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Net ecosystem production of a Douglas‐fir stand for 3 years following clearcut harvesting

2005· article· en· W2119035029 on OpenAlexafffundabout
Elyn Humphreys, T. Andrew Black, Kai Morgenstern, Zhong Li, Zoran Nesic

Bibliographic record

VenueGlobal Change Biology · 2005
Typearticle
Languageen
FieldEnvironmental Science
TopicPlant Water Relations and Carbon Dynamics
Canadian institutionsUniversity of British Columbia
FundersNatural Sciences and Engineering Research Council of CanadaCanadian Foundation for Climate and Atmospheric Sciences
KeywordsEcosystem respirationEnvironmental sciencePhotosynthetically active radiationEcosystemUnderstoryLeaf area indexGrowing seasonPrimary productionEddy covarianceForestryAtmospheric sciencesAgronomyCanopyGeographyEcologyBotanyBiologyPhotosynthesis

Abstract

fetched live from OpenAlex

Abstract To investigate the variations in annual and seasonal net ecosystem production ( F NEP ) during the development of a young forest, 3 years of continuous eddy covariance measurements of carbon dioxide (CO 2 ) fluxes were collected following clearcut harvesting and replanting of a coastal Douglas‐fir stand on the east coast of Vancouver Island, BC, Canada. The impact of changing weather and stand structure on F NEP was examined by developing relationships between F NEP and variables such as light, temperature, soil moisture, and leaf area index (LAI). In all 3 years, the stand was a large source of CO 2 (620, 520, and 600 g C m −2 yr −1 in the first, second, and third years, respectively). During this period, the growth of pioneer and understory species resulted in an increase in maximum growing season LAI from 0.2 in the year the seedlings were planted to 2.5 in the third year. The associated increase in annual gross ecosystem production ( P = F NEP − R e , where R e is ecosystem respiration) from 220 g C m −2 yr −1 in the first year to 640 g C m −2 yr −1 in the third year was exceeded by an increase in annual R e from 840 to 1240 g C m −2 yr −1 . Seasonal and interannual variations in daytime F NEP and P were well described by variations in photosynthetically active radiation, temperature, and changes in LAI. Night‐time measurements of R e exponentially increased with 2 cm soil temperature with an average Q 10 of 2 (relative increase in R e for a 10°C increase in temperature) and R 10 ( R e at 10°C) that increased from 2.1 in the first year to 2.5 in the second year to 3.2 μmol m −2 s −1 in the third year. Although the re‐establishment of vegetation in this stand had a major impact on both P and R e , interannual variations in weather also affected annual F NEP . Drought, in the summer of the third year, resulted in early senescence and reduced both P and R e . This resulted in more C being lost from the stand in the third year after harvesting than in the second year.

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 distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.661
Threshold uncertainty score0.246

Codex and Gemma teacher scores by category

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

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 head0.025
GPT teacher head0.254
Teacher spread0.229 · 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 teacher head, 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

Citations78
Published2005
Admission routes3
Has abstractyes

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