196 OUR FORESTS AND WOODLANDS 
cultivation of poplars, but none of the good 
kind will thrive to the best profit on dry, 
high-lying land. Given those favourable condi- 
tions, the Canadian poplar is the species whose 
cultivation is most likely to yield good and profit- 
able returns. It is hardy, and shows itself more 
accommodating with regard to soil than either of 
the other two kinds; while it is extremely rapid 
in growth, produces wood of better quality than 
the common black poplar or the abele, arid can, 
though essentially a light-demanding tree, be 
grown somewhat closer together than either of 
these. These advantages can perhaps best be 
estimated when it is recollected that even the 
common black poplar often yields an average of 
two feet per tree per annum at thirty years of age 
when grown in a free position. Though this 
growth would, of course, be less in highwoods, 
yet the quality of the cleaner timber would be 
better for all kinds of technical purposes. The 
white poplar is somewhat more exacting than 
either of the black poplars as to the kind of soil 
upon which it grows. It thrives best on loamy 
or sandy land; on anything like stiff clay soils it 
is apt to become dry in the top. Though it 
