Solr Search · GéoProdig, portail d'information géographique

Contribution of dead wood to the carbon flux in forested streams

Contribution of dead wood to the carbon flux in forested streams
Wood in world rivers. Special issue
The AA. evaluated the contribution of dead wood to the total carbon flux in 2 headwaters forested streams in northern Spain, one running under mature deciduous forest, the other under eucalyptus plantations. Breakdown rates were measured from
branches and compared with the breakdown loss of leaf litter calculated for the same reaches. So, fine dead wood contributes to a significant fraction of the total breakdown of allochtonous organic matter in the studied streams; other sizes of dead wood
increase the breakdown by an order of magnitude, and thus can result in a large part of the carbon flux being derived from wood.

Living trees provide stable large wood in streams

Living trees provide stable large wood in streams
Wood in world rivers. Special issue
California ; Channel geometry ; Habitat ; Riparian vegetation ; Stream ; United States of America ; Vegetation ; Wood
for a wood jam at a smaller size than dead wood and had a greater influence on channel morphology. Due to living wood, the range of tree species and sizes that provide stable and functional in-stream large wood may be broader than previously described.
The AA. surveyed 20 stream reaches in Northern California with riparian corridors dominated by broadleaved trees and found that a high proportion of wood jams had key pieces that were still living. Living wood was capable of serving as a key piece

Down dead wood in a forest – still an obstacle to forest management or already an ecological issue ?

Down dead wood in a forest – still an obstacle to forest management or already an ecological issue ?
Classification ; Dead wood ; Environmental management ; Experiment plot ; Forest ; Forestry ; Methodology ; North America ; Poland ; Soil properties ; Sustainable development
This paper consists of 3 complementary sections, preceded by a short review of various Polish publications. The first section is a review of the main assumptions of the American approach to measuring down dead wood (DDW). The second section presents

The basics of sustainable forest management in forest promotional complexes

Biodiversity ; Concept ; Dead wood ; Decision making process ; Ecosystem ; Environmental management ; Forest ; Forestry ; Sustainable development
protection and to introduce the rules of sustainable and balanced forest development. Main subject of this study is a dead wood and its ecological functions in managed forests and chosen FPC reserves. The problem of naturalization or ecologisation of forest

Walter F. WOOD and his science of quantitative terrain analysis

Walter F. WOOD and his science of quantitative terrain analysis
Advances in geomorphometry. Proceedings of the Walter F. Wood memorial symposium
Biobibliographie ; Biographie ; Etats-Unis ; Géomorphologie appliquée ; Géomorphométrie ; Modèle numérique ; Topographie ; WOOD W.F.
A leader in geomorphometry in the 1950's and '60's, the American geographer W.F. Wood published little in the open literature. His best known work was a numerical system of terrain description. This paper reviews Wood's many contributions and lists

Wood storage within the active zone of a large European gravel-bed river

Wood storage within the active zone of a large European gravel-bed river
Ecosystem ; Floodplain ; Fluvial dynamics ; Friuli-Venezia Giulia ; Italy ; Riparian vegetation ; Stream ; Wood
Wood storage within the active zone of the dynamic, gravel-bed, Fiume Tagliamento, Italy, was investigated at 8 sites along the river's main stem. The objective was to study variations in the distribution and abundance of wood at a sample of sites
, in order to identify downstream trends and to understand how the controls on wood storage change along the length of the river.

A journey to the source of the River Oxus

Afghanistan ; Amou Daria ; Asie Centrale ; Exploration ; Histoire de la géographie ; Oxus ; Siècle XIX ; Wood (Captain John)
WOOD Captain John

Deforestation and the uses of wood in the Ecuadorian Andes

Deforestation and the uses of wood in the Ecuadorian Andes
Andes ; Charcoal ; Deforestation ; Domestic use ; Ecuador ; Firewood ; Land use ; Living standard ; Mountain ; Rural economy ; Wood
Wood use is examined in four study areas in highland Ecuador in terms of its importance for the rural economy and its relation to deforestation. Concludes that the need for firewood does not explain deforestation; rather it responds to the demand

Industrial geography

WOOD, P. A.

Impacts of river restoration on small-wood dynamics in a low-gradient headwater stream

Impacts of river restoration on small-wood dynamics in a low-gradient headwater stream
Wood in world rivers. Special issue
Based on tracing dowels to simulate small wood in 3 study reaches before and after restoration, this study provides a detailed representation of the influence of restoration on small-wood transport and the relative importance of different trapping

Dynamics of wood transport in streams : a flume experiment

Dynamics of wood transport in streams : a flume experiment
Carrying capacity ; Experimentation ; Fluvial dynamics ; Japan ; Model ; River bed ; River transport ; Stream ; Stream flow ; Transport ; Wood
The AA. examine some dynamics of wood transport in streams through a series of flume experiments, at the Publish Works Research Institute (PWRI), Tsukuba, Japan, and observe 3 distinct woodtransport regimes : uncongested, congested and semi
-congested. They present an analytical model that predicts flow conditions required to entrain individual pieces. These experiments examined wood movement as a function of flow conditions, channel morphology, and wood size and input rate. Results
of these experiments provide insight into how the depositional fabric of wood accumulations can be used to infer transport dynamics.

Characterizing the variability of wood in streams : simulation modelling compared with multiple-reach surveys

Characterizing the variability of wood in streams : simulation modelling compared with multiple-reach surveys
Wood in world rivers. Special issue
The AA. present 2 independent but complementary methods to develop frequency-volume distributions for wood in 200 m and 400 m reaches on tributaries of the Waihaha River, New Zealand. The first method uses a sliding window analysis of extensive wood
survey data, and the second method uses numerical models based on the Monte Carlo technique. The volume frequency distributions produced by the 2 methods are compared and their value in describing wood abundance in streams is discussed as well
as the implications for management of wood in streams.

A conceptual model for the longitudinal distribution of wood in mountain streams

A conceptual model for the longitudinal distribution of wood in mountain streams
In this study, the AA. evaluate longitudinal patterns of wood distribution in forested headwater streams of the Colorado Front Range, and potential channel-, valley- and watershed-scale controls on these patterns. Based on studies in other
environments, they hypothesize that wood load decreases downstream. Based on qualitative observations of wood in streams of the study area over many years, they hypothesize that wood is non-randomly distributed at channel lengths of tens to hundreds of meters
as a result of the presence of wood jams. They also hypothesize that the proportion of wood clustered into jams increases with drainage area as a result of downstream increases in relative capacity of a stream to transport wood introduced from the adjacent
riparian zone and valley bottom. Results support the first and second hypotheses, but are inconclusive with respect to the third hypothesis. The AA. use these results to propose a conceptual model illustrating downstream trends in wood within streams

Decadal changes in distribution and frequency of wood in a free meandering river, the Ain River, France

Decadal changes in distribution and frequency of wood in a free meandering river, the Ain River, France
Ain ; Bank erosion ; Channel geometry ; Ecosystem ; France ; Jura ; Meander ; Riparian vegetation ; Stream ; The 1950's ; The 1990's ; The 2000's ; Wood ; Woody debris
This study examined the temporal dynamics and longitudinal distribution of wood over a multi-decadal timescale at the river reach scale (36 km) and a meander bend scale (300-600 m) in the Ain River, a large gravel-bed river flowing through
a forested corridor, and adjusting to regulation and floodplain land-use change. At the reach scale they estimate wood production to the river from the riparian forest by bank erosion over a six-decade time period, and describe the distribution (longitudinal
and cross-sectional) and abundance of wood over a ten-year period. At the sub-reach scale, they describe the change in wood distribution and mass over a ten-year period. The increase in wood since 1950 is a response to floodplain afforestation, to a change
from braided to meandering channel pattern in response to regulation, and to recent large floods. The results, and the link between sinuosity and wood frequency, establish geomorphology as a dominant wood storage and recruitment control in large gravel

A flume experiment on wood storage and remobilization in braided river systems

A flume experiment on wood storage and remobilization in braided river systems
This work investigates wood dynamics in braided streams through physical modelling in a mobile bed laboratory flume. Temporal evolution of wood deposition patterns and remobilization rates were monitored by a series of vertical images that permitted
the recognition of individual logs. Results show that wood tends to disperse in generally small accumulations, with higher spatial density on top of sediment bars, and is frequently remobilized due to the intense morphological changes. The amount of wood stored
in the channel depends on log input rate through a non-linear relationship, and input rates exceeding approximately 100 logs/hour determine a sharp change in wood dynamics. Turnover rates of logs were similar in the 3 flumes, independently of wood input rate
and largely resembling the turnover rate of exposed bars. For the simulated conditions, significant effects of wood on bed morphology were not observed, suggesting that interactions with fine sediments and living vegetation are crucial to form large, stable
wood jams able to bring about relevant morphological changes.

Implementation and validation of video monitoring for wood budgeting in a wandering piedmont river, the Ain River (France)

Implementation and validation of video monitoring for wood budgeting in a wandering piedmont river, the Ain River (France)
The AA. use a streamside video camera to detect wood passage and measure quasi-instantaneous rates of wood transport in the Ain River, France. The aims are to verify the procedure, describe the relation between wood transport and discharge
, and construct and validate a wood budget for the reach upstream of the camera. Verification of the procedure includes tests of detection frequency, wood velocity, and piece size. A log base two transformation is proposed to classify wood by piece length
. It was found that a wood transport threshold occurs at approximately two thirds of the bankfull discharge. Wood transport follows a positive linear relation with discharge up to the bankfull discharge but is both more variable and less sensitive to discharge

Forest age, wood and nutrient dynamics in headwater streams of the Hubbard Brook Experimental Forest, NH

Forest age, wood and nutrient dynamics in headwater streams of the Hubbard Brook Experimental Forest, NH
Wood in world rivers. Special issue
This study tested how instream uptake of nitrate and phosphate were affected by successional differences in the accumulation of large wood and debris dams in a 66-year chronosequence formed by 5 watersheds within the Hubbard Brook Experimental
age/large wood volume to increased abiotic adsorption of phosphate by the inorganic sediments retained by wood.

Oxygen isotope ratios from tree rings containing compression wood

Oxygen isotope ratios from tree rings containing compression wood
During studies of oxygen isotope : temperature relationships for tree rings in the Canadian Rockies, the AA. noted differences in oxygen isotope ratios between samples from compression wood and normal radii in the same stem. This paper briefly

Population studies

WOODS, R.

Scales and arrangements of large wood in first- through fifth-order streams of the Blue Ridge Mountains

Scales and arrangements of large wood in first- through fifth-order streams of the Blue Ridge Mountains
Large wood frequency and volume were examined as a function of landscape characteristics at different spatial and temporal scales in 50 reaches of the Upper Little Tennessee River basin. Riparian cover was analyzed with geomorphic and additional
landscape variables to isolate factors that most influence wood in streams. Forested area immediately surrounding the reach was the strongest predictor of wood frequency and volume, although upstream riparian cover can explain additional variation in wood
distributions. An optimal forested buffer width around the stream for large wood was not evident. The relationship between the riparian forest and wood weakens in bigger channels, as fluvial transport of pieces increases. Resurveys demonstrate that large wood

Résultats de la recherche (621 résultats)

Affinez votre recherche