Open AccessWater and carbon dioxide exchange at a boreal young jack pine forest in the BOREAS northern study area
Author(s) -
Joiner David W.,
McCaughey J. Harry,
Lafleur Peter M.,
Bartlett Paul A.
Publication year - 1999
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999jd900368
Subject(s) - environmental science , atmospheric sciences , morning , flux (metallurgy) , boreal , carbon dioxide , atmosphere (unit) , taiga , zoology , hydrology (agriculture) , climatology , forestry , ecology , botany , geography , geology , chemistry , biology , meteorology , geotechnical engineering , organic chemistry
Climatological measurements, including carbon dioxide flux density, were made from May to September 1994 and from May to November 1996 at a young jack pine ( Pinus banksiana Lamb.) forest near Thompson, Manitoba, Canada, as part of the Boreal Ecosystem‐Atmosphere Study (BOREAS). The study periods were warmer and drier than the 24 year climate normals, and in general, 1996 was warmer but wetter than 1994. Volumetric soil moisture above a depth of 8 cm in 1994 was often less than 5%. Albedos for solar radiation and photosynthetic photon flux density (PPFD) were 0.13 and 0.05, respectively, in both years. The Bowen ratio for days of year 144–262 was 1.7 in 1994 and 1.5 in 1996, with maximum daily Bowen ratios from 4 to 6. The range in CO 2 flux densities was the same in both years, with maximum uptake values of −0.55 mg m −2 s −1 in midsummer. Average diurnal patterns of CO 2 exchange for 1994 were similar to those for 1996, characterized by maximum uptake in the morning and a gradual decrease through the afternoon. Rectangular hyperbolic response curves showing CO 2 uptake in relation to incident PPFD show that changes between the morning and the afternoon, and because of environmental controls, were as great or greater than changes between designated 3 and 4 week measurement periods. Over a period of 119 days the young jack pine forest accumulated approximately −200 g C m −2 in 1994 and −267 g C m −2 in 1996. Reproduction of CO 2 exchange trends will be important for modeling efforts involving northern ecosystems.