18. POPULUS ALBA White Poplae. 



19. POPULUS PYRAMID ALIS Lombardy Poplar. 



20. QUERCUS PEDUNCULATA English Oak. 



21. SALIX ALBA White Willow. 



22. SALIX FRAGILIS Crack Willow. 



23. TILIA EUROPAEA Linden. 



(Lime-tree.) 



24. ULMUS CAMPESTRIS English Elm. 



25. ULMUS MONTANA Scots or Wych Elm. 



NATURAL FOREST IN CONTRAST TO WOODLOT. 



The forest has been spoken of as an organism and the forest tree 

 finds its best development as one of a community. Proper soil condi- 

 tions, influence of trees upon each other, etc., are all lacking- in the 

 common woodlot or in the case of the roadside tree. It should be under- 

 stood that the woodlot and roadside tree grow under different conditions 

 from the forest tree, the former lacking many factors which influence 

 the latter. 



To understand the abnormal state of roadside and woodlot trees it 

 is advisable to study the conditions of the forest. 



The forest may be discussed in relation to the forest floor and the 

 trees themselves. The forest floor meaning the soil, humus, leaf litter 

 and undergrowth. 



The nature of the soil in the forest is greatly influenced by the pro- 

 tection and cover afforded by the trees and by the amount of humus it 

 contains. 



Humus is formed by the decomposition of foliage, twigs and other 

 organic elements falling to the ground. It makes heavy soil less stiff 

 and sandy soils more binding. It aids in preparing food for the trees 

 and possesses great capacity for absorbing water. Humus is very es- 

 sential to the proper development of trees. The lack of it in the wood- 

 lot, owing to driving winds, makes a great difference between woodlot 

 and forest. The litter of leaves, etc., has less opportunity of collecting 

 and forming humus in the open woodlot. 



In the natural forest, where normal conditions prevail the under- 

 growth is composed of the more delicate plants which are not a menace 

 to the reproduction of tret species. When an opening is created in the 

 forest, soil conditions are such that tree seeds have an opportunity to 

 germinate and grow before the opening is filled with grass and weeds, 

 as is the case with the average woodlot. In the forest the tree seeds 

 fall to the ground and are protected from sudden changes of tempera- 

 ture and moisture conditions by the leaf litter. Of course in many cases 

 the leaf litter is a hindrance, as it prevents the seed from reaching the 

 mineral soil. In the woodlot the seed may fall on the mineral soil, but 

 the lack of protection prevents it from properly germinating. 



