Pre- and post-forest management investigations of factors affecting sediment movement in riparian areas in Northwestern Ontario / by Darren J. McCormick. --
Notice bibliographique
Résumé
The principal objectives of this study were to measure the impacts of timber harvesting on sediment transport rates (mineral and organic) associated with two clearcut areas in northwestern Ontario and to evaluate the sediment controlling effectiveness of 30 m wide riparian reserves that were prescribed in accordance with Ontario's Timber Management Guidelines For The Protection Of Fish Habitat Guidelines (OMNR, 1988).A goal of this study was to provide a practical means for assessing potential changes to sediment transport rates resulting from impacts of forest management activities in Ontario.Prior to road building and full tree logging with feller bunchers and grapple skidders, a sediment sampler was installed in each of 16 sub-catchments.Samplers were situated at a distance of either 0, 10, 20, or 30 m, measured into the reserve areas from the boundaries o f planned clearcuts.Mineral and organic sediment collected in the samplers were monitored for one year (late spring to late fall) before, and two years (late spring to late fall) after impacts, and data were standardized with the amount of precipitation that fell during the respective sampling year.Indices of change were calculated to quantify differences in mineral and organic collection rates for each sampler in the first or second post-impact year compared to those in the pre-impact year.Field and GIS data (including: sampler position in the reserve, sub-catchment area, distance from road, presence of surface runoff, occurrence of trees thrown by wind, crown closure, thickness of soil organic layers (LFH), terrain slope, and a topographic index (TI) derived from GIS data describing upstream contributing area and slope) were collected in an attempt to quantify the capacity of the reserve areas to impede (or encourage) sediment collection in each sampler.The results clearly demonstrate that sediment movement in riparian reserve areas does not increase universally following forest management.Sediment attenuation through the reserve areas was variable, indicating that factors in addition to the width of a filter strip can function to control the distance to which eroded sediment is transported.Catchment area was not related to the rates that sediment was collected in samplers.Sediment collection rates were higher in samplers located closer to the road; however, the results can not be used to support categorically the accepted model whereby areas closer to roads are subject to higher erosion rates than areas further away from roads.The occurrence of surface runoff and windthrow, especially when combined, were predominant factors that contributed to increased sediment collection rates in samplers.The amount of crown closure and the thickness of LFH layers influenced rates of erosion, but the magnitudes of their influences were marginal compared to those of flow and windthrow.Steeper slopes did not consistently generate higher sediment transport rates, but the evaluation of the
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,006 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».