THt: WORK OF STEMS 245 



out can thoughtlessly destroy a tree by hacking it 

 without realizing the injury he is inflicting. 



In connection with the study of wood and its struc- 

 ture, take up as far as possible the practical aspects of 

 the matter. What is meant by the seasoning of wood? 

 What does this involve! How is it best accomplished? 

 Why? Does the water escape principally through the 

 sides or through the end of the log? What occurs if 

 the end is painted or rendered water-proof? Does the 

 wood crack less if allowed to season with the leaves 

 on? What kinds of wood shrink most in drying? 

 What kinds contain most water? ^ 



What determines the usefulness of a wood? What 

 kinds of woods are used for the various parts of 

 wagons? Why? Can you explain their peculiarities by 

 a study of their cell structure? What woods growing 

 in your region are useful in any way? Why? What 

 woods last longest when exposed to the weather? 

 What is the best treatment to preserve woods ?2 



Learn how to read the history of a branch by the 

 inspection of the scars on it.^ In some cases (e.g., 

 Alder) this history can be read back many years. 



As the sap-wood grows older it changes into heart- 



1 In regard to the absorption of water by wood, see pag:e 68. 



2 See articles in the Year-Book of the U. S. Department of Agriculture for 

 1894 by Fernow; for 1896 by Roth; for 1903 by von Schrenk. On the manage- 

 ment of forests, etc., see Roth: "First Book of Forestry"; Pinchot: "Primer of 

 Forestry"; also articles in the Year-Book for 1895 by Fernow; for 1898 and 1899 

 by Pinchot. 



3 See Bailey: "Lessons with Plants," p. 73 ff. 



