Tree-ring width and vessel characteristics of oriental beech (Fagus Orientalis) along an altitudinal gradient in the caspian forests, northern iran

IAWA Journal ◽  
2011 ◽  
Vol 32 (4) ◽  
pp. 461-473 ◽  
Author(s):  
Kambiz Pourtahmasi ◽  
Neda Lotfiomran ◽  
Achim Bräuning ◽  
Davoud Parsapajouh

Vessel features of broadleaf trees may contain information about both spatial and temporal variations of environmental conditions. We report quantitative data about annual vessel characteristics for Oriental beech (Fagus orientalis Lipsky) in the Caspian forest in the Alborz Mountains, northern Iran. Time series of tree-ring width and of various vessel variables were constructed over a 50-year period for three sites along an altitudinal gradient from 1260 to 2200 m a.s.l. We evaluated the dependencies between ring width and vessel variables and estimated the influence of altitude and climate on these variables.Mean ring width and average vessel-lumen area decreased towards the high-elevation site whereas total vessel-lumen area was independent from altitude, and vessel density increased. Above-average warm summer and autumn seasons in the year prior to growth were negatively correlated with ring width and average vessel-lumen area whereas precipitation in the current June showed a positive association; vessel density responded exactly opposite to these climatic variables. Total vessel-lumen area was the only variable that reacted differently from site to site, mainly positively to temperature at 1200 m a.s.l. and negatively at 2000 and 2200 m a.s.l., whereas a consistent response to precipitation was lacking. The results indicate that vessel variables are meaningful indicators of changes in dynamics of wood formation in relation to climate along an altitudinal gradient in the Caspian mountains. As for climate reconstruction, we have to conclude that for our study area, vessel variables do not add much to information derived from ring width.

IAWA Journal ◽  
2015 ◽  
Vol 36 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Neda Lotfiomran ◽  
Jörg Fromm ◽  
Gerrit A. Luinstra

Anatomical responses and annual ring-width of beech and poplar saplings were studied under elevated CO2-concentrations (770/950 ppm) with different nu-trient supplies during two growth periods. At the end of each growth season, saplings were harvested and stem vessel characteristics as well as annual growth-rings were analysed. In both study years, elevated CO2 caused a significant increase in ring width (RW) of beech but not of poplar. However, fertilization increased RW in poplar saplings. In beech total vessel lumen area (TVLA) and vessel density (VD) increased under elevated CO2 and both parameters decreased by fertilization. Poplar saplings grown under elevated CO2 had significantly larger vessels as well as TVLA while fertilization induced reduction in average vessel lumen area (AVLA) and TVLA. Vessel density of poplar showed no significant response to different growth conditions. Altogether, the effects of elevated CO2 and fertilization on anatomical features were independent of each other.


2020 ◽  
Author(s):  
Giovanna Battipaglia ◽  
Arturo Pacheco ◽  
Julio Camarero ◽  
Marin Pompa-Garcia ◽  
Jordi Voltas ◽  
...  

<p>An improvement of our understanding of how tree species will respond to warmer conditions and longer droughts requires comparing their responses across different environmental settings and considering a multi-proxy approach. We used different xylem traits (tree-ring width, formation of intra-annual density fluctuations –IADFs, wood anatomy, D<sup>13</sup>C and d<sup>18</sup>O records) to retrospectively quantify these responses in three conifers inhabiting two different drought-prone areas in northwestern Mexico. A fir species (Abies durangensis) was studied in a higher altitude and more humid site and two pine species were sampled in a nearby, drier site (Pinus engelmannii, Pinus cembroides). Tree-ring-width indices (TRWi) of all the species showed very similar year-to-year variability, likely indicating a common climatic signal throughout the whole region. Wood anatomy analyses, covering over 3.5 million measured cells, showed that P. cembroides lumen area was much smaller than in the other two species and it remained constant along all the studied period (over 64 years). Alternately, cell wall was ticker in P. engelmannii which also presented the highest amount of intra-annual density fluctuations. Climate and wood anatomy correlations pointed out that lumen area was positively affected by winter precipitation for all the species, while cell-wall thickness was negatively affected by current season precipitation in all species but P. cembroides, suggesting this taxon may be better adapted to withstand drought than its coexisting conifer with thinner cell walls resulting from wet winters. Stable isotope analysis showed in P. cembroides some of the lowest cellulose-Δ<sup>13</sup>C mean values ever reported in the literature for a forest tree species, although there were no particular trend differences between the studied species. As well, no significant δ<sup>18</sup>O differences where found between the three species, but they shared a common decreasing trend. With very distinct wood anatomical traits (smaller cells, compact morphology), P. cembroides stood out as the better-adapted species in its current environment and could be less affected by future drier climate. P. engelmannii and A. durangensis showed high plasticity at wood anatomical level, allowing them to promptly respond to seasonal water availability, however this feature may provide few advantages on future climate scenarios with longer and more frequent drought spells. Further research, including xylogenesis analysis and monitoring of different populations of these tree species, would be still necessary to reach a clearer understanding of their future responses to weather patterns. Our multi-proxy approach could be used in other forests to characterize the in situ functioning of trees, e.g. growth, water use, and development of strategies for forest management under the current climate change scenarios.</p>


2021 ◽  
Vol 303 ◽  
pp. 108394
Author(s):  
Nathsuda Pumijumnong ◽  
Piyarat Songtrirat ◽  
Supaporn Buajan ◽  
Sineenart Preechamart ◽  
Uthai Chareonwong ◽  
...  

2010 ◽  
Vol 29 (17-18) ◽  
pp. 2111-2122 ◽  
Author(s):  
X. Shao ◽  
Y. Xu ◽  
Z.-Y. Yin ◽  
E. Liang ◽  
H. Zhu ◽  
...  

2017 ◽  
Vol 41 (4) ◽  
pp. 478-495 ◽  
Author(s):  
UK Thapa ◽  
S St. George ◽  
DK Kharal ◽  
NP Gaire

The climate of Nepal has changed rapidly over the recent decades, but most instrumental records of weather and hydrology only extend back to the 1980s. Tree rings can provide a longer perspective on recent environmental changes, and since the early 2000s, a new round of field initiatives by international researchers and Nepali scientists have more than doubled the size of the country’s tree-ring network. In this paper, we present a comprehensive analysis of the current tree-ring width network for Nepal, and use this network to estimate changes in forest growth nation-wide during the last four centuries. Ring-width chronologies in Nepal have been developed from 11 tree species, and half of the records span at least 290 years. The Nepal tree-ring width network provides a robust estimate of annual forest growth over roughly the last four centuries, but prior to this point, our mean ring-width composite fluctuates wildly due to low sample replication. Over the last four centuries, two major events are prominent in the all-Nepal composite: (i) a prolonged and widespread growth suppression during the early 1800s; and (ii) heightened growth during the most recent decade. The early 19th century decline in tree growth coincides with two major Indonesian eruptions, and suggests that short-term disturbances related to climate extremes can exert a lasting influence on the vigor of Nepal’s forests. Growth increases since AD 2000 are mainly apparent in high-elevation fir, which may be a consequence of the observed trend towards warmer temperatures, particularly during winter. This synthesis effort should be useful to establish baselines for tree-ring data in Nepal and provide a broader context to evaluate the sensitivity or behavior of this proxy in the central Himalayas.


The Holocene ◽  
2021 ◽  
pp. 095968362110116
Author(s):  
Jeroen DM Schreel

Over the last few decades – at a range of northern sites – changes in tree-ring width and latewood density have not followed mean summertime temperature fluctuations. This discrepancy sharply contrasts an earlier correlation between those variables. As the origin of this inconsistency has not been fully deciphered, questions have emerged regarding the use of tree-ring width and latewood density as a proxy in dendrochronological climate reconstructions. I suggest that temperature is no longer the most limiting factor in certain boreal areas, which might explain the observed divergence.


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