22 BULLETIN 614, U. S. DEPARTMENT OF AGRICULTURE. 



toward a vase shape with open head. In the better cared-for or- 

 chards three to five leaders usually were chosen and headed back 

 for the first 3 to 5 years, after which the pruning may be said to have 

 consisted of merely the thinning out of the heavier lateral growth 

 along the main limbs each year. When these trees reach the age of 

 12 years they usually are severely headed back, and from then on 

 are pruned in such a manner as to prevent them from reaching a 

 size or shape which will inconvenience the operator in doing the 

 principal orchard operations. In the older orchards comparatively 

 little heavy wood is cut from the trees. 



Many factors affect the time required for this operation, chief 

 among them being the variety, size, age, and number of trees per acre, 

 as well as the expertness of the pruner. Perhaps the greatest of 

 these factors is the pruner himself. His skill and ideals are told 

 by each tree throughout the orchard. In considering these data no 

 detailed study was made of the influence of these factors, the object 

 being merely to obtain the average time required for the operation. 



There appears to be little difference in the cost of this operation in 

 the two districts. (See Table XIV). The majority of farms and 

 orchards do not vary greatly in size, so that the time required for 

 the pruning is not affected greatly by the size factor. However, 

 where the ranches are small a larger percentage of the acreage is in 

 bearing apples and usually there is a greater number of trees per 

 acre. In the Nob Hill section this is especially true, for the orchards 

 occupy such a large percentage of the total acreages and there is 

 usually so little other work to be done that the men spend more 

 time on this operation than do the farmers of the Zillah district, 

 because they do not feel the pressure of other work. 



Apparently there is little difference in the cost of pruning the 

 trees under clean-cultural management as compared with those 

 under mulch-crop management. There is, however, considerable 

 variation in the number of trees which some men give as the average 

 number which they are able to prune per day, the extremes being 

 6 and 60. Considering the valley as a whole, it is found that a man 

 will prune an average of 14 trees 12.6 years of age in a 10-hour day. 



The acre cost for pruning in the North Yakima district is $13.90; 

 in the Zillah district it is $12.27. Considering the valley as a whole, 

 the pruning cost is 19.5 per cent of the gross labor cost up to har- 

 vesting time. The tree cost for this operation (18 cents) is the same 

 in both districts. The difference in the acre cost is due to the fact 

 that there are 78.2 trees per acre in Yakima and but 68.2 in Zillah. 

 Taking the valley as a whole, with an average of 73.55 trees per acre 

 having an average of 12.6 years, 52.55 man-hours are required to 

 prune an acre, at a cost of $13.14, or 18 cents per tree. 



