NORWAY PINE IN THE LAKE STATES. 27 
CLEANING OR WEEDING. 
To produce timber of high quality it is essential in most cases to 
tend the stand practically from the start. One of the mam cultural 
operations is to clean or weed the young stand of undesirable trees. 
While such an operation maybe permissible from a financial standpoint 
in a mixed hardwood forest, it would scarcely be justified in the case 
of Norway pine. To clean or weed the young Norway j^ine stands 
will entail an expense of from $2 to $4 per acre. Two dollars at 5 
per cent compound interest amounts to $697.82 for a rotation of 120 
years, and few operators could afford this expenditure. Where the 
owner maintains a protective force the rangers may make systematic 
weedings. For example, if jack pine is temporarily suppressing the 
Norway pine, the ranger can top the jack pine and lessen the strug- 
gle for light. Norway pine seedlings under aspen or underbrush 
can be liberated. If this weeding can be done in connection with 
other duties, even at a small additional expense, it is certainly worth 
while. In Minnesota, for example, there are thousands of acres of 
natural forests of Norway pine, from 10 to 30 years old, which deserve 
attention from the owners, and which it would be profitable to hold 
in view of the increasing demand for small mine timbers. 
THINNINGS. 
The removal of undesirable or competing trees from a stand is 
called thinning. This reduces the loss which ordinarily takes place 
in the struggle for light. The silvicultural value of thinnings in 
Norway pine can not be questioned, although they are not of the 
same vital importance as in a mixed forest. In a widely spaced 
plantation thinnings would probably not be needed before the 
twentieth or thirtieth year, but will be necessary after that. Timely 
thinnings are important in securing natural reproduction, since they 
result in a final stand of trees with well-developed crowns, thus 
insuring abundant production of seed. Moreover, every lumberman 
would prefer to cut 88 20-inch boles, rather than 338 13-inch, 1 because 
wide lumber brings better prices than narrow boards. Under 
present conditions thinnings on a large scale are justified only when 
the sale of the products at least pays the cost. The owner of a small 
area of timber can improve his stand without expense by selecting 
the small poles needed for farm construction from dense groups of 
Norway pine, instead of adopting the possibly more convenient pro- 
cedure of cutting a portion of his woodlot clear. Thinnings in pine 
stands should begin early, and be made lightly and often. In a 
dense Norway pine stand the first thinning should be made when the 
trees are from 20 to 30 years old, removing from 10 to 15 per cent of 
1 See Table 11 for yield data on unthinned stands on Quality II soil. 
