FOREST KERVICE. 409 



mineral soil in which the seed germinates, and then protecting the 

 land from subsequent fires. These measures will promote the devcl()[)- 

 mcnt of a second crop of growth as rapid and quality as high as the 

 orij^inal forest. 



In western Washington and Oregon Douglas fir is an extremely 

 rapid growing tree. Measurements from trees grown on the bettei 

 class of forest soils show that the average tree is 15 inches in diameter 

 and over 100 feet high. It is not uncommon for trees from 10 to 

 80 years old to add 4 feet to their height and three-fourths of an 

 inch to their diameter in one year. At 50 years the a,verage tree 

 contains 238 board feet, and at 60 years 386 board feet. Between 

 50 and 60 years old the average stand per acre will increase from 

 28,000 to 41,000 board feet, or 1,300 board feet per year, and between 

 60 and 80 years the rate of growth is still greater. Under con- 

 servative forest management it will be most profitable to grow 

 Douglas fir on a rotation of about 80 years, when the yield per acre 

 is about 70,000 board feet. This may seem a very short rotation, 

 considering that the majority of timber now standing in Washington 

 and Oregon is upwards of 200 years old. That the growing of 

 Douglas fir on cut-over areas will be financially profitable to private 

 owners as well as to the Government seems assured in view of the 

 certain rise in the value of stumpage and the growing scarcity of 

 timber land investments, provided the present system of taxing 

 timber lands is reformed. 



Much interest has developed in Florida in the possibility of growing 

 eucalypts for commercial purposes. The Forest Service undertook 

 last winter an investigation to learn what species of eucalypts can 

 be successfully grown in difl"erent parts of the State. Some fifteen 

 dilToront species were found growing in various places with varying 

 degrees of success. The region in which eucalypts can })c suc- 

 cessfully grown ma}'' be roughly defined as the orange belt, or about 

 40 per cent of the total area of the State. The climate and soil con- 

 ditions there compare favorably with those of the native habitat 

 of these trees in Australia. Tentative conclusions were reached as 

 to the species seemingly suited to the climatic conditions and the 

 methods of raising and planting the young trees likely to be success- 

 ful. To supplement the knowledge already obtained, a series of 

 experiments m planting is now being carried on at Miami, in cooper- 

 ation with the Bureau of Plant Industry. These experiments will 

 extend over a period of about five years, at the end of which time 

 it is believed that full knowledge of how to grow young plants and 

 of what varieties are adapted to difl'erent parts of the State will 

 have been gained. 



In a study of yield from eucalypt plantations made in cooperation 

 with the California state board of forestry practically all the im- 

 portant eucalypt groves in the State were examined. Sample plots, 

 usually a quarter of an acre in area, were measured o(T withm groves 

 showing the best growth. At seven years the yield per acre was 

 estimated at from 1.000 to 2,300 board feet; at ten years from 

 13,000 to 16,000 board feet. Groves of from 20 to 30 years of age 

 yield from 20,000 to 35,000 board feet, accordin"; to the quality of 

 soil in whidi the trees were grown. This study shows that many of 

 the claims of extraordinary yields are considerabh* exaggerated. 



