1901. AMERICAN FORESTRY ASSOCIATION. 63 



EXTERMINATION OF THE OAK AT LAKE GENEVA, 



WISCONSIN. 



By James Jensen. 



THE threatened destruction of the ered as if struck by blight. In some in- 

 beautiful forest lands around the stances this withering of the leaves was 

 well known summer resort, Lake confined to certain limbs or branchlets 

 Geneva, Wisconsin, has become an im- only. Supposing that this sudden attack 

 portant question to those owning houses, was caused by a fungus of some kind, I sent 

 and passing the summer months at this several leaves to Professor Bryon H. Hal- 

 place. In my profession as landscape stead for examination. The reply was: 

 architect, the opportunity offered itself to "The oak leaves you send show some 

 make a careful study of those causes de- trouble but not so clearly that the diag- 

 stroying the great oaks in wholesale nosis is satisfactory " ; and he further sug- 

 fashion. gested that the trouble might be at the 

 The contour of the land is rolling, some- roots, clue to some change that lessened 

 times changing into abrupt grades towards the subterranean water supply. Upon 

 the Lake or natural water courses. Gravel this suggestion several roots were sent ; 

 orgravelly soil prevails on the higher lands. but neither in this instance could there 

 On lower lands the gravel is covered by be found any indication of the trouble 

 layers, varying in thickness, of hard pan prevalent. This satisfied me that fungus 

 in some instances, and of a gravelly clay had nothing, or very little, to do with the 

 containing some vegetable matter in othres. extermination of the Oak; but that Pro- 

 Seemingly these layers have been washed fessor Halstead's suggestion as to lack of 

 down from the higher lands. The low water supply was correct, even if the 

 lands along the natural water courses con- roots did not indicate it. 

 sist of black loam or decayed vegetable The cause which led to this wholesale 

 matter that, in some instances, becomes dying out is undoubtedly not of recent 

 boggy; but this is of no special interest date; and to get at the root of the trouble 

 here, as it is on the gravel or clay lands it would be necessary to turn back for al- 

 that the oak has made its home. Close most a decade. 



observation shows that trees growing on The drouths of 1893, 94 and '95 are still 

 the " hard-pan" lands have suffered more fresh in the memory of every one engaged 

 than those on more porous grounds, and in agriculture or horticulture; the drouth 

 especially on lands turned into private being quite general over the country, 

 parks, whether of gravel or clay substance. Losses were great in both industries, 

 Besides the oak, the Ironwood ( Car- especially on higher levels or near large 

 pinus betula) is gradually becoming ex- cities where artifical sewerage assisted in 

 tinct. The affliction is general; young the work of destruction. During those 

 and old are alike effected/ Such varieties, three years the earth dried out to a Con- 

 or species as the Scarlet Oak(^>. coccinea), siderable depth. Then I noticed by dig- 

 the White Oak (^>. alba), the Red Oak ging a sewer that at a depth of ten feet or 

 (4>. rubra), suffer most; whereas the more the ditch was perfectly dry: when 

 Bur-Oak or Mossycup Oak (^. macro- under ordinary conditions water could be 

 carpa), holds its own. The Pin Oak (^. found at a depth of three or four feet. 

 palustris) and several other species are not Was it possible for trees to obtain suffi- 

 found in sufficient numbers in this district cient moisture under such conditions ? As- 

 to permit satisfactory observation. suredly not. And here we max look for 

 During the latter part of July and the the starting point of those causes destroy- 

 first part of August last trees in sup- ing the oak forest at Lake Geneva and 

 posedly healthy condition suddenly with- other points. 



