STEMS 137 



Query. Compare the number of strong, healthy buds 

 on any twig with the number of weak, small, and dormant 

 buds. How many of each? 



What are the good results of pruning? What are the 

 bad results of overpruning ? Of insufficient pruning ? What 

 is the effect of pruning the lower branches ? How can prun- 

 ing cure a crooked tree? Why is the lilac shrub pruned 

 differently from the forsythia? Why do we pinch out the 

 terminal buds of coleus plant used in bedding ? How does a 

 plant cover its wounds ? 



121. GIRDLING 



Object. To find out the effect of -girdling on a woody- 

 stem plant. 



Apparatus. Any common tree or shrub, and a sharp knife. 



Method. With a sharp knife carefully remove a strip 

 of bark two inches wide clear around the stem about three 

 feet from the end, and cut in deep enough to sever the living 

 part (cambium) which lies just inside the bark. Observe 

 the twig from day to day and make note of the result. How 

 does Experiment 114 explain the result? 



Conclusion. State the effect of girdling on the part 

 beyond the wound. 



Note. In girdling trees the incision is usually made deeper than 

 the cambium, for there is considerable sap in the outer rings (sap- 

 wood). The object is to cut off all upward flow of sap from the 

 root. 



Reference Work 



Directions. Weigh two potatoes of about equal size 

 and carefully peel the heavier one until they weigh alike. 

 Now leave them lying side by side in a dry place where there 

 is free circulation of air for several days. Reweigh. 



