STATE FORESTS OF PRUSSIA. ,as 
sands and marls. The quality of the soil for the growth of trees 
depends largely on the depth of the marl and onits degree of 
weathering. The surface geology of the whole district has been 
very carefully worked out, so that it is known exactly which trees 
will thrive best in the various situations. The silver fir and 
spruce are not indigenous to this district, but the latter is used to 
some extent in filling up blanks. Here, asin East Prussia generally, 
the Seots fir and oak are the most important trees, the beech 
being found growing in pure woods only in the most favourable 
situations. The hornbeam also is largely used for filling up in 
Scots fir woods, and for protecting the soil. Alder, too, is profit- 
ably cultivated in marshy places. According as the soil is loamy 
or sandy, so do we find the oak or Scots fir predominating. It is 
found that the timber of Scots fir grown on loam is much inferior 
in quality to that furnished by trees growing on sand, although, 
so far as yield is concerned, the former situation may produce 
more than the latter. At the age of 120 to 140 years, woods 
of Scots fir yield from 4300 to 4800 cubic feet of timber per acre 
(English measurement), which commands an average price of 
about 63d. per cubic foot, though for wood of very fine quality 
10d. or more is obtained. The oak forests take 200 to 240 years 
to reach maturity, and then they yield 2150 to 2500 cubic feet 
per acre, which sells for from 10d. to 1s. 1d. per cubic foot. The 
tendency in this district at present.is to reduce the area under 
oak, and to increase that under Scots fir, for it is believed that 
although oak timber is getting scarcer, its price will not rise in 
proportion, owing to its being supplanted by iron and many foreign 
woods. 
Leaving alder coppice aside, we have, in this district, to deal 
with three principal systems of sylviculture, namely—oak mixed 
with beech and Scots fir, Scots fir mixed with oak and beech, 
and pure woods of Scots fir. 
1. Oak, with Beech and Scots Fir as a Mixture.—This mixture 
is managed according to the quality of the situation. On the best 
class of soils the object is to gradually remove the Scots firs and 
beeches in the thinnings, so that at the end of the rotation 
practically a pure oak wood remains. On poorer soils, on the 
other hand, the Scots firs are allowed to compete on equal terms 
with the oaks, while the beeches are kept under, and serve the 
purpose of a soil-protection wood. At the end of 120 years 
the Scots firs are felled, while the oaks are left for another period 
of 120 years, making the total length of the rotation 240 years. 
In some cases, also, the beeches are allowed to get up to the same 
height as the oaks and Scots firs, in which case the firs are 
removed at the end of 120 years, and the oaks and beeches at 
the age of 240 years.. 
