304 WOODLAND IN EUROPEAN COUNTRIES. 
upon the cost of obtaining them from other countries, or upon 
their commercial value as articles of export. 
Upon the whole, taking civilized Europe and America 
together, it is probable that from twenty to twenty-five per 
cent. of well-wooded surface is indispensable for the mainte- 
nance of normal physical conditions, and for the supply of ma- 
terials so essential to every branch of human industry and every 
form of social life as those which compose the harvest of the 
woods. 
There is probably no country—there are few large farms 
even—where at least one-fourth of the soil is not either unfit 
for agricultural use, or so unproductive that, as pasture or 
as ploughland, it yields less pecuniary return than a thrifty 
wood. Every prairie has its sloughs where willows and poplars 
would find a fitting soil, every Eastern farm its rocky nooks and 
its barren hillsides suited to the growth of some species from 
our rich forest flora, and everywhere belts of trees might ad- 
yantageously be planted along the roadsides and the boundaries 
and dividing fences. In most cases, it will be found that trees 
may be made to grow well where cultivated crops will not re- 
pay the ontlay of tillage, and it is a very plain dictate of sound 
economy that if trees produce a better profit than the same 
ground would return if devoted to grass or grain, the wood 
should be substituted for the field. 
Woodland in European Countries. 
In 1862, Rentzsch calculated the proportions of woodland in 
different European countries as follows : * 
INOXWAY 5 Ace cue eatiodiss stds Sees ae Sects . 66 ~— percent. 
SWEGEN serra eRe aes, celeloer aes os a slae . 60 a 
Russiat cal 4584 Bas ese ih ee, Seas Ma isisctse aioe 30.90 J 
Germany. iiss ee cae SCAR TDA OS OAS EES 26.58 At 
Belen awmiy 414, See a keistelare jist slay ooh oles 18.52 ie 
ECANCO! 2), fercpsir clan eine staat eave Bie selene 16.79 cs 
Swatzerlandy% Sie ceveeleatee. Seat aven ofe's 15 Oe 
* Der Wald, pp. 123, 124, 
