Tfmfnr-Line. Decline in Fruit Production, etc. 25 



injury to young timber, and these become more liable to occurrence 

 as the wood near the summit is destroyed. The snow then drifts 

 over and forms great overhanging masses on the leeward side, which 

 are liable to heroine detached and to slide down into the valleys, car- 

 rying every thing before them. 



lor>. Young seedlings when covered with the snow are sometimes 

 broken down by its weight, as it settles from melting on the under 

 side. 



107. The TindxT-L'ut'' is the upper limit of tree growth upon 

 mountains. Its height is greatest within the tropics, and it descends 

 as we go north or south, until it reaches the surface in tin- Arctic 

 zone. It also decrea-es a- we approach the sea-cast, and it is often, 

 from local caiiM-s. higher on one side of a mountain than on the 

 other. In the Himalayas, this line is about 11,800 feet high. On 

 the Alp- it averages i,400 H H -t, and in the Kocky Mountains it 

 vurii-s from !UMi l( , IIMMIO feet 1 



108. In ascending to the timber-line, no great diHI-rence in the 

 size of the timber is observed until within a lew hundred feet of the 

 limit, when the trees begin to appear short and wide-spreading, and 

 at last almost flat, and leaning from the prevailing winds. Ai 

 the line, no trees whatever are found, and but little vegetation of 

 any kind, the mountain ri-ing bleak and barren t< it- summit, or 

 until it reaches the eternal snows. This snow line varies with the 

 seasons, and is in some years higher or lower than in others, accord- 

 ing as the prevailing conditions of the weather may have varied. 



Decline of Frtiif /V</<-//o,j mnl //.- Cause. 



109. It is not unusual to hear old people recall the memories of 

 their youth, when peaches and other fruits grew luxuriantly and 

 without special care, in regions where they are now unknown, or 

 are raised only in favorable seasons and with extraordinary care. 



(1) Prof. C. C. Parry, in Prof. Huyd.-n's Report of 1872, gives the heigh 

 of the timber line in some twenty places, some of them being us follows: 



FEET. FEET. 



Mount Shasta, Cal .................... 8,000 Gilbert' Peak, t'intas ............... 11,100 



Cwead linage, Or ............. ...... 7,000 Audobon's Peak. Colo .............. n.32.5 



Wanl s IVak. Motita ................. 8,781 Mt. Knpelmann, Colo .............. 11,518 



Briber's Peak ............. .......... 9,0!>J Cray's I'.-ak. Colo .................... 11,643 



Near Henry's Lake, Idaho. ........... 9,36d Pike's Peak ....................... 12,040 



Wind Hiver Mts ..................... 10,100 Colorado generally ......... 11,600 to 12,000 



Long's Peak, Colo ....... 10,800 



