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Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential.

Hafner P, Gričar J, Skudnik M, Levanič T - PLoS ONE (2015)

Bottom Line: We discovered that W oaks grew significantly better over the whole analysed period.The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood.Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon isotope discrimination provides complementary information in Q. robur dendroecology.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Yield and Silviculture, Slovenian Forestry Institute, Ljubljana, Slovenia.

ABSTRACT
We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW). For that purpose EW and LW widths and carbon isotope discrimination for the period 1970-2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August) climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon isotope discrimination provides complementary information in Q. robur dendroecology.

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Related in: MedlinePlus

Time series of anlysed tree-ring parameters.(A) Raw earlywood widths, (B) raw latewood widths, (C) earlywood carbon isotope discrimination and (D) latewood carbon isotope discrimination of wet (W) and dry (D) oaks for the period 1970–2008.
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pone.0143918.g005: Time series of anlysed tree-ring parameters.(A) Raw earlywood widths, (B) raw latewood widths, (C) earlywood carbon isotope discrimination and (D) latewood carbon isotope discrimination of wet (W) and dry (D) oaks for the period 1970–2008.

Mentions: Tree-ring widths of oaks from the wetter plot (W oaks) were considerably wider than those of oaks from the drier plot (D oaks) over the whole analysed period (i.e., 1970–2008) (Fig 4). Average widths of EW and LW significantly differed between D and W oaks; t = 15.195, p < 0.001 and t = 16.210, p < 0.001, respectively (Table 1). The difference in growth trends became particularly visible around 1990. A tree-ring width decline in D oaks was apparent in LW, where widths were narrower than 0.2 mm in the last analysed years (Fig 5A) indicating negligible production of LW. EW-W in the two analysed groups of oaks were fairly constant (Fig 5B). There was a weak but significant difference in Δ in EW (t = –2.522, p < 0.05) between the oak groups (Fig 5C) but no difference in Δ in LW (t = –0.925, p > 0.10) (Fig 5D).


Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential.

Hafner P, Gričar J, Skudnik M, Levanič T - PLoS ONE (2015)

Time series of anlysed tree-ring parameters.(A) Raw earlywood widths, (B) raw latewood widths, (C) earlywood carbon isotope discrimination and (D) latewood carbon isotope discrimination of wet (W) and dry (D) oaks for the period 1970–2008.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664244&req=5

pone.0143918.g005: Time series of anlysed tree-ring parameters.(A) Raw earlywood widths, (B) raw latewood widths, (C) earlywood carbon isotope discrimination and (D) latewood carbon isotope discrimination of wet (W) and dry (D) oaks for the period 1970–2008.
Mentions: Tree-ring widths of oaks from the wetter plot (W oaks) were considerably wider than those of oaks from the drier plot (D oaks) over the whole analysed period (i.e., 1970–2008) (Fig 4). Average widths of EW and LW significantly differed between D and W oaks; t = 15.195, p < 0.001 and t = 16.210, p < 0.001, respectively (Table 1). The difference in growth trends became particularly visible around 1990. A tree-ring width decline in D oaks was apparent in LW, where widths were narrower than 0.2 mm in the last analysed years (Fig 5A) indicating negligible production of LW. EW-W in the two analysed groups of oaks were fairly constant (Fig 5B). There was a weak but significant difference in Δ in EW (t = –2.522, p < 0.05) between the oak groups (Fig 5C) but no difference in Δ in LW (t = –0.925, p > 0.10) (Fig 5D).

Bottom Line: We discovered that W oaks grew significantly better over the whole analysed period.The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood.Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon isotope discrimination provides complementary information in Q. robur dendroecology.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Yield and Silviculture, Slovenian Forestry Institute, Ljubljana, Slovenia.

ABSTRACT
We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW). For that purpose EW and LW widths and carbon isotope discrimination for the period 1970-2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August) climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon isotope discrimination provides complementary information in Q. robur dendroecology.

Show MeSH
Related in: MedlinePlus