Ap U. S. DEPARTMENT OF AGRICULTURE BULLETIN NO. 484, 
CONDITIONS UNDER WHICH POTENTIALLY CONTROLLING TREES OF THE WHITE- 
PINE REGION MAY BECOME ACTIVE CONTROLLING FACTORS IN MANAGEMENT. 
THE ASPENS.* 
The aspen and large-tooth aspen, if few in number in a stand, 
may be disregarded. They will not control the form of man- 
agement; that is, they may be cut or left according to the owner’s 
preference. If very numerous or if in pure stands they can not be 
disregarded, and they become controlling factors because of their 
rapid growth and power of abundant reproduction by root suckers. 
Even if not numerous in the stand then under consideration, these 
species may be controlling factors in management in that stand if 
there are numerous seed trees near by, or if the stand contains rela- 
tively large areas of bare mineral soil or has recently been burned 
over. This is because of their power of abundant reproduction by 
seed and their ability to germinate on such sites. 
BEECH. 
The power to survive under dense shade and to reproduce vigor- 
ously from root suckers makes the beech a controlling factor in man- 
agement of stands where it is found in sufficient numbers. It sprouts 
from the stump, but these sprouts seldom amount to anything. In 
the southern part of the white-pine region beech reproduction is 
chiefly by root suckers. In the northern part it can be more easily 
eliminated from stands if this is desired, because there it reproduces 
chiefiy from seed. 
GRAY BIRCH. 
Many stands of gray birch, covering in the aggregate large areas, 
are found throughout the white-pine region. They are characteristic 
of old pastures, and the rapid growth and the power of abundant 
reproduction of this species, both by seeds and by sprouts, make it 
an exceedingly difficult and expensive undertaking to eliminate it or 
even to alter materially the composition of stands in which it is 
numerous. Under such conditions it becomes a controlling factor in 
management and can not be disregarded, if success is expected. 
SCRUB OAR, 
This species (Quercus pumila |Marsh.] Sudw.) occupies large 
areas of so-called waste land, especially in southeastern Massa- 
chusetts. The sites on which it occurs are often too poor for agri- 
cultural crops but excellent for tree growth, which in most cases 
originally occupied them. The seeding and sprouting capacity of the 
1 For further details see Forest Service Bulletin 93, The Aspens, Their Growth and 
Management, by W. S. Weigle and E. H. Frothingham. 
