GROWING TIMBER. 123 
Clean and uniform growth, and freedom from defects arising from 
large knots, together with thorough seasoning, are, therefore, the 
characteristics of imported wood, while the reverse is too often the 
condition of our home productions. The value of clean growth 
and seasoned condition is obvious; but we may briefly give a few 
reasons for supposing that a slow and regular growth produces 
better coniferous timber than that from rapidly grown trees. The 
annual wood-ring of a pine or spruce is composed, as already 
stated, of two distinct zones, the “spring” or ‘‘summer-wood,” 
formed during the early part of the growing season, and the 
‘‘autumn-wood,” formed in late summer or autumn. These two 
zones differ little as regards their structure, the same elements 
being found in both; but the cell-walls are thicker and better 
lignified in the autumn than in the spring wood, and this raises its 
specific gravity and quality. The greater durability and hardness 
of this autumn-wood is nowhere better exemplified than in larch 
or Scots pine fencing posts. After a few years’ exposure, the 
spring-wood zones are found to have so far decayed as to leave 
shallow circular pits in the transverse surface of the post, while 
the autumn-wood is still intact. The exact causes which bring 
about the formation of this autumn-wood are not definitely known, 
but the general opinion is that it is due to the better nourishment 
of the cambium layer at the time of the formation of this zone, 
together with the pressure exerted by the bark upon the new ring. 
It is evident, therefore, that the greater the proportion of autumn- 
wood in the annual ring, the better the quality of the timber, other 
things being equal. Now, we invariably find that the relative breadth 
of the spring-zone is much greater in the case of a fast-growing tree 
than in one of slow growth, and it consequently follows that a piece 
of timber made up of narrow rings contains a larger proportion of 
autumn-wood than a piece formed of broad rings, and we may 
assume, in a general way, that the former is of better quality than 
the latter. 
But while slow growth may be an advantage so far as quality of 
timber goes, and timber produced by it in natural forests duly 
appreciated, it may be carried to an undesirable extent in planta- 
tions grown for profit, for rapid growth is a quality we cannot 
afford to undervalue or ignore. 
This brings us to our second point: Can home timber be pro- 
duced and remuneratively sold at the same price as that imported? 
When we consider that our foreign imports are almost entirely 
VOL. XIV. PART III. M 
