PE EIE[R-Rg RESEARCH ON - HJ Andrews Experimental Forest

asis of the structure of the different pin e
crops (tables 1 and 5 and comparable descriptions
from references in table 7) that the
three lodgepole pine stands of this study carry
appreciably greater burdens of respiratory
biomass (Yoda et al. 1965). The major limitation
of pine productivity in the Central and
Northern Rocky Mountains may be the generally
infertile soils and inimical continental
climates. Under these environmental conditions
not even the thinning treatment (stand
4.3) and subsequent surge of productivity i n
surviving stems gave increased yield on an are a
basis (table 6) .
Management decisions in the Colorad o
Lodgepole Pine Zone must recognize th e
inherent low productivity of P. contorta .
Where wood production must continue t o
have management priority, efficiency o f
utilization can be increased at least 10 percent
if live branches can be economically include d
in the harvest (table 5) (Young 1968) . Management
can also be directed toward uneven -
aged stands for purposes of esthetics, enhanced
groundcover production, or better
game utilization. Small, irregularly shaped
clearcut areas are also an attractive management
possibility for long-term planning in this
low productivity region . This study suggests
strongly that because of its very low productivity,
especially when compared against th e
productivity of intensively managed pin e
plantations, lodgepole pine stands in environments
of site index of 90 or less should b e
regarded as only minor resources of woo d
harvest. A greater percentage of such land i n
the lodgepole pine region of North Americ a
might be devoted to recreational usage .
A much neglected management tool in
lodgepole pine forests is prescribed burning .
Periodic fires were an important feature of
lodgepole forests (Moir 1969) . This study and
others (Kiil 1968) reveal that high quantities
of slowly decomposable materials build up
within natural stands . Fairly high quantities
of nutrients become locked up in the forest
floor humus (Moir and Grier 1969) ; this
humus together with the shaded condition of
the forest floor in closed stands has adverse
effect upon the ground flora (Basile and
Jensen 1971, Moir 1966). Controlled fire has
at least four possible beneficial effects in
lodgepole pine forests : (1) The reduction of
fuel and wildfire probability, (2) stimulatio n
of ground vegetation, (3) a nutrient "pulse"
effect stimulating tree production, (4) tree
thinning and conversion to uneven-age d
stands. The possible use of controlled surfac e
fires in P. contorta should be given
considerably more attention .
Acknowledgments
Work reported in this paper was supporte d
by the National Science Foundation, Grant No .
B020357 in cooperation with the Coniferou s
Forest Biome, U .S. Analysis of Ecosystems ,
International Biological Program . This is Contribution
No. 35 to the Coniferous Forest
Biome .
Literature Cited
Art, H. W., and P. L. Marks. 1971. A summary
table of biomass and net annual primary
production in forest ecosystems o f
the world . In Forest biomass studies, 15th
IUFRO Congr., p. 3-32 . Orono : Univ.
Maine Press .
Basile, J. V., and C. E. Jensen . 1971 . Grazing
potential on lodgepole pine clearcuts i n
Montana. USDA Forest Serv . Res. Pap.
INT-98, 11 p . Intermountain Forest &
Range Exp . Stn ., Ogden, Utah .
Forrest, W. G. 1969. Variations in the accumulation,
distribution and movement of
mineral materials in radiata pine plantations.
276 p. Ph .D. thesis on file at
Australian Nat . Univ., Canberra .
Hatiya, K., K. Doi, and R. Kobayashi. 1965 .
Analysis of the growth in Japanese red pin e
(Pinus densiflora) stands. A report on th e
matured plantation in Iwate Prefecture .
Govt. For. Exp. Stn. Bull. (Tokyo) 176 :
75-88 .
Johnstone, W . D. 1971 . Total standing cro p
and tree component distributions in thre e
stands of 100-year-old lodgepole pine . In
Forest biomass studies, 15th IUFR O
Congr., p. 81-89 . Orono : Univ. Maine Press .
197