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ARBORETUM AND FRUTICETUM. 



PART 111 



2266 



early as seven or eight 

 years after planting, 

 and in all it seems to 

 proceed with the great- 

 est rapidity ; some- 

 times destroying the 

 trees entirely, between 

 15 and 2.5 years old, 

 on soils in which the 

 oak prospers. (See 

 p. 2376.) With regard 

 to the cause of this 

 disease, it is by most planters attributed to the soil and situation ; and by 

 some to improper management. The latter seems to l)e supposed to con- 

 sist chiefly in improper pruning, that is, cutting off part of its roots in the 

 process of planting, or depriving the tree of part of its branches in the 

 early stages of it growth. The rot in the larch, Mr, Gorrie observes, " has 

 been found to prevail on rich deep soils, and in poor shallow soils, on 

 retentive and porous subsoils, on soils incumbent on freestone, limestone, 

 and whin, or green, stone; and. also, on all these descriptions of soil and 

 subsoil, the larch has been found tolerably free from this hidden disease. This 

 being the case, we are led to suppose that the rot in larch takes its rise from 

 something accidental, rather than from any natural property in the soil. It has 

 been a common practice to follow a crop of Scotch pine with this more lofty 

 and promising plant; and the writer of this has recently discovered, in nume- 

 rous instances, that, where this has taken place, the rot uniformly commences in 

 fearfully numerous instances. Tiiis effect is produced as soon as 7 or 8 years 

 after planting; while plantations of the same plant, on the same estate, planted at 

 the same period, and in every respect similarly circumstanced to the other, 

 with the important exception that they did not follow the Scotch pine, con- 

 tinue entirely free from the rot. In old plantations, too, where the Scotch 

 pine and larch had been mixed together, and where the disease was by no 

 means prevalent, the new crop of larch was completely affected ; giving room 

 to infer that the rotting roots of the Plnus sylvestris, or Scotch pine form, at 

 least, one powerful agent in promoting this disease." {Gard. Mag., vol vii. 

 p. 574.) In the Quart. Jour, of AgrL, vol. v., Mr. Gorrie repeats the above 

 observations, and adds : " In this opinion I am supported by my esteemed 

 friend, Mr, James Young of Pitfour, whose sound judgment and practical 

 skill place him high in the estimation of his professional brethren." Mr. 

 Gorrie then gives some extracts from a comnumication by Mr. Young, from 

 which it appears that Mr. Young, when thinning out a plantation of young 

 larches, (which had been planted as nurses to oaks, and had succeeded a crop of 

 Scotch pines,) found the proportion of decaying plants about GOOO to 50 ; 

 while larches in the neighbourhood, on similar soil, but not succeeding the 

 Scotch pine, were found, when cut down at 60 years' growth, "to be of 

 excellent quality, only one in six or eight showing slight s}mptoms of the 

 disease." Mr. Young adds that he cannot bring himself to believe that 

 there is anything deleterious in the soil naturally ; but that he thinks it pos- 

 sible that the Scotch pine " roots, in the course of decay, after the trees 

 have been cut down, may have com.municated some poisonous quality to the 

 soil, which promotes or originates this disease in the larch." Mr. Webster 

 observes that the disease is most prevalent in plantations of the larch 

 where the trees are planted so closely together as not to admit a free circu- 

 lation of air. Mr. Munro thinks it probable that an extensive annual deposit of 

 albumen, when the tree is young, is the cause of the rot. {Gard. Mag., vol. ix. 

 p. 555.) ; but Mr. Gorrie has shown {Ibid., vol. x. p. 546.) that this is not 

 likely to be the case. Mr. INIatthew, finding the rot in trees which had 

 been chilled in wet cold clays, and in others which had been starved in dry 

 sand, and, again, in the most luxuriant-growing plants, in open situations. 



