492 BULLETIN 460, U. S. DEPARTMENT OF AGRICULTURE. 
scant, and uneven; but reproduction on burned-over lands is, with — 
aid of fire (which opens the cones), exceedingly thick and even. Full — 
light and exposed mineral soil are requisites of good reproduction. 
This favorable condition of the soil is produced by fire, which, 
when it does not consume the cones, leaves them open or in condition 
to open and release their seeds. 
LONGEVITY. 
Lodgepole pine attains an age of from 100 to 175 years, but doubt- 
less it is capable of reaching from 200 to possibly 300 years, if pro- 
tected from fire, to which it quickly succumbs on account of its thin 
bark. Few stands have in the past attained an age of over 60 years 
before being killed by forest fires. 
JACK PINE. 
Pinus banksiana Lambert. 
COMMON NAME AND EARLY HISTORY, 
Pinus banksiana does not occur within our Rocky Mountain region, 
but it enters the Canadian territory immediately north of this region 
(map No. 14) and it is included here in order to present an account 
of al] the pines in the Rocky Mountain ee irrespective of national 
boundaries. 
Jack pine is best known to the public as a tree of southeastern 
Canadian provinces and of our Great Lakes country, where it is 
variously called jack pine, scrub pine, black jack pine, gray pine, 
black pine, Banksian pine, and Hudson Bay pine. The name jack 
pine is, however, widely used and perhaps the most appropriate. 
There appears to be no authentic record of when jack pine was 
first discovered. It must have been well known to the French ex- 
plorers and settlers of eastern Canada at least asearly as the sixteenth 
century. Strangely enough the first record of its existence is based 
on trees cultivated in England,’ where the species is believed to have 
been planted prior to 1735. By whom and from what part of its 
range in this country the seeds or plants were sent to England is 
unknown. It seems likely, however, that seeds were sent from east- 
ern Canada. The first technical name, Pinus sylvestris, 3 divaricata 
Aiton, given to this tree was published in 1789 by William Aiton, 
a Scottish botanist and gardener, who based his brief descrip- 
tion of it on trees growing in the Royal Botanical Garden at Kew, 
England, of which he was then director. Correctly speaking, the 
logical name for this pine should be Pinus divaricata (Ait.) Du 
Mont de Courset, which is based on this early one of Aiton. But 
1Loudon, Arb. et Frut. Brit., iv, 2192. 1838. 
