FORESTRY. 643 



FORESTRY. 



Engelmann spruce in the Rocky Mountains, with special reference to 

 growth, volume, and reproduction, E. II. IIodson and J. II. Fostek {U. S. 

 Dept. Agt\, Forest Scrv. Virc. 170, pp. 23).— The data presented were collected 

 from the National Forests of Colorado and Utah. The following phases are 

 discussed in detail : Economic importance, distribution and local occurrence, 

 silvical characteristics, reproduction, and management. Tables are given show- 

 ing the diameter, height, and volume growth of trees of various ages, as well 

 as the progress of reproduction in different typos of locality. 



It is concluded that P^ngelmann spruce type is distinctly a protection forest. 

 At least two-thirds of the stand should be reserved for protection purposes and 

 heavy cuttings avoided at all times. In mixtures such as Engelmann spruce 

 with Alpine fir, or with lodgepole pine, fellings should be made in favor of the 

 spruce. In mixtures of Engelmann spruce with Douglas fir, however, the fir 

 should be favored because of its greater economic value. 



On northern exposures and flats with abundant surface-soil moisture oi' with 

 the mineral soil exposed, the spruce reproduction appears to be satisfactory, 

 whereas on dry south exposures Alpine flr commonly forms over ;jO per cent of 

 the new growth and not iufretpiently over DO per cent. This suggests that the 

 lack of spruce reproduction may be due to seed bed conditions and not to light 

 conditions. 



A study of the fundamentals of spi'uce growing, A. Sciiiffel {CciUbl. 

 Gesam. Forstw., 36 {1910), No. 7, pp. 291-309, figs. 2).— Experiments extending 

 over a number of years are reported in detail, in which it v\'as sought to deter- 

 mine the effect of various densities of forest canopy on the best development of 

 spruce trees. 



The work thus far indicates that spruce trees should not be planted too 

 thickly. About 2,500 trees per hectare (or 1,000 trees per acre), evenly spaced, 

 would appear to be the maximum number for the best development of saw logs. 

 The diameter accretion is intimately connected with crown development. Dur- 

 ing the period of greatest wood accretion the length of the crown should not be 

 less than half of the stem length. Any deterioration in the crown length is in- 

 dicated by a diminution of diameter growth. 



Thinnings which are not thorough enough to open up the forest canopy to 

 some extent will not serve to prevent deterioration of crown and stem growth. 



Experiments on the use of red beech wood for railroad ties, A. Scnw.\r- 

 PACH (Ztschr. Font u. Jagdw., //3 {1910), No. 7, pp. ^27-^32). — The experiments 

 reported cover a period of several years. 



The conclusions thus far reached are that healthy white heart beech wood 

 impregnated with creosote tar oil will prove an excellent material for railroad 

 ties, lasting under ordinary conditions for from 20 to 25 years. Sound retl heart 

 beech wood may be used if the red heart does not consist of more than 25 per 

 cent of a cpuirter sawed log, and does not extend into the upper (n- outer layers 

 of the tie. 



Unsatisfactory experiments with beech ties are attributed largely to careless 

 handling and seasoning before the ties are given the preservative treatment. 



Beech railroad ties, I). SciiNEurr (O.s/r/v, Vrtlj>ivhr. Forntir.. ii..scr.,2S ( 1910), 

 No. 3, pp. 1')7-I83, figs. II).— \ general review of the experience gained in 

 France, Germany, and Austria relntivo to the Impregnation of hocch wood with 

 wood preservatives. The author is of thr «i|)inion that the successful results 

 thus far obtained shouhl be snilii-icnt to overcome the former iire.jndice against 

 beech ties which under projier (leatnieut have proved to be both durable and 

 cheap. 



