44 BULLETIN 149 7, U. S. DEPAE1MEXT OF AGRICHLTDBE 
ber about S40 a thousand board feet. The same owner concluded 
that it did not par to prune Norway pine. 
In an unpruned pine or spruce plantation during the first 15 
years the limbs have needles almost to the ground., and the risk of 
complete destruction if fire gets started in the plantation is great. 
Pruning unquestionably reduces this fire risk. But pruning costs, 
from ?5 to S20 an acre, or as much as the planting of the trees in 
the first place. So large a cost is not justified as a protection 
measure, because effective fire protection can be obtained at much 
lower cost by the construction of fire lines and the maintenance of 
a fine-protective organization during dangerous seasons. Pruning for 
protection can only be justified over small areas where it may be done 
in spare time by an owner himself or by a fire guard on rainy days, 
the cost thus being only incidental. 
As a means of increasing the value of the timber, if the results 
obtained in Xew Hampshire with northern white pine are appli- 
cable elsewhere, pruning is amply justified: though there is always 
the chance that the wounds made by cutting the branches may result 
in attacks and losses from insects and diseases which might offset 
the increased value due to improved quality of the product. Prun- 
ing is chiefly desirable in plantations which are widely spaced or 
composed of trees, like northern white pine, which do not shed their 
branches easily. 
Cuttings to release planted trees will be needed on cut-over lands 
where hardwood stumps sprout or where there is a natural growth 
of aspen, paper birch, oaks, jack pine, or other trees which have 
a start over the planted trees or grow more rapidly than they can 
during the first few years and are likely to crowd them out. Xorth- 
ern white pine and the spruces will ordinarily suffer only a little 
retardation of growth, and the plantations may even benefit from 
overhead shade by increased survival until they are 15 or 20 years 
old and 5 or 10 feet high. About that time the larger natural 
growth of other species should be cut. If the brush is dense, 
however, and the planted trees are being damaged, it may be wise 
to release them within five years after planting. 
In plantations of jack and Norway pine, any competing natural 
tree growth should be cut as soon as possible so that the planted trees 
may have the benefit of ample light and space for their roots. 
Faster-growing hardwoods that appear about the time of planting 
and are likely within the next 10 years to damage the planted trees 
by crowding them and by whipping back and forth in the wind 
should be removed while rhey are still small, when the operation can 
be done most cheaply. It is not safe to wait until the hardwoods 
are of merchantable size. The best time to remove them is when they 
are still so small that a man with an ax or brush hock can cut them 
off with a single stroke for each stem. At the time the cleanings are 
made, any of the planted trees which are diseased or badly infested 
with insects should also be removed. This first release cutting or 
cleaning, usually made when the plantation is 3 to 5 years old. should 
be repeated five years later and if needful at intervals thereafter 
until the planted trees are as tall as the competing growth. Trees 
of desirable kinds which occur naturally on the area and are not 
interfering with the planted trees should be left to form a mixed 
stand. 
