*' BOUND disease" OF THE PINE. 179 



unfortunately common in Sologne, where it has done much injury. It 

 makes its appearance in the pineries by attacking two, three, four, or 

 five piues in a place, and every year from around these centers, some 

 more piues die, leaving openings more or less circular, and sometimes 

 widening out irregularly until whole forests are gradually destroyed. 

 From its thus working out in a circular manner it has acquired the 

 name above given. Among the causes assigned, are, by some, insects 

 of different families, chiefly of the Coleoptera, certain genera of which 

 live under the bark of these pines. Others think that it is communi- 

 cated by the roots. Others, that it is due to old coalpits, or places 

 where fiVes have been made; and still others (we think with more rea- 

 son), that it is due to conditions in the soil. It is remarked that it oc- 

 curs ofteuer in gravelly soil, and very seldom where pebbles are absent. 



As for these theories, it may bo remarked that insects generally do 

 not attack the bark of a vigorous growing tree, but only when it has 

 come to the age of decay. Those who attribute the malady to insects 

 appear to take the effect for the cause, and, moreover, the rooting up and 

 even burning of the wood has never stopped the progress of the disease ; 

 and as the trees are always attacked in patches, it seems to be due to 

 something inherent in the soil. In the midst of these infested places 

 sound trees are often found, which could not be if the infection was 

 carried by the roots. It seems more probable that these favored trees 

 have penetrated to a better soil. Even the roots of trees affected have 

 been found growing to those that were not, and attempts at isolation 

 by digging trenches have failed.^ The disease will sometimes, stop 

 without anything being done. As for the theory of old charcoal beds, 

 there is little to support it. The disease appears more frequently in 

 soils of fine sand mixed with sandy gravel than in silicio-argillaceous 

 soils. As already remarked, the investigations that have been made 

 have hitherto failed to fix with certainty the cause or to furnish a 

 emedy. ^ 



The first years of the maritime pine show much vigor of growth till 

 eight, fourteen, or eighteen years, and sometimes till twenty-five or 

 thirty, according to locality. Beyond this it will sometimes begin in 

 some points to lose a part of its vigor, an incident of apparently small 

 imi)ortance, but affording some hint in the solution of the problem. It 

 shows us that at this time the main root has met with a soil not conge- 

 nial for it and perishes, and the mortality finally extends to the whole 

 tree. 



Toward the end of the last century, millions of larch were sown in 

 England and Scotland in places that appeared unfit for other cultiva- 

 tion. As in the case of the maritime pine in France, these plantations 

 in the first years made a vigorous growth, and, like them, as they grew 

 old they fell sick ; so that at twenty-five or thirty years many of them 

 died standing, and like the pines became covered with mosses, lichens, 

 and mushrooms. The disease was compared by some to the potato- rot 

 iu its destructive effects and obscure cause. The remedy appears to be, 

 to seek other profitable species for cultivation where one has been found 

 •to fail. The Piniis sylvcstris might perhaps with advantage replace the 

 maritime pine. It has proved itself adapted to a wide range of climate 

 and a great variety of soil, is easily acclimated, and would doubtless 

 thrive in conditions where the maritime pine refuses to prosper. When- 

 ever a given species begins to sho^ a lack of vitality, as shown by a 

 covering of mosses and lichens, the sap-wood becomes liable to the 



' It is stated by M. Bagueris that in the Laudes this disease has been stopped by dig- 

 ging a trench 0.7 meters (about 3d inches) deep around the infected part. 



