TREE FORMS IN WINTER 



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the bough, and may be caused by some wood-boring insect, 

 such as a beetle or gall-fly. 



Most trees of the poplar tribe have broad and branching 

 tops, and sparse and open tracery in the smaller twigs. The 

 common black poplar is very conspicuous with its wide head 



BLACK POPLAR 



formed by several large limbs stretching at an obtuse angle 

 from the main stem, which generally vanishes towards the 

 top of the tree, merging in one or other of its offshoots. 

 This structure is obviously top-heavy and unsafe, and is all 

 the more so for the brittleness of the poplar's white wood. 

 Most large black poplars lose one or more of their main 

 boughs, which leave a shattered fracture and a ragged and 



