448 Forestry Quarterly 



Skidding Time with Logs of Different Sizes — (Overhead 



Skidder) 



Time Required to 

 Average Diameter Skid M Bd. Ft. a 

 at Small End of Distance of 1000 ft. 

 16' Logs Minutes 



8 55 



9 48 



10 43 



11 38 



12 34 



13 31 



14 28 



15 26 



16 24 



17 23 



18 22 



19 21 



20 19 



Loading and Hauling 



The cost of loading varied almost directly with the number of 

 logs per M board feet mill cut. The cost of hauling varies with the 

 weight of the logs, and consequently it varies somewhat more than 

 the mill factor or the ratio of the number of board feet mill cut to 

 the cubic feet of round timber. This amounts, as shown in the 

 table, to doubling the cost of hauling between logs averaging 10 

 inches in diameter and 15 inches in diameter. In loading, as in 

 skidding, large logs and small ones were mixed indiscriminately on 

 cars and it was necessary to compute the average sized log from 

 the cars as loaded. 



The following table gives, for logs of different diameter, the 

 loading time per M board feet ; the nimiber of logs loaded per car, 

 and the number of board feet per car of logs of different average 

 sizes. 



It reqxiires nearly six times as long to load a car with logs which 

 average 10 inches in diameter as to load a car with logs which 

 average 24 inches. At the same time the car capacity in board feet 

 is three and one half times as great when loaded with logs averaging 

 24 inches in diameter as when loaded with logs averaging 

 10 inches. Shortening the length of logs also adds to loading time 

 and decreases carrying capacity per car. The weight of a loaded 

 car is practically the same irrespective of the average size of the 

 logs, consequently a locomotive can haul less than one third of the 

 volume in board feet of logs averaging 10 inches in diameter as of 



* The fractional logs are due to logs not having a uniform length of 16 feet. 



