74 Transactions. 
misty summer nights. Trees also, it was obvious, checked eva- 
poration from the soil, which had been ascertained to be about ~ 
fourteen times less in woods than when the ground was bare. 
With regard to springs, it was matter of frequent experience 
that the destruction of wood dried these up in many cases. The 
general effect of woodland was to make the climate of the district 
more humid ; the planting, early in the century, of the hills on 
the west side of the vale of Dumfries had made sheep-feeding 
unprofitable in that quarter, although trees in the course of their 
growth dried wet land. 
The evil wrought by forest destruction in temperate climates 
was manifested in devastating floods. When the ground was 
bare of trees, the rain collected in torrents and rushed off towards 
the sea, swelling the rivers to a great height suddenly, The 
south of France was exceedingly liable to destructive outbreaks 
of the streams that rise on the northern flanks of the Pyrenees, 
the lofty summits of which intercepted and condensed the warm 
vapours brought by south-western gales from the Atlantic. 
Various steps had been taken, especially of late years, to arrest 
the destruction of forests in France, Italy, Germany, and the 
United States. Only in this country had nothing been done to 
that end. In one direction, however, there had been gratifying 
progress—the planting of trees along the streets of the Metropolis 
and other large towns ; and there seemed no reason why the good 
example should not be followed in smaller towns. 
The subject of the economical value of plantations was well 
worthy of investigation. When, in the early years of this 
century, the planting of forest trees was strongly advocated by 
the Highland Society, Dr Hamilton, at its instigation, wrote a 
treatise of forestry for the use of landholders and tenants, in 
which he maintained that if two million acres of the waste land 
of Scotland were planted with larch and other forest trees, their 
value in a century would equal the amount of the National Debt, 
besides improving the remainder of the land to the extent of ten 
millions sterling per annum. ‘Trees, the author observed in con- 
clusion, unlike all other crops, increased nearly all the year 
round, and depended less than any on the character of the season; 
and there were many additional reasons for the practice of arbori- 
culture, all tending to enforce the exhortation of the moribund 
laird of Dumbiedykes—“ Aye be stickin’ in a tree, Jock ; it'll be 
70) 
growin’ when ye’re sleepin’. 
