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Growth of the Coco Palm. It has often been stated that this tree cannot grow at any distance from the sea, but it has now been proved that it thrives as far as 300 km. (186 miles) inland. The neighbourhood of the sea is, nevertheless, beneficial to this palm, and in the Philippines, for instance, the coast is almost uniformly bordered by stands of coco-trees. On the other hand, the excessive transpiration of the leaves, which in the case of a tree in full growth, can amount to 45 litres (10 gals.) per day, necessitates a climate of sufficient humidity to compensate for the large amount of water lost by this means.
Making a plantation. After comparing the different estimates and schemes published by various writers, and making allowance for the fact, that during the first 7 years only expense can be looked for, M. Main concludes, that the expense of an area of 2470 acres planted with 100 000 coco palms should be estimated at from £11 4s to £16 per acre. It is not possible, at present, to reduce the difference between these two figures, but writers who estimate by the single tree and reckon the cost price of a palm of from 6 to 8 years at 6s 2 1⁄2d or 6s 8 31 d, consider, taking about 40 trees per acre, that the results work out in accordance with the above figures. It seems thus reasonable to fix the capital necessary for making a plantationof 2470 acres with 100 000 coco-palms at from £32 000 to £36 000; necessarily, the sum is not equally divided over the first 7 years.
Selection and Varieties.
Messrs. Barrett, Zaepernick and Smith are not all agreed as to the existence of true varieties for selection and of general rules to be observed in order to improve the production. Nevertheless, it seems certain that the copra yield varies with the district and the cultivation and probably also according to the varieties. About 20 varieties are believed to exist in Malaysia.
Interplanted Crops. As a rule, the cultural operations are not the subject of much controversy; but on the other hand, the question of associated crops is much discussed. The latter are increasingly planted under certain conditions. The present idea is, that those crops must be selected which give an immediate return, as they can only be planted the second year, and must be given up after the fifth, or sometimes even after the fourth year, in order, that the coco-palm may derive the entire benefit from the nutritive substances present in the soil. The plants most used are manioc, pineapple, pepper-plant, coffee (Coffea robusta), mimosa, and various Leguminosae, agave, maize, earth-nut, etc. Amongst the Leguminosae, Crotalaria is an especial favourite. Coffea robusta is well spoken of also, as from its second year, it is capable of yielding 160 lbs. to 180 lbs. per acre; in the third year the crop exceeds 450 lbs. and is 1800 lbs. the two succeeding seasons. These figures largely counterbalance the cost of plantation and allow of the crop being up-rooted after the fourth year, should the state of the coco palms require it.
It seems the general opinion that coco trees which are manured by grazing live stock yield earlier and larger crops; but the age at which
the trees have nothing to fear from the animals is, however, still a moot point, and there are no data available as to the facilities for the purchase and sale of live stock.
Improvements and fertilizers.
It is generally recognized that phosphoric acid and nitrogen are more clearly useful than potash, although the latter is also necessary.
Farm-yard manure is one of the best fertilizers; cakes, organic manures and ground bones are also excellent, as is also especially the green manure consisting of the Leguminosae which have formed the intercalary crop. Common salt, which has been hitherto regarded as a very good fertilizer for the coco-palm, is no longer in favour and it is considered that chloride of potash fertilizers are sufficient.
Yield. The different writers estimate the number of nuts required to produce 1 ton of copra, at from 4000 to 7000. The divergence between the figures is doutless due to the differences in the weight of the nuts borne by the different varieties which are planted.
Opening and drying the nuts. There are a few machines for opening coco-nuts, but the writers have, so far, not taken them into account, for the extraction of the kernel by means of an iron rod, or "bolo" is considered almost generally to be the best method, and it is still believed that an excellent quality of copra can only be obtained by drying the nuts in the sun. The drying apparatus are not as yet perfect, but when they work well, they furnish a copra which is preferred by some producers and exporters.
Hamel Smith's book gives interesting details concerning the mechanical extraction of "coir ", and in particular, a description of little-known machines. The mechanical preparation of "coir " may be considered as an improvement, which permits of its being always utilized, and removes the prejudice according to which it was considered an unimportant byproduct to be collected only when possible:
Diseases and insect pests. The writers who have been consulted mention rats as being enemies of the coco-palm, in addition to discases and insects. Zaepernick advises the use of zinc bands to protect the trees from the attacks of these rodents. These bands are used in Europe for fruit-trees, but would be very costly in the case of a plantation of 100 000 palms. O. W. Barret gives an account of the Coleoptera, which can only be controlled by collecting them. "Bud rot" is the most serious bacterial disease from which the cocoa-tree suffers, it appears to be caused by Bacillus coli. The only method of control is up-rooting the infected palms and burning them (1).
(1) On the diseases and enemies of the coco-palm, see amongst other abstracts in this Balldin, those which deal specially with "bul-rot" Pp. 358, 360 B. Dec. 1910.
The Economic Importance to Portugal of the Cork Oak and its
Naturwissenschaftliche Zeitschrift für Forst und Landwirtschaft, Year
10, Part 11, pp. 549-559. Stuttgart, November 1912.
Thanks to its geographical situation, its soil and its climate, Portugal possesses a rich tree flora. The forest timber which exists is mostly indigenous, but trees which have been introduced flourish equally well. Of great importance among the latter is Cupressus glauca; this occurs in large stands in Busaco and reaches huge dimensions; Acacia melanoxylon and Eucalyptus globulus should also be mentioned, and it is the latter which imparts to the Southern Provinces their characteristic note. From the forestry standpoint, Portugal is divided into three districts; the first that of Pinus pinaster Ait (pinheiro bravo), which extends from the Sado to the Minho and from the sea to the mountain chain and is swept by the sea winds. The second district is that of Quercus suber (sobreiro) and Quercus ilex (azinheiro), these trees here form not very dense forests extending over vast stretches of country, which are called "montados". This region extends from south of the Tagus to the coast of Algarve, and is almost throughout slightly undulating. Its climate is hot and dry, since rain rarely falls here between May and October. The third district is that of Quercus pedunculata (carvalho alvarinho), Quercus tozza (carvalho negral) and Quercus lusitanica, but the latter is of rarer occurrence and prefers the flat central portion, which it shares with Castanea vesca. This territory north of the Tagus is in places very mountainous, and the climate is variable and humid; heavy rain occurs, especially in the district between the Douro and the Minho. Until some decades ago, Pinus pinea grew in great masses in the valleys of the Tagus and Sado. But there was so large a demand for the wood of this tree for shipbuilding purposes and railroad construction, that the pines were cut down in large numbers and have not been replanted, or even replaced by the less valuable but more rapidly growing Pinus maritima. Now the mistake has been seen and this latter species is being chiefly planted.
The Cork Oak. -After Quercus ilex, which covers 618 000 acres, Quercus suber is the tree most widely grown in Portugal, where it occupies an area of 519 000 acres. The regions where it is chiefly cultivated lie south of the Tagus and indeed principally in the districts of Beja and Evora, in the centre of Pontalegre and in the Province of Algarve; here it often forms extensive closely growing stands. In the Tagus valley, the districts of Lisbon and Santarem and that of Castello Branco, this tree is not so well represented, but it still grows in large stands; these decrease in size towards the north, and finally only solitary individuals occur.
In south and central Portugal, the cork oak shows its usual habit; its stem is normally short and its growth compact, it branches at from 5 to 10 ft. above the ground and forms a spreading bushy crown. In the north, on the contrary, where this species occurs mixed with Pinus maritima, its trunk is more slender and often attains a considerable height; but this change of habit is also due to the method of pruning adopted. Here,
too dense a shade is avoided, as space is needed for intercalary crops, while in the south, where the cultivation is less intense and the estates larger, more stress is laid upon a greater production of cork and acorns. In the north, the development of horizontal branches is encouraged, which are carefully pruned in order to expose the crown to the effect of light and air.
The flowering and fruiting seasons and the time of the fall of the acorns are at approximately the same dates as in other Mediterranean countries. Sometimes cork oaks attain quite large dimensions. As an example, the writer cites a tree growing in the Estremoz district, which in one season yielded 3960 lbs. of cork. As regards their growth, many young plantations ("chapparaes ") yield cork fit for use 23 years after planting, while male cork is produced sooner, but the latter cannot be used in the manufacture of bottle corks.
The acorns are devoted to the fattening of pigs, although they are more bitter than the fruit of Quercus ilex. It is estimated that of the million pigs which are reared annually in Portugal, one third are fed on the acorns of the cork oak and holm oak (Q. ilex). The total harvest amounts to 200 000 tons. If the proprietor is not himself a pig-breeder, he farms out the oak forest at the rate of from 20 to 25 shillings per head of swine to be fattened. The number of these animals to be fattened in a forest is decided empirically. As a rule, the ground beneath the oaks is kept free from underwood and bushes; this promotes the growth of intercalary crops, obviates any danger of forest fires, and enables the pigs to find the acorns with greater ease. The formation and ripening of the cork is hastened by working the ground, manuring for intercalary crops, and by the pigs during the fattening season. The cork is finest and thickest when it has formed quickest. All existing cork oak forests are of natural growth, and most new plantations that are made arise by protecting a certain area against pigs and fire.
Lately, new plantations are made by sowing late autumn acorns, which are preferably obtained from oaks already known to be good cork producers. The acorns germinate very rapidly, the young trees require no further care, and on good soil, the first crop of male cork can be stripped off at the end of ten years. Planting is rare and only occurs for small stands, or in order to fill up gaps. The cork oak forests are almost exclusively the property of private individuals, who either strip off the cork themselves, or lease the forest for 20 to 40 years.
By the terms of the contract, the owner is often obliged to strip off the male cork and to superintend the clearing of the crown, etc. The tenant always undertakes to leave untouched the cambium layer ("mae "). The male cork is usually removed when the trees are from 15 to 20 years old. The operation generally takes place between June I and August 30, but is sometimes, though not frequently, effected in the second half of May. An interval of 9 or 10 years, often of from 8 to 12 years, intervenes between each stripping; this time is necessary to obtain cork 32 mm. (1 1⁄4 in) thick. In order not to weaken the tree unduly, and also because branch cork grows more slowly than stem cork, the stripping is confined to one portion of the ok at a time.
Cork Production. An axe with a wide sickle-shaped blade is used for removing the cork. The sale unit is the "arroba" (32.38 lbs.). Cork is seldom exported in a raw condition, but is usually cut into strips according to classification; these are steamed and flattened after the defective portions have been removed. The pieces ("pranchas ") thus prepared are compressed into bales of 59 X 27.5 X 23.6 inches and bound with iron bands. When bottle corks are made, the sheets are once more steamed and then cut into cubes (quadros); these are trimmed to shape, either by hand with a knife, or by means of a machine. Champagne corks are not manufactured in Portugal.
The wine corks of commerce owe their appearance to being placed in a solution of oxalic acid. When needed for other purposes, they are subjected to other operations. There are no linoleum factories in Portugal, where the cork refuse can be turned to account. The latter is, however, ground and used for floor cement; or is made into insulators.
Amongst the defects that occur in cork, "jaspeada "must be mentioned; this is a dark cloudy discoloration giving a marbled appearance to the cork. Green patches also are to be found, caused by a mould, which grows on the unripe cork; other defects are due to the injuries caused by various insects; those due to the attacks of the Buprestidae, Coroebus undatus, Coroebus bifasciatus, and Agrilus, and which consist of tunnels bored in the cambium layer, are called "colebra." Ants of the genus Cremastogaster cause similar damage, while Tortrix viridana (“burgo") attacks the leaves and The best quality of Portuguese cork comes from the districts of Beja, Evora, Portalegre and Algarve.
The annual yield of good dry cork amounts to about 50 000 tons; the total production of cork is 58 192 tons (according to the latest statistics); of this about II tons are used in Portugal, while the rest is exported mainly to Germany, Belgium, the United States, Brazil and especially to England. The last country buys the most prepared corks.
The writer gives several tables of the analyses of Portuguese cork, as well as of the acorns of different species of Quercus together with their relative nutritive value.