TORREYA 



Vol. 8. 



SOME EFFECTS 



February, 1908 



No. 2. 



THE SOUTHWEST 



OF FROST IN 



By J. C. Blumer 



To what extent a severe spring frost in the southwest may 

 injure forest growth is shown by a series of interesting observa- 

 tions by Mr. Frank J. Phillips.* The fact that a large number 

 of tree species in the Chiricahua Mountains of Arizona failed to 

 bear fruit in the autumn of 1907, may have been due to the same 

 cold wave that defoliated the young trees in certain parts of the 

 New Mexican mountains. In 1906 many of these species fruited 

 abundantly notwithstanding the fact that this was a drier season 

 than 1907. It is possible that the general backwardness of the 

 latter season also may have had something to do with it. The 

 pines, however, are known to be intermittent in their seed-bear- 

 ing habits. The following is a list of Chiricahua species with the 

 seed crops of 1906 and 1907 compared. In many cases the same 

 individuals were observed both years : 



Walnut [Jiiglans rupestris ) 

 Sycamore {^Platanus 



Wrightii ) 

 Cherry ( Primus salicifolia ) 



Box elder ( Acer Negundo ) 



Ash ( Fraximis sp. ) 



Cascara (^Rhamnus sp. ) 



Grape ( Vitis sp. ) 



Oaks, seven species ob- 

 served 



Arizona pine i^Pinus ari- 

 zonica) 



An abundant crop of nuts 

 Balls plentiful 



1907 

 Not a single nut found 

 No balls apparent 



A good crop of wild Not a single cherry seen 

 cherries 



A limited crop of samaras 



Trees loaded with fruit 



Fruiting abundantly 



A large crop 



Acorns common to abun- 

 dant 



Good crop, many trees 

 loaded with cones 



No samaras found 

 Crop small or absent 

 No fruit observed 

 A small crop 

 Acorns absent or few f 



Crop very poor, one might 

 travel half a day to find 

 one cone 

 * Forestry and Irrigation, September, 1907. 



I One or two species, however, ranging below 5,000 feet altitude, bore an abundant 

 crop. With exception of these and the ash, none of the species named descends to 

 this level within the region observed. 



[No. ^, Vol. 8, of ToRREYA, comprising pages 1-24, was issued January 27, 

 190S.] 



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