NOTES ON CONTINENTAL FORESTRY IN 1905. 177 
condense his twenty pages of measurements and remarks thereon, 
his conclusions (affecting spruce-woods only, of course) are 
that— 
t. Growth in very close cover produces badly developed 
crowns, and reduces their power of assimilation. 
2. The present system of growing spruce closely at first, and 
then thinning freely only during middle age, does not 
utilise the productivity of the land fully, and therefore 
causes loss to the proprietor. 
3. The badly-developed crowns can only rehabilitate them- 
selves slowly, and on poor soil often not at all; hence 
late thinning does not exercise any very beneficial effect 
on the total increment. 
National treatment of spruce-woods should therefore consist 
in— 
4. Not forming the young crops too thick—say, where planting 
is adopted, using from 1600 to 2400 plants per acre [7.e., 
about 44 feet apart (in squares), which would give an 
average growing-space of about 20} square feet]. 
5. The number of poles to be gradually decreased by fre- 
quently repeated cleanings, and by thinnings as soon 
as the lower branches begin to die off to a height of about 
15 or 16 feet. 
6. The aim of thinning should be to produce the largest 
possible number of stems of good growth, with well 
developed and regular crowns, and distributed as equally 
as possible over the whole area. 
7. The live, actively vegetating part of the crown should, on 
the average, never come down below 30 per cent. of the 
height of the tree. 
In a subsequent article on the economic effect of heavy 
thinning, Schwappach considers the question of such treatment 
of pine, spruce, beech, and oak in respect to total increment, 
both as regards volume and value, and arrives at the following 
conclusions :— 
1. Zhe total increment in volume is certainly not diminished by 
heavy thinning, but is more or less enhanced, except in 
the case of Scots pine, where, however, it cannot as yet 
be shown to have occasioned any decrease. 
VOL. XIX. PART 1. M 
