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area of calm in the blow sand zone.- A windbreak of trees will lessen
the horizontal force of the wind for a distance of 20 times its height.
Hence, by the time the block or row of trees on the windward side
reaches 10 feet in height, it will be helpful in stopping the wind for a
distance of 200 feet. Future plantings on the leeward of the original
block of trees should be made on the blow sand spots as rapidly as
they fall within this protected zone.
Planting a windbreak on drifting sand. See picture on opposite page.
  A four by four-foot spacing instead of the standard six by six-foot
spacing is recommended in blow sand areas. The earlier the roots and
the crowns interlock, the more effective the plantation will be. Even
with most favorable growing conditions, a number of years are re-
quired for trees at a six-foot spacing to close in on each other; on
sandy soil this period is considerably longer.
  The V-shaped slit type of planting hole is best adapted to sand, and
may be made either with a flat planting bar or spade. Fall planting
is desirable, because it gives the young trees full advantage of the
moisture which may be in the soil at the opening of the growing sea-
son in the spring. Too often spring planting is delayed until much of
the soil moisture has evaporated or drained away.
Decomposed Sandstone and the Sand Plains
  Extensive areas of sandy soil in central and northern Wisconsin, re-
sulting from the weathering of the sandstone hills, or from glacial
lakes and deltas, have been so completely deforested as to need re-
planting if a valuable crop of trees is to be grown on them. Blow sand
soils are found within this type. Where such sandy soils have re-
mained comparatively undisturbed the objectives and methods of
planting will be different than for strictly blow sand areas.
  Because of their low fertility and susceptibility to drifting once they
are broken, many of these soils are not desirable for agriculture. They
are adapted to growing trees. Present markets indicate that for some
time to come the growing of pulpwood products is the most promis-
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