1919] FORESTRY. 149 



served that iron must be frequently supplied to the plant during the periods 

 of rapid growth, but that comparatively few sprayings are necessary during 

 quiescent periods. Methods of treating manganese soil before planting to sup- 

 ply iron to the plant have thus far given no success, except where stable ma- 

 nure was used, in which case the pineapple is grown on the manure rather 

 than on the soil. 



Series of experiments were made with rice grown in nutrient solutions to 

 determine the effect of additions of manganese dioxid and manganous sulphate 

 in the presence of different amounts of ferrous sulphate, preliminary experi- 

 ments having indicated that the effect of manganese depends largely on the 

 amount of iron supplied by the solution. With the smallest amount of ii'on 

 supplied, 5 mg. per liter, which was sufficient for the normal growth of the 

 checks, manganese dioxid and manganous sulphate caused an extreme depres- 

 sion in growth, the plants in these sohitions being light yellow in color with 

 brownish spots. As the amounts of iron were increased up to the very exces- 

 sive amount of 80 mg. per liter the injurious effects of the manganese w^ere 

 overcome and growth approached that of the checks. Dipping the leaves of the 

 plants at intervals in a dilute solution of ferrous sulphate was also partially 

 effective in overcoming the injurious effects of manganese dioxid. The experi- 

 ment was repeated with ferric chlorid and with ferric citrate as sources of iron 

 and gave similar results. The beneficial effect on growth of adding manganese 

 to mitrient solutions claimed by several investigators is believed to be due to 

 the facts that in most cases the effect on growth was determined only by rough 

 measurements of the increase in the height of the plants and that the iron 

 content of the nutrient solutions used was not only sufficient for normal growth 

 but was so excessive as to mask the injurious effects of manganese. 



FOEESTRY. 



A national lumber and forest policy, H. S. Graves {U. S. Dept. Agr., Off. 

 Sec. Circ. 134 U919), pp. U; Jour. Forestry, 17 (1919), No. 4, pp. 351-363).— 

 An address delivered before the American Lumber Congress at Chicago, 111., 

 April 16, 1919, in which the author discusses the problems causing the present 

 unstable condition of the lumber industry, and makes an appeal for coopera- 

 tion in laying the groundwork for a national policy in carrying out and admin- 

 istering the great private resources of timber so as to prevent the present waste 

 and uneconomic overproduction and at the same time to insure forest renewal. 

 Some of the principles, aims, and problems of such a national policy are briefly 

 outlined. Among other points the acquisition on the part of the Federal Gov- 

 ernment and the States and municipalities of cut-over and nonagricultural 

 lands, especially those bordered by watersheds, with the object of reforesting 

 them is advocated. 



Vacation days in the Battlement National Forest (U. S. Dept. Agr., Forest 

 Serv., 1919, pp. IS, pi. 1, figs. //). — A popular document describing the recrea- 

 tional features of the Battlement National Forest in Colorado. 



Report of the superintendent of forestry, C, S. Judd ([Bien.'i Rpt. Bd. 

 Comrs. Agr. and Forestry Ilaicaii, 1917-18, pp. 19-46, pis. 9). — A report for the 

 calendar years 1917 and 1918 relative to the work of forest protection and ex- 

 tension, including operations on the Government reserves and nurseries and 

 private planting work. 



The work of examining, surveying, and setting aside the main forest reserve 

 system has been concluded. The reserves which are shown on maps now include 

 814,920 acres, 68 per cent of which is Government land. The results of experi- 



