FOREST EXTENSION IN THE WHITE 



MOUNTAINS.* 



INTERESTING STUDY OF REPRODUCTION OF SCRUB 

 SPRUCE AND BALSAM IN ALPINE SITUATIONS. 



BY 



T. L, HOOVER. 



BL/ACK spruce (Picea mariana) and 

 balsam (Abies balsamea) have 

 climbed almost to the summit of the 

 Presidential range. Balsam was ob- 

 served as high as 5,500 feet on Mt. 

 Washington and spruce at 5,300 feet on 

 Mt. Clay. Seeking shelter among the 

 rocks and crouching in the surface hol- 

 lows, their stunted forms reach out the 

 gnarled and twisted branches, as if 

 joining hands for mutual encourage- 

 ment and support, and bid defiance to 

 the elements. 



This steady upward progress, persist- 

 ent in the face of adverse conditions of 

 soil and climate, must be the work of 

 many successive generations. And yet 

 a striking fact in this connection is the 

 almost entire absence of fruiting bodies 

 on the upper limits of growth. By the 

 casual observer a cone on either species 

 is seldom seen in these lofty situations, 

 and only careful search will reveal them 

 to a close observer. How, then, does 

 reproduction, so necessary to this steady 

 advance of the species, take place? 



In uprooting a balsam for an exami- 

 nation of its root system, the writer was 

 obliged to follow out carefully a slen- 

 der, wiry root for a distance of six or 

 eight feet from the stock. But the root, 

 instead of tapering down and ending in 

 fine rootlets, was found to be attached 

 to the stock of another scrub balsam. 

 Further examination disclosed the fact 

 that other roots of the same plant ter- 

 minated likewise in attached but vir- 

 tually independent plants. In some 

 instances these primary offspring were 

 found to have given rise to a still more 

 recent generation. Thus from a single 

 parent stock a whole clump had been 

 formed . 



This, then, is the solution. Instead 

 of being dependent upon the usual re- 

 production from seed, the plant under 

 unusual conditions has evolved a pro- 

 cess of natural root-layering. 



Subsequent investigation revealed the 

 same method of reproduction with both 

 the balsam and the spruce. In the 

 shallow, scanty soil the roots of a plant 

 run far out, but close to the surface. 

 Then by some process an aerial system 

 develops from the root, and a new plant 

 comes into being, which in time devel- 

 ops its own root system, and thus estab- 

 lishes an independent existence. In 

 some instances the genealogies of living 

 plants were traced back directly to an 

 old dead stock; hence a clump of scrub 

 may be regarded as a vitally connected 

 colony arising from one or several par- 

 ent stocks. 



With this explanation in mind, the 

 question arises, ' ' To what extent do 

 the seeds occasionally produced take 

 part in reproduction?' The writer 

 was not successful in finding any seed 

 of the previous season. All seed col- 

 lected was several or many years old. 

 The cones were all undersized, and 

 none of the seeds seemed plump and 

 sound. 



Of the seed collected the following 

 was submitted for testing to the Seed 

 Laboratory of the United States De- 

 partment of Agriculture: Picea mariana, 

 5,100 feet; Abies balsamea, 5,000 feet, 

 and Picea mariana, 4,400 feet. The 

 first two specimens gave no results 

 whatever. The last gave a germina- 

 tion of 6 per cent. This evidence 

 clearly shows that whatever reproduc- 

 tion takes place in such situations can be 

 to only a very small extent from seed. 



* All altitudes are measured from sea level. 

 (225) 



