76 



Cultivation of the Oak.' 



Vol. XII. 



hints that may, in the future, be useful as a 

 rallying point to others that can claim a pre- 

 cedence over their more humble brothers in 

 the profession of science. The modern use 

 of iron in the construction of marine vessels 

 has been thought, at a subsequent period, 

 would supersede that of wood ; we should 

 then have oxides to contend with instead of 

 fungi; but we do not believe the former will 

 ever supersede that of the latter. As the 

 grand engine of navigation is deteriorating 

 every day from the causes of decay, it may 

 be asked, what is the dry rot? and how long 

 has it been known to affect the timbers of 

 vessels, and the cause of this effect ? Well, 

 in answer to the former, the dry rot is caused 

 by the spontaneous decomposition of the ve- 

 getable albumen which acts as a ferment on 

 the other constituent principles that may be 

 present in the wood, as sugar and starch, 

 which disintegrates the fibres of the wood, 

 and accelerates the growth of mushrooms 

 by the formation of ammoniacal salts. Of 

 these fungi, there are two species, — as the 

 Xylostroma giganteum, which grows in the 

 timber like a thin broad patch of yellow 

 leather, and the Serpula distruens, which is 

 not so large, of a reddish colour, and white 

 at the edge growing externally. As the 

 cause of this dry rot proceeds from an ex- 

 cess of vegetable albumen in those woods 

 that have been in modern use for ship-build- 

 ing, we may answer the latter question by 

 saying that the primitive oaks of Great Brit- 

 ain, and those of our country, which were 

 used in the early construction of their na- 

 vies, were not so rich in albuminous matter 

 as the oaks of secondary growths, and those 

 of various locations, are now; therefore the 

 dry rot and fungous growths in such timbers 

 were not known, nor never would have been, 

 had we the timber now of those primitive 

 forests of our country, Europe, and Great 

 Britain. It will appear, by these observa- 

 tions, that we intend to maintain that the 

 cause of dry rot proceeds from the negli- 

 gence and want of knowledge in the selec- 

 tion of those trees which resist the effects of 

 time and exposure without the process of 

 decay. Such is our position, and without 

 further comment, we proceed to illustrate 

 many points connected with the subject un- 

 der consideration, as it is one of the most 

 important to which the attention of a mari- 

 time people can be turned. 



The oaks of North America, as described 

 by Andrew Michaux, consist of twenty-nine 

 species and varieties, most of which are use- 

 ful in ship-building; the one considered the 

 most useful, and stands at the head of the 

 list, is the live oak, Quercus virens. It is 

 a perennial tree, of slow growth, like the 



rest of its congeners, and is common to Flo- 

 rida, where Che most extensive forests of this 

 tree are seen. It is generally found grow- 

 ing from latitude 37° to Florida, "and west- 

 ward to the mouth of the Sabine River," 

 but never more than fifteen or twenty miles 

 from the sea. This valuable tree can be 

 said to contain less of the causes of decom- 

 position, as albumen, sugar, and starch, than 

 any of the species hitherto described; there- 

 fore, it is the most durable, and less liable to 

 decay; and with all this natural immunity 

 against spontaneous decomposition, we should 

 not overlook the locality of its growth, age, 

 and season of cutting for ship timber. This 

 is a necessary precaution, which is applica- 

 ble to the whole tribe of oaks that are used 

 in the mechanics. The best localities for 

 the selection of durable timber from those 

 trees, are elevated regions, high table lands, 

 and an open country, where they are not 

 overshadowed by other growths. They 

 should stand where there is ample room for 

 their branches, with a free access of air, 

 heat, and light on all sides, as often seen on 

 the boundary of some plantation, or as orna- 

 ments which venerate the mansion of the 

 planter, or such like places. The woody 

 fibres of such trees are more dense ; they 

 contain more carbon or astringent qualities, 

 with less vegetable albumen: whereas, to 

 the contrary of this, should such timber be 

 cut in low wet grounds, ravines and shady 

 places where they grow compact, it would 

 be liable to decay from the causes mentioned, 

 as there would be an excess of those constit- 

 uent principles, and a softer structure that 

 would hasten the decay, and cause the dry 

 rot, so deleterious to our navies. The age 

 of the oaks is next to be considered. They 

 generally attain their maximum height and 

 full development at the age of fifty or sixty 

 years, and after that period, they progress 

 but slowly, until they arrive at a very ad- 

 vanced age, as two or three hundred years 

 or more. Those of the live oak that can be 

 best recommended for durable timber, are 

 such as have arrived at the period of a hun- 

 dred years or more, if the constitutions of 

 the trees are sound, and no visible decay is 

 present. The gigantic growth of this tree 

 at the age last mentioned far surpasses any 

 of its species. The measurement of one of 

 its limbs by myself in a horizontal line ex- 

 ceeded sixty-five feet, while the diameter at 

 the junction exceeded the size of the bodies 

 of many red and black oak species of a full 

 size, or secondary growths that have sur- 

 vived seventy winters. We repeat that the 

 maturity of the species of oaks must be con^ 

 sidered before used or appropriated for ship- 

 building; for it is at this period the strength 



