Science and Practice in Farm Cultivation Part 31

J. E. Sowerby, sc.

W. West, imp.

Quercus Robur Sessiliflora.]

1st. _Quercus Robur pedunculata_ is readily distinguished in trees separate from others by its robust habits, thick, gnarled, twisted, and more or less horizontally inclined branches. The leaves have comparatively few broad, wavy indentations, and are set on a short leaf-stalk (petiole) (Plate I. fig. _a_), the fruit being situate on long footstalks (peduncles), varying from two to upwards of four inches (fig. _b_).

This is the typical British oak, the pride of our sailors, when men fought bravely and did not care to vie with each other as to who should make the most secure skulking-places. The tree-

Whose roots descend As low towards Pluto's realms, as high in air Its ma.s.sive branches rise. The utmost rage Of wintry storms howls o'er its strength in vain.

Successive generations of mankind, Revolving ages flourish and decay, Yet still immovable it stands, and throws Its vigorous limbs around, and proudly bears With firm and solid trunk its stately form, A mighty canopy of thickest shade.

VIRGIL, _Georg._ ii. 291.

This is the tree that seems to be longer lived than any other in Britain, and though it would appear to be the prey of nearly, if not quite, two hundred species of insects, it has still had vigour of const.i.tution to survive them all; and in many instances we might point to brave old trees which must have been veterans at the time of the Norman Conquest. Now, however, they are old and staggy, with hollow trunks truly-but what trunks!-from forty to fifty feet in circ.u.mference, presenting the following picture to us as it did to Spenser:-

There grew an aged tree on the green, A goodly oak some time had it been, With arms full long, and largely displayed, But of their leaves they were disarrayed; The body big, and mightily pight, Thoroughly rooted, and of wond'rous height: Whilom had been the king of the field, And mockel mast to the husband did yield; And with his nuts larded many a swine, But now the grey moss marred his rine; His bared boughs were beaten with storms, His top was bald and wasted with worms, His honour decay'd, his branches sere.

_Shepherd's Calendar._

This, indeed, is a melancholy sight, like the Stag's Horn Oak by the roadside between Farnham and Woolmer, in the ancient boundary of Alice Holt Forest; yet this has a young tree growing by its side, perhaps one of his own children, which gracefully conceals much of his gaunt nakedness. In the same forest are many old staggy trees, their contorted horn-like branches sticking out in a most picturesque manner from the top and sides of a still leafy head. In these the white owls may yet be seen peering out of dark cavernous hollows as they did in Gilbert White's day; and during the summer of 1861 we with pleasure watched their motions, which so minutely agreed with those described by the father of observing naturalists, that we cannot forbear quoting his remarks thereon in his "Natural History of Selborne," a not very distant parish from the Holt, and to which he indeed often refers:-

As I have paid particular attention to the manner of life of these birds (the White Owl), during their season of breeding, which lasts the summer through, the following remarks may not be unacceptable.

About an hour before sunset (for then the mice begin to run), they sally forth in quest of prey, and hunt all round the hedges of meadows and small enclosures for them, which seem to be their only food. In this irregular country we can stand on an eminence and see them beat the fields over like a setting-dog, and often drop down in the gra.s.s or corn. I have minuted these birds with my watch for an hour together, and have found that they return to their nest, the one or the other of them, about once in five minutes; reflecting at the same time on the adroitness that every animal is possessed of as far as regards the well-being of itself and offspring.

Notwithstanding the good done by these birds in keeping under mice, all our eloquence could scarcely preserve them from the onslaught of the keeper; they were, however, protected during our pleasant sojourn at the Holt; but we much fear only, after all, to gratify the taste for stuffed birds, a _love_ which is equally fatal to the feathered race (and especially the finest examples thereof) as the _hate_ of the keeper.

But we are digressing sadly, and must return to _Quercus Robur pedunculata_, and complete our observations thereon with the statement that most, if not all, the n.o.bler examples of oaks in England belong to this form. Selby directs attention to the "Flitton Oak, in Devonshire, of the _Sessiliflora_ variety, supposed to be one thousand years old, and which is thirty-three feet in circ.u.mference at one foot from the ground." However, nearly every historical oak is of the pedunculate variety. In the Holt forest are still left some huge examples; the same in the Dean forest; and Braydon, near Swindon, Wilts, though disafforested, can yet show n.o.ble trees of this form. Indeed, throughout England it is difficult to meet with many examples of any other form, except in Wyre forest, Worcestershire, where the tree next to be described is perhaps the more general, and it would also appear that in the New Forest the _Q. sessiliflora_ is also frequently met with.

_Quercus Robur sessiliflora_ may be generally described as of a more upright and formal habit. Limbs straighter and less gnarled. Bark usually smoother than the former. The leaf has many sinuosities, and is set on a comparatively long leaf-stalk (petiole) (Plate II. fig. _a_).

The fruit, on the contrary, is so nearly sessile that it may be said to have little more than the indication of a peduncle (fig. _b_).

We have already stated our opinion that the sessile-fruited oak does not usually attain the huge dimensions of the pedunculate form; but on the other hand we incline to the belief that it grows more rapidly, and is best adapted for a lighter soil than the latter. There are conditions which might to a greater or less extent affect the quality of its timber, but we do not think that there is much difference in this respect. We believe that their wood has been used indifferently, and the quality is influenced by surrounding circ.u.mstances. Selby, in his "History of Forest Trees," states on this head:-"The result, perhaps, of some original const.i.tutional defect, or arising from the nature of the soil, situation, or other local peculiarities of the ground upon which the timber has been raised; such at least is the result of our own experience, as we have met with oak of the _peduncled_ kind, its timber possessing all the inferior qualities attributed to, and supposed to be possessed exclusively by, _Q. sessiliflora_." The longer, straighter spars of the Sessiliflora, in days when oak was so uniformly used for roofs, seem to have pointed out this variety for roof-timbering; and hence some of the finest ancient timbered roofs of this country have been ascertained to have been formed from its wood. With respect to these the opinion long prevailed that they were formed of the wood of the Spanish chestnut. This, however, is but a poor timber tree, as, long before it could afford so large a scantling as would be required by the roof of the Parliament House at Edinburgh or of Westminster Abbey (both of which were supposed to be of chestnut), the chestnut would begin to decay at the heart; in fact, just at the period when the heart-wood of oak begins to harden, that of the chestnut would appear to deteriorate.

_Quercus Robur intermedia_, having a petiole intermediate in length between the other two varieties described, and a peduncle varying from a quarter to one inch in length, may with propriety be deemed a variety intermediate between "Sessiliflora" and "Pedunculata," and a comparison of the three will substantiate its claim to this t.i.tle.

As a tree it is impossible to make out any specific character from its mode of growth, and, indeed, without the fruit, it is extremely difficult even to distinguish it as a variety.

It occurs-only occasionally-in the Cotteswold district, and we suppose the same elsewhere. One meets with it here and there in the hedge-rows, and in Oakley Park, the seat of Earl Bathurst, we can point out a few specimens.

[Ill.u.s.tration: Galls of the _Cynips Quercus petiolata_.

(Natural size.)]

Pa.s.sing from the subject of the varieties of our British oak, it now remains to mention a most formidable enemy by which it has of late years been attacked, and so exclusively, that in plantations where may be found the American oaks, the Ilex oak, and Turkey oak trees, it has been the only one subjected to the operations of the new gall pest. It has long been known that our native oaks were subject to excrescences of different forms and sizes, such, for example, as oak-apples, oakleaf galls, oak spangles, &c., all of which were ascertained to be caused by several species of _cynips_; but lately we have to lament the introduction of a new species of the same insect, forming a new kind of gall, which, instead of attacking the backs of the leaves, as does the oakleaf gall, occupies the stem that belongs to the leaf; in fact, the attacked leaves seem to be converted into bunches of galls, as represented in the adjoining figure, which presents an ill.u.s.tration of the new pest. They are hard galls, more or less like the "nut-gall" from Aleppo, of which ink is made, and it will be seen that the little twig supports no less than five galls, in the interior of each of which may be found the maggot or _larva_ of an insect; and, as this is affected at the expense of the buds and leaves, the mode of injury must be obvious, as the new twigs which would have been formed, had there been no galls, would in their turn have produced branches and leaves. Trees thus infested are crippled as though they had been subjected to constant pruning.

As much of the natural history of the _cynips_, by which these gall-nuts are formed, as is necessary for our purpose, may be gathered from a paper by Mr. Parfitt, who seems to have well studied the gall insect in Devon, its head-quarters. We quote it from the Journal of the Bath and West of England Agricultural Society for 1861:-

The eggs deposited by the females in the oak buds in September remain there in a state of apparent quiescence till the following spring; then, as soon as the sap begins to flow, the irritant injected into the wound at the same time the _egg_ was deposited, or possibly the combined action of the egg and irritant, causes the sap to diverge; that portion of the bud which should have formed a young shoot is converted into a spherical ball; the outer scales of the bud fall away, and it is the woody secretion which entirely forms the gall. The cells in the gall are not elongated and regular, as in the young shoot, but confused and irregular; and in the centre of each gall lies a young grub of the _cynips_, forming a living nucleus, around which is deposited a thin, hard, woody envelope, much more compact in substance than the sponge-like tissue which fills up the interstice between it and the shining outer coat of the gall. This compactness of structure is a necessary and all-wise provision of nature for protecting the delicate insect which lies within from destruction; for if the gall were composed entirely of large spongy cells, the rapid flow of sap in the early spring would be more than the creature could consume, and it would consequently be drowned. I am aware that some naturalists incline to the opinion that the _larvae_ of the _cynips_ feed on the gall. From this view, however, I venture to dissent; for not only is it inconsistent with the structure of the creature's mouth, and the position in which the young _larvae_ are invariably found, with the head tucked under the apex of the abdomen, but if they fed on the substance or crude material of the gall, the undigested parts would certainly be found in the interior of its cell: in other words, the excrement would be there, for there is no outlet, and the lacteals or absorbent vessels of the gall could not take it up. I therefore think that the creature feeds entirely on the sap of the tree-an elaborate food fit for it without the need of mastication. This explains how it happens that the galls of commerce, with the insects in them, are so much better and dearer than those from which the _cynips_ has escaped; in a word, the tannic acid is more abundant.

It has been before observed, that there are two broods of the insect in a season; thus, those which do not emerge from the gall in September remain on till the following April or May. This is a wise provision of nature for continuing the species, should anything befall the autumn brood; and it is the more deserving of notice, because the gall-producing _cynips_ has a deadly enemy which accompanies or follows it in its flight from bud to bud, and deposits an egg wherever it finds the egg of the _cynips_. Here, as soon as the _cynips_ larva is hatched, the larva of the parasite is hatched also; forthwith the latter proceeds to eat a hole in the skin of the rightful occupant of the nidus, and the two larvae go on growing together till the _cynips_ is ready to a.s.sume the pupal state; then the parasite cuts the vital thread of the _cynips_, and uses its skin for a pupal envelope for itself; and thus, instead of the gall-fly emerging into day, a beautiful green insect makes its appearance on the stage of life. I had the pleasure of first discovering this parasite while engaged in studying the _cynips_; it belongs to the genus _Callimone_, and from the fact of having discovered it in Devonshire, I gave it the name of _Callimone Devoniensis_. It is one of the handsomest of our British insects; its costume a brilliant green, shot with gold; the abdominal segments green, gold, and purple; legs yellow; tarsi reddish; and it has four beautiful transparent and iridescent wings.

It has been stated that oak-galls are produced at the expense of acorns. From this view my experience leads me to dissent. In exceptional instances it may have been the case; but as a rule the _cynips_ confines its attacks to young trees and young growths in hedges, within a range of ten or twelve feet from the ground, and the nearer the ground the more numerous the galls. Young trees which have not attained a greater height than that I have indicated suffer so much that many of them can scarcely make headway against their foe; and in several nurseries I have visited, where it might be expected that greater care would be paid than in the case of ordinary plantations, the young stock of oaks has been rendered quite unsaleable by the pest. This year I have noticed the progress of the insect on two groups of young English and Turkey oaks growing side by side; and although there are hundreds of galls on the English oaks, there are none on the Turkey oaks. From this I am led to infer that the species of _cynips_ now under notice is confined in its depredations to the English oak; and as it invariably selects trees of younger or restricted growth-probably because the temperature at a higher elevation than ten or twelve feet from the earth is unfavourable to it-it would seem that children might be advantageously employed in young plantations in collecting the galls by means of cutting-hooks, such as are used for thistles. The galls, when once collected, might either be crushed for tanning purposes, or consumed by fire, and if the process were repeated for two or three seasons, it is more than probable that the plantation would be altogether free from the pest.

These able remarks not only well describe the nature of the attack, but also point to a cure-a matter to which we would direct the most serious attention of the planter; for we may state that, in 1853, we saw some very small oak trees, in the neighbourhood of Dawlish, Devon, from which some hundreds of these galls might have been gathered. This was the first time we had noticed this pest, though it appears that it had been under Mr. Parfitt's notice as long as a dozen years. Since then (1853) we have traced it in its progress as follows:-

Having observed the galls in Devon in 1853, we were yearly on the look-out in the Midland and Eastern counties for its appearance, and the following dates will show that its spread, though gradual, was sufficiently rapid:-

The galls were gathered in Devon in 1853 The same kind in Somerset, in 1854 In Gloucester, on the west side of the river Severn, Forest of Dean, in 1855 In Gloucester, east side of the Severn, and as far as Oakley Park, Cirencester, in 1856 In Worcestershire, in 1857 In North Wales, Beddgelert (pointed out to us by John Savory, Esq.), in 1859 In Suss.e.x, very sparingly, in 1860 In Alice Holt Forest, and far from abundant, in 1861 About Hastings, very plentifully, in 1862

We have this season observed a lot of the young galls; but last year, for the first time, we discovered that, in many cases, the maggot had been extracted by some small bird, one of the t.i.tmice (_Parus caeruleus_); and, if so, wherever young oaks may be growing, it should afford an additional reason for the protection of these useful birds.

The magnitude of the evil, unless checked by some means, may be estimated from the fact that, in 1856, we could scarcely find half a dozen galls within a wide district, and now all around may be found trees, not more than 10 feet high, upon which are no less than from one to five hundred distinct galls.

We conclude these remarks upon our native oaks with the fervent hope that in "Merry England" it may ever be as described by dear old Chaucer:-

A pleasant grove

In which were okes grete, streight as a line, Undir the which the gra.s.s so fresh of hew Was newly sp.r.o.ng, and an eight fote, or nine, Every tree well from his fellow grew, With branches brode, laden with levis new, That, sp.r.o.ngin out agen, the sonne shene.

Some very rede; and some a glad light grene.

_The Floure and the Leafe._

CHAPTER XLIII.

ON THE CHESTNUT AND WALNUT.

The Chestnut and Walnut are here brought together, not only as producing two useful kinds of hard-wooded timber, but from the fact of both being bearers of esteemed kinds of fruit. They are neither grown to the same extent in England as on the Continent, and probably neither of them is indigenous to this country, although it is stated by Sir W. Hooker to grow in woods apparently wild, in the south and south-west of England.

As regards the fruit of the former, it may be said that in parts of Spain "Spanish Chestnuts" are a staple article of food. In England they are sometimes brought to table as a stuffing for turkeys, or roasted for dessert; but their greatest consumption among us is with the poor, who, in winter, with a halfpenny-worth of roasted chestnuts enjoy the double luxury of warm fingers and a sweet nutritious diet. Walnuts, as a fruit, are highly esteemed by all cla.s.ses: as much by those who crack and peel them in a second or third cla.s.s railway carriage, as by the squire who takes them as a concomitant with his gla.s.s of port. With us they are only cared for while they can be peeled, but abroad they are carefully dried, in which state they form an important article of commerce. In the Portuguese court of the International Exhibition of 1861, in our capacity of juryman, we had brought before us specimens of dried walnuts from as many as fifty exhibitors.

The Spanish chestnut (_Castanea vulgaris_) has no relationship with the so-called horse-chestnut, which latter, we might just mention, is solely employed as an ornamental tree, if we except its occasional use in cabinet-work. Evelyn, sixty years ago, speaks of it as being "all the mode for the avenues to their country palaces in France." It has been much used for this purpose with us, and its magnificent flowers and fine foliage will ever recommend it as an ornament about country residences.

But to return to the Spanish chestnut. This tree is planted with us both for the growth of timber or as underwood for poles; for the latter purpose it answers well, as it soon grows up again after cutting, and in its young state it goes so soon to heart-wood that the poles are remarkably strong and tough.

As a timber tree, the chestnut has been very extensively extolled both in this country and on the Continent; it may, however, be concluded that although its wood is exceedingly useful, it has never been put to the important uses which have been claimed for it.

Evelyn, speaking of chestnut-wood, says:-"I had once a very large barn near the city, framed entirely of this timber."

Sir T. D. Lauder tells us that the roof of the Parliament House in Edinburgh is constructed of chestnut, and we have often seen it stated that the magnificent roof of Westminster Hall has been framed of this timber;[28] but to quote from Selby's admirable "History of British Forest Trees":-

The fact is, as Buffon first observed, the wood of the oak, more particularly that of the sessile-fruited variety, a.s.sumes, in course of time, a near resemblance in colour to that of the chestnut in its best condition, or when young and untainted at heart; and as few chestnuts could have acquired the scantling frequently observed in the timbers of these ancient buildings at the age dialling or decay almost invariably commences, this in itself furnishes a strong argument against the use of chestnut timbers and beams by our ancestors, inasmuch as the trees must become unfit for the purpose long before they had attained the necessary dimensions.-P. 326.