ON PRUNING FOREST TREES, ETC. 139 
of the foliage. Spring, however, should be avoided with 
respect to sycamore, maple, and birch, which are apt to bleed 
like vines until the leaves are developed ; but it is found that 
the best time to remove the branches from the bole is de- 
cidedly early in autumn, say August or early in September, 
then no sooner are they removed than the descending sap 
immediately cicatrizes the wounds, which close up in course 
of a few weeks. 
Mr. Cree, an authority on pruning, says, “If we form an 
estimate of the comparative value of pruned and unpruned 
trees raised within an equal number of years, the advantage 
which the former possess over the latter is very great. Take 
twenty-five elms indiscriminately of a size suitable for making 
naves for wheels, it will be found, if unpruned, that the 
quantity of timber will not average in each above five feet. 
Twenty-five trees which I have pruned will each contain 
more than thirty feet of timber when arrived at the age of 
the trees I have described above. Pruning is equally bene- 
ficial to all sorts of deciduous trees.” 
On pruning oak for naval purposes it is an important 
object to manage it in such a way as to produce the greatest 
proportion of bent pieces, or knees, which are always more 
valuable for shipbuilding than straight timber. It is there- 
fore indispensable that the trees have considerable space ; the 
proximity of roads, rivers, the outside of a plantation, or any 
circumstance affording open space to some extent, is most 
suitable for this purpose, and as the close pruning of the stem 
near the surface of the ground has a tendency to make trees 
ramify, when young oaks have advanced to the height of 
from eight to ten feet. their lateral branches should be pruned 
from the surface upwards close to the stem to the height of 
from three to four feet, and if they are inclined to grow with 
a straight top the leading shoot should be cut off, and two of the 
strongest lateral branches which take a horizontal direction 
should be left at those points where they will be least confined, 
and the next largest branches should be shortened at the 
same time. In the course of three years, or, if the plantation 
