410 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Because of the fjreat abundance in many regions of aspen trees, 

 their good and bad elTects on otlier species, and their undovd)ted 

 value, particuhirly for wood ])ulp antl excelsior, they will always 

 form an important element in the northern forests. On this account 

 a study was made of these trees. Until the usefulness of aspen for 

 paper was discovered, it was considered an encumbrance of the 

 ground. As with a few other species, fire, properly handled, is a 

 silvicultural tool of great importance for regenerating aspen stands, 

 since it exposes the mineral soil, clears land of brush and shrubs, 

 and prepares the ground for the thrifty development of the trees. 

 The advantages of aspen as a perpetual crop lie in its adaptability 

 to short rotations on account of its relatively rapid growth and the 

 small sizes which are merchantable, and in its usefulness in the 

 paper-making industry. 



During the year permanent sample plots established in several of the 

 Eastern States in 1904, 1905, and 1906 were remeasured. The purpose 

 of these plots is to determine b}^ repeated me;isuremcnts the exact 

 elFect of certain methods of treatment. Usually two plots are care- 

 fully laid oiT in the same stand, one of which is treated and the other 

 remains intact for comparison. The experiments cover a consider- 

 able range of subjects, such as the eiFect of thinnings, the best meth- 

 ods of securing natural reproduction, the development of reprochic- 

 tion under different conditions, the effects of fire, and artificial 

 reproduction. 



The experiments in thinnings in white pine showed that a stand 

 40 years old in 1905, thinned at that time by the removal of 1,360 cubic 

 feet per acre, had increased in volume during the five-year period 

 at a rate over 40 per cent greater than that of the corresponding 

 unthinned stand. A still greater advantage is gained in the decided 

 quality increase. There is also a substantial yield in material. 



Studies were made of the potential range in the United States of a 

 number of European trees. 



In the basket -willow investigations of ten or twelve European 

 varieties of willow, a three years' test has shown only the three spe- 

 cies Salix amygdalina americana, S. daplinoides, and 8. purpurea No. 

 2 to be of value. However, further experiments will be made with 

 S. purpurea X viminalis and S. dasy dados, as they may respond to 

 special treatment. A distribution of cuttings was made in the spring. 

 A call for reports from all persons who had previously received free 

 cuttings brought replies from 41 per cent, of whom about one-half 

 reported success. The basket-willow experiments were extended by 

 the establishment of a willow holt at Blacksburg, Va., and lowland 

 and upland holts at College Park, Md., under formal cooperative 

 agreements with the respective state experiment stations. Less for- 

 mal cooperative work was begun at Salamanca, N., Y., Sitka, Alaska, 

 and South Frammgham, j\Iass. A cooperative experiment with New 

 Jersey was planned for 1911. 



Trial of American species of willow as basket willows was begun in 

 the spring. Of ten species planted three made an excellent growth 

 for the first year. From thirty to forty species and varieties from 

 many sources will be planted in 1911. The results thus far obtained 

 indicate that some of the native species may be adaptable to basket- 

 willow culture. 



