts of England, are collected by thecountry people, and sold to the nurserymen. This is, indeed, the mode bywhich young trees and hedge plants of every kind were obtained before theestablishment of commercial nurseries. Young birch plants which have beenpulled out of coppice woods, when about two years old, we are informed byMessrs. Young and Penny, of the Milford Nursery, who adopt the practiceextensively, “ are found to root much better than seedlings of the same ageand size taken out of a regular seed-bed; doubtless because, in the lattercase, a greater proportion of the taproot requires to be cut off. In the caseof the young birches pulled out of the copses, the taproot, which could notget far down into the hard soil, has its substance in a more concentrated form,and is more branching; hence, little requires to be cut off it, except the raggedrootlets, or fibres; and it may be considered as acting as a bulb to the upperpart of the plant. The tops of these seedling birches are shortened beforeplanting; and the plants, Mr. Young informs us, make as much wood in oneyear as regular nursery-reared birch seedlings will in two. It is found in thispart of the country, that the downy-leaved black-barked seedling birches(B. a. pubescens) stole much more freely, when cut down as coppice-wood,than the smooth-leaved white-barked weeping variety (B. a. pendula). (SeeGard. Mag., vol. xi. p. 506.) It appears from Boutcher, that this mode ofobtaining young birch trees, was formerly practised in Scotland.

In France and Germany, plantations of birch are frequently made by sowingthe seed where the trees are intended finally to remain. For this purposethe poorest soils are harrowed in humid weather, in the month of October, orof November, and 151b. of seed, as it is taken from the catkins along withthe scales, is sown on an acre, and afterwards covered with a bush harrow.Where the ground is under corn, the seed is sown with the last corn crop, asclover is in England; and,where it abounds with weeds and bushes, these areset fire to, early in the autumn, and the seed sown as soon afterwards as it isgathered from the trees. It is observed by Michaux, that burnt soil is pecu-liarly favourable to the growth of the birch, which in America reappears,as if by enchantment, in forests that have been burnt down.

Accidents, Insects , and Diseases. Pallas observes that, in some parts of