摘要：The Saint-Jean River (SRJ) in Eastern Canada is prone to the
formation of very large rafts of wood. Managers of the SJR suspected these
jams to influence salmon migration and carried out a dismantling operation
to remove large wood accumulated in a 1.2 km long wood raft. This
operation became a great opportunity to address key issues relating to large
wood dynamics in a fluvial system: residence time and flood contribution
to wood recruitment and transport. During the dismantling, we
systematically sampled 319 trees from which year of death could be
estimated from dendrochronology and year of accumulation in the raft
could be obtained from satellite and aerial photos. These two dates allowed
us to quantify the residence time for 262 datable large wood (LW) within
the fluvial system, to examine the peak years of LW recruitment and to
correlate the raft growth rate with hydrometeorological conditions since
1993. The results also emphasized four types of LW flood related to wood
dynamics: 1) an erosive flood that produces a large amount of wood in
river, 2) a mobilizing flood that carries large quantities of wood, 3) a flood
mix that both recruits and transports large quantities of wood, and 4) an
ice-breakup flood.
其他摘要：The Saint-Jean River (SRJ) in Eastern Canada is prone to the formation of very large rafts of wood. Managers of the SJR suspected these jams to influence salmon migration and carried out a dismantling operation to remove large wood accumulated in a 1.2 km long wood raft. This operation became a great opportunity to address key issues relating to large wood dynamics in a fluvial system: residence time and flood contribution to wood recruitment and transport. During the dismantling, we systematically sampled 319 trees from which year of death could be estimated from dendrochronology and year of accumulation in the raft could be obtained from satellite and aerial photos. These two dates allowed us to quantify the residence time for 262 datable large wood (LW) within the fluvial system, to examine the peak years of LW recruitment and to correlate the raft growth rate with hydrometeorological conditions since 1993. The results also emphasized four types of LW flood related to wood dynamics: 1) an erosive flood that produces a large amount of wood in river, 2) a mobilizing flood that carries large quantities of wood, 3) a flood mix that both recruits and transports large quantities of wood, and 4) an ice-breakup flood.
