178 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
form, and surrounding these with wind-breaks of a suitable width 
—with trees of a wind-resisting character, which would also serve 
as a protection against fire. The latter is essential, especially along 
the sides of railway lines, where the sparks from passing engines 
are liable to fire the adjoining woods. A precaution adopted in 
Germany against fire from that cause is to plough a strip about 
9 feet in width annually along each side of the rails or on the top 
of the embankment, so that no herbage exists to lead the fire into 
the adjoining timber. For future convenience and guidance, these 
sections should each have a stone block erected at a suitable point, 
with a number, the acreage, and date of planting cut into it. Par- 
ticulars of each should also be kept in the forest register. 
It may be confidently asserted that nothing has contributed, 
to a greater extent in Britain, to the production of inferior and 
in many cases unsaleable timber, than our methods of thinning. 
These need not be recapitulated, further than to point out that 
the effect is to produce coarse, knotty, uneven-zoned wood, which, 
as compared with that grown in Germany, would be considered, 
with few exceptions, of a very inferior class indeed. 
When young woods are freely opened up by thinning, the 
branches become unduly developed at the expense of the stems. 
It is therefore necessary, to obtain these of a tall clean character, 
to preserve density in the crop, so far as that is consistent with its 
health and vigour, so that the side branches may be suppressed 
before they become strong enough to form large knots in the 
timber, and that the ground may be shaded to prevent surface 
growth, and generally to maintain the productiveness of the soil. 
Whether it is desirable to delay thinning until the twenty- 
fifth or thirtieth year or later, as is the case in Germany, where 
the results, as was evident, fully justified that procedure, is a 
question that must be solved by wider experience. There is, 
however, no doubt about the necessity of maintaining such a 
density during the principal height-growth of the crop, that the 
ultimate yield of timber may be proportionate to the capacity of 
the soil, and be of a tall, clean, and full-wooded character. Where 
the overhead covering, in the later stages of thinning, becomes 
broken, it seems desirable, as for instance with Scots fir, to 
introduce a soil-protection wood. Financial considerations may 
operate against that course, but where the soil has been well shaded 
previously, the operation would be attended with small expense. 
Where large areas, after clear felling, fall to be regenerated, 
