Forests

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12 pages, 1684 KiB

Open AccessArticle

Increasing Wood δ¹⁵N in Response to Pig Manure Application

by Jesús Julio Camarero, Antonio Gazol, Ester González de Andrés, Cristina Valeriano, José M. Igual and Jesús Causapé

Forests 2023, 14(1), 8; https://doi.org/10.3390/f14010008 - 21 Dec 2022

Viewed by 1753

Abstract

Intensive livestock management impacts forest and trees in different ways. Pig manure is a major source of nitrogen (N) pollution of surface and ground waters in some European regions such as north-eastern Spain, but it is understudied how manure application impacts agroforestry systems. [...] Read more.

Intensive livestock management impacts forest and trees in different ways. Pig manure is a major source of nitrogen (N) pollution of surface and ground waters in some European regions such as north-eastern Spain, but it is understudied how manure application impacts agroforestry systems. How pig manure affects tree radial growth and the N cycle was assessed by measuring N concentrations in soil, leaves and wood and δ¹⁵N in tree-ring wood in two tree species widely planted for agricultural (Prunus dulcis) and reforestation (Pinus halepensis) purposes in the study area. Soil physicochemical characteristics and the biomass and structure of major soil microbial groups were also measured. Trees irrigated with pig effluent (manure application) and control trees not subjected to manure application were compared. Soil N, phosphorus (P) and potassium (K) concentrations of fertilized trees increased, but soil microbiota biomass decreased. Similar growth between fertilized and non-fertilized pine trees was found, but lower growth in fertilized almond trees was observed. Leaf N concentrations decreased but δ¹⁵N wood increased in trees subjected to pig manure application. Pig manure application alters the N cycling in the soil and within trees. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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15 pages, 2762 KiB

Open AccessArticle

Douglas Fir Multiproxy Tree-Ring Data Glimpse MIS 5 Environment in the U.S. Pacific Northwest

by Irina P. Panyushkina, Steven W. Leavitt, David M. Meko, Bryan A. Black, A. J. Timothy Jull, Peter Van de Water, Joe Squire and Nicholas R. Testa

Forests 2022, 13(12), 2161; https://doi.org/10.3390/f13122161 - 16 Dec 2022

Cited by 1 | Viewed by 1767

Abstract

Proxy records from the late Quaternary help in understanding climate variability on extended time scales. An ancient landslide deposit in Oregon U.S.A. preserved large logs from Douglas fir trees (Pseudotsuga menziesii (Mirb.) Franco) and afforded an opportunity to explore the response of [...] Read more.

Proxy records from the late Quaternary help in understanding climate variability on extended time scales. An ancient landslide deposit in Oregon U.S.A. preserved large logs from Douglas fir trees (Pseudotsuga menziesii (Mirb.) Franco) and afforded an opportunity to explore the response of tree growth to climate on annual and decadal scales. High-precision radiocarbon dating indicates an age exceeding 63 ka, i.e., the trees grew within the generally cool Marine Isotope Stage 5 (MIS 5), likely during a warmer interval optimal for Douglas fir establishment. This would include the prolonged warm MIS 5e (ca. 110–130 ka), corresponding approximately to the Eemian interglacial, which was warm like the current Holocene interglacial. A 297-year tree-ring width chronology from 12 Douglas fir logs and 227-year tree-ring δ¹³C and δ¹⁸O records are analyzed with spectral and wavelet analysis. Variance of the ancient rings is consistent with modern Douglas fir growth sensitive to moisture and ecological disturbances. Spectra of ancient and modern chronologies are dominated by low frequencies with significant spectral peaks appearing at high frequencies (2.1–4 years) and cyclic behavior transient over centuries. It is conceivable that the O-isotopes track moisture and that C-isotopes track temperature or sunlight. The findings illustrate the challenges in assessing the response of ancient tree-ring properties to late Quaternary climate variability. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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16 pages, 3331 KiB

Open AccessArticle

Isotopic Composition (δ¹⁵N and δ¹⁸O) of Urban Forests in Different Climate Types Indicates the Potential Influences of Traffic Exhaust and Relative Humidity

by Cheng Gong, Chaofan Xian and Zhiyun Ouyang

Forests 2022, 13(12), 2060; https://doi.org/10.3390/f13122060 - 4 Dec 2022

Viewed by 1562

Abstract

Previous studies have shown that climatic and anthropogenic factors influence the variations in the stable isotope signature of tree materials in an urban ecosystem. However, the responses of urban trees to various anthropogenic and precipitation interventions are unclear. To fill the research gap, [...] Read more.

Previous studies have shown that climatic and anthropogenic factors influence the variations in the stable isotope signature of tree materials in an urban ecosystem. However, the responses of urban trees to various anthropogenic and precipitation interventions are unclear. To fill the research gap, the isotopic composition (δ¹⁵N and δ¹⁸O) and total nitrogen content of the soil-plant system of urban forests were measured, focusing on typical urban tree species (Populus tomentosa and Ficus virens). The research was done under various land uses in China’s Beijing and Shenzhen megacities (with different humidity conditions). The linear mixed-effect model revealed that the δ¹⁵N values in the leaves of roadside Ficus virens were significantly higher than those in urban park sites, away from the road (δ¹⁵N difference = 7.2‰). In contrast, Populus tomentosa leaves exhibited a non-significant difference (δ¹⁵N difference = −1.8‰). Further regression analysis revealed that the variations in δ¹⁵N in tree leaves could be attributed to the proximity to highways, suggesting the influence of vehicle exhaust on δ¹⁵N values in roadside trees. The linear mixed-effect model also revealed δ¹⁸O values significantly higher in Populus tomentosa leaves than in Ficus virens leaves. To assess the influence of humidity conditions on δ¹⁸O values in the leaves, the ratio of the atmospheric and intercellular vapor pressures (e_a/e_i) of tree canopies was estimated. The result revealed that the e_a/e_i of Ficus virens was significantly higher than for Populus tomentosa, ascribed to the variation in the humidity conditions of the two megacities. These results highlight that urban trees can potentially serve as bioindicators for atmospheric pollution and humidity. Our findings highlight the ecophysiological responses of urban forests related to N and O as they vary according to traffic exhaust and relative humidity. Consequently, they are potentially valuable indicators of urban atmospheric contamination, forming a nature-based solution for citizen welfare improvement. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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13 pages, 2958 KiB

Open AccessArticle

The Stable Carbon Isotope Composition of Pinus yunnanensis Pollen and Leaf in Northwestern Yunnan, China

by Wenjun Sun, Caiming Shen, Linpei Huang, Hongwei Meng and Binbin Ren

Forests 2022, 13(11), 1747; https://doi.org/10.3390/f13111747 - 24 Oct 2022

Cited by 1 | Viewed by 1539

Abstract

The basis for the δ¹³C values of plant tissues used to infer past ecological environments is their relationships with modern ecological conditions. A total of 71 pairs of pollen and leaf samples were collected from Pinus yunnanensis, an endemic species [...] Read more.

The basis for the δ¹³C values of plant tissues used to infer past ecological environments is their relationships with modern ecological conditions. A total of 71 pairs of pollen and leaf samples were collected from Pinus yunnanensis, an endemic species of the Yunnan plateau, in northwestern Yunnan, China. Their carbon isotopic composition was examined to investigate the two tissues’ difference of stable carbon isotopes, possible factors affecting their δ¹³C values, and their distinctiveness within Pinus and Pinaceae. Our study showed that pollen δ¹³C values range from −32.92 to −26.34‰ with an average of −30.88‰, whereas leaf δ¹³C values vary between −33.79 and −28.96‰ with an average value of −31.2‰, suggesting an isotope fractionation between the two tissues. A statistically significant negative correlation between the pollen δ¹³C values and altitudes of the sampling sites as well as no significant correlation between the leaf δ¹³C values and altitudes suggested that pollen may be more sensitive to some climatic parameters than leaf. A comparison of the pollen and leaf δ¹³C values from Pinus yunnanensis with the available data from other Pinus species and other genus species of Pinaceae indicated that the pollen and leaf δ¹³C values of Pinus yunnanensis are the lowest, partially due to the effects of water availability. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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16 pages, 2320 KiB

Open AccessArticle

δ¹⁵N in Birch and Pine Leaves in the Vicinity of a Large Copper Smelter Indicating a Change in the Conditions of Their Soil Nutrition

by Denis Veselkin, Nadezhda Kuyantseva, Aleksandr Mumber, Darya Molchanova and Daria Kiseleva

Forests 2022, 13(8), 1299; https://doi.org/10.3390/f13081299 - 15 Aug 2022

Cited by 4 | Viewed by 1890

Abstract

δ¹³C and δ¹⁵N were analyzed in the leaves of Pinus sylvestris L. and Betula spp. under the conditions of severe heavy metal (Zn, Cu, Cd, and Pb) contamination. Twenty-seven plots located near the Karabash copper smelter (Russia) were studied. [...] Read more.

δ¹³C and δ¹⁵N were analyzed in the leaves of Pinus sylvestris L. and Betula spp. under the conditions of severe heavy metal (Zn, Cu, Cd, and Pb) contamination. Twenty-seven plots located near the Karabash copper smelter (Russia) were studied. No reliable correlation of ¹³C in tree leaves with the level of pollution was observed. δ¹⁵N, both in Pinus sylvestris and Betula spp., increased similarly in polluted areas. δ¹⁵N was increased by 2.3‰ in the needles of Pinus sylvestris and by 1.6‰ in the leaves of Betula spp. in polluted plots compared to the background ones. The probable reasons for the increase in δ¹⁵N were estimated using multiple regression. The regression model, which includes two predictors: δ¹⁵N in the humus horizon and the occurrence of roots in the litter, explains 33% of the total variability of δ¹⁵N in leaves. Thus, in ecosystems polluted with heavy metals, the state of trees is determined not only by the direct toxic effects of heavy metals but also by indirect ones associated with the features of plant mineral nutrition. This fact opens the way to the search for opportunities to control the state of plants in disturbed ecosystems by regulating the content of mineral nutrition elements. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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15 pages, 3217 KiB

Open AccessArticle

Towards the Third Millennium Changes in Siberian Triple Tree-Ring Stable Isotopes

by Olga V. Churakova (Sidorova), Marina V. Fonti, Valentin V. Barinov, Mikhail S. Zharkov, Anna V. Taynik, Tatyana V. Trushkina, Alexander V. Kirdyanov, Alberto Arzac and Matthias Saurer

Forests 2022, 13(6), 934; https://doi.org/10.3390/f13060934 - 15 Jun 2022

Cited by 4 | Viewed by 2419

Abstract

Significant air temperature and precipitation changes have occurred since the 2000s in vulnerable Siberian subarctic regions and urged updates of available chronologies towards the third millennium. It is important to better understand recent climatic changes compared to the past decades, centuries and even [...] Read more.

Significant air temperature and precipitation changes have occurred since the 2000s in vulnerable Siberian subarctic regions and urged updates of available chronologies towards the third millennium. It is important to better understand recent climatic changes compared to the past decades, centuries and even millennia. In this study, we present the first annually resolved triple tree-ring isotope dataset (δ¹³C, δ¹⁸O and δ²H) for the eastern part of the Taimyr Peninsula (TAY) and northeastern Yakutia (YAK) from 1900 to 2021. We found that the novel and largely unexplored δ²H of larch tree-ring cellulose was linked significantly with δ¹⁸O for the YAK site, which was affected by averaged April–June air temperatures and evaporation. Simulated by the Land Surface Processes and Exchanges (LPX-Bern 1.0) model, the water fraction per year for soil depths at 0–20 and 20–30 cm was significantly linked with the new eco-hydrological tree-ring δ²H data. Our results suggest increasing evapotranspiration and response of trees’ water relation to rising thaw water uptake from lower (20–30 cm) soil depth. A positive effect of July air temperature on tree-ring δ¹⁸O and a negative impact of July precipitation were found, indicating dry conditions. The δ¹³C in larch tree-ring cellulose for both sites showed negative correlations with July precipitation and relative humidity, confirming dry environmental conditions towards the third millennium. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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17 pages, 2685 KiB

Open AccessArticle

Fire as a Major Factor in Dynamics of Tree-Growth and Stable δ¹³C and δ¹⁸O Variations in Larch in the Permafrost Zone

by Anastasia A. Knorre, Rolf T. W. Siegwolf, Alexander V. Kirdyanov, Matthias Saurer, Olga V. Churakova (Sidorova) and Anatoly S. Prokushkin

Forests 2022, 13(5), 725; https://doi.org/10.3390/f13050725 - 5 May 2022

Cited by 4 | Viewed by 2260

Abstract

Wildfires are one of the most important environmental factors controlling forest ecosystem physiology and the carbon balance in the permafrost zone of North Siberia. We investigated tree-ring width (TRW) and stable isotope chronologies in tree-ring cellulose (δ¹³C_Cell, δ¹⁸ [...] Read more.

Wildfires are one of the most important environmental factors controlling forest ecosystem physiology and the carbon balance in the permafrost zone of North Siberia. We investigated tree-ring width (TRW) and stable isotope chronologies in tree-ring cellulose (δ¹³C_Cell, δ¹⁸O_Cell) of Larix Gmelinii (Rupr.) Rupr. from a wet (WS) and a dry (DS) site. These sites are characterized by different fire histories (fire in 1852 at the wet and 1896 at the dry sites, respectively). TRW and δ¹⁸OCell are identified to be the most sensitive parameters in the changing tree growth conditions after fire. The differences in the soil seasonal thermal regime of sites after fires are shown in the relationship between the studied parameters. The δ¹³C_Cell values in tree rings from the two sites are positively correlated independently of the fire impact. This fact indicates that δ¹³C_Cell chronologies might be more adequate for climatic reconstruction in the region due to the climate signal consistency. Relationships of δ¹⁸O_Cell values between the two sites are still significantly positive 60 years after the fire impact. Dendroclimatic analysis indicates significant changes in tree-ring growth and isotopic ratio responses to climate due to the increased demand of water for trees during the post-fire period (deeper seasonal subsidence of permafrost). Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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12 pages, 3220 KiB

Open AccessArticle

Investigating Masking Effects of Age Trends on the Correlations among Tree Ring Proxies

by Tito Arosio, Malin Michelle Ziehmer-Wenz, Kurt Nicolussi, Christian Schlüchter and Markus Christian Leuenberger

Forests 2021, 12(11), 1523; https://doi.org/10.3390/f12111523 - 4 Nov 2021

Cited by 5 | Viewed by 2018

Abstract

Age-related trends are present in tree-ring widths (TRW), but their presence in tree rings isotope is debated. It is unclear how cambial age influences the relationships between TRW and isotopes. Tree-ring isotopes of alpine larch and cembran-pine trees showed only trends in the [...] Read more.

Age-related trends are present in tree-ring widths (TRW), but their presence in tree rings isotope is debated. It is unclear how cambial age influences the relationships between TRW and isotopes. Tree-ring isotopes of alpine larch and cembran-pine trees showed only trends in the juvenile period (>100 years), which might mask the inter-relations between tree-ring proxies during cambial age. This work tries to unmask the age-trend influences by examining the correlations in TRW—stable isotopes with and without age-trend correction. The non-detrended and linear-detrended values of TRW, of δD and δ¹⁸O showed significant correlations for ages up to 100 years, but not afterward. However, the correlation values, after spline or first-difference time-series detrending, were not age-related. Thus, detrending methods affect the correlations in the juvenile phase and may affect climate-related interpretations. The correlations between TRW and δ¹³C were not age-related, while those among the isotopes were significant throughout the ages. The correlation between δ¹³C and δD was the exception, as it became significant only after age > 100 years, suggesting a different use of reserves in the juvenile phase. In conclusion, the relationships among the tree-ring parameters are stable in all the different detrend scenarios after the juvenile phase, and they can be used together in multi-proxy paleoclimatic studies. The data of the juvenile phase can be used after spline-detrending or first-difference time-series calculation, depending on the purpose of the analysis to remove age-related trends. The work also provides clues on the possible causes of juvenile age trends. Full article

(This article belongs to the Special Issue Stable Isotopes in Dendroecology)

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