Research

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13 pages, 1331 KiB

Open AccessArticle

Effects of Arbuscular Mycorrhizal Fungi on the Vegetative Vigor of Ailanthus altissima (Mill.) Swingle Seedlings under Sustained Pot Limitation

by Emilio Badalamenti, Marco Ciolfi, Marco Lauteri, Paola Quatrini and Tommaso La Mantia

Forests 2018, 9(7), 409; https://doi.org/10.3390/f9070409 - 06 Jul 2018

Cited by 3 | Viewed by 2959

Abstract

In order to invade new ecosystems, invasive alien plants need to cope with different microbial communities. Whilst the ability to avoid antagonists is well recognized, the opportunity to establish mutualistic associations is less known, even in widespread invasive species such as Ailanthus altissima [...] Read more.

In order to invade new ecosystems, invasive alien plants need to cope with different microbial communities. Whilst the ability to avoid antagonists is well recognized, the opportunity to establish mutualistic associations is less known, even in widespread invasive species such as Ailanthus altissima (Mill.) Swingle. We sought to evaluate whether the beneficial effects of arbuscular mycorrhizal fungi (AMF) on Ailanthus seedlings are maintained over time, under prolonged pot limitation. We compared three-month-, three-year- and four-year-old mycorrhizal seedlings grown in natural forest soil (NT) with seedlings grown in sterilized (ST) and non-mycorrhizal (NM) soils, in pots of 3.4 L (22 × 15 cm). Growth parameters and leaf traits were assessed, including carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope compositions. NT seedlings showed relatively higher vigor in the early stage but, subsequently, the benefits provided by AMF were lost. Interestingly, mycorrhizal seedlings consistently showed about 2‰ δ¹³C enrichment, relatively to the other treatments. Negative linear relationships between leaf δ¹³C and N content were found. Higher photosynthesis rates and WUE are the likely causes of the early enhanced growth in mycorrhizal seedlings. The symbiotic relationship between AMF and Ailanthus could be driven by resource availability. Greater insights into such aspects could provide an improved perspective on the ecological limits of Ailanthus. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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14 pages, 3186 KiB

Open AccessArticle

Age-Effect on Intra-Annual δ¹³C-Variability within Scots Pine Tree-Rings from Central Siberia

by Marina V. Fonti, Eugene A. Vaganov, Christian Wirth, Alexander V. Shashkin, Natalya V. Astrakhantseva and Еrnst-Detlef Schulze

Forests 2018, 9(6), 364; https://doi.org/10.3390/f9060364 - 19 Jun 2018

Cited by 12 | Viewed by 4054

Abstract

Intra-annual tree-ring parameters are increasingly used in dendroecology thanks to their high temporal resolution. To better understand the nature of intra-ring proxy signals, we compared old and young trees according to the different ways in which they respond to climate. The study was [...] Read more.

Intra-annual tree-ring parameters are increasingly used in dendroecology thanks to their high temporal resolution. To better understand the nature of intra-ring proxy signals, we compared old and young trees according to the different ways in which they respond to climate. The study was carried out in central Siberia (Russia, 60°75′ N, 89°38′ E) in two even-aged Pinus sylvestris L. stands of different ages (20 and 220 years). Ring width, cell size, and intra-annual δ¹³С were measured for 4 to 27 tree rings, depending on age group (young vs. old) and tree-ring parameter. Wood formation was monitored to link tree-ring position to its time of formation. Results indicated more distinct intra-annual δ¹³С patterns at both the beginning and end of the ring of young trees compared to old ones. Older trees showed a stronger significant correlation between δ¹³С across the ring border, indicating a stronger carry-over effect of the previous year’s growing conditions on current year wood production. This suggests that tree age/size influences the magnitude of the transfer of mobile carbon reserves across the years. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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12 pages, 3522 KiB

Open AccessArticle

Compound-Specific Carbon Isotopes and Concentrations of Carbohydrates and Organic Acids as Indicators of Tree Decline in Mountain Pine

by Olga V. Churakova (Sidorova), Marco M. Lehmann, Matthias Saurer, Marina V. Fonti, Rolf T. W. Siegwolf and Christof Bigler

Forests 2018, 9(6), 363; https://doi.org/10.3390/f9060363 - 19 Jun 2018

Cited by 10 | Viewed by 3423

Abstract

We investigated seasonal variations in δ¹³C values and concentrations of carbohydrates and organic acids in needles of declining and healthy mountain pine (Pinus mugo ssp. uncinata (DC.) Domin) trees from the Swiss National Park (SNP), using compound-specific isotopes analysis (CSIA). [...] Read more.

We investigated seasonal variations in δ¹³C values and concentrations of carbohydrates and organic acids in needles of declining and healthy mountain pine (Pinus mugo ssp. uncinata (DC.) Domin) trees from the Swiss National Park (SNP), using compound-specific isotopes analysis (CSIA). Our goal was to study the impact of climatic drivers on the individual compounds and understand the reasons of partial tree declines in relation to healthy mountain pine trees under seasonal weather patterns. We found that temperature is the main climatic driver determining the seasonal carbon dynamics at the needle level. Lower seasonal δ¹³C variability and lower concentration levels of sucrose in needles suggest less photosynthetic activity and sink carbon demand in declining compared to healthy mountain pine trees. Higher concentration levels of hexose (glucose and fructose) can play a reserve function for surviving mechanisms of mountain pine trees. Seasonal patterns of organic acid (malate and citrate) suggest an increasing investment in maintenance and repair mechanisms. The seasonal course of carbohydrates and organic acids can therefore be considered an indicator for a modified carbon metabolism within the leaves and possibly within the other tree tissues, partially explaining the decline of mountain pine trees. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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18 pages, 3349 KiB

Open AccessArticle

Permafrost Regime Affects the Nutritional Status and Productivity of Larches in Central Siberia

by Anatoly S. Prokushkin, Frank Hagedorn, Oleg S. Pokrovsky, Jerome Viers, Alexander V. Kirdyanov, Oxana V. Masyagina, Marina P. Prokushkina and William H. McDowell

Forests 2018, 9(6), 314; https://doi.org/10.3390/f9060314 - 01 Jun 2018

Cited by 21 | Viewed by 4211

Abstract

Permafrost exerts strong controls on forest development through nutrient availability. The key question of this study was to assess the effect of site conditions on macroelement concentration and stable isotope (δ¹³C and δ¹⁵N) dynamics during the growing season, and [...] Read more.

Permafrost exerts strong controls on forest development through nutrient availability. The key question of this study was to assess the effect of site conditions on macroelement concentration and stable isotope (δ¹³C and δ¹⁵N) dynamics during the growing season, and nutrient stoichiometry and resorption efficiency in the foliage of two common larch species in Siberia. Foliar nutrient (N, P and K) concentrations of larches grown on permafrost soils were exceptionally high in juvenile needles compared to those from a permafrost-free region (+50% and 130% for P and K), but were two-fold lower at needle maturation. Within permafrost terrain trees, sites with a warmer and deeper soil active layer had 15–60% greater nutrient concentrations and higher δ¹⁵N in their needles compared to shallower, colder soils. Larch of permafrost-free sites demonstrated an enrichment of foliage in ¹⁵N (+1.4% to +2.4‰) in comparison to permafrost terrain (−2.0% to −6.9‰). At all sites, foliar δ¹³C decreased from June to August, which very likely results from an increasing contribution of current photoassimilates to build foliar biomass. With senescence, nutrient concentrations in larch needles decreased significantly by 60–90%. This strong ability of larch to retain nutrients through resorption is the essential mechanism that maintains tree growth early in the growing season when soil remains frozen. The high resorptive efficiency found for K and P for larches established on permafrost suggests nutrient limitation of tree growth within the Central Siberian Plateau not only by N, as previously reported, but also by P and K. The increasing nutrient concentrations and a ¹⁵N enrichment of foliage towards warmer sites was paralleled by an up to 50-fold increase in biomass production, strongly suggesting that accelerated nutrient cycling with permafrost degradation contributes to an increased productivity of Siberian larch forests. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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15 pages, 3735 KiB

Open AccessArticle

Spatial Variation in Leaf Stable Carbon Isotope Composition of Three Caragana Species in Northern China

by Fei Ma, Wenyu Liang, Zhaona Zhou, Guoju Xiao, Jili Liu, Jun He, Bingzhong Jiao and Tingting Xu

Forests 2018, 9(6), 297; https://doi.org/10.3390/f9060297 - 25 May 2018

Cited by 12 | Viewed by 3416

Abstract

Leaf stable carbon isotope (δ¹³C) composition provides comprehensive insight into plant carbon cycles and water use efficiency and has also been widely used to evaluate the response of plants to environmental change. In the present study, leaf δ¹³C was [...] Read more.

Leaf stable carbon isotope (δ¹³C) composition provides comprehensive insight into plant carbon cycles and water use efficiency and has also been widely used to evaluate the response of plants to environmental change. In the present study, leaf δ¹³C was analyzed in samples of Caragana microphylla Lam., C. liouana Zhao, and C. korshinskii Kom. from 38 populations. These species provide great environmental benefits and economic value and are distributed east to west continuously across northern China. We studied the relationship of δ¹³C to altitude, mean annual precipitation (MAP), mean annual temperature (MAT), mean annual relative humidity (RH), leaf nitrogen (N), and phosphorus (P) concentrations to examine the patterns and controls of leaf δ¹³C variation in each species. Results indicated that, across the three species, leaf δ¹³C significantly decreased with MAP, RH, and leaf N and P concentrations, while it increased with altitude and MAT. However, patterns and environmental controls of leaf δ¹³C varied proportionally with species. C. korshinskii was mainly controlled by MAP and leaf N concentration, C. liouana was controlled by both MAT and MAP, and C. microphylla was mainly controlled by MAT. Further analysis indicated significant differences in leaf δ¹³C between species, which tended to increase from C. microphylla to C. korshinskii. Overall, these results suggest that the three Caragana species may respond differently to future climate change due to different controlling factors on leaf δ¹³C variation, as well as differentiation in water use efficiency, which likely contributes to the geographical distribution of these species. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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11083 KiB

Open AccessArticle

Warming Effects on Pinus sylvestris in the Cold–Dry Siberian Forest–Steppe: Positive or Negative Balance of Trade?

by Tatiana A. Shestakova, Jordi Voltas, Matthias Saurer, Rolf T. W. Siegwolf and Alexander V. Kirdyanov

Forests 2017, 8(12), 490; https://doi.org/10.3390/f8120490 - 07 Dec 2017

Cited by 24 | Viewed by 5414

Abstract

Understanding climate change impacts on drought-prone forests is a critical issue. We investigated ring-width and stable isotopes (Δ¹³C and δ¹⁸O) in two Pinus sylvestris stands of the cold–dry Siberian forest–steppe growing under contrasting climatic trends over the last 75 [...] Read more.

Understanding climate change impacts on drought-prone forests is a critical issue. We investigated ring-width and stable isotopes (Δ¹³C and δ¹⁸O) in two Pinus sylvestris stands of the cold–dry Siberian forest–steppe growing under contrasting climatic trends over the last 75 years. Despite regional warming, there was increasing precipitation during the growing period at the southern site (MIN) but increasing water deficit (WD) at the northern site (BER). Intrinsic water use efficiency (WUE_i) increased similarly (ca. 22%) in response to warming and rising atmospheric CO₂. However, the steady increase in WUE_i was accompanied by divergent growth patterns since 1980: increasing basal area increment (BAI) in MIN (slope = 0.102 cm² year⁻²) and decreasing BAI in BER (slope = −0.129 cm² year⁻²). This suggests that increased precipitation, mediated by CO₂ effects, promoted growth in MIN, whereas intensified drought stress led to decreased carbon gain and productivity in BER. When compared to warm–dry stands of eastern Spain, the WUE_i dependence on WD was three-fold greater in Siberia. Conversely, BAI was more affected by the relative impact of water stress within each region. These results indicate contrasting future trajectories of P. sylvestris forests, which challenge forecasting growth and carbon sequestration in cold–dry areas. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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2206 KiB

Open AccessArticle

Hoof Growth Rates of the European Roe Deer (Capreolus capreolus) for Dating the Hoof’s Isotopic Archive

by Benjamin D. Hafner, Andreas König and Karl Auerswald

Forests 2017, 8(12), 462; https://doi.org/10.3390/f8120462 - 24 Nov 2017

Cited by 1 | Viewed by 8623

Abstract

Hooves preserve the isotopic information laid down during their growth and may be used for reconstruction of animal feeding history. To assign certain positions along hooves to corresponding times, growth rates are required. Hoof growth rates are known for domestic animals; however, they [...] Read more.

Hooves preserve the isotopic information laid down during their growth and may be used for reconstruction of animal feeding history. To assign certain positions along hooves to corresponding times, growth rates are required. Hoof growth rates are known for domestic animals; however, they cannot be obtained easily in wild animals. We estimated the hoof growth rate of the European roe deer (Capreolus capreolus L.) by using the immediate drop in δ¹³C along the hoof as a tag that is assigned to the date of maize (Zea mays L.) harvest. Keratin samples were taken each mm along 17 hooves and analyzed for their δ¹³C. A linear regression between (1) time differences of expected maize harvest to animal death and (2) distances between the points of the δ¹³C drop to the periople yielded the growth rate. Mean hoof growth rate was 0.122 mm/day (95% CI 0.014 mm/day) and 0.365%/day (±0.026%/day) of the hoof length and within the range of domestic animals. The method may be applied to determine growth rates of other incrementally growing tissues. Our estimated growth rate fosters dating isotopic information in hooves, facilitating research on feed resources and space use of roe deer. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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3014 KiB

Open AccessFeature PaperArticle

Effects of Drought on Xylem Anatomy and Water-Use Efficiency of Two Co-Occurring Pine Species

by Dario Martin-Benito, Kevin J. Anchukaitis, Michael N. Evans, Miren Del Río, Hans Beeckman and Isabel Cañellas

Forests 2017, 8(9), 332; https://doi.org/10.3390/f8090332 - 08 Sep 2017

Cited by 47 | Viewed by 8809

Abstract

Exploring how drought influences growth, performance, and survival in different species is crucial to understanding the impacts of climate change on forest ecosystems. Here, we investigate the responses of two co-occurring pines (Pinus nigra and Pinus sylvestris) to interannual drought in [...] Read more.

Exploring how drought influences growth, performance, and survival in different species is crucial to understanding the impacts of climate change on forest ecosystems. Here, we investigate the responses of two co-occurring pines (Pinus nigra and Pinus sylvestris) to interannual drought in east-central Spain by dendrochronological and wood anatomical features integrated with isotopic ratios of carbon (δ¹³C) and oxygen (δ¹⁸O) in tree rings. Our results showed that drought induces both species to allocate less carbon to build tracheid cell-walls but increases tracheid lumen diameters, particularly in the transition wood between early and latewood, potentially maximizing hydraulic conductivity but reducing resistance to embolism at a critical phase during the growing season. The thicker cell-wall-to-lumen ratio in P. nigra could imply that its xylem may be more resistant to bending stress and drought-induced cavitation than P. sylvestris. In contrast, the higher intrinsic water-use efficiency (iWUE) in P. sylvestris suggests that it relies more on a water-saving strategy. Our results suggest that narrower cell-walls and reduced growth under drought are not necessarily linked to increased iWUE. At our site P. nigra showed a higher growth plasticity, grew faster and was more competitive than P. sylvestris. In the long term, these sustained differences in iWUE and anatomical characters could affect forest species performance and composition, particularly under increased drought stress. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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Review

Jump to: Research

21 pages, 12408 KiB

Open AccessReview

Plant Water Use Strategy in Response to Spatial and Temporal Variation in Precipitation Patterns in China: A Stable Isotope Analysis

by Ying Zhao and Li Wang

Forests 2018, 9(3), 123; https://doi.org/10.3390/f9030123 - 06 Mar 2018

Cited by 25 | Viewed by 4661

Abstract

Spatial and temporal variation in precipitation patterns can directly alter the survival and growth of plants, yet in China there is no comprehensive and systematic strategy for plant use based on the effects of precipitation patterns. Here, we examined information from 93 published [...] Read more.

Spatial and temporal variation in precipitation patterns can directly alter the survival and growth of plants, yet in China there is no comprehensive and systematic strategy for plant use based on the effects of precipitation patterns. Here, we examined information from 93 published papers (368 plant species) on plant xylem water stable isotopes (δD and δ¹⁸O) in China. The results showed that: (1) The slope of the local meteoric water line (LMWL) gradually increased from inland areas to the coast, as a result of continental and seasonal effects. The correlation between δD and δ¹⁸O in plant stem water is also well fitted and the correlation coefficients range from 0.78 to 0.89. With respect to the soil water line, the δ¹⁸O values in relation to depth (0–100 cm) varied over time; (2) Plants’ main water sources are largely affected by precipitation patterns. In general, plants prioritize the use of stable and continuous water sources, while they have a more variable water uptake strategy under drought conditions; (3) There are no spatial and temporal variations in the contribution of the main water source (p > 0.05) because plants maintain growth by shifting their use of water sources when resources are unreliable. Full article

(This article belongs to the Special Issue Isotope Application in Forest Growth Assessment)

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