566 KANSAS CITY REVIEW OF SCIENCE. 



lower down, form forests of considerable height, and which, as timber trees, make 

 what is known to mountain travelers as the "Timber Line." Thus in the mount- 

 ains of Colorado, the forests commence at about 7,000 feet above the sea level, 

 and continue up to about 11,000 feet, where they suddenly cease, and form at 

 that elevation what is there shown as the "Timber Line." On Gray's Peak he 

 found Pinus aristata, Pinus flexilis, Abies concolor, and Abies Engelmannii, with 

 some willows, forming the timber line. The Coniferous trees wer& probably thirty 

 or forty feet high, and it was interesting to note that this tall timber as suddenly 

 ceased, as if a wood had been cut half a way by a woodman's axe, But at once 

 commencing where the tall timber ceased, the same species exist as dwarf, stunted 

 shrubs seldom exceeding three or four feet in height, and often but a foot, though 

 trailing widely over the ground. In this stunted condition the species would 

 often extend some fifteen hundred feet higher up, or half way from the recog- 

 nized timber line to the top of the mountain. Other observers have noted that 

 the average of 11,000 feet marks the entire timber line of the Rocky Mountain 

 range. 



So far as he knew, this peculiar timber line has been referred wholly to cli- 

 matic conditions, of which temperature and moisture have been regarded as the 

 chief elements in producing the results. That admirable botanist and energetic 

 collector. Dr. C. C. Parry, in a paper on the Rocky Mountain alpine region, 

 published in the " Proceedings of the American Association for the Advancement 

 of Science" for 1869, p. 249, remarks that the most satisfactory explanation is 

 that the so called timber line marks the extreme point of minimum temperature 

 below which no exposed phenogamous plant can exist. All that survives above 

 this point does so by submitting to a winter burial of snow, beneath which pro- 

 tecting cover it is enabled to maintain its torpid existence. 



The great objection which this purely meteorological view presented to Mr. 

 Meehan's mind was that the dwarfed and gnarled coniferse extending so many 

 hundred feet up the mountain sides, never produced seed, and we are reduced 

 to the alternative of believing either that the seeds have been carried up the 

 mountain sides in enormous quantities and to enormous distances from the fruitive 

 trees below by winds, or else that there were seed-bearing progenitors of these 

 scrubby pines, beneath the tall protecting branches of which they had their ear- 

 liest stages of growth. He was satisfied from subsequent observations in the 

 mountains of North CaroHna, and in the White Mountains of New Hampshire, 

 that this last view is the correct one, — that large timber trees at no very remote 

 period extended much further up the mountain sides than they do now, and that 

 they have since disappeared for reasons presently to be stated, leaving only the 

 younger trees to struggle on as best they may. 



Roan Mountain in North Carolina is about 6,300 feet above the level of the 

 sea. Timber extends to its summit on some parts of it, while in other parts it is 

 destitute of timber for many hundreds of feet down its sides. The species on the 

 summit is Abies Frazeri, and Abies nigra. Oak and other trees come occasionally 

 to near the top and at about 6,000 feet he measured a black oak — Quercus tinctoria. 



