CALCAREOUS MANURES— APPENDIX. 



259 



The entire absence of trees for 900 miles across tlie Pampas between Bu- 

 enos Ayres and the Andes, has been still more absurdly attributed to the 

 winds (called pamperos) which often sweep across those wide plains with 

 such violence, that no trees could withstand their power. I have seen in 

 our forests where a hurricane had uprooted or broken off every tree of size 

 in its course. But no wind could destroy the young and flexible under- 

 wood ; and if such winds swept the same track ever}'' year, or every 

 month, they would not prevent it being thickly covered with young sapling 

 trees. 



The downs in England, which have not been tilled for hundreds of years, 

 and are only valuable for sheep pasture, show no rising "growth of trees. 

 This is not held strange there, but would be supposed sufficiently account- 

 ed for by the poverty of the soil, and the (supposed) impossibility of young 

 trees growing, even if planted on open pasture land, without any care, and 

 where they were always exposed to the attacks of live stock. But in 

 Virginia, no degree of poverty, no exposure to grazing, will prevent untilled 

 land growing up in wood. Annual fires, grazing animals, and poverty, 

 wetness or sandiness of soil, all may prevent the growth of trees, as 

 alleged in different countries ; but all these are but secondary causes which 

 would have little or no effect, without the more powerful operation of some 

 other and primary cause. This cause will befoimd in the peculiar constitu- 

 tion of the soil; and I will proceed to state my reasons for believing that 

 the cause of the different conditions of land as to being naturally covered 

 with trees, or not so in general is merely the deficiency of lime in the soil, or 

 its abundance— the former state being friendly to forest growth, and the 

 latter being as unfriendly. Or — in terms so general as to cov^Jfe,ll the ex- 

 ceptions which will hereafter be admitted to the foregoing position— it may 

 be stated, that the formation of prairies, &c., is caused by the existence of 

 such circumstances as favor the growth of grass in a far greater degree 

 than the growth of trees — and of all such circumstances, the abundance of 

 calcareous matter in the soil is the most efficient. 



In addressing readers residing in, or otherwise well acquainted with the 

 Atlantic states, it is unnecessary to adduce facts to prove the general and 

 strong disposition of the soil to produce trees, in vigor and luxuriance— to 

 resist the labors of man for their destruction— and to return to the state of 

 forest whenever tillage is intermit "ed. No untilled land will long remain 

 naked, or in grass ; and even under a regular rotation of crops, the labor of 

 grubbing to destroy young trees is continually required on most lands, and 

 particularly on those originally of inferior quality. Our poorest lands in 

 lower Virginia, are generally covered with young pines in four or five years 

 after being left without tillage, and their after-growth is as rapid and heavy 

 as European timber growers would expect on the best lands, and with every 

 care bestowed for that end. But it is not only to pines, (though that is the 

 most striking case,) that this applies. In the higher and stiffer lands, where 

 pines are rare, the springing of other young trees shows the same general 

 tendency of the soil. If this tendency can be said to be feeble any where 

 in lower Virginia (and it may be presumed that the same state of things ex- 

 ists in all the Atlantic states,) it is on the few naturally rich soils on the 

 rivers, some of which are the only lands naturally calcareous in the country, 

 and all of which derived their natural fertility and permanent value from 

 possessing lime in some form as an ingredient. In the ' Essay on Calcareous 

 Manures' proofs have been exhibited of this supposed quality of such lands,* 

 and therefore they will not be repeated here. It has also been maintaned 



* Part 1, chapter vii. — On noutral soils. 



