2i2 POPULAR SCIENCE MONTHLY 



tion. Our soils and climate are almost everywhere well adapted to 

 its growth, its abundant seeds germinate readily, and it responds 

 promptly to the forester's care. The danger of failure in growing this 

 tree for economic uses lies, not in the character of the tree nor in that 

 of our soils or climate, but in the persistent attacks of destructive in- 

 sects which are natives of the same region with the tree, which follow 

 it in its geographical distribution, and which presently will be further 

 referred to. 



There are two North American trees which bear the popular name 

 of locust, the one already mentioned and the honey locust, Gleditschia 

 triacanthus ; but it is only the black locust that is referred to in these 

 remarks. This tree originally was known only in that region which 

 lies east of the Allegheny Mountains and between New York and 

 Louisiana. By natural dispersion and artificial propagation, however, 

 it has grown for many years more or less commonly, but for the most 

 part unthriftily, in nearly all the eastern half of the United States, as 

 well as in other parts of North America. Early after its first dis- 

 covery its seeds were carried to other countries, where the tree was suc- 

 cessfully progagated from them. In Europe, especially, where its 

 American insect despoilers never have been introduced, where the in- 

 digenous insects never molest it, and where it readily adapts itself to 

 the local climatic and terreous conditions, it has always grown thriftily 

 and symmetrically, reaching a maximum size comparable with that of 

 the oaks. Being there esteemed as an ornamental tree, it is often 

 grown in public parks, and it is also much cultivated in preserved 

 forests for its valuable wood. 



This European experience with the black locust tree well illus- 

 trates its extraordinary vigor and its ability to reach full maturity of 

 growth under a wide diversity of conditions of soil and climate. Its 

 completely successful growth to trees of medium size in formerly iso- 

 lated North American districts west of its native regional habitat, and 

 its persistent struggle for existence against its insect despoilers wherever 

 it has been established in our country show that our soil and climate 

 ,are entirely favorable to its growth and that it is only accessory, but 

 dominant, conditions that are unfavorable. These accessory conditions 

 are now known to be the result of ravages upon the living parts of the 

 tree by the insects referred to. Indeed this tree presents the remark- 

 able case of a strong arboreal species doomed on its native ground and 

 in contiguous regions, to a constant state of suppression of its natural 

 development, and even to local extermination, by insect despoilers 

 which are natives of the same region with the tree and wholly dependent 

 upon it for their own existence. There is no other North American 

 tree, perhaps, excepting the common mezquite of our southwestern states 

 and Mexico, which is so disastrously damaged in its growing condition 

 by indigenous insects as is the black locust, and both of these trees 



