I^'iRTiiKR XoTKs OX Rock Elm 



The notes on rock elm, which appeared in last month's Journal, 

 stated the opinion that most of the commercial rock elm of Wisconsin 

 and Michigan was not identical with the true rock elm, or cork elm 

 (Ulnui^ raceiiiosa), but was only a denser wooded form of white elm 

 (Ulmiis americana). This was a wrong conclusion. Later informa- 

 tion shows beyond question that the bulk of the commercial supplies of 

 rock elm are in reality Ulmus racemosa. This correction had been sup- 

 plied considerably before the last issue of the Journal went to press, 

 but had not been brought to the Editor's attention. The mistake arose 

 mainly through attaching too much importance to the roughness of the 

 twigs as a distinguishing character. This feature is inconspicuous or 

 lacking in large rock-elm trees in the forest. The attempt to distinguish 

 a dense-wooded, high ground form of white elm is therefore erroneous, 

 and the description of such a form given in the previous notes should 

 be understood to apply to the true cork elm. 



From the available data, it seems probable that the annual cut of 

 rock-elm lumber in Wisconsin is close to one-quarter of the total cut 

 of elm lumber of all species, amounting probably to about 10,000,000 

 board feet. The largest supplies are found in a strip embracing all or 

 parts of the following counties : Oconto, Langlade, Shawano, Marathon, 

 Taylor, Clarke, Chippewa, and Eau Claire. At a few mills in Shawano, 

 Langlade, and adjacent counties it may form half or even a greater 

 part of the annual cut of elm. The commercial range extends consid- 

 erably farther north of the limits shown for it in the map of distri- 

 bution given in Department of Agriculture Bulletin 683. In lower 

 Michigan tlie supply is practically exhausted as a result of many years 

 selective cutting of rock elm for ship timbers. Here, again, the range 

 extends farther north than as shown on the map above mentioned. In 

 the vicinity of Cadillac there are second-growth woodlots in which rock 

 elm of good quality is the predominant species, and it is a conspicuous 

 roadside tree. 



E. H. Frotiiingham. 



Influenck of thf Perennial Lupin 



Fifteen years ago. in the forest district of Haid (western Bohemia), 

 an experiment was started to test the influence of the perennial lupin 

 {Luphius percnnis L.) on the development of forest trees in poor soils. 

 Two plots were planted with spruce, one with and another without 



