PMID- 12651384
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 1758-4469 (Electronic)
IS  - 0829-318X (Linking)
VI  - 18
IP  - 3
DP  - 1998 Mar
TI  - Parameterization and testing of a coupled photosynthesis-stomatal conductance 
      model for boreal trees.
PG  - 141-153
AB  - A coupled photosynthesis-stomatal conductance model was parameterized and tested 
      with branches of black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus 
      banksiana Lamb.) trees growing in the Northern Study Area of the Boreal 
      Ecosystem-Atmosphere Study (BOREAS) in Manitoba, Canada. Branch samples 
      containing foliage of all age-classes were harvested from a lowland old black 
      spruce (OBS) and an old jack pine (OJP) stand and the responses of photosynthesis 
      (A(n)) and stomatal conductance (g(s)) to temperature, CO(2), light, and 
      leaf-to-air vapor pressure difference (VPD) were determined under controlled 
      laboratory conditions at the beginning, middle, and end of the growing season 
      (Intensive Field Campaigns (IFC) 1, 2, and 3, respectively). The parameterized 
      model was then tested against in situ field gas-exchange measurements in a young 
      jack pine (YJP) and an upland black spruce (UBS) stand as well as in the OBS and 
      OJP stands. Parameterization showed that Rubisco capacity (V(max)), apparent 
      quantum yield (alpha') and Q(10) for sink limitation were the most crucial 
      parameters for the photosynthesis sub-model and that V(max) varied among 
      different measurement series in the laboratory. Verification of the model against 
      the data used to parameterize it yielded correlation coefficients (r) of 0.97 and 
      0.93 for black spruce and jack pine, respectively, when IFC-specific parameters 
      were used, and 0.77 and 0.87 when IFC-2 parameters were applied to all IFCs. For 
      both measured and modeled g(s), the stomatal conductance sub-model, which 
      linearly relates g(s) to (A(n)h(s))/c(s) (where h(s) and c(s) are relative 
      humidity and CO(2) mole fraction at the leaf surface, respectively), had 
      significantly steeper slopes and higher r values when only the VPD response data 
      were used for parameterization than when all of the response data were used for 
      parameterization. Testing the photosynthesis sub-model against upper canopy field 
      data yielded poor results when laboratory estimates of V(max) were used. Use of 
      the mean V(max) estimated for all upper canopy branches measured on a given day 
      improved model performance for jack pine (from a nonsignificant correlation 
      between measured and modeled A(n) to r = 0.45), but not for black spruce (r = 
      0.45 for both cases). However, when V(max) was estimated for each branch sample 
      individually, the model accurately predicted the 23 to 137% diurnal variation in 
      A(n) for all stands for both the upper and lower canopy. This was true both when 
      all of the other parameters were IFC-specific (r = 0.93 and 0.92 for black spruce 
      and jack pine, respectively) and when only mid-growing season (IFC-2) values were 
      used (r = 0.92 for both species). Branch-specific V(max) estimates also permitted 
      accurate prediction of field g(s) (r = 0.75 and 0.89 for black spruce and jack 
      pine, respectively), although parameterization with all of the response data 
      overestimated g(s) in the field, whereas parameterization with only the VPD 
      response data provided unbiased predictions. Thus, after parameterization with 
      the laboratory data, accurately modeling the range of A(n) and g(s) encountered 
      in the field for both black spruce and jack pine was reduced to a single unknown 
      parameter, V(max).
FAU - Dang, Qing-Lai
AU  - Dang QL
AD  - Centre de Recherche en Biologie Forestiere, Faculte de Foresterie et de 
      Geomatique, Universite Laval, Sainte-Foy, Quebec G1K 7P4, Canada.
FAU - Margolis, Hank A
AU  - Margolis HA
FAU - Collatz, G James
AU  - Collatz GJ
LA  - eng
PT  - Journal Article
PL  - Canada
TA  - Tree Physiol
JT  - Tree physiology
JID - 100955338
EDAT- 2003/03/26 04:00
MHDA- 2003/03/26 04:01
CRDT- 2003/03/26 04:00
PHST- 2003/03/26 04:00 [pubmed]
PHST- 2003/03/26 04:01 [medline]
PHST- 2003/03/26 04:00 [entrez]
AID - 10.1093/treephys/18.3.141 [doi]
PST - ppublish
SO  - Tree Physiol. 1998 Mar;18(3):141-153. doi: 10.1093/treephys/18.3.141.