The Trees of Vermont 



li»5 



wood elements peculiar to each tree. It is by reason of their structure 

 that some woods are heavier, stronger and stiffer than others, that 

 some are straight- and others are cross-grained, that some are hard and 

 some soft and that some season rapidly and without injury while others 

 have a tendency to check and split. The wide medullary rays of the 

 oak explain the pleasing effect of the wood when quarter-sawed and 

 polished to bring out the grain. The peculiar undulations of the growth 



VIII. Log Cut to Show 

 Features. 

 a. Bark. 

 6. Sapwood. 



c. Heartwood. 



d. Cross-section, 

 c. Radial-section. 



/. Tangential-section. 

 g. Pith. 

 h. Growth ring. 

 i. Medullary ray. 



IX. Tyi'ical Wood Elements, Dia- 

 grammatic. Greatly Enlarged. 



Tracheid, showing bordered pits. 

 Scheme of bordered pit in section 



and surface views. 

 Segment or single cells of a vessel, 



showing spiral thickenings. 

 Wood or bast fiber. 

 Group of wood-parenchyma cells. 



rings sometimes found in the maple produce the "bird's-eye" markings 

 which make the lumber so prized in the manufacture of furniture. It 

 is our purpose to consider briefly the structure of a tree trunk and the 

 various elements of the woody tissues. 



If we should go into a forest where felling operations are in 

 progress or into a sawmill where there are unsawed logs, we would, 

 have an opportunity to examine the smooth-cut end of a mature log. 

 We would note that it exhibits several well-defined areas or layers. 



