FROST 
1909, comparatively little attention was 
given to measures to protect fruit from 
frost injury. The spring of 1909 was 
one noted for a succession of damaging 
frosts, resulting in almost a complete 
failure in many orchards. This failure 
turned the attention of the growers to- 
ward protective measures, and some of 
the more progressive of them provided 
themselves with oil pots and oil for use 
in 1910. The spring of 1910 was much 
more favorable for fruit than that of 
1909, so much so that there was a good 
yield of fruit in most of the unprotected 
orchards, aS well as in those that were 
protected. This being true, there was 
little increase in 1911 over the area 
heated in 1910; the entire area in the 
upper part of the valley adjacent to 
Boise probably not exceeding 1,000 acres. 
Like that of 1910, the spring of 1911 was 
not a good one to demonstrate the effi- 
ciency of protective measures, for while 
some very low temperatures were eéx- 
perienced, these low temperatures oc- 
curred when the buds were least suscep- 
tible to injury, and little damage oc- 
curred that could be directly traced to 
frosts. 
1017 
It is probable that orchard heating 
will not become common in this valley 
as it is in the Grand valley in Colorado 
and in the Rogue River region in Oregon, 
until another season like that of 1909 
is experienced, when the practical value 
of heating can be demonstrated. 
The topography of this region is pe- 
culiar and gives rise to some weather 
conditions that make frost forecasting 
a difficult matter. The Boise river, in 
its upper reaches, flows through a rugged 
mountainous region. About six miles 
southeast of Boise it emerges from a 
deep box canyon, the mouth of which 
marks the head of what is known as the 
Boise valley, which extends thence 
northwestward with increasing width to- 
ward the Snake river. Northeast of 
Boise are the Boise mountains, reaching 
in 12 miles an elevation of 7,500 feet, or 
4,800 feet above the city. Toward the 
southwest the ground rises in a series 
of widening benches. Through this bench 
land, where most of the large orchards 
are located, run several water courses, 
rather unimportant naturally, but form- 
ing a means for air and water drainage, 
and apparently playing an important 
Freer MALS 
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Se 
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Fig. 4. Boise Valley Fruit District 
_ o. TABLE Fock 
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e . Pp 
paul qn 
4 foces Ofte Hearn, 
er Bu, 
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—After Reed. 
