METHODS 169 



particular of the main plant associations. Don't bother about 

 details yet, but simply try and get a grasp of the big habitats 

 and habitat gradients. When you have made a list of the 

 important habitats, come down more to details and subdivide 

 these into smaller areas or zones, in the manner indicated in 

 Chapter II. Thus, at this point your notes would be in the 

 following form : 



" The country can be divided roughly into the lower- 

 lying parts which are cultivated, and the upper hilly parts 

 which are not. The uncultivated area can be divided into 

 three very distinct main zones : 

 '' I. Grassland. 



''2. Bracken, with scattered trees, forming a sort of 

 bracken savannah. 

 " 3. Woodland. 



" I and 2 are more or less abruptly separated, but 2 and 3 

 grade into one another at their margins owing to the com- 

 plicated distribution of shrubs, such as bramble, and small 

 trees, such as hawthorn." 



Supposing we then took the woodland, the notes would go 

 on something Hke this : 



" There are several fairly distinct types of woodland. 

 " I. Ash, with some sycamore. 



"2. Oak woods (which species ?), with hazel undergrowth. 

 "3. Oak and sweet chestnut woods. 



" These again vary much in undergrov^h owing to the 

 effects of fires, and felling, and age. N.B. This summer is 

 dry enough to have caused grass fires, but the woods have not 

 caught seriously." 



If, then, we considered the oak-hazel wood, we might 

 write : 



" The oak wood can be divided into vertical strata : 

 " I. Tree-tops — 

 " (a) Leaves. 



" (b) Twigs and branches. 

 *' (c) Under bark and rotten wood of branches. 

 " 2. Trunks— 



*' (a) Upper part with lichens (drier). 



