116 FOREST BOTANY AND FORESTRY [BoT. Absts., Vol. VII, 



790. Hall, Thos. D. Food value of willow leaves. Jour. Dept. Agric. Union of South 

 Africa 1:456-457. 1920. 



791. Hawley, L. F., and Calderwood, H. N., Jr. Tar still operation in hard wood dis- 

 tillation plants. Jour. Indust. Eng. Chem. 12:684-686. 1920. 



792. Henkel, J. S. Forestry in Rhodesia. Timber trees in the Umtali Park. Rhodesia 

 Agric. Jour. 17:335-339. 2 pi. 1920. 



793. Henkel, J. S. Forestry in Rhodesia. Two useful softwoods. Rhodesia Agric. 

 Jour. 17:238-243. 1920. 



794. Hess, N. Experiences in plant hybridization. Proc. Amer. See. Hortic. Sci. 16: 

 52-60. (1919)-1920.— See Bot. Absts. 6, Entry 1818. 



795. HiLEY, W. E. The fungal diseases of the common larch. 8 vo., xii + 20Ji. p., 73 pi. 

 Clarendon Press: Oxford, 1920.— See Bot. Absts. 6, Entry 1947. 



796. HuFFEL, G. Le mouvement forestier a I'etranger: station de recherches forestilres 

 Suisse. [Developments at the Swiss forest experiment station.] Rev. Eaux et Forets 58: 

 249-254. 1920.— Since 1900 the Swiss forest experiment station has been studying the influ- 

 ence of a forest cover on stream-flow in two neighboring and comparable water-sheds, one of 

 which was 97 per cent and the other 29 per cent forested. Actual measurements show that 

 forest soils in good condition absorb the bulk of the precipitation, which later runs off sub- 

 terraneously; while in soils not so protected there is an immediate surface run-off accompanied 

 by erosion and gullying, particularly on steep, turfed slopes. This beneficial influence of the 

 forest is due to the permeability and porosity of its soil rather than to the great hygroscopicity 

 of the humus and moss cover, which if too abundant may actually, after becoming saturated, 

 have the opposite effect and stimulate surface run-off. During periods of rapid snow melting 

 both the peak of the flood and the total discharge were less from the well-forested than from 

 the poorly forested water-shed. The run-off from the former after heavy or torrential down- 

 pours was only a third to a half of that from the latter. After prolonged rains the influence 

 of the forest depended on whether the soil was comparatively dry or saturated at the begin- 

 ning of the wet spell. In any event, however, erosion is less on well-forested water-sheds, 

 and the flood waters from them, having a lower velocity and carrying less detritus, do less 

 damage. During periods of prolonged drought the stream from the well-forested water- 

 shed never went dry, while that from the poorly forested one often did so for a month or two 

 at a time. All of these differences would have been more marked if the well-forested water- 

 shed had not had appreciably steeper slopes than the other, and if the latter had been 

 completely deforested. — S. T. Dana. 



797. HuFFEL, G. Statistique des forets de 1' Alsace-Lorraine. [Forest statistics for 

 Alsace-Lorraine.] Rev. Eaux et Forets 58: 185-188. 1920.— The director general of forests 

 at Strassburg has published a 98-page volume of statistical information regarding the forests 

 of Alsace-Lorraine. Among other things this shows that the forest area of the two provinces 

 on April 1, 1916, was 440,594 hectares, of which 31 per cent was owned by the state, 4 per 

 cent was undivided between the state and a commune, 46 per cent was in the hands of com- 

 munes and public institutions, and 19 per cent was held by private owners. Since 1871 the 

 forest area has decreased 5,673 hectares, or slightly more than 1 per cent. During the same 

 period gross prices of timber have increased 34 per cent and of flrewood 47 per cent, but there 

 has been a constant tendency to include smaller and smaller material in the former class. 

 The annual yield of the forests owned by the state and of those undivided between the state 

 and a commune is estimated at 551,422 cubic meters of large timber, including both inter- 

 mediate and final products. During the war, however, the actual cut and other matters of 

 administration were decidedly abnormal. — <S. T. Dana. 



