24 



BULLETIN 1225, U. S. DEPARTMENT OF AGRICULTURE. 



plior thrips. Without a single exception all trees cut near the ground 

 sent up snoots from the crown, and in no instance did these shoots 

 originate near the cut end of the stump. It is the nature of the trees 

 to sprout from the crown instead of from any other place on the body 

 of the tree. After a year or more these sprouts became rather large 

 and vigorous and showed practically no damage from thrips. (PI. VI, 

 B; fig. 7.) 



The camphor trees on a 60-acre tract at Satsuma were cut off at the 

 level of the ground in November. The tops were not removed imme- 

 diately, however, but were allowed to remain a few days after being 

 cut down. This probably permitted some of the insects to reinfest 

 the field. Neither were all of the small shoots growing near the base 

 of the trees cut off, and they furnished a food supply for such insects 

 as escaped from the cut tops. The work, however, was done on a 



Fig. 7.— A field of camphor trees three months after being cut off at level of ground. The new growth 

 originates at the crown and grows rapidly. 



good commercial basis and no doubt was carried on as efficiently as 

 could be expected. Repeated visits to this field showed that every 

 tree sent forth sprouts from the crown and about a year afterward 

 these were from 5 to 7 feet high. To be sure, some injury from thrips 

 was noticed, but the damage was very slight. The greatest injury 

 was on those trees located nearest the old unpruned trees across the 

 road. The stumps were not treated with any material to prevent 

 wood decay or kill thrips. 



Pruning experiments were also conducted in a 10-acre field which 

 had three sides not bordered by camphor trees. The trees in this 

 field, also, were cut down at the level of the ground and all tops 

 removed at once. All small shoots growing near the base of the 

 stump were likewise carefully destroyed. In so far as was possible 

 all sources of reinfestation from insects within the field were removed. 

 Repeated visits to this field showed that all trees put forth sprouts 

 from the crown and after the expiration of a year had attained a 



