GRAPE-PRUNING ON THE PACIFIC SLOPE 159 



cipally at the part of the trunk farthest removed from the 

 root is counteracted by the horizontal position. There is not 

 the same difficulty therefore in maintaining this form of vine 

 permanently that there is with the vertical cordon. 



This system should not be used for small weak vines, whether 

 the weakness is a characteristic of the variety or due to the 

 nature of the soil. It is suited only to very vigorous varieties 

 such as Emperor, Almeria, and the Persian grapes when grow- 

 ing far apart in rich, moist soil. 



Periods of development. 



The first year in the life of a vine is devoted to developing 

 a vigorous root system ; the next two or three years to building 

 up a shapely trunk and head, and a like period to forming the 

 full complement of arms. At the end of from five to nine 

 years the framework of the vine is complete and should undergo 

 no particular change of shape except a gradual thickening of 

 trunk and arms. 



There are, therefore, several periods in the life of the vine 

 with varying objects, and the methods of pruning must vary 

 accordingly . These periods do not correspond exactly to periods 

 of time, so it may be misleading to speak of pruning a two-year- 

 old or a three-year-old vine. One vine under certain conditions 

 will reach the same stage of development in two years that 

 another will reach only in three or four years under other con- 

 ditions. The range of time of these periods is about as follows : 



First period Formation of a strong root system . 1 to 2 years 

 Second period Formation of stem or trunk 1 year 



Third period Formation of head 2 to 3 years 



Fourth period Complete development of the arms 2 to 3 years 



Total time of formation of framework . . . . 6 to 9 years 



Under exceptionally favorable conditions the first and second 

 periods may be included in the first year and a completely 

 formed vine may be obtained in five years. 



