The Trunk 81 



CHAPTER X 



THE TRUNK 



Season. Fourth week in February. 

 Materials required for each pupil. 



A section of wood showing rings, with bark attached 

 (see Appendix). A mounted wood shaving (see Appen- 

 dix, or those from a carpenter's workshop may be used). 

 A narcissus head with long stalk. Glass tube. Twigs 

 of beech, elder, Scotch pine, horse-chestnut, willow, oak, 

 to show lenticels. 



For Demonstration. Beetroot. Natural uncut 

 cork. Oak bark as before use in tanneries. 



If you look at the stump of a tree which has been 

 cut down you will see a number of rings one inside the 

 other. These rings consist of bundles of pipes up which 

 the sap passes on its way to the branches, and of 

 strengthening fibres, and their number depends upon 

 the age of the tree. Each year it adds a new ring outside 

 the old ones, and the sap passes up the new ring as well 

 as up the others. After a certain number of years the 

 rings in the middle of the trunk dry up. The old wood, 

 although no longer alive, is kept from decay by the 

 living ring round it and acts as a girder to hold the 

 trunk together and help it to bear the branches and 

 masses of leaves. It is called the heart wood, while 

 the new ring through which the sap flows is the sap 

 wood (Fig. 41). The heart wood is darker in colour 

 than the other, and, as it is harder and more durable, 



Q. 6 



