192 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



The appearance of the blister rust in the Xorthwest directly men- 

 aces seven different species of live-needled pine that are native to the 

 JRocky Mountain and Pacific Coast States, all of which are suscep- 

 tible to the white-pine blister rust. The present total merchantable 

 stand of western white and su<rar pine, the principal commercial 

 species, is estimated at over 57,000.000,000 board feet, with a stump- 

 a.ge value of $228,400,000, about half of which is owned by the 

 Federal Government. Even more important from the standpoint 

 of future forest production are the 12,000.000 to 13,000,000 acres of 

 second growth in which western white and sugar pine will form an 

 important part of the timber crop. 



rubber! 



A HARDY RUBBER TREE FROM CHINA. 



The need of developing home supplies of rubber is becoming recog- 

 nized, in view of the danger of complete dependence on the remote 

 East Indies for this essential raw material. It is known that sev- 

 eral species of rubber-producing plants can be grown in the United 

 States if practical methods of utilization can be devised. One of 

 the hardiest species is the Chinese rubber-bark tree {Eucomniia 

 ulmoides) , which produces a gum of potential value, with qualities 

 somewhat intermediate between rubber and gutta-percha. This tree 

 is deciduous and is not affected by low winter temperatures in the 

 vicinity of Washington, D. C, though the flowers may be killed by 

 late frosts, so that seed is not set every year. As the trees are of 

 se2:)arate sexes and are wind pollinated the production of seed on 

 isolated trees is not to be expected. Suppression of the terminal 

 bud of each shoot is another peculiar and apparently normal habit 

 of this tree and not an indication of frost injury, as might be inferred. 



UTILIZATION OF THE CENTRAL AMERICAN RUBBER TREEu 



The Central American rubber tree (Castilla) is considered inferior 

 to the Para rubber tree (Hevea) for purposes of commercial cultiva- 

 tion by methods employed in the East Indies, but Castilla may have 

 a special value in developing rubber reserves in tropical America. 

 Such reserves of rubber should be available in regions contiguous to 

 the United States in case of emergencies that might interfere with 

 communication or with the production of rubber in the East Indies. 

 For emergency use Castilla would have an advantage in yielding its 

 latex more readily and in the lower cost of collecting. Investigation 

 is needed to improve the methods of extraction that might give the 

 tree a better agricultural status. Study of the habits and distribu- 

 tion of different species of Castilla shows that they occupy a wide 

 area in the lowlands of Central America and southern Mexico, includ- 

 ing many districts that have very few people, so that the forests are 

 left undisturbed and could be utilized as rubber reserves, either by 

 planting or by preserving the natural forest growth of Castilla. 



SERVICE ACTIVITIES. 



CONGRESSIONAL SEED DISTRIBUTION. 



During the fiscal year 1922 there were distributed on congressional 

 and miscellaneous requests 11,198,385 packages of vegetable seed and 

 2,015,115 packages of flower seed, or a total of 13,213,500 packages, 



