A lonely dot on the map: Exploring the climate signal in tree-ring density and stable isotopes of clanwilliam cedar, South Africa

2021 ◽  
Vol 69 ◽  
pp. 125879
Author(s):  
Tom De Mil ◽  
Matthew Meko ◽  
Soumaya Belmecheri ◽  
Edmund February ◽  
Matthew Therrell ◽  
...  
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Tree Ring ◽  
Climate Signal ◽  
Ring Density

Exploring the climate signal in tree-ring density of Clanwilliam cedar, South Africa

2020 ◽  
Author(s):  
Valerie Trouet ◽  
Tom De Mil ◽  
Matthew Meko ◽  
Jan Van den Bulcke
Keyword(s):  
South Africa ◽  
Tree Ring ◽  
Southern Africa ◽  
Ring Width ◽  
Future Climate Change ◽  
Spring Precipitation ◽  
Climate Signal ◽  
Climatic Signal ◽  
X Ray Computed ◽  
Instrumental Records

<p>High-resolution annual precipitation and temperature proxies are largely lacking in Southern Africa, partly due to the scarcely available tree species that are suitable for dendrochronology. Clanwilliam cedar (Widdringtonia cedarbergensis) from Cape Province, South Africa, is a long-lived conifer with distinct tree rings and thus a strong dendroclimatic potential. However, the climatic signal in its tree-ring width (TRW) is weak and other tree-ring parameters such as density need to be explored to extract climatic information from this proxy. Here we investigate the climatic signal of density parameters in 17 Clanwilliam cedar samples (9 trees) collected in 1978 (Dunwiddie & LaMarche, 1980). We use a non-destructive X-ray Computed Tomography facility to develop minimum density (MIND) and maximum density (MXD) chronologies from 1900 until 1977. EPS for both density series exceeded 0.85. For the period 1930-1977 (reliable instrumental records), MIND correlates negatively with early-growing season precipitation (Oct-Nov), whereas MXD correlates negatively with end-of-season (March) temperature. The spatial correlation between MIND and spring precipitation spans the winter rainfall zone of South Africa. Clanwilliam cedar can live to be 356 years old and the current TRW chronology extends to 1564 CE. Full-length density chronologies for this long-lived species could provide a precipitation reconstruction for southern Africa, a region where historical climate observations are limited and where societal vulnerability to future climate change is high.</p><p>References:</p><p>Dunwiddie, P. W., & LaMarche, V. C. (1980). A climatically responsive tree-ring record from Widdringtonia cedarbergensis, Cape Province, South Africa. Nature, 286(5775), 796–797.</p>

scholarly journals Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

2021 ◽  
Author(s):  
Paolo Cherubini ◽  
Giovanna Battipaglia ◽  
John L. Innes
Keyword(s):  
Air Pollution ◽  
Stable Isotopes ◽  
Tree Ring ◽  
Forest Decline ◽  
Forest Health ◽  
Stress Factors ◽  
Tree Vitality ◽  
The Past ◽  
Physiological Processes

Abstract Purpose of Review Society is concerned about the long-term condition of the forests. Although a clear definition of forest health is still missing, to evaluate forest health, monitoring efforts in the past 40 years have concentrated on the assessment of tree vitality, trying to estimate tree photosynthesis rates and productivity. Used in monitoring forest decline in Central Europe since the 1980s, crown foliage transparency has been commonly believed to be the best indicator of tree condition in relation to air pollution, although annual variations appear more closely related to water stress. Although crown transparency is not a good indicator of tree photosynthesis rates, defoliation is still one of the most used indicators of tree vitality. Tree rings have been often used as indicators of past productivity. However, long-term tree growth trends are difficult to interpret because of sampling bias, and ring width patterns do not provide any information about tree physiological processes. Recent Findings In the past two decades, tree-ring stable isotopes have been used not only to reconstruct the impact of past climatic events, such as drought, but also in the study of forest decline induced by air pollution episodes, and other natural disturbances and environmental stress, such as pest outbreaks and wildfires. They have proven to be useful tools for understanding physiological processes and tree response to such stress factors. Summary Tree-ring stable isotopes integrate crown transpiration rates and photosynthesis rates and may enhance our understanding of tree vitality. They are promising indicators of tree vitality. We call for the use of tree-ring stable isotopes in future monitoring programmes.

scholarly journals Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world’s highest elevation tree-species

2021 ◽  
Author(s):  
Milagros Rodriguez-Caton ◽  
Laia Andreu-Hayles ◽  
Mariano S Morales ◽  
Valérie Daux ◽  
Duncan A Christie ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Carbon Source ◽  
Tree Ring ◽  
Tree Growth ◽  
Carbon Sink ◽  
Growing Season ◽  
Wood Formation ◽  
Aridity Gradient ◽  
Leaf Level ◽  
Δ13c And Δ18o

Abstract Tree growth is generally considered to be temperature-limited at upper elevation treelines. Yet, climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polyepis tarapacana, the world’s highest elevation tree-species found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4,400 meters in elevation, along a 500-km latitude-aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon-sink processes along the gradient. Current-growing season temperature regulated RWI at wetter-northern sites, while prior-growing season precipitation determined RWI at arid-southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site-water availability. In contrast, warm and dry growing-seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern-drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. The manuscript also highlights a coupling and decoupling of physiological processes at leaf level versus wood formation depending on their respectively uniform and distinct sensitivity to climate. This study contributes to better understand and predict the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.

scholarly journals Climate signal in tree-ring chronologies in a temperate climate: A multi-species approach

2009 ◽  
Vol 27 (3) ◽  
pp. 183-198 ◽  
Author(s):  
A.M. García-Suárez ◽  
C.J. Butler ◽  
M.G.L. Baillie
Keyword(s):  
Tree Ring ◽  
Temperate Climate ◽  
Climate Signal

scholarly journals Historical Forest Management Practices Influence Tree-Ring Based Climate Reconstructions

2021 ◽  
Vol 9 ◽  
Author(s):  
Georgios Skiadaresis ◽  
Bernhard Muigg ◽  
Willy Tegel
Keyword(s):  
Forest Management ◽  
Tree Ring ◽  
Management Practices ◽  
Growth Patterns ◽  
Climate Control ◽  
Climate Signal ◽  
Forest Management Practices ◽  
Management Interventions ◽  
Climate Reconstructions ◽  
Historical Forest

Tree-ring widths (TRW) of historical and archeological wood provide crucial proxies, frequently used for high-resolution multi-millennial paleoclimate reconstructions. Former growing conditions of the utilized trees, however, are largely unknown. Potential influences of historical forest management practices on climatic information, derived from TRW variability need to be considered but have not been assessed so far. Here, we examined the suitability of TRW series from traditionally managed oak forests (Quercus spp.) for climate reconstructions. We compared the climate signal in TRW chronologies of trees originating from high forests and coppice-with-standards (CWS) forests, a silvicultural management practice widely used in Europe for most of the common era. We expected a less distinct climate control in CWS due to management-induced growth patterns, yet an improved climate-growth relationship with TRW data from conventionally managed high forests. CWS tree rings showed considerably weaker correlations with hydroclimatic variables than non-CWS trees. The greatest potential for hydroclimate reconstructions was found for a large dataset containing both CWS and non-CWS trees, randomly collected from lumber yards, resembling the randomness in sources of historical material. Our results imply that growth patterns induced by management interventions can dampen climate signals in TRW chronologies. However, their impact can be minimized in well replicated, randomly sampled regional chronologies.

scholarly journals Contamination of the Bushveld Complex (South Africa) magmas by basinal brines: Stable isotopes in phlogopite from the UG2 chromitite

Geology ◽  
2021 ◽  
Author(s):  
Haoyang Zhou ◽  
Robert B. Trumbull ◽  
Ilya V. Veksler ◽  
Ilya N. Bindeman ◽  
Johannes Glodny ◽  
...  
Keyword(s):  
South Africa ◽  
Stable Isotopes ◽  
Hydrogen Isotope ◽  
Bushveld Complex ◽  
Isotope Ratios ◽  
Second Step ◽  
Merensky Reef ◽  
Oxygen Isotope Ratios ◽  
Abundant Evidence ◽  
Hydrogen Isotope Ratios

There is abundant evidence for significant H2O in evolved melts from the platinum-rich UG2 chromitite and the Merensky Reef of the Bushveld Complex (South Africa), but there is no consensus about the source of H2O. We report triple-oxygen and hydrogen isotope ratios of interstitial, late-magmatic phlogopite from three localities of the UG2 layer. The phlogopite yielded δD values of –43‰ to –23‰, which is >30‰ higher than previously known from Bushveld rocks and far above the mantle values of ~–75‰. The phlogopite triple-oxygen isotope ratios are the first to be reported for Bushveld rocks, with values of Δ′17O0.5305 (17O excess relative to the reference line 0.5305) from –0.069‰ to –0.044‰ (δ18O 5.2‰–6.2‰). The oxygen data support existing models of as much as 30%–40% contamination of mantlederived magmas in the lower to middle crust. However, the high δ values require a second step of contamination, which we attribute to brines from the marine sediments in the Transvaal Basin at the emplacement level.

scholarly journals Growth and yield estimation of Chamaecyparis spp. through tree ring analysis

2013 ◽  
Vol 22 (2) ◽  
pp. 36-42 ◽  
Author(s):  
D. K. Kharal ◽  
T. Fujiwara
Keyword(s):  
Tree Ring ◽  
Radial Growth ◽  
Ring Width ◽  
Forest Products ◽  
Growth And Yield ◽  
Tree Age ◽  
Biomass Estimation ◽  
Tree Ring Analysis ◽  
Ring Density ◽  
Ring Analysis

Tree ring analysis is one of the most useful methods in volume and biomass estimation especially of the conifer trees. Ring width and ring density are important parameters in dendrochronological research. The present research was carried out with the aim of estimating the radial and volumetric growth of the Japanese Cypress trees (Chamaecyperis obstusa and C. pisifera). Destructive method was used while collecting the wood samples from the selected trees. Ring width and ring density were measured using soft X-ray densitometry method using micro-densitometer. Computer programme, developed by the Forestry and Forest Products Research Institute, Japan was used to analyze the ring with and ring density data. The average ring width of the Chamaecyparis spp. was found to be about 3.4 mm at the age of 30 years. However, two types of growth pattern were observed in the trees. Average radial growth was about 5% every year during the first 20 years of the tree age, whereas, the average radial growth was negative during the age of 20–30 years. Average density of the tree rings were increased by about 11% in each height of the trees starting from the ground. Similarly, the stem density decreased by about 3.4% annually along the radial direction from the pith.DOI: http://dx.doi.org/10.3126/banko.v22i2.9197Banko Janakari: A Journal of Forestry Information for NepalVol. 22, No. 2, 2012 November Page: 36-42 Uploaded date: 12/1/2013 

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