316 



NEW ENGLAND TREES IN WINTER. 



Fig. 3. Height Measurer in position for sighting to base of tree. 



respectively. In figure 2, the eye is assumed to be on the level 

 with the base of the tree and only a single sight is necessary. In 

 figure 3, the base of tree is below eye level and the distance CD 

 must be found by a downward sight and added to the reading 

 obtained for BC. It can be readily seen from inspection of the 

 figures that the method is based upon the similarity of the triangles 

 ABC and ACD with the smaller triangles abc and acd. 



Two general habit types are recognized the spreading and the 

 erect often termed deliquescent and excurrent respectively. The 

 former is well represented by the Apple (p. 487) and White Elm 

 (p. 461) and the latter by the Evergreens and those of the Poplars 

 that form narrow conical heads (p. 395-397). By its more erect 

 habit of growth the Sweet Cherry (p. 503) is readily distinguished 

 from the Sour Cherry (p. 505) and in like manner the Pear 

 (p. 485) from the Apple (p. 487). It is these habit differences 

 that form the most ready means of separating the contrasted trees 

 just mentioned which may closely resemble each other in twig char- 

 acters. The angle which the branches make with the trunk is 

 frequently a diagnostic character of considerable value. For 

 example, the ascending and gracefully outward curving limbs of 

 the American White Elm (p. 461) stand in contrast with the 

 sharply divergent limbs of the English Elm (p. 459). Likewise the 

 horizontal branches of the Tupelo (p. 555) and the strongly pendant 

 lower limbs of the Swamp White Oak (p. 439) are characteristic 

 of these species. The relative thickness of the branchlets contrasted 



