40 BULLETIN 299, U. S. DEPARTMENT OF AGRICULTURE. 
supplementary species to white ash and can be advantageously sub- 
stituted for it on drier soils in the Central States and in the southern 
Appalachians at an elevation of from 1,000 to 2,500 feet. Texas ash 
is the natural substitute for white ash on uplands in central Texas, 
but is not important for commercial timber growing. Red and 
pumpkin ash are two excellent substitutes for green ash, the former 
adapted to somewhat drier soils and more rigorous climate than green 
(extending farther north), and the latter to somewhat wetter soil 
conditions in the central and eastern parts of its range. 
Possibilities of reforestation by natural reproduction are quite good 
with white and green ash, but naturally very limited with the other 
less abundant species. 
In planting or sowing ash it is advisable to use seed from trees of 
species common in the region (and on similar sites, if possible) where 
the reforesting is to be done, or from a region with a slightly more 
rigorous climate. Also seed should always be secured, if possible, 
from vigorous, rapid-growing individuals. 
NATURAL VERSUS ARTIFICIAL REFORESTATION. 
Wherever it is possible to secure natural reproduction by using 
such methods as are described later every effort should be made to 
do so. Artificial reproduction is more expensive and less certain of 
ultimate success. Planting should be confined to spots where natural 
reproduction is incomplete or to areas where there is no possibility 
of natural growth. It will sometimes be more advisable, however, 
especially on cheap land, to spend money for disengagement cuttings, 
to liberate the ash and other desirable species from suppression, 
rather than for ' supplementary planting work. In other cases it 
may be well to divide the money to be spent between planting and 
disengagement work. In general, the more expensive the land and 
the higher the stumpage values the more profitable will it be to 
spend money on artificial reproduction in order to secure fully stocked 
stands with the largest possible per acre per annum growth instead 
of being satisfied with incomplete natural reproduction at no expense 
and giving smaller yields per acre. For instance, Table 18 shows 
that a 5,000 yield on $20 land with no cost of esablishment will not 
pay as well as a 10,000 yield on the same with $5 to $15 cost of estab- 
lishment, while on $5 land a 5,000 yield without^cost of establishment 
would pay best. Similarly the less the natural yield capacity of the 
soil and the lower the stumpage values the less likely is it to be profit- 
able to spend money in establishing a stand. 
Adequate reproduction of ash, resulting in highest yields, demands 
that on every separate square rod of space there should be at the 
start a minimum of one thrifty ash seedling, together with at least 
