6 THE OAK 
The shoot-system consists of the stem and all that it 
supports. The stem or trunk is usually irregular when 
young, but becomes more symmetrical later, and after 
fifty years or so it normally consists of a nearly straight 
and cylindrical shaft with a broad base and spreading 
branches. The main branches come out at a wide angle, 
and spread irregularly, with a zigzag course, due to the 
short annual growths of the terminal shoots and the 
few axillary buds behind, and also to the fact that many 
of the axillary lateral buds develop more slowly than 
their parent shoot, and are cut off in the autumn. 
Another phenomenon which co-operates in producing 
the very irregular spreading habit of the branches is the 
almost total suppression of some of the closely-crowded 
buds ; these may remain dormant for many years, and 
then, under changed circumstances, put forth accessory 
shoots. Such shoots are very commonly seen on the 
stems and main branches of large oaks to which an 
increased accession of light is given by the thinning out 
of surrounding trees. 
The short ovoid buds develop into shoots so short 
that they are commonly referred to as tufts of leaves, 
though longer summer shoots often arise later. The 
latter are also called Lammas shoots. The crown of 
foliage is thus very dense, and the bright green of the 
leaves in early summer is very characteristic, especially 
in connection with the horizontal, zigzag spreading 
of the shoots. 
While still young the tree is apt to keep its dead 
