Analyse dendrochronologique d'un glissement de terrain de la région du Lac à l'Eau Claire (Québec nordique)

1985 ◽  
Vol 22 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Christian Bégin ◽  
Louise Filion
Keyword(s):  
Tree Ring ◽  
Forest Regeneration ◽  
Climatic Conditions ◽  
Reaction Wood ◽  
Growth Rings ◽  
Glissement De Terrain ◽  
Landslide Occurrence ◽  
Slow Progression ◽  
Ring Analysis

A landslide in Clearwater Lake has been dated to spring of 1933 from tree-ring analysis (reaction wood, growth suppression, and corrosion scars). From the 52 sampled trees, seven peak periods of movement were registered within the site before landslide occurrence: 1785, 1815, 1827, 1829, 1852–1853, 1871–1872, 1897, and 1926. After a slow progression lasting 200 years, the slope movements accelerated in 1926, as indicated by suppressed growth rings. It is proposed here that the landslide was the outcome of a long-term slope development partly controlled by climate (precipitation). Postdisturbance forest regeneration (between 1950 and 1976) on the newly exposed substrate is also related to climatic conditions.

scholarly journals Jahrringe als Indikatoren für extreme Standortsbedingungen im Gebirge: Schnee, Lawinen und Permafrost | Growth rings as indicators of extreme site conditions in the mountains: snow, avalanches and permafrost

2004 ◽  
Vol 155 (6) ◽  
pp. 208-212 ◽  
Author(s):  
Peter Bebi ◽  
Alejandro Casteller ◽  
Andrea Corinna Mayer ◽  
Veronika Stöckli
Keyword(s):  
Natural Hazards ◽  
Growth Ring ◽  
Management Strategies ◽  
Extreme Conditions ◽  
Site Conditions ◽  
Snow Avalanches ◽  
Growth Rings ◽  
Survival And Growth ◽  
Ring Analysis

Snow, avalanches, and permafrost are extreme site conditions for plants. Reactions and adaptations to such extreme conditions can be reconstructed with growth ring analysis and linked with corresponding climate and disturbance data. On the basis of five case studies in and around the long-term research site Stillberg, near Davos, we discuss both the potential and the limits of dendroecology to understand the effect of such extreme site conditions. Despite some uncertainties in reliably assigning plant reactions, growth ring analysis is a valuable addition to better understand the effects of extreme site conditions on the survival and growth of plants. This can lead to improved management strategies associated with natural hazards, especially in the case of avalanches.

scholarly journals Episodic and Systematic Tree Ring-Width Variation (AD 1763–2013) in the Takhini Valley, Southwest Yukon, Canada

ARCTIC ◽  
2017 ◽  
Vol 70 (4) ◽  
Author(s):  
Wayne L Strong
Keyword(s):  
Tree Ring ◽  
Polynomial Regression ◽  
Ring Width ◽  
Steady Increase ◽  
Tree Ring Width ◽  
Moisture Index ◽  
Local Climate ◽  
Ring Analysis ◽  
Environmental Events

A tree-ring analysis of 764 western white spruce (Picea albertiana) in the Takhini Valley of southwest Yukon was conducted to assess short- and long-term variation in growth and local climate. The resulting chronology spanned the period from AD 1763 to 2013. A polynomial regression (R = 0.720, p < 0.001) indicated that the pre-1840 segment of the chronology had below-normal tree ring-width index (RWI) values (average 0.64, with modest variation), but the subsequent segment had greater variation and a steady increase in RWI values (average 0.89) until ~1920. After 1930, RWI values began to increase again (average 1.06) with 51% more variation than had previously occurred. Peak RWI values after 1930 were double those of the early 1800s. RWI values were uncorrelated with air temperature variables (except September minima), but weakly and positively correlated (r < 0.35) with precipitation variables. RWI values were moderately correlated with annual heat-moisture index values (r = −0.415, p < 0.001), although more strongly with RWI values less than 1.1 (R = −0.631, p < 0.001). Therefore, the RWI chronology was interpreted from an ecological moisture-balance perspective, with possible long-term temperature changes estimated from archival sources. The latter suggested a 2.1˚ – 3.1˚C rise since the early 1800s. Extreme RWI values and portions of the chronology were associated with known environmental events.

scholarly journals TREE RING ANALYSIS OF BRACHYSTEGIA SPICIFORMIS AND ISOBERLINIA TOMENTOSA: EVALUATION OF THE ENSO-SIGNAL IN THE MIOMBO WOODLAND OF EASTERN AFRICA

IAWA Journal ◽  
2001 ◽  
Vol 22 (4) ◽  
pp. 385-399 ◽  
Author(s):  
Valérie Trouet ◽  
Kristof Haneca ◽  
Pol Coppin ◽  
Hans Beeckman
Keyword(s):  
Tree Ring ◽  
Southern Oscillation ◽  
Growth Ring ◽  
Eastern Africa ◽  
Monthly Precipitation ◽  
Miombo Woodland ◽  
Growth Rings ◽  
Ring Analysis ◽  
Cross Dating ◽  
Brachystegia Spiciformis

The value of growth rings as proxy data for climate reconstruction was studied in two miombo woodland species in eastern Africa. Growth rings, marked by terminal parenchyma, were visually detectable on carefully prepared stem discs of Isoberlinia tomentosa and Brachystegia spiciformis, dominant species of the miombo woodland in north-western Tanzania. However, the presence of multiple growth ring anomalies rendered cross-dating of the growth ring series between trees difficult. Cross-dating succeeded for eight out of thirteen samples for Isoberlinia tomentosa, but was unsuccessful for Brachystegia spiciformis. A mean series of 38 years was calculated for Isoberlinia tomentosa only. Monthly precipitation, monthly maximum air temperature and monthly SOI-value (Southern Oscillation Index) correlated significantly with tree ring widths of the mean series. These correlations are strong indicators of the annual character of the growth rings. They also suggest that Isoberlinia tomentosa provides an appropriate paleoclimatic record for dendroclimatic reconstruction.

No evidence for consistent long-term growth stimulation of 13 tropical tree species: results from tree-ring analysis

2015 ◽  
Vol 21 (10) ◽  
pp. 3762-3776 ◽  
Author(s):  
Peter Groenendijk ◽  
Peter van der Sleen ◽  
Mart Vlam ◽  
Sarayudh Bunyavejchewin ◽  
Frans Bongers ◽  
...  
Keyword(s):  
Tree Ring ◽  
Tree Species ◽  
Growth Stimulation ◽  
Tropical Tree ◽  
Tree Ring Analysis ◽  
Tropical Tree Species ◽  
Ring Analysis ◽  
Stimulation Of

Wood anatomy and growth ring boundaries of Copaifera lucens (Fabaceae)

IAWA Journal ◽  
2018 ◽  
Vol 39 (4) ◽  
pp. 395-405 ◽  
Author(s):  
Cláudia Fontana ◽  
Gonzalo Pérez-de-Lis ◽  
Luiz Santini-Junior ◽  
Paulo César Botosso ◽  
Cristina Nabais ◽  
...  
Keyword(s):  
Tree Ring ◽  
Wood Anatomy ◽  
Growth Ring ◽  
Mature Wood ◽  
Growth Rings ◽  
False Rings ◽  
Naked Eye ◽  
Gelatinous Fibers ◽  
Secretory Canals ◽  
Ring Analysis

ABSTRACTThe wood anatomy of Copaifera lucens Dwyer was studied with an emphasis on its growth ring boundaries. Growth rings are visible to the naked eye and demarcated by marginal parenchyma bands and, sometimes, by thick-walled fibers in the latewood. Secretory canals are associated with marginal parenchyma bands, but not all marginal parenchyma bands are associated with canals. Paratracheal parenchyma is vasicentric to lozenge-aliform. Rays are 1–4-seriate, heterocellular and non-storied. Vessels are visible to the naked eye, diffuse, predominantly solitary, some in multiples, sometimes filled with gums. Crystals present. Wood anatomical characteristics of C. lucens are in agreement with those previously reported for other species of Copaifera. In addition to what had already been described for C. lucens, we observed gelatinous fibers, and some bifurcate fibers, and extremely rare clustered vessels. The growth ring boundaries are well-defined in mature wood but less distinctive near the pith. There are also partial and confluent (wedging) rings, which are difficult to classify by anatomy only, but which represent false rings and complicate tree-ring analysis in this species.

Ancient charcoal as a natural archive for paleofire regime and vegetation change in the Mayumbe, Democratic Republic of the Congo

2013 ◽  
Vol 80 (2) ◽  
pp. 326-340 ◽  
Author(s):  
Wannes Hubau ◽  
Jan Van den Bulcke ◽  
Peter Kitin ◽  
Florias Mees ◽  
Geert Baert ◽  
...  
Keyword(s):  
Forest Regeneration ◽  
Vegetation Change ◽  
Democratic Republic ◽  
Climatic Conditions ◽  
Medieval Climate Anomaly ◽  
Climate Anomalies ◽  
Republic Of The Congo ◽  
Natural Archive ◽  
Forest Boundary

Charcoal was sampled in four soil profiles at the Mayumbe forest boundary (DRC). Five fire events were recorded and 44 charcoal types were identified. One stratified profile yielded charcoal assemblages around 530 cal yr BP and > 43.5 cal ka BP in age. The oldest assemblage precedes the period of recorded anthropogenic burning, illustrating occasional long-term absence of fire but also natural wildfire occurrences within tropical rainforest. No other charcoal assemblages older than 2500 cal yr BP were recorded, perhaps due to bioturbation and colluvial reworking. The recorded paleofires were possibly associated with short-lived climate anomalies. Progressively dry climatic conditions since ca. 4000 cal yr BP onward did not promote paleofire occurrence until increasing seasonality affected vegetation at the end of the third millennium BP, as illustrated by a fire occurring in mature rainforest that persisted until around 2050 cal yr BP. During a drought episode coinciding with the "Medieval Climate Anomaly", mature rainforest was locally replaced by woodland savanna. Charcoal remains from pioneer forest indicate that fire hampered forest regeneration after climatic drought episodes. The presence of pottery shards and oil-palm endocarps associated with two relatively recent paleofires suggests that the effects of climate variability were amplified by human activities.

scholarly journals STAV VÝZKUMU BLOKOVOBAHENNÍCH PROUDŮ NA ZÁPADNÍCH SVAZÍCH KEPRNICKÉ HORNATINY (HRUBÝ JESENÍK)

2014 ◽  
Vol 21 (1-2) ◽  
Author(s):  
Radek Tichavský ◽  
Karel Šilhán
Keyword(s):  
Debris Flow ◽  
Tree Ring ◽  
Debris Flows ◽  
Drainage Basin ◽  
Climatic Conditions ◽  
Tree Ring Analysis ◽  
Geomorphological Mapping ◽  
Spatial Dimensions ◽  
Ring Analysis ◽  
Channel Bottom

The debris flows are fast dangerous processes initiated also in mid-mountains of the Czech Republic, frequently damaging forest stands. An occurrence of debris flows in the Hrubý Jeseník Mts. is connected with steep slopes and high-gradient channels predisposed by landuse, morphometric, lithological and especially climatic conditions. The first stage of research was implemented in the Klepáčský brook drainage basin. In 2013, a field geomorphological mapping and sampling of disturbed trees for dendrogeomorphic research (tree ring analysis) were carried out. There are preserved several remnants of former debris flows. The oldest accumulations in a form of terraces above the channel bottom, younger but stable and overgrown lateral levees and recent fresh frontal lobes directly in the channel were distinguished. At least 9 debris flow events in the last 60 years were dated in the Klepáčský brook from the tree ring analysis; the year 2010 was the last known and the most represented period in the tree ring series. Spatial dimensions, magnitudes of debris flows and places of their origin has been changed during the last decades so we could analyze their different behaviour patterns (e. g. 1991, 1997 and 2010), recorded in disturbed trees along the brook. The research will be extended to other basins in the Keprnická hornatina Mts., focusing on factors of debris flow predisposition and chronology with an application of dendrogeomorphic methods being actually the most accurate approach for dating of events in far-flung tree-covered basins.

scholarly journals Growth-Climate Relationships and Long-Term Growth Trends of the Tropical Forest Tree Choerospondias axillaris (Anacardiaceous) in East-Central Thailand

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1655
Author(s):  
Wisawakorn Surayothee ◽  
Supaporn Buajan ◽  
Peili Fu ◽  
Nathsuda Pumijumnong ◽  
Zexin Fan ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Tree Ring ◽  
Monsoon Season ◽  
Forest Tree ◽  
East Central ◽  
Tree Ring Analysis ◽  
Growth Trends ◽  
Ring Analysis ◽  
Central Thailand

Tropical forests play important roles in global carbon cycling. Tree-ring analysis can provide important information for understanding long-term trends in carbon-fixation capacity under climate change. However, tree-ring studies in tropical regions are limited. We carried out a tree-ring analysis to investigate the dendrochronological potential of the tropical forest tree Choerospondias axillaris (Anacardiaceae) in east-central Thailand. Our study focused on growth-climate relationships and long-term growth trends. A chronology was constructed covering the period from 1932 to 2019. The tree-ring width index of C.axillaris was positively correlated with precipitation in June, July, and October. Furthermore, growth of C.axillaris was positively correlated with the Standardized Precipitation-Evapotranspiration Index (SPEI) from July to October, indicating that growth of C.axillaris is mainly limited by moisture availability in the late monsoon season. Moving correlation analysis further revealed the consistency and temporal stability of the relationship of tree growth with monsoon season precipitation and SPEI during the period under study. There was a significant increasing trend in long-term growth from 1932 to 2002 (slope = 0.017, p < 0.001); however, long-term growth decreased from 2003 to 2019 (slope = −0.014, p < 0.001). Our study provides important insight into the growth-climate correlations of a broad-leaved tree species in a dry evergreen forest in tropical Asia.

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