REPORT ON FORESTS. 243 



pine. Throughout every pine woods are scattered here and 

 there suppressed oaks, the seeds of which may have been dropped 

 by jays or chickarees. Just as soon as the pines are cut, these 

 oaks, owing to increase of light and room, grow quickly. In 

 spite of the poverty of the soil and the inroads of insects, and 

 although burnt and cut again and again, they show remarkable 

 vigor.* 



Even scientific men have advanced the theory that one species 

 of tree follows another because the first exhausts certain ingre- 

 dients in the soil which it must have and which another species 

 may not need. Such statements are rarely founded on facts. 

 The reason one species follows another may be easily determined 

 in almost every case with a little observation and study. Trees 

 do not generally exhaust the soil, but, by bringing inorganic 

 materials from deep layers of the soil and depositing these in the 

 form of litter on the surface, and by protecting it from the beat- 

 ing and leaching of rain and scorching effects of wind and sun, 

 improve its quality. In moist pine regions which have been burnt 

 over several times and on which everything is killed, birch often 

 springs up in an almost magical way. This is due to the facts 

 that the seeds of the birch are quickly distributed by the wind 

 and quickly germinate, and that the birch is capable of living on 

 extremely poor soil. 



Many dry leaves cling to the small oak trees until the follow- 

 ing spring ;t the limbs reach close to the ground, and fire, there- 

 fore, in the late winter or early spring, before there is much sap 

 in the wood, kills them, although the stumps live on, and with 

 great persistency produce a fresh growth. In the struggle for 

 existence the scrub oak and the black jack (Q. marilandica) 

 usually survive. Although these two oaks are of slight economic 

 importance, it is due to their pertinacity that in many places 

 the soil has been prevented from shifting. The species which 

 form this coppice are, post oak (Q. minor\ black oak (Q. velu- 

 tinci), white oak (Q. alba], chestnut oak {Q. prinus), Spanish 

 oak (Q. digitatci], red oak (Q. rubra], black jack (Q. mari- 



* It is well known, however, that oaks, chestnuts, and similar trees, lose their vitality when a*exually 

 reproduced for a great length of time. 



fit has been suggested by botanists that these clinging leaves indicate a tendency or are a step 

 toward the evergreen state. The magnolia glauca is almost evergreen in Southern New Jersey. When 

 leaves cling in this way it is an indication that the species is frost-tender and that the leaves were injured 

 by frost before the normal corky layer was formed at the base of the petiole. 



