8 FORESTEY [BoT. Absts., Vol. X, 



54. Howard, M. S. A forestry enabling law. Jour. Forest. 19: 500-505. 1921.— The 

 methods advocated for reforestation call for the expenditure of large sums of money by the 

 governmental agencies or by individuals or corporations. IMost of the latter class do not 

 consider it possible to undertake such measures now. The reforestation could be made 

 secure by giving a bond and taking a mortgage on the property to be released at the time of 

 timber harvesting. — E. N. Munns. 



55. Jones, Owen. Forestry in relation to engineering and architecture. Australian 

 Forest. Jour. 4: 132-134. 1921. — This paper discusses forestry principles and the importance 

 to engineering and architecture of adequate timber supplies. — C. F. Korstian. 



56. Kat, James. The more important trees of British Columbia. Quart. Jour. Forest. 

 15: 134-142. 1921. — A dendrological description is given of Pseudotsuga taxifolia, Tsuga 

 heterophylla, and Thuja plicata. — C. R. Tillotson. 



57. Kellogg, R. S. Notes upon the paper industry and'the pulpwood supply. Jour. Forest. 

 19: 495-499. 1921. — The consumption of paper has risen in this country to nearly 8 million 

 tons per year, or 147 pounds per capita. The decreased supplies and increased uses and de- 

 mand have made it possible for the forester to prove the truth of his assertions to the manu- 

 facturers. It should be possible to pay as high as 15 dollars per acre for the land and restock 

 it, and, with an annual protection charge, give a return of 6 per cent on the investment. 

 Yields of 20 cords per acre in 40 years are predicted with a return of more than 10 dollars per 

 cord. — E. N. Munns. 



58. Krogness, C. Om temperaturmaalingerne i skogsdistrikteme i Nord-Norge sommeren 

 1919. [The temperature observations in the forests in northern Norway summer 1919.] Bilag 

 Tidsskr. Skogbruk 28'/": 39-56. 1920. — Fifteen stations have been installed for the purpose 

 of studying more closely the relation between air temperature and seed production along the 

 northern timber-line in Norway. It has been found by borings and silvical study that 

 successful natural reproduction periods are about 100 years apart, not because the seed is 

 produced so seldom but because favorable temperature conditions for blossoming and seed 

 ripening require 3 seasons of relatively high air temperature. Dr. Hagem of the Bergen 

 experiment station has found by testing pine seed from different parts of Norway, including 

 that from the northern timber-line, that the latter is practically worthless, and that a mean 

 air temperature of at least 10.5°C. must prevail during the period of ripening. During some 

 seed years the average temperature often falls below this in the northern section. — J. A. 

 Larsen. 



59. Llewelyn, William Craven. Forest soils of Wales. Quart. Jour. Forest. 15: 

 128-133. 1921.— ;Statistics of yield of forest trees growing on soils of divers geological origin 

 indicate that no sharp demarcation exists between the yield of coniferous species, provided 

 the aspect, altitude, and a few other factors are favorable. — C. R. Tillotson. 



60. Munns, E. N. Evaporation and forest fires. Monthly Weather Rev. 49: 149-152. 

 Fig. 1-4. 1921. — Hitherto, apparently, little attempt has been made by foresters and meteor- 

 ologists to correlate the factors of climate and forest fires. The purpose of the present paper 

 is to show that the occurrence and spread of large forest fires are coincident with a greatly 

 increased rate of evaporation or a decrease in vapor pressure. Since evaporation is a climatic 

 complex dependent on the 3 major factors of temperature, humidity, and wind, the influence 

 of any one of these may be offset by a pronounced change in either or both of the other two. 

 The close relation between periods of high evaporation and forest fires is strikingly brought 

 out in figures 1 and 2, which also show that the rate of evaporation does not follow constantly 

 either temperature, humidity, or wind. In some cases it follows wind alone, in others tem- 

 perature, while in still others it follows changes in relative humidity only. In southern 

 California the wind direction is highly important. For example, an east wind blowing directly 

 off the great deserts brings excessively dry, hot air, resulting in extraordinary dryness in a 

 short time. In examining the vapor pressure data for the period 1911-1920, it was found 



