178 INJUfilES FROM FROST, ETC. 



strength. Trees growing in a damp soil, with an eastern or northern 

 exposure, are most liable to these accidents. 



Heavy winter frosts doubtless cause much injury to trees, when they 

 do not entirely destroy them. It often happens that the branches alone 

 are injured, while the trunk remains sound ; and again, the trunk will 

 sometimes perish and the root survive, and in condition to produce 

 new shoots. Trees exposed to the north are, for obvious reasons, more 

 liable to injurj" from this cause.* 



Du Hamel remarks that vigorous plants, having a rapid growth, are 

 less liable to damage by frosts than those in a feeble condition, and that 

 when a tree has been much injured by frosts, the withered leaves will 

 remain on through the winter.^ 



It is observed in the Eucalyptus, that after a few years the tree ac- 

 quires a considerable degree of hardiness, so as to be able to resist frost, 

 and although the young tree may snfter, the trunk will put forth fresh 

 branches with undiminished vigor.^ 



The winter of 1871-'72 was particularly injurious to evergreen trees 

 in the Northern States, and various causes were assigned for this fatality. 

 It could scarcely be ascribed to insects, because the damage happened 

 in the season when they are generally dormant, and although the sum- 

 mer following may have shown them unusually abundant in some local- 

 ities, this might more properly be regarded as among the effects, rather 

 than as a cause. It is well known that many of the Coleoptera burrow under 

 the bark and through the sap-wood of dead coniferous trees, and to such 

 an extent, that it is sometimes necessary to remove the bark from saw- 

 logs to prevent serious loss. The same remark applies to a supposed 

 origin from fungi, as these seldom spare a dead tree of this class, and 

 as seldom appear in the tissues of healthy living trees.* 



A third, and highly probable theory, ascribes the damage to a climatic 

 cause; but whether this be unusual drought, cold, or other agency is 

 unknown. 



THE "ROUND DISEASE" OF THE PINE.^ 



For a long time sylviculturists have been occupied in studying a dis- 

 ease of the maritime pine, known in Loiret as the maladis du rond, and 



• Physique dea Arbres, ii, 130. 



« lb., ii, 346. 



s Martin Ann. des Fonts et CJiauss^, Oct., 1877. 



•'Upon tlie high mountains of Essex County, New York, Prof. Charles H. Peck, 

 botanist at the State Cabinet of Natural History, noticed the feeble spraces badly in- 

 fested by a rnst-fnngus, the Pcridermum decolorant, which attacked the leaves, and so 

 discolored them that the foliage showed a yellowish hue to a considerable distance. It 

 wa« not found on trees of vigorous growth in the lower regions, and might have been 

 an effect rather than a cause. 



The cold of the winter of 1872-'73 was of great severity. Its eifect upon trees 

 and shrubs at the Agricultural College, Lansing, Mich., is thus recorded by Professor 

 Beal: 



Uninjured and hardy. — Austrian pine, American weeping-willow, mock-orange, com- 

 mon and Persian lilacs, white pine, Pinus pumilo, flowering almond, gingko, black 

 spruce, Lombardy poplar, locust, chestnut, snowball, red cedar. 



More or less injured. — Norway spruce, bald Cyprus (some small limbs most exposed 

 were dead); cutr-leaved Persian lilac (killed) ; horse-chestnut (a few injuretl a litrle) ; 

 arbor-vitne, fringe tree, tulip tree. Spiraea chamsedrifolia (some injured); hemlock, 

 ailanthus (dead at the top) ; Irish juniper (partly dead) ;) Cydoniajivponica, tamarix, 

 ■Robina hispida, small trees (dead to snow) ; double apple (one killed) ; doul)le flower- 

 •ing cherry (grew but little, — otfcerwi*8e looks well) ; Aralia spinosa (mosly killed) ; 

 smoke tree (much injured); red-bud (killed to ground, as has often been before); 

 •roses (mostly killed to ground). 



'■Condensed from an article by Baron de Morgues, published in ia Beveu des Eaux 

 et Forets, 1875, p. 186. 



