DETERMINATION OF THE TOTAL AGES OF TREES 57 



3. Even- or uneven-aged stand. 



4. Pure or mixed stand. 



5. Forest type. 



6. Soil or site quality. 



7. Density. 



8. Number of trees upon which the study is based. 



9. Locality. 



10. Virgin or second growth. 



11. Date. 



12. Be sure to indicate units of measurement (feet, inches, B.M., etc.) and 



kind of growth (Dia., Vol., P. A. G., C. A. G., etc.) on all curves and 

 tables, 



PROBLEM 25. (Field.) The Determination of the Total Ages of Trees. 



Explanation. — In this problem it is assumed that we have determined the 

 ages at the stump of a large number of trees. In order to determine the 

 total ages of these trees it would be necessary to cut the trees near the sur- 

 face of the ground because that is the only portion where a growth ring has 

 been added each year from the time the tree was a one year old seedling, 

 several inches high, to the time of cutting. To cut large trees near the sur- 

 face of the ground would, of course, be impracticable. Hence the ages at the 

 stumps must be corrected by a separate study of height growth on seedlings 

 whose total heights vary about as the stump heights. 



Illustration. — To determine the total ages of the trees analyzed in Prob- 

 lem 7. 



Directions: 



A. Parties. — Each student can work to advantage by himself. 



B. Equipment. 



1 sharp pocket knife. 



1 rule or tape graduated to inches. 



1 hand lens. 



Pencil and field notebook with Form 1. 



C. Method of Procedure. 



1. Select trees of the same species and of about the heights of the stumps 



and under the same conditions of growth as those whose total ages 

 it is desired to find. 



2. With the pocket knife cut from 10 to 15 seedlings at about one inch 



from the surface of the ground. The heights should vary about as 

 the heights of the stumps of the trees whose ages are to be corrected. 



3. Determine the age and height of each. In conifers this may be done 



by countmg the whorls of branches and checking by ring counts: 



