780 EXPERIMENT STATION RECORD. 



which was somewhat loss vigorous than the suniuier jrrowtli. The length of the two 

 artive periods varied with different species and cliiiiatc, and the j)eriod of summer 

 rest varied from 8 to 8 weeks. • The i)eriod of niaxiinuiii root growth coincided with 

 that of maximum shoot growth. In the fall ami winter Mii' temperature of the soil 

 was found to influence growth, all growth ceasing at from 5 to 6° C. for beech and 2 

 to 3° C. for maple. 



Attention is called to the jiractical liearing <>f tliese investigations on the time of 

 transphmting. For the most successful efforts in this line, trees should he trans- 

 planted shortly after root growth is most active. Deciduous trees can be planted in 

 autumn with more satisfaction than conifers, because their root activity lasts longer 

 and the <lemand for water at the toj) ceases sooner. 



A nitrogen-gatherer among trees (Nomk Ltmdmandshlad, 22 {1903), No. 18, pp. 

 231-233). — An account is given of the activity of the Danish Heather Improvement 

 Society in planting trees on the barren sandy stretches on the western coast of Jut- 

 land. It has been found that spruce will make an excellent growth on these waste 

 areas in the immediate vicinity of mountain pine, even if the soil is practically free 

 from food materials. The root system of the spruce trees has only a poor develop- 

 ment to the side where there is no mountain pine, while to the side where such a 

 tree stands, a strong root system is developed that intertwines with the roots of the 

 pine, often coming in immediate contact with tliese. 



There appears to exist a symbiotic relation l)etvveen these two kinds of trees, which 

 is of mutual benefit to both. If the pine is cut down while the spruce is still young, 

 the latter will die or make a sickly growth; if, on the other hand, it is not cut until 

 after several years, the spruce will not only survive but appears to grow faster than 

 would have been the case if the pine had been left standing. Planting these two 

 trees together has come to be a general practice of the Society. There is no direct 

 experimental evidence presented in explanation of these phenomena, but it is stated 

 as the result of investigations ])y many scientists that the mountain pine is a nitrogen- 

 gatherer and can utilize the free atmospheric nitrogen, even when growing in places 

 where i)ractically no supply of nitrogen can be obtained from the soil itself. — f. w. 



wo LI.. 



The effects of frost upon forest vegetation, R. (t. Zon ( Forestry Quart. , ;? ( l!)03 ) , 

 No. 1, pp. 14-21). — A discussion is given of the effects of early and late frosts upon 

 forest vegetation, and the manner in which the young growth is affected is described. 

 The effect of winter frosts is also shown, and various preventive measures like drain- 

 age, planting, etc., are described. 



Forest protection and extension, M. Manson ( Water and Forest, 3 {1904), No. 

 4, ]>■ 7). — An outline i)lan is given for forest protection and extension, the first of 

 which consists of fire protection, the second of tree planting. For fire protection the 

 author thinks that a study should l)e made of forest fires, and that all areas liable to 

 injury should be mapped and patrolled for their protection. In regard to tree plant- 

 ing, the author l)elieves that conifers offer the most promising field for investigation 

 and suggests methods for collecting and planting their seed. 



Forest fires in the Adirondacks, A. Knechtel {Forestry Quart., 2 {1903), iVo. 

 1, pp. 2-13). — A discussion is given of the causes of forest fires, means of controlling 

 them, the c(mdition in which the forest is left after a fire, and the vegetation that 

 may spring up over the burned areas. The chief periods of forest fires in this region 

 are April and May, and September and t)ctober. The causes of fires are quite 

 numennis, all of which are discussed. 



In the Adirondacks the beech and hard maple are the most resistant to fire, while 

 birch, on account of its loose bark, suffers severely. Hemlock and spruce are badly 

 injured, and white pine, although somewhat resistant, is more easily injured than 

 the hard woods. The burned-over areas of State lands are described and attention 



