92 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
following the law of gravitation, find its way into the pockets of 
the proprietors of the forests. 
In order to bring this about, the first and foremost requirements 
of our forest estates is, then, that they should be managed according 
to well-considered plans of operations, technically called working 
plans, which lay down the cuttings to be made for a series of 
years, thus leading to the method of a sustained yield. But 
working plans do more than this, they provide for the systematic 
and orderly performance of all other work to be attended to, 
such as the general method of treatment, the execution of 
regeneration, thinnings, construction of roads, etc., in short, for 
the whole business connected with forest management. 
And this brings me to the next point, namely, the interference 
caused to an orderly systematic management by violent gales. 
No doubt this is a great source of annoyance in a country situated 
like Scotland. Although the forester cannot altogether prevent 
such disasters, he can do much to reduce their extent, partly by 
grouping the woods of different ages in a reasonable manner, 
and partly by mixing shallow-rooted species with deep-rooted 
ones. 
Most strong gales come from a fairly fixed direction; in this 
country generally from a direction oscillating between north-west 
and south-west, in so far as deviations are not caused by the 
configuration of the locality, such as mountain ranges, deep 
valleys, etc. It is also well known that gales do special damage 
if they rush into the open front of the wood, or one which has 
suddenly been too heavily thinned. If, therefore, a cutting has 
been made by which the western front of an adjoining wood 
standing on the lea side is exposed, it is as likely as not that the 
next heavy gale will throw it down. If, on the other hand, we 
arrange the cuttings so that they begin in the east, and proceed 
gradually towards the west, we avoid offering to the wind 
specially favourable conditions for causing havoc. The wood 
at the western edge having grown up gradually under constant 
exposure to the western gales, will have developed strong edge 
trees, especially if they have been somewhat heavily thinned during 
early youth, and they will, in the majority of cases, resist gales. 
Hence they should not fall under the axe until all the woods 
behind them have been cut over. 
Mixed Woods.—Again, it is highly desivable that shallow-rooted 
species, like spruce, should be mixed with species which have a 
