10 
BULLETIN" 149 7, U. S. DEPARTMENT OP AGRICULTURE 
In addition to serving as a site indicator, the cover, composed of 
natural tree or other growth already on the area, directly affects the 
success of planting and must be considered in this light in the selec- 
tion of a planting site. At one extreme are the cleared and culti- 
vated lands which have already been considered separately. As 
natural tree growth increases, the plan for planting must be modi- 
fied so that trees may be planted which are best adapted to meet 
the competition. Ordinarily, an area of which more than 40 per 
cent is occupied by natural tree growth requires a different plan from 
that for the same area with less than 40 per cent of tree cover. 
Where planting is done under a natural tree growth which occupies 
more than 40 per cent of an area, frequently called " underplanting," 
the trees should be planted in the openings wherever possible, and 
not close under the crowns of the larger trees, 
CONSIDERATIONS IN SELECTING SPECIES TO PLANT 
In selecting the kinds of trees to plant, there are five major con- 
siderations: (1) Their adaptability to the planting site; (2) the 
use for which the wood crop is desired; (3) the rate of growth; (4) 
the value of the wood products; and (5) their susceptibility to dam- 
age by insects, diseases, or other causes. 
ADAPTABILITY TO PLANTING SITE 
In choosing trees adapted to a planting site, as a general rule plant 
those kinds which are growing or have grown naturally, or have been 
planted successfully, on the same site. Largely on this basis certain 
species may be recommended for each of the sites distinguished pre- 
viously, (Table 1.) For the jack pine-oak sandy soils, Norway pine 
and jack pine are the two species recommended. If bare sands are 
to be planted jack pine is the most promising species, reinforced if 
further movement of the sand seems likely by eastern cottonwood and 
willows (33, 56). If there is more than 50 per cent cover of natural 
jack pine planting will usually be unnecessary and undesirable. If 
the cover is of oak, however, the planting of Norway pine and north- 
ern white pine is likely to give the best results. 
Table 1. — Kinds of trees to plant on different sites 
Site* 
Species to plant according to the degree of natural tree growth on 
the area 
Less than 40 per cent 
More than 40 per cent 
Jack pine-oak sands... 
Norway pine and jack pine 
Norway pine, northern white 
pine, white spruce, and red oak. 
Norway pine, northern white 
pine, white spruce, white ash, 
green ash, and red oak. 
Norway pine and northern 
Better sands or sandy loam soils 
without jack pine or raspberry; 
usually with paper birch or pin 
cherry. 
Loam soils with sugar maple, bass- 
wood, or raspberry. 
white pine. 
Northern white pine and 
white spruce. 
1 Too little is known about swamp planting to make specific recommendations. The cleared and culti- 
vated soils are not shown as a separate site in this table because the species to plant on them are the same 
as are recommended for the corresponding uncultivated sites with less than 40 per cent of natural tree 
growth. 
