REVIEWS 717 



"Tests made to determine the effect of incising on strength indicated 

 that with the type and arrangement of projections used the reduction 

 in strength was so sHght as to be negligible." 



With a two-hour pressure period a very uniform penetration of 

 heartwood hemlock, estimated to average ^ inch with 18.9 pounds to 

 the cubic foot, was secured, and in jack-pine, with one-half hour and 

 1 1.2 pounds, the penetration (% inch) was excellent. 



Trials of this incision method on a commercial scale seem desirable, 

 provided the mechanical wear on the rather soft ties will warrant the 

 expenditure in lengthening the life of the tie from the point of view of 

 rot, or can by tie-plates be compensated. 



B. E. F. 



Forestry as Applied in Hazvaii. By C. S. Judd. (Reprint from the 

 Hawaiian Forester and Agriculturist, Vol. 15, pp. 1 17-133, Alay, 1918.) 



This paper, originally delivered as an address, is divided into two 

 parts — the first a popular discussion of forestry in general, and the 

 second covering Hawaiian problems. Once heavily forested except on 

 the lee slopes, these islands now have only 20 per cent of their area 

 forested. There are four general types of forest — the Algaroba type 

 (Prosopis jiiliflora), the lowest, followed by the Kukui type (Aleurites 

 mollncana) , Ohia lehua type (Metrosideros collina polymorpha) , and 

 the Mamani type (Sophora chrysophylla). The Ohia lehua type is 

 protection forest, pure and simple, and the types adjoining above and 

 below have a large protective value, although they may be worked for 

 their timber in a minor way. The Algaroba type alone is primarily 

 commercial. Protection is a prime requisite, because the irrigated sugar 

 industry in the lowlands depends upon these rain forests. Cutting, but 

 more particularly grazing, has caused the deterioration of the forests 

 and their replacement by hilo grass. Methods of ridding the forests of 

 this grass are discussed, and warning is sounded against wholesale 

 importation of exotics which mav prove worthless pests in Hawaii. 



F. S. B. 



JJlwt the National Forests Mean to the JJ'ater User. By S. T. 

 Dana. U. S. Department of Agriculture. Contribution from the For- 

 est Service. Washington, D. C. 1919. Pp. 52. 



This is a "stylish" publication, in artistic dress, on glazed paper, 

 highly finished pictures comprising more than half the contents. The 



