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 ;f 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. mznor), black oak (Q. velu- 
tina), white oak (Q. alba), chestnut oak (Q. prznus), Spanish 
oak (Q. digitata), red oak (Q. rubra), black jack (Q. marz- 
*It is well known, however, that oaks, chestnuts, and similar trees, lose their vitality when asexually 
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. 
