842 EXPERIMENT STATION RECORD. [V&l. 40 



conifer shelter belts. Suggestions for growing such shelter belts are also 

 included. 



Care of cooperative shelter belts on the northern Great Plains ( V. S. Dcpt. 

 Agr., Bur. Plant Indus., 1919, pp. 5). — Instructions are given for the care of 

 shelter belts, and their protection from insects, animal pests, and diseases. 



Some biological and economic aspects of the chaparral, E. N. Mrxxs (four. 

 Forestry, 17 (1919), No. 1, pp. 9-14). — The author briefly discusses the influence 

 of chaparral on forest reproduction and the present economic uses of chaparral 

 growth. 



Bear clover, Chamaebatia foliolosa (mountain misery, bear-mat. tarweed), 

 J. A. Mitchell (Jour. Forestry, 17 (1919), No. 1, pp. 39-^3). — A discussion of 

 the influence of bear clover (C. foliolosa) on forest reproduction, including 

 tabular data Showing the results of observations made by G. W. Lyons and 

 J. V. Wulff on the Eldorado and Stanislaus National Forests in 1912. 



These observations indicate that in general reproduction on a given site 

 is adversely affected by a ground cover of bear clover, and that the relative 

 percentage of incense cedar reproduction increases while the percentage of 

 pine reproduction falls off as the density of the bear clover cover increases. In 

 the densest stand of bear clover the reproduction of all species has been com- 

 pletely excluded. 



The influence of thinning on western hemlock and grand fir infected with 

 Echinodontium tinctorium, J. R. Wkik and E. E. Hubert (Jour. Forestry, 17 

 (1919), No. 1, pp. 21-35, fig. 1). — Experiments conducted in the Priest River 

 Valley, Idaho, under the direction of the Bureau Of riant Industry of the U. S. 

 Department Of Agriculture are reported. The thinning experiments were eon- 

 ducted without regard to the selection of marketable timber, but as a method 

 of opening up the original stand. 



The results thus far secured Indicate that a less favorable condition for 

 fungus activity exists within the CUt-OVCT area, and show plainly that a highly 

 favorable condition for the fungus Is present in the uncut areas. The total 

 number of Infected trees, the total number of live sporophorea, and the total 

 number of sporophore-bearing trees are comparatively less on the cut-over area 

 for both species of trees. 



Thinning was found to affect appreciably the vigor of the trees of the cut- 

 over areas, as shown by the increased diameter, crown, and height growth, as 

 well as the number Of injuries healed. The thinning influences affecting the 

 fungus /•:. tinctorium were not considered to be of sufficient importance to cause 

 any variation from the predetermined sanitation rules to be applied to these 

 species of trees. 



Importance of clearing out hardwoods and balsam fir emphasized by ex- 

 perience, W. R. Bbown (Candd. Forestry Jour., l.' f (1919), No. 3. pp. 169-113. 

 fig. 1). — The author briefly describes the general silvical systems employed by a 

 large lumber company in northern New Hampshire and Maine, and the results 

 obtained from them twenty years later. 



The relation of gray birch to the regeneration of white pine, J. W. Tovmkv 

 (Jour. Forestry, 17 (1919), No. 1, pp. 15-20). — The author reports some studies 

 relative to the effect Of gray birch of varying ages and densities on white pine 

 reproduction and on its rate of height growth. The studies were conducted 

 largely on the forests owned by the Yale School of Forestry at Eeene, N. H.. 

 and in adjoining forests. 



The results Indicate that pure stands of gray birch in southern New Hamp- 

 shire are never sufficiently dense to cause the death from shading of white 

 pine growing beneath. The rapidity of height growth in white pine tinder 



