82 ANNUAL REPORT. 
For Manufacturing Purposes. 
The value of evergreens for forest planting 1s not to be measured by their lim- _ : 
- ited use for ornamental purposes, or by the present value of the marketable 
products, which owing to the low cost of timber lands, is far below the intrinsic 
value, taking into consideration the many centuries of time required to produce 
the primeval forest, and as compared with the supply, consumption and eisciesd 
and the future demands of an ever increasing population. 
It is estimated that over fifty per cent. of the various kinds of wood consumed 
is of the resinous species, principally white pine, and that with the continuance 
of the same ratio of increase of population, consumption of manufactured products 
as in the two last decades, combined with the same proportionate waste of mate- 
rial in the process of the manufacture of the rough lumber, and the continued 
destruction by casualties of the primeval forest now within the reach of the 
manufacturing industries and the centre of population, must necessarily result 
in a scarcity of available supply and enhanced prices, at a period of time long 
before the trees, if now planted in cultivated forest, can be grown of sufficient 
size for manufacturing into dimension lumber. 
For Protection, 
Besides the economic value of resinous woods, cultivated forests composed in 
whole or in part with an admixture of evergreens, are important factors in their 
effects in modifying climatic conditions; the extent of these modifications being 
largely determined by altitude, the extent, the form, the distribution, and, to 
some extent the species of trees contained 1n the forests. 
Form of Plantation. 
The limits of this paper confine us to the consideration of that portion ot the 
subject relating to the best form of planting and the most desirable species of 
evergreens to be grown. The method of planting forests in the square form 
seems to have been copied from the plan in vogue among the primeval forest 
pioneers, who having an imperfect knowledge of the climatology of forests, com- 
menced making clearings on one side of the tract of land, and extending the 
clearing year by year, leaving the forest reserve on one side or one corner of the 
farm. The general result of this form of forest reservation and plan of planting 
forests, is to dot the surtace of the country with groups of timber. The cleared 
fielis between these groups are swept by winds moving at times with accelerated 
velocity caused by the divergence of the atmospheric currents deflected by the 
groups and their junction with the direct current moving between the groups. 
To these causes and to the summer heated surfaces and to the rarefied atmo- 
sphere of the treeless spaces may be ascribed the rotary motion of air currents 
and the increased trequency of the devastating tornadoes in Wisconsin, Illinois 
and lowa, where the principal primeval forest reservations and the cultivated 
forests are in the group form. 
The isolated or group form of planting is aidonbtedly the best on the banks 
of streams to prevent their wear and caving, and upon embankments or hilly 
and broken surfaces, as a means of preventing their erasion, and the inundation 
and injury to the crop and soil of adjacent valleys and plams by the debris of 
sand and gravel, transported and deposited by torrents, and to preserve the soil 
