FORESTRY MANUAL. 29 



In Europe, where tree-planting is more of a science, and to which our Na- 

 tional Horticultural Society proposes sending learned men to take lessons in 

 tree planting, it is one of their rules not to confine a grove to any one spe- 

 cies, but the greater the mixture the better the success. One species of tree 

 obtains from the soil all the elements suitable for its growth, while it leaves 

 or rejects that which is suitable for another species. The different writers 

 upon the subject have not settled the exact reason why a heavier growth 

 and longer life were guaranteed to trees when there is a general mixture of 

 ^lie species of forestry, yet experiment and observation have established the 

 fact. 



Prof. Aughey, of Nebraska, a scientific man on forestry, strongly urges 

 the vital importance of mixing groves. He says he "has observed many of 

 the exclusively Cottonwood groves decay from various causes, when from 

 four to twenty years of age. This, he claims, is only what would naturally 

 be expected by a European forester. If they had been mingled with other 

 trees, such as maples, walnuts, box-elders and lindens, it would probably 

 have preserved them intact, besides making them intrinsically more val- 

 uable." The vast forests of beech in Denmark are known by reputation 

 the world over. Years ago they showed signs of rapid decay, and the 

 authorities had other species of trees planted in all the open spaces, such as 

 aspen, willow, oak, birch, maple and fir, and Naupel concedes that this prob- 

 ably saved the forests. 



And the forest of Fontainbleau, the Queen's most valuable timber lands, 

 and the one of all her vast domains which shows the most vigor in growth, 

 is a mixture of all the species suitable to that climate. Clave speaks of it 

 in his reports, as follows : " Oaks mingled with beeches in due proportion, 

 may arrive at the age of five hundred to six hundred years in full vigor, and 

 attain dimensions which I have never seen surpassed ; when, however, they 

 are wholly unmixed with other trees, they begin to decay and die at the top, 

 at the age of forty or fifty years, like men old before their time, weary of the 

 world and longing to quit it. It was then proposed to introduce the pine 

 and plant it in the vacancies and glades. By this means the forest was 

 saved from the ruin which threatened it, and now more than ten thousand 

 acres of pines, from fifteen to thirty years old, are disseminated at various 

 points, intermixed with broad leaved trees, and sometimes forming groves 

 by themselves." 



Professor Agassiz, after having visited all the best artificial groves of this 

 country, as well as the dense sylvas of Central and South America, was con- 

 vinced that the mixture of such a great variety of species as he found in 

 the south, instead of exhausting the soil, added largely to its wealth of fer- 

 tility. He found over on9 hundred species to the acre. And he was of the 

 opinion that when nature's method was violated it tended to dwarf and 

 shorten the age of the trees. 



And the Hon. John J. Thomas, a New York horticulturist of note, says 

 in some of his official publications, that "it is the opinion of some planters 

 that a heavier growth may be obtained from a given extent of land by inter- 



