THE WINDFALL PROBLEM 839 



our violent winds are straight blows accompanying widespread regional 

 storms. 



On September 18, 191-i. when the timber sales on the Whitman Forest 

 lost so heavily from windthrow, the maximum velocity recorded at the 

 Baker weather office w.as 42 miles per hour. Mr. Wells remarked 

 that a wind, the velocity of which was 42 miles an hour at Baker, 

 might have had a volocity greater or less at the point of the timber 

 sales 50 miles away. The velocity there might have been as much 

 as 60 miles, because topography greatly influences velocity. Forty 

 miles is not a strong wind and as a rule it would take more nearly 

 a 60-mile wind to blow down trees. His only observation of wind- 

 throw was at Boise, Idaho, in June, 1900, when a number of shade 

 trees were blown down by a 55-mile wind. In this connection, it 

 should be mentioned that trees weakened by clearance, as are our 

 reserved trees, can not stand so much buffeting force as a shade tree — 

 perhaps not more than a 45 or 50 mile wind. 



It is interesting to note the maximum wind velocities on April 2, 

 as recorded by the several stations in the State : Portland showed 33 

 miles per hour; Baker, 8 miles; Marshfield, 6 miles; and Roseburg, 

 which lies in a depression, less than 5 miles. The North Head Station 

 (at the mouth of the Columbia River), on the other hand, recorded 

 a maximum of 52 miles in the forenoon and 64 miles in the afternoon. 



Suitable wind records for the Klamath region are not available for 

 correlation. In lieu of these, records for Baker which are readily 

 available have been worked up. These cover a period of 25 years 

 and extend from 1890 to ]9]4. During this time maximum wind 

 velocities of 35 to 40 miles per hour occurred in nine years, of 40 

 to 45 miles in three years, and of 45 to 50 miles in three years. Dur- 

 ing ten years the maximtmi velocity attained was under 35 miles per 

 hour. According to the records, these velocities endured in each case 

 from 4 to 30 minutes. 



It is interesting to speculate as to the possible relation of these 

 Baker records to windfall in the forest. For the sake of discussion 

 it is assumed that at least a 40-mile wind is necessary to blow down 

 trees in a timber sale cutting. In 25 years, maximum velocities of 40 

 miles an hour and more were attained six times and occurred in the 

 following years: 1892, 1896, 1897, 1900, 1902 and 1914. While this 

 indicates no definite periodicity, it does show that one storm of this 

 severity occurred practically every two years for the eleven vears 



