Cell formation in growth rings of balsam fir (Abies balsamea (L.) Mill) the boreal forest was studied to describe timing ring and development patterns earlywood latewood. Wood micro-cores were extracted during growing season from 1998 2000. The stained with cresyl fast violet facilitate counting number cells radial enlargement, wall thickening phases, mature cell phases. periods required complete these various phases then estimated. Variations beginning (May 7 – June 7), earlywood–latewood...

Age structures and growth curves were used to determine the origin follow development of 17 balsam fir (Abiesbalsamea (L.) Mill.) stands in middle Boreal Zone north Lake Saint-Jean, Quebec. Every curve from studied sites presented a more or less long period suppression early fir, followed by marked release synchronous between trees given site. Generally, cohort established just before release. Characteristic releases generally occurred after formation exceptionally narrow rings, which took...

Balsam fir (Abiesbalsamea (L.) Mill.) mortality caused by the last spruce budworm (Choristoneurafumiferana (Clem.)) outbreak (1970–1987) was studied in 624 sites belonging to a complex natural forest mosaic originating from different fires northwestern Quebec. Multiple regression analyses were used assess respective effects of stand structure, species composition, site characteristics, and composition surrounding on observed mortality. Mortality increase relation diameter trees, basal area...

Climate change is altering insect disturbance regimes via temperature‐mediated phenological changes and trophic interactions among host trees, herbivorous insects, their natural enemies in boreal forests. Range expansion increase outbreak severity of forest insects are occurring Europe North America. The degree to which northern ecosystems resilient novel will have direct consequences for the provisioning goods services from these forests long‐term management planning. Among major ecological...

The chronology of eastern spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks in the vicinity Lake Duparquet Abitibi region, Quebec, was determined for a period 200 years using dendroecological methods. Growth patterns two host species, balsam fir (Abiesbalsamea (L.) Mill.) and white (Piceaglauca (Moench) Voss), were compared with cedar (Thujaoccidentalis L.), nonhost maps defoliation surveys. method permitted precise dating past prior to last decades, where cartographic information...

In scenarios of future climate change, there is a projected increase in the occurrence and severity natural disturbances boreal forests. Spruce budworm (Choristoneura fumiferana) (SBW) main defoliator conifer trees North American forests affecting large areas causing marked losses timber supplies. However, impact spatiotemporal patterns SBW dynamics at landscape scale over last century remain poorly known. This particularly true for northern regions dominated by spruce species. The goal this...

In extratropical ecosystems, the growth of trees is cyclic, producing tree rings composed large-lumen and thin-walled cells (earlywood) alternating with narrow-lumen thick-walled (latewood). So far, physiology behind wood formation processes associated kinetics has rarely been considered to explain this pattern. We developed a process-based mechanistic model that simulates development conifer tracheids, explicitly considering cell enlargement deposition lignification walls. The assumes (1)...

It is argued that spruce budworm ( Choristoneura fumiferana (Clemens)) (SBW) outbreaks have tended to be more frequent, severe, and spatially synchronized since the beginning of 20th century. However, few studies assessed long-term (>200 years) variations in SBW outbreak dynamics. We reconstructed history at northern limit temperate forest southern Quebec using dendrochronological material from old buildings five old-growth stands. Our regional tree-ring chronology (1551–1995) represents...

Partial cutting is thought to be an alternative achieve sustainable management in boreal forests. However, the effects of intermediate harvest intensity (45%–80%) on growth remain unknown black spruce (Picea mariana (Mill.) B.S.P.) stands, one most widely distributed species with great commercial interest. In this study, we analysed effect three experimental shelterwood and seed-tree treatments tree radial even-aged 10 years after intervention. Our results show that response 8–10 was 41% 62%...

Forest ecosystem management heads towards the use of partial cuttings. However, wide variation in growth response residual trees remains unexplained, preventing a suitable prediction forest productivity. The aim study was to assess individual and identify driving factors involved responses trees. Six blocks even-aged black spruce [Picea mariana (Mill.) B.S.P.] stands eastern Canadian boreal were submitted experimental shelterwood seed-tree treatments. Individual-tree models applied 1039...

Partial cutting has been recommended as an alternative harvesting method to ensure the sustainable management of boreal forests. The success this approach is closely linked survival residual trees additional losses through mortality could affect post-cutting timber production at harvest. To better quantify in previously unmanaged forests, we addressed two main questions: (1) what level ten years after cutting? and (2) ecological factors are involved phenomenon? Even-aged black spruce [Picea...

Forest regeneration is a key element in achieving sustainable forest management. Partial harvest methods have been used extensively temperate broadleaf and mixedwood ecosystems to promote on poorly stocked sites maintain composition productivity. However, their effectiveness promoting conifer establishment has yet be demonstrated unmanaged boreal forests, especially those dominated by black spruce (Picea mariana (Mill.) BSP) where constraints for differ from found more meridional regions. We...

A time series analysis was performed on 32 dendrochronological chronologies using Dutilleul's multi frequential periodo gram. Our aim to estimate the periodicities of spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks in province Quebec. estimated a signal 25-38 years corresponding outbreaks. Analyses conducted 20th century indicated existence true half suggesting local population dynamics. These were be 29-34 years. For other series, explained by addition second periodic component...

In the short term, trees rely on internal storage of water because it affects their ability to sustain photosynthesis and growth. However, is not rapidly available for transpiration from all compartments plant living tissues stem act as a buffer preclude low potentials during peaks transpiration. this paper, electronic dendrometers were used mid-June mid-September 2008 compare radius variations in roots black spruce [Picea mariana (Mill.) B.S.P.] two sites boreal forest Quebec, Canada, with...

Characterizing millennial and multi-millennial variability in disturbance regimes will be crucial improving knowledge within the context of a changing climate development sustainable forest management practices eastern Canadian mixed boreal forest. The major biotic abiotic disturbances are spruce budworm, fire, respectively. ability to reconstruct these agents under different conditions over long time periods help elucidate interaction between their dynamics objective this observational...

Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses timber supplies. In 2017, spruce affected more than 7 million ha Eastern Canadian forest. Defoliation was particularly severe for black (Picea mariana (Mill.) B.S.P.), one most important commercial Canada. During last decades, intensive forest exploitation practices have created vast stands young balsam fir (Abies balsamea...

Natural disturbance is one of the major topics in ecology. However, most paleoecological studies have only considered influence wildfire as an agent disturbance, with fire history based primarily on use charcoal a proxy for events. The frequency and intensity insect outbreaks their effect forest landscape been neglected due to absence effective tool. Finding indicators able provide insight into impacts past therefore essential. Fossil moth (Lepidoptera) wing scales offer new approach...

Secondary growth is a process related to the formation of new cells that increase in size and wall thickness during xylogenesis. Temporal dynamics wood influence cell traits, turn affecting patterns across tree ring. We verified hypothesis diameter are positively correlated with duration their differentiation phases.Histological sections were produced by microcores assess periods black spruce [Picea mariana (Mill.) B.S.P.]. Samples collected weekly between 2002 2016 from total 50 trees five...

Les banques de semis 14 peuplements sapin baumier (Abies balsamea (L.) Mill.) d'âges varies affectes a differents niveaux par la demiere epidemie tordeuse des bourgeons l'epinette (Choristoneura fumiferana (Clem.)) ont ete etudiees dans zone boreale situee au nord du Lac Saint-Jean, Quebec. objectifs l'etude etaient (1) caracteriser structure d'âge populations sapin, (2) d'observer relations entre les structures et celle strate arborescente (3) d'evaluer l'impact derniere sur comparer date...