- 15 - 
Spencer, D. A., and Potts, C. G. 
1933. Sheep raising in U. S. has changed greatly since pioneer period. 
U. S. Dept. Agr. Yearbook 1933: 264-273. 
p. 264: Sheep are also tensively in the grass-produc- 
ing areas of the Eastern and Central S cularly in rolling 
a nd hilly s e ctions . Since sheep are_fond of a great variety of weeds 
and underbrush which cattle and horses do not relish, they are useful 
in keeping fields and fence corners clean and in utilizing forage not 
so well adapted to other livestock. 
p. 267: Except where flocks are kept to produce purebred stock, 
special crops are seldom grown for the sheep, wh ich are genera lly 
turned . onto pasture as s oon as the grass begi ns to g row in the spring 
and rem ain th er e until t h e crops have been harv ested, when they are 
usually give n th e run of the fie lds to graze and to clean up the 
we eds , and remain there until snow falls. They are then carried through 
the winter on hay and some of the unsalable roughage, with little or 
no grain. 
Forest, Brush, and Grass Fires 
Forest, brush, and grass fires destroy all kinds of wild life, 
including pollinating insects-. The practice of burning fence rows, rail- 
road right-of-ways, pastures, etc., is highly detrimental to wild pollin- 
ating insects, most of which nest in or near the ground. 
Sirns, I. H., Munns, E. N. , and Auten, J. T. 
1938 Management of forest soils. U. S. Dept. Agr. Yearbook (Soils 
and Men) 1938: 737-750. 
p. 741: Heavy cutting has commonly been followed by fire, and 
examples of serious soil deterioration due to this combination of 
treatments can be found in practically every forest region of the 
country. Some 60 million acres of land have been so completely dev- 
astated by this combination that they are unlikely to reforest naturally 
and must be planted. total is being swelled currently by the 
addition of 850,000 acres each year, three- fourths of which is land 
formerly occupied by conifer stands. 
When cut-over land is burned the fire accomplishes in minutes 
the degree of litter removal that would be achieved naturally only 
after several years... This sudden removal of the litter and its 
living population set- otion a chain of events leading directly to 
deterioration or loss of the soil . 
p. 743: Extreme soil temperatures frequently develop during 
the great conflagrations and humus in the upper horizons is oxidized 
immediately. The mineral soil has much the same appearance as samples 
ignited in a furnace. Accumulations of he debris bu rn 
i ntensity that the soil is sterilized for years . 
