354 



Canadian Forestry Journal, September, 1919 



The foregoing tabulation shows that trees 

 grow about twice as much at night as during 

 the day. By using instruments of greater pre- 

 cision the percentages would no doubt be 

 changed somewhat, but the general compara- 

 tive rate of growth would still stand unchanged. 



To some persons it may appear that the 

 problem of growth behaviour of trees has 

 only an academic application. This point 

 of view is, however, untenable for there 

 is an economic side to the study. If con- 

 ducted in a scientific manner it will supply 

 the basic data for the preparation of a 

 rational schedule for transplanting in the 

 nursery and setting out trees in the wood— lot 

 and forest. Foresters, sylviculturists, and 

 plant physiologists recommend that planting 

 and transplanting operations should be con- 

 ducted when the material to be planted is in 

 a dormant condition. No fault can be found 

 with their recommendation, but in order to 

 execute it properly one must know when trees 

 really are dormant. This can be ascertained 

 best by determining when trees grow, since 

 growth is so evident and measurable, and 

 whenever trees are not growing they are dor- 

 m ant, that is, in a static condition, the dura- 

 tion of which is hard to determine. 



Furthermore, such a study facilitates the 

 preparation of a schedule for field work cover- 

 ing the problem of growth. That determination 

 of the quantitative and qualitative growth on 

 cut-over lands is one of the most important and 

 urgent problems in American forestry is con- 

 ceded by the most authoritative foresters. Here- 

 tofore, we have generally been instructed that 

 the height growth of the season cannot be ac- 

 curately ascertained until late in fall or during 

 the winter months when the weather is relatively 



unfavorable for field work and the days rather 

 short. Consequently, it now follows that since 

 trees actually cease growing in height in May 

 or June, no reasonable exceptions can hence- 

 forth be filed against the collection of height 

 growth data immediately after the cessation of 

 growth in summer. 



It should be understood, however, that the 

 problem When Trees Grow is but a prelude to the 

 major problem, which is far more comprehen- 

 sive, and includes also a study of diameter and 

 volume growth of the stem and the growth of 

 roots, all of which should be undertaken; for the 

 results derived therefrom would be of great 

 economic value. 



A knowledge of When Frees Grow also aids in 

 the determination of the best time to peel bark. 

 Bark can be peeled satisfactorily only when the 

 sap IS abundant and active. Briefly, the bark 

 peeling season coincides with the growing sea- 

 son of trees. 



Light on Annual Rings. 



A thorough study of the growth of trees will 

 also furnish much-needed information to the 

 legal profession. Many legal decisions concern- 

 ing boundaries and titles hinge on the question 

 whether each growth ring represents the growth 

 of one season, or if fictitious rings are some- 

 times formed. The writer examined a large 

 number of Pitch Pine and Chestnut Oak trees 

 and found that fictitious rings are regularly 

 formed when a prolonged resting period occurs 

 within the growing season. Hence, in some 

 cases two rings represent the growth of a season, 

 instead of one annual ring. 



I wish to add that the problem. When Trees 

 Grow, is not only of technical interest and 

 economic value, but might be used as a means 

 of developing real tree appreciation among the 

 children of our public schools. 



PLANNING FOR FOREST REPRODUCTION 



Dr. C. D. Howe visited the provincial forest 

 survey parties on the head waters of the 

 Miramichi, about 40 miles north of Boiestown, 

 New Brunswick. The limits in this vicinity are 

 mainly held by the Miramichi Lumber Com- 

 pany. Arrangements were made whereby a 

 special party of four men will carry on the re- 

 generation work and annual growth study the 

 entire season directly under Dr. Howe's super- 

 vision. Dr. Howe spent about ten days with 

 this field party. The balance of the time was 

 spent in visiting the limits of the Bathurst Lum- 

 ber Company and the Pejepscot Lumber Com- 



pany, in order to study the condition of their 

 lands which have been cut three times. Also 

 slow-growing lands were examined, and it is 

 possible that through the co-operation of the 

 Bathurst Lumber Company and the New Bruns- 

 wick Government an experimental plot of 600 

 acres may be established and receive special 

 treatment in the method of cutting. This will 

 come directly under Dr. Howe's supervision, 

 through the New Brunswick Forest Service. If 

 this plot is established it will be one of the 

 largest in Eastern Canada. 



