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

Proceedings-Research on Coniferous Forest Ecosystems-A symposium .
Bellingham, Washington-March 23-24, 197 2
Terrestrial process studies i n
conifers: a review
Abstract
R . B . Walker, Department of Botan y
D . R . M . Scott, College of Forest Resource s
D . J. Salo, Department of Botan y
aqd
K . L . Reed, College of Forest Resources
University of Washingto n
Seattle, Washingto n
A few studies on the physiological processes of conifers go back as much as a century, but most informatio n
has been accumulated during the past 40 years . These efforts have involved most of the widely distribute d
species to some extent, but limited information is available even on those species most studied, and very little
on the remainder. With Douglas-fir (Pseudotsuga menziesii), the most studied species of our region, considerable
information is available, but insufficient for process modeling . Of other species of the Western United State s
much less is known . Thus intensive studies ofphysiological processes will be necessary in the Coniferous Biom e
effort on each of the species of principal importance . In this paper, the current status of information on th e
following topics is reviewed: CO 2 assimilation and respiration; transpiration, water conduction and wate r
deficits; translocation of photosynthates; and mineral nutrition . Stomatal behavior and leaf resistance are
considered with respect to the various gas exchanges . Energy budgets, nutrient cycling, growth, and modeling o f
processes are closely related to the foregoing topics, but are covered elsewhere in this symposium.
Introduction
Central in the goals of the IBP is the measurement
of productivity and production, and
particularly the understanding and predictio n
of these for vegetation and ecosystems . It
follows that a basic knowledge of the physiological
and related processes involved is
essential to reaching these goals . In the Coniferous
Forest Biome our concern is naturally
centered around the conifers, although associated
deciduous and herbaceous species are
also important. However, this review concentrates
on the conifers as the species demanding
our principal efforts .
Experimentation with conifers, which began
about a century ago and was taken up by
various workers periodically, has been included
in several general reviews in the Encyclopedia
of Plant Physiology (Leyton 1958,
Huber 1956, Stalfelt 1956, Pisek 1960), an d
discussed in detail by Kramer and Kozlowski
(1960) . Since then, a number of reviews concerning
woody plants have covered various
aspects: viz. food relations (Kozlowski an d
Keller 1966), mineral nutrition (Baule an d
Fricker 1967), and translocation (Zimmermann
and Brown 1971) . Of course, the results
of many experiments with broadleafed wood y
plants are pertinent to conifers . Further, general
principles established with herbaceou s
plants may be applicable to conifers, although
this carryover is more tenuous and in each
case usually demands experimental verification .
This review will concentrate on findings o f
the past decade which, together with the
work discussed in the reviews mentione d
above, serves as the background on which th e
studies of the Coniferous Biome are based .
Included is considerable unpublished material
211