that is, forests that have had little or no assistance from man in the way of pro- 

 moting tree-growth, it is seldom that a forest consists wholly of one variety of 

 trees. There may be, and in most cases there actually is, one type of tree that 

 greatly outnumbers all the others; this type is said to .form the dominant species, 

 and it is customary to use its name as generally descriptive of the whole forest. 

 For instance, we speak of jarrah forests, but in every jarrah forest other kinds of 

 trees are found, although the jarrah vastly outnumbers all these. In forests* 

 planted by man very often only one class of tree is to be found, for such planta- 

 tions are usually made with the definite object of producing one class of timber 

 only. 



All trees have some common features. All of them have roots, and a trunk 

 or trunks, and branches and leaves or substitutes for leaves. 



A tree is a woody growth springing from the ground, with, as a rule, one 

 straight bole or trunk only. Jarrah, karri, and many other AVestern Australian 

 trees are examples in point. Others again have only^ a very ,short bole which 

 divides at or near the ground into several large branches, each having all the appear- 

 ance and functions of a trunk. York Gum is an example of this class. There 

 are still others which send up a large number of boles direct from the roots, giving 

 the tree a shrubby appearance: such trees do not attain the size of the types 

 already mentioned. Many species of trees growing in the Eastern Goldfields and 

 the drier regions of Australia adopt this habit of growth, and the mallee is the 

 typical example of this class. The three kinds named may be regarded as tjhe 

 standard or general forms which trees take, but there are other forest growths 

 usually called "trees" which differ so very much in appearance from the standard 

 types that it seems scarcely right to apply the term "'tree'' to them. The "black- 

 boy," the "grass tree," and Zamia palm are cases in point. From the point of view 

 of the botanist, however, these odd forest growths are very similar to trees, for 

 they have roots and boles and branches and parts which perform the same functions 

 as do the leaves in trees of the ordinary character. 



A tree is made up of three parts. Firstly, the roots, which extend into tho 

 ground to a depth and width of spread that depends very much on the kind o! 

 tree, and also upon the kind of soil in which the tree is growing. The roots are 

 the great feeders of trees; they take up from the soil water and certain mineral 

 substances that are essential to tree life. Secondly, the bole or trunk or stem, 

 which supports the branches and crown and is the channel through which water 

 and food are supplied to these. Thirdly, the branches and crown, with their network 

 of foliage (leaves and buds). It is in the green portions of the foliage only that 

 all the food taken up by the tree from the soil and air is worked over and trans- 

 formed and made ready to assist in the growth of the whole tree. The crown of a 

 tree has quite as much to do with its growth and healthy life as the other partis. 

 If the crown be totally destroyed and not allowed to develop again, the tree will 

 die just as surely as if its roots had been destroyed. In the crown the most Im- 

 portant processes in the reproduction of the tree and in the digestion of its food 

 take place. For the reason that it is possible to control its size and shape, the 

 crown is of much importance to those engaged in forestry work. When the forester 

 is growing a crop of trees he can by skilful attention to the crown produce the 

 class of tree that best suits the object he has in view. 



The Food of a Tree. — A tree has two storehouses from which it gets its food 

 — the soil and the air. If the rootlets or root filaments — for many of them are no 

 thicker than a thread — be examined, it will be noticed that they are thickly covered 

 with minute hairs. These hairs have an important function, for it is they that 

 take up water from the ground. At the same time, they absorb various substances, 

 almost wholly mineral in character, which water holds in solution. These other 

 substances are the earthy constituents of the tree, and when timber is burnt we 

 have left them once more in the ashes. The water containing the mineral con- 



