84 Forestry Quarterly 



nearer to our understanding the hitherto puzzling appearance of 

 change between the period of rest or the growth of the beech 

 sprouts. 



Formerly, attempts were made from the scientific point of view 

 to interrupt at will the winter rest period of our woody growths. 

 By etherization, by warm water treatment, and in other ways, 

 attempts were successful in inducing a number of woody plants 

 to sprout in the middle of winter. No result was attained with 

 the beech. From numerous experiments, it was concluded that 

 a period of rest, harmonizing with climatic conditions, takes 

 place "from inner causes," which may be altered but not done 

 away with. Klebs succeeded by uninterrupted electric lighting, 

 using lights of strength of 200 to 1,000 candle power, in inducing 

 beech plants and cuttings to sprout as desired during the usual 

 rest period, sprouting continuously from November to spring and 

 forming far more leaves than were evidently in the bud at the 

 beginning of the experiment. 



The conviction reached by the author was that the relation 

 between the supply of carbo-hydrate and food salts to the growing 

 points determined whether growth or rest takes place in our trees. 

 The influence of light is also brought into relation in his experi- 

 ments. In the light space the breathing was always more in- 

 tensive than the carbonic acid assimilation, so that the food salts 

 were able to flow to the buds and excite them to unfold. Quanti- 

 tative differences in the supply of food stuff of the different buds 

 explain the changing behavior of the experimental twigs. Klebs 

 explains behavior of beech in natiure thus: the buds develop in 

 spring as a result of the increase of light, in conjunction with 

 sufficient food salts from the ground. Summer budding ceases 

 because the competition of the leaves and of the cambium inter- 

 feres with the food supply to the buds, and the accumulation of 

 the assimilates stops the energy of the growing points. The 

 mid-summer growth signifies the victory of the strong light 

 effect. Sleeping buds are those which do not possess the faculty 

 of acquiring for themselves the flow of food salts going past them 

 to the end buds. Removal of competing buds, however, causes 

 them to sprout. 



Klebs, also, made observations on the anatomical structure of 

 the leaves and annual ring formation. He is incHned to explain 

 with R. Hartig and Wieler the differences between late and early 



