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Record W4245074182 · doi:10.24124/2001/bpgub194

Carbon sequestration in British Columbian sub-boreal cut blocks

2001· dissertation· en· W4245074182 on OpenAlexfundno aff
Thomas G. Pypker

Bibliographic record

Venuenot available
Typedissertation
Languageen
FieldEnvironmental Science
TopicPlant Water Relations and Carbon Dynamics
Canadian institutionsnot available
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsBowen ratioEnvironmental scienceEcosystemFlux (metallurgy)ShrubSink (geography)Atmospheric sciencesGrowing seasonHerbaceous plantTaigaHydrology (agriculture)EcologyCarbon sinkForestryEnergy balanceGeographyPhysicsBiologyGeologyChemistry

Abstract

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During the summers of 1999 and 2000 measurments of component and ecosystem-level C02 fluxes were taken in seven cut blocks aged 0, 2, 3, 5, 6, 9 and 10years since harvest in the Aleza Lake Research Forest, near Prince George, British Columbia. A Bowen ratio energy balance (BREB) system was placed within a 5 to 6 year-old planted interior spruce (Picea glauca x Picea engelmanniz) clearcut to measure the ecosystem C02 flux during the 1999 and 2000 growing seasons. To substantiate the BREB measures of the ecosystem C02 flux a second method, called the component model, was established based on instantaneous measurements of component C02 fluxes (conifer, herbaceous plant, woody shrub and below ground) scaled up to the ecosystem-level. Both approaches indicated inter-annual variation in the growing season C02 fluxes. The 1999 growing season ecosystem C02 flux measurements estimated the clearcut to be a sink of -20 ~ 43 g C m~2 and -86 g C m~2 from 27 June to 3 September, using the BREB method and component model respectively. In contrast, in 2000 the growing season C02 flux during the same time period was a source of 43 g C m~2 (BREB method) and 66 ~44 g C m~2 (component model) during the same period. In 2000, an additional 50 days of measurement, from 24 May to 20 September, indicated an even larger source of C02 totaling 143 ~57 and 103 g C m~2 using the BREB method and component model, respectively. However, regardless of the approach used, both years would have been sources of C02 if additional measures were taken for the entire year. The component fluxes were dominated by the C02 source from below ground (338 and 466 g C m~2 in 1999 and 2000, respectively) and the C02 sink provided by the deciduous plants (-382 and -365 g C m~2 in 1999 and 2000 respectively). The conifer photosynthetic C02 uptake for the 5 to 6 year-old clearcut was meager in comparison (-47 and -57 g C m~2 in 1999 and 2000, respectively). During the 2000 growing season, the below ground C02 flux and above ground biomass was measured in 7 cut blocks aged 0, 2, 3, 5, 6, 9 and 10 years and one mature stand. All sites were in the SBS wkl 08 or 07 except the 0 and 9 year-old sites that were of the sub series 01. The growing season below ground C02 flux was similar for all cut blocks, including the mature forest. Furthermore, there was little change in above ground biomass carbon uptake between the different aged cut blocks. Hence, when biomass was incorporated with the below ground C02 fluxes all cut blocks were sources for C02\u2022 Therefore, cut blocks within the Aleza Lake region (SBS wk1 07 or 08) are sources of C02 for at least 10 years after harvest because the conifer component of the C02 flux is incapable of surmounting the loss of C02 from below ground.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.047
Threshold uncertainty score0.094

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.001
Science and technology studies0.0010.000
Scholarly communication0.0010.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.004
GPT teacher head0.200
Teacher spread0.196 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2001
Admission routes1
Has abstractyes

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