144 BOTANICAL GAZETTE [FEBRUARY 
at the rate of 70 per 25°1™ were found beneath a 24-year old stand. 
There were 7.5 pitch pine on 2557". Unfortunately these stands are 
periodically burned and the seedlings are killed, so there is little 
opportunity of observing the older stages of this undergrowth of white 
pine. On the Macomber lot, however, where fire has been rigorously 
+ 
8 8 8 8 
|_| _j8 
5 1 B 8 8 
PSs 
LPS. 
B a 
8 PS 10 8 8 Be See ee 
Ba Se Ge Ee 
ae 
a es 
BE SEE my 8 cf 8 
TT ips PS'10 8 a ie eee 
8 8 8 B 8 PS io | 
8 |_jPS10_} 48 
8 a 
6] |e 8 = 
Ciel Et ese i ss 
on a es 
JAR naa 
8 8 (Gey ined 1h Deh 
8 8 
8 5 8 PS ie SS BE Ss Ge ee ee 
3 
He GSS oa 2 ae ak 
igh Gas Wis Res al hs 
8 8 BER ae & 
os 
é ‘ 1 co ee 
8 eS as 4 
OR ee BE a ek Se ad 
8 8 B| [8 = 
8 
ast Sn ene a Ge Ga | 
8 8 a os oan eee Ge es | U rT 
B bles oe 
ie we 
PSia Wve Be eee = 
8 3 a Baas & 
P8a2 Be ee = 
PSi2 bia’ 
_ 
PS ba 8 i 
= 
8 3 a 
_ 
Fic. 12.—Sample plot 9. White birch 15 years old, Colchester plain, 5 meters 
square; under layer, Polytrichum, Onoclea sensibilis, Rubus hispidus; B, Betula populi- 
jolia 68; PS, Pinus Strobus 18; PT, Populus tremuloides 1; S, Spiraea tomentosa I. 
excluded for many years, one may find the older stages. Sample plot 
35 (fig. 9) shows white pine 23 years old beneath pitch pine 40 years 
old. There is little doubt of the ultimate control of such pitch pine 
stands by white pine, were forest fires excluded. — 
White birch in the old pastures usually forms dense pure stands. 
The series of stands shown in figs. 10-13 illustrates displacement of 
