Oak decline in a southern Finnish forest as affected by a drought sequence

Sohar, Kristina; Helama, Samuli; Läänelaid, Alar; Raisio, Juha; Tuomenvirta, Heikki

doi:10.2478/s13386-013-0137-2

Cited by 41 publications

(25 citation statements)

References 115 publications

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“…5 is suggestive of this point of view and emphasizes the importance of EW in the interpretation of the local climatic variations. It is noteworthy that most studies (Garcia-González & Eckstein, 2003;Tardif & Conciatori, 2006;Sohar et al, 2013;Kern et al, 2013) emphasize the importance of LW, disregarding the potential of EW. Our results reveal that differentiating the analysis of Fig.…”

Section: Discussionmentioning

confidence: 99%

Interpreting the effect of regional climate fluctuations on Quercus robur L. trees under a temperate continental climate (southern Romania)

Nechita¹,

Chiriloaei²

2017

Dendrobiology

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Interpreting the effect of regional climate fluctuations on Quercus robur L. trees under a temperate continental climate (southern Romania) Received: 6 July 2017; Accepted: 27 November 2017 Abstract: To determine oak tree sensitivity to climate fluctuations as a precipitation predictor, we eliminated monthly climate data and computed the growth-precipitation correlation using mean daily values calculated in time intervals. Precipitation from March through May is the primary limiting factor in intra-annual tree-ring growth for Quercus robur L. in southern Romania. Bootstrap correlations between the residual series and monthly average precipitation showed a positive dependence (r = 0.4). Using CLIMTREG software and daily climate data, we obtained correlation values of (0.6) and a better understanding of on-going tree radial growth. We found that the oak growth process is active during two distinct periods in the study area, December 22 th -February 10 th (earlywood) and March 04 th -June 13 th (latewood). For the studied oak tree population, the correlation with climate was positive with respect to precipitation and negative with respect to temperature. This indicates that annual tree-ring formation was influenced by the precipitation regime and frequency and by the degree of drought. These results also indicate that different behaviours occur among the examined earlywood and latewood under the same climatic conditions, which were then analysed.

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Section: Discussionmentioning

confidence: 99%

Interpreting the effect of regional climate fluctuations on Quercus robur L. trees under a temperate continental climate (southern Romania)

Nechita¹,

Chiriloaei²

2017

Dendrobiology

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“…In recent years, an oak decline has been observed in many areas in Europe, mostly due to changes in the climatic and hydrological conditions (Führer 1998;Klimo and Hager 2001;Di Filippo et al 2010;Doležal et al 2010;Matisons et al 2013;Sohar et al 2013). On the other hand, Tulik and Bijak (2016) found a less significant effect of climate on oak decline.…”

Section: Introductionmentioning

confidence: 99%

Does tree-ring formation follow leaf phenology in Pedunculate oak (Quercus robur L.)?

et al. 2017

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We monitored leaf phenology and xylogenesis of 12 Pedunculate oaks in northern Poland in 2014. We hypothesized that the individual trees, which differed in size, age and habitat (tree stand or gap), also diverged in terms of the seasonal patterns of leaf phenology and xylogenesis. The samples used for wood formation observations were collected most frequently during the early leaf phenophases (from March to end of June). The transverse sections of the cambial region were cut with a sledge microtome. We counted the number of cambial cells, measured the width of xylem increment and assessed the timing of xylogenesis and earlywood-vessel formation. We found significant differences in leaf phenology and timing of xylogenesis among individual trees. The smallest differences in wood formation among the trees were observed at the beginning of the vegetation season when the first earlywood vessels were detected (9 days). The dates of completion of the first tangential row of earlywood vessels varied by up to 30 days, while for the completion of the entire earlywood dates varied by up to 32 days. The highest productivity of cambial cells (13 cell layers) was observed around the time of bud swelling at mid-April. In the last days of April, the number of cambial cell layers decreased and subsequently increased again when the leaves were nearly fully expanded at the end of May. To summarize, we observed a high seasonal variability in the number of cambial cell layers. Differences in the time of cessation of cambial activity and xylogenesis amounted to 1 month. We conclude that: (1) oak tree-ring widths and earlywoodvessel sizes and numbers may not be sensitive indicators for early spring temperature and spring defoliation; (2) the missing association between leaf phenophases and xylogenesis as well as the phenological variability may be the reasons for the lack of a clear climatic effect on the abovementioned parameters.

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“…Among the more sensitive species growing in Poland is pedunculate oak Quercus robur L., which easily experiences problems in conducting water through the wood due to embolism. Studies found that summer droughts inhibit the growth of oaks, and the recurring droughts in the coming years will lead to their gradual weakening and dying [25]. It has been pointed out that the increased frequency of droughts caused by global warming will increase the mortality of pedunculate oaks [26].…”

Section: Resultsmentioning

confidence: 99%