Effect of Soil Water Content on Carbon Dioxide Flux at a Sparse-Canopy Forest in the Canadian Boreal Ecosystem

Iwashita, Hirokazu; Saigusa, Nobuko; Murayama, Shohei; McCaughey, Harry; Black, Andy; Barr, Alan G.; Higuchi, Kaz; Yamamoto, Susumu

doi:10.2480/agrmet.61.131

Cited by 8 publications

(5 citation statements)

References 22 publications

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“…Night‐time NEE data were excluded below a friction velocity u * threshold (Fig. 1; Griffis et al , 2003; Iwashita et al , 2005), determined from the data to be 0.10, 0.10, 0.25, and 0.25 m s −1 for HJP02, HJP94, HJP75, and OJP, respectively. On average, about 16%, 11%, 26%, and 21% data were excluded by the u * threshold for the four sites, respectively.…”

Section: Methodsmentioning

confidence: 99%

Carbon sequestration in boreal jack pine stands following harvesting

Zha

Barr

Black

et al. 2009

Global Change Biology

112

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A large area of boreal jack pine (Pinus banksiana Lamb.) forest in Canada is recovering from clear-cut harvesting, and the carbon (C) balance of these regenerating forests remains uncertain. Net ecosystem CO 2 exchange was measured using the eddycovariance technique at four jack pine sites representing different stages of stand development: three postharvest sites (HJP02, HJP94, and HJP75) and one preharvest site (OJP). The four sites, located in the southern Canadian boreal forest, Saskatchewan, Canada, are typical of low productivity jack pine stands and were 2, 10, 29, and 90 years old in 2004, respectively. Mean annual net ecosystem production (NEP) for 2004 and 2005 was À137 AE 11, 19 AE 16, 73 AE 28, and 22 AE 30 g C m À2 yr À1 at HJP02, HJP94, HJP75 and OJP, respectively, showing the postharvest jack pine stands to be moderate C sources immediately after harvesting, weak sinks at 10 years, moderate C sinks at 30 years, then weak C sinks at 90 years. Mean annual gross ecosystem photosynthesis (GEP) for the 2 years was 96 AE 10, 347 AE 20, 576 AE 34, and 583 AE 35 g C m À2 yr À1 at HJP02, HJP94, HJP75, and OJP, respectively. The ratio of annual ecosystem respiration (R) to annual GEP was 2.51 AE 0.15, 0.95 AE 0.04, 0.87 AE 0.03, and 0.96 AE 0.03. Seasonally, NEP peaked in May or June at all four sites but GEP and R were highest in July. R at a reference soil temperature of 10 1C, ecosystem quantum yield and photosynthetic capacity were lowest for the 2-year-old stand. R was most sensitive to soil temperature for the 90-year-old stand. The primary source of variability in NEP over the course of succession of the jack pine ecosystem following harvesting was stand age due to the changes in leaf area index. Intersite variability in GEP and R was an order of magnitude greater than interannual variability at OJP. For both young and old stands, GEP had greater interannual variability than R and played a more important role than R in interannual variation in NEP. Based on year-round flux measurements from 2000 to 2005, the 10-year stand had larger interannual variability in GEP and R than the 90-year stand. Interannual variability in NEP was driven primarily by early-growing-season temperature and growing-season length. Photosynthesis played a dominant role in the rapid rise in NEP early in stand development. Late in stand development, however, the subtle decrease in NEP resulted primarily from increasing respiration.

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Section: Methodsmentioning

confidence: 99%

Carbon sequestration in boreal jack pine stands following harvesting

Zha

Barr

Black

et al. 2009

Global Change Biology

112

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“…EC instrumentation and techniques were the same at HJP02, HJP75 and SOJP (Kidson, 2006). EC instrumentation and techniques at HJP94 were described in Iwashita et al (2005). Closed-path infrared gas analysers were used at all sites.…”

Section: Experimental Sitesmentioning

confidence: 99%

Net ecosystem productivity of boreal jack pine stands regenerating from clearcutting under current and future climates

Grant

Barr²,

Black

et al. 2007

Global Change Biology

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Life cycle analysis of climate and disturbance effects on forest net ecosystem productivity (NEP) is necessary to assess changes in forest carbon (C) stocks under current or future climates. Ecosystem models used in such assessments need to undergo well-constrained tests of their hypotheses for climate and disturbance effects on the processes that determine CO 2 exchange between forests and the atmosphere. We tested the ability of the model ecosys to simulate diurnal changes in CO 2 fluxes under changing air temperatures (T a ) and soil water contents during forest regeneration with eddy covariance measurements over boreal jack pine (Pinus banksiana) stands along a postclearcut chronosequence. Model hypotheses for hydraulic and nutrient constraints on CO 2 fixation allowed ecosys to simulate the recovery of C cycling during the transition of boreal jack pine stands from C sources following clearcutting (NEP from À150 to À200 g C m À2 yr À1 ) to C sinks at maturity (NEP from 20 to 80 g C m À2 yr À1 ) with large interannual variability. Over a 126-year logging cycle, annualized NEP, C harvest, and net biome productivity (NBP 5 NEP-harvest removals) of boreal jack pine averaged 47, 33 and 14 g C m À2 yr À1 . Under an IPCC SRES climate change scenario, rising T a exacerbated hydraulic constraints that adversely affected NEP of boreal jack pine after 75 years. These adverse effects were avoided in the model by replacing the boreal jack pine ecotype with one adapted to warmer T a . This replacement raised annualized NEP, C harvest, and NBP to 81, 56 and 25 g C m À2 yr À1 during a 126-year logging cycle under the same climate change scenario.

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“…Furthermore, wide range temperature and low precipitation might affect each process differently. For instance, different responses to summer drought were reported in boreal ecosystems (Arneth et al, 2002;Iwashita et al, 2005). To better understand the ecosystem responses to the current warming, it is important to evaluate the two processes separately.…”

Section: Introductionmentioning

confidence: 99%

Controlling factors on the interannual CO<sub>2</sub> budget at a subarctic black spruce forest in interior Alaska

Ueyama¹,

Harazono

Ohtaki

et al. 2006

Tellus B: Chemical and Physical Meteorology

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A B S T R A C TThe eddy covariance method was applied to measure net ecosystem CO 2 exchange (NEE) at a subarctic black spruce forest in interior Alaska during 2003 and 2004. To clarify the budget of CO 2 , we divided photosynthesis and respiration by applying the Carbon Budget Analysis Tool, in which the potential photosynthetic rate, the light use efficiency, and the suppression factors on photosynthesis were evaluated.The potential photosynthetic rate and the light use efficiency were related with the understory leaf area index. The determined optimal temperature of photosynthesis was higher than 15 • C, which was higher than that of other boreal forests. Drought in midsummer of 2004 suppressed both photosynthesis and respiration, but the suppression was more effective in photosynthesis, resulting in a slightly decreased NEE. Cumulative respiration and photosynthesis were 2.

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Effect of Soil Water Content on Carbon Dioxide Flux at a Sparse-Canopy Forest in the Canadian Boreal Ecosystem

Cited by 8 publications

References 22 publications

Carbon sequestration in boreal jack pine stands following harvesting

Carbon sequestration in boreal jack pine stands following harvesting

Net ecosystem productivity of boreal jack pine stands regenerating from clearcutting under current and future climates

Controlling factors on the interannual CO<sub>2</sub> budget at a subarctic black spruce forest in interior Alaska

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