The size of the openings and the rapidity with which they should be
enlarged vary, of course, with local conditions and the species which
is to 'be favored, the light-needing species requiring larger openings
and quicker light additions than the shade-enduring. It is difficult to
give any rules, since the modifications due to local conditions are so
manifold, requiring observation and judgment. Caution in not opening
too much at a time and too quickly may avoid failure in securing good
stands.
In general, the first openings may contain from one-fourth to one-half
an acre or more, and the gradual enlarging may progress by clearing
bands of a breadth not to exceed the height of the surrounding timber.
The time of the year when the cutting is to be done is naturally in
winter, when the farmer has the most leisure, and when the wood seasons
best after felling and is also most readily moved. Since it is expected
that the seed fallen in the autumn will sprout in the spring, all wood
should, of course, be removed from the seed ground.
The first opening, as well as the enlargement of the groups, should
not be made at once, but by gradual thinning out, if the soil is
not in good condition to receive and germinate the seed and it is
impracticable to put it in such condition by artificial means--hoeing
or plowing.
It is, of course, quite practicable--nay, sometimes very desirable--to
prepare the soil for the reception and germination of the seed. Where
undesirable undergrowth has started, it should be cut out, and where
the soil is deteriorated with weed growth or compacted by the tramping
of cattle, it should be hoed or otherwise scarified, so that the seed
may find favorable conditions. To let pigs do the plowing and the
covering of acorns is not an uncommon practice abroad.
It is also quite proper, if the reproduction from the seed of the
surrounding mother trees does not progress satisfactorily, to assist,
when an opportunity is afforded, by planting such desirable species as
were or were not in the composition of the original crop.
It may require ten, twenty, or forty years or more to secure the
reproduction of a wood lot in this way. A new growth, denser and better
than the old, with timber of varying age, will be the result. The
progress of the regeneration in groups is shown on the accompanying
plan, the different shadings showing the successive additions of young
crop, the darkest denoting the oldest parts, first regenerated. If we
should make a section through any one of the groups, this, ideally
represented, would be like figure 14, the old growth on the outside,
the youngest new crop adjoining it, and tiers of older growths of
varying height toward the center of the group.