MASS FLOW TRANSPORT TOWARDS THE ROOT SYSTEMS OF TWO FOREST ECOSYSTEMS IN RELATION TO THE UPTAKE BY THE ABOVE GROUND TREE PARTS

The persistence of mycorrhizal fungi in undisturbed coniferous forest ecosystems is assumed by the renewed appearance of their sporocarps each year. Sporocarps, however, are not produced in areas severely disturbed by fire or clearcutting; yet spores and other propagules of some species of hypogeous fungi are present in the soil in the absence of suitable mycorrhizal hosts, and are capable of forming mycorrhizae several years after clear-cutting or fire (Miller et al. 1989). In fact, hypogeous fungi such as Rhizopogon spp. are typically the first to recolonize root systems of new seedlings after large scale disturbance such as fire, insect attack, or clearcutting (Miller et al. 1989). Are these fungi residual in the soil from previously existing spore banks, or are they continuously being restocked into the area? Information on strategies for persistence, propagation and survival of ectomycorrhizal fungi is required before responses of forest ecosystems to fire and other disturbance can be understood.

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Microscale evidence of the role of water during the emplacement of mass flows in glacial environments

Quarterly Journal of Engineering Geology and Hydrogeology ◽

10.1144/qjegh2021-026 ◽

2021 ◽

pp. qjegh2021-026

Author(s):

Emrys Phillips ◽

Gareth Carter ◽

Derek Teasdale

Keyword(s):

Mass Flow ◽

Content Type ◽

Flow Transport ◽

Initial Soil ◽

Glacial Environments ◽

Mass Flows ◽

Proglacial Lake ◽

Potential Impact ◽

Basal Shear

Microscale analysis of unlithified glacial soils can provide far greater detail regarding their depositional and deformation histories than can be obtained from macroscale studies alone. This paper presents the results of three detailed case studies which examine the processes occurring during overriding and emplacement of mass flows in glacial environments: (i) laminated soils deposited in a proglacial lake setting at Heinabergsjökull, Iceland; (ii) a channelised, ice-marginal to submarginal mass flow at Whitburn (County Durham), England; and (iii) a mass flow exposed at Carstairs, Central Scotland which was emplaced in a glaciofluvial to glaciolacustrine setting. Microscale evidence from all three sites is combined to develop a conceptual model of the role played by water during mass flow; from the initial soil disruption under and/or in front of an advancing mass flow, to the formation of a basal shear zone facilitating mass flow transport and emplacement, through to the decoupling of the flow from the underlying substrate as a result of the injection of fluidised soil along its base. The development of these detachments during mass flow has the potential to increase the velocity of the flow and its run out distance, increasing the potential impact of these geohazards.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

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Transport of Nutrients to Tree Root Systems

Canadian Journal of Forest Research ◽

10.1139/x74-083 ◽

1974 ◽

Vol 4 (4) ◽

pp. 563-565 ◽

Cited By ~ 5

Author(s):

T. M. Ballard ◽

D. W. Cole

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Mass Flow ◽

Nutrient Transport ◽

Root Systems ◽

Douglas Fir ◽

Nitrogen Transport ◽

Ca Uptake ◽

Glacial Outwash

Calculations suggest that nutrient transport through the soil to roots by mass flow accounts for less than 22, 37, and 80%, respectively, of the N, K, and Ca uptake by a Douglas-fir stand growing on a nitrogen-deficient soil derived from glacial outwash. Diffusion and dispersion, though limited by soil water content, are evidently especially important in nitrogen transport to root systems in this soil.

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