Browsing by Author "Delard, Claudia"

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    Dendrochronological Analysis of Pinus pinea in Central Chile and South Spain for Sustainable Forest Management
    (2024) Loewe-Munoz, Veronica; Cachinero-Vivar, Antonio M.; Camarero, Jesus Julio; Del Rio, Rodrigo; Delard, Claudia; Navarro-Cerrillo, Rafael M.
    Pinus pinea is an important Mediterranean species due to its adaptability and tolerance to aridity and its high-quality pine nuts. Different forest types located in Mediterranean native and non-native environments provide the opportunity to perform comparative studies on the species' response to climate change. The aims of this study were to elucidate growth patterns of the species growing in native and exotic habitats and to analyze its response to climatic fluctuations, particularly drought, in both geographical contexts. Understanding stone pine (Pinus pinea) growth responses to climate variability in native and exotic habitats by comparing natural stands and plantations may provide useful information to plan adequate management under climate change. By doing so, we enhance the understanding of P. pinea's adaptability and provide practical approaches to its sustainable management. In this study, we reconstructed and compared the stem radial growth of seven stone pine stands, two in southern Spain and five in central-southern Chile, growing under different climatic conditions. We quantified the relationships between growth variability and climate variables (total rainfall, mean temperature, and SPEI drought index). Growth was positively correlated with autumn rainfall in plantations and with autumn-winter rainfall in natural stands. Growth was also enhanced by high autumn-to-spring rainfall in the driest Chilean plantation, whereas in the wettest and coolest plantation, such correlation was found in winter and summer. A negative impact of summer temperature was found only in one of the five Chilean plantations and in a Spanish site. The correlation between SPEI and tree-ring width indices showed different patterns between and within countries. Overall, exotic plantations showed lower sensitivity to climate variability than native stands. Therefore, stone pine plantations may be useful to assist in mitigating climate change.
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    Effect of fertilization on Pinus pinea cone to seed and kernel yields
    (2023) Loewe-Munoz, Veronica; del Rio, Rodrigo; Delard, Claudia; Balzarini, Monica
    Stone pine (Pinus pinea L.) is a species of economic interest mainly due to its pine nuts, the most expensive nut in the world. Despite the high value of pine nuts, cones are mainly harvested from unmanaged forests. Therefore, research and its applications are needed to develop nutritional management techniques among other cultivation practices intened to boost production. This study evaluated the effect of fertilization on cone production and quality (cone weight and size, number of seeds and kernels, and health status), which in turn may affect cone to seed and cone to kernel yields. Fertilization consisted of two applications of macro and micronutrients in two adult plantations twice in the growing season (in spring and fall). Morphometric variables, cone production per tree and cone health were evaluated during two years after fertilization. Fertilization effect on cone production was positive and significant in both years, with variations between years. Most of the morphometric variables were positively impacted by fertilization, including cone diameter (3.5% increase), kernel weight and length (7.7% and 2.7% increase, respectively), and total seed and kernel weight per cone (20.9% and 18.6% increase, respectively). Fertilized stone pine trees increased production and quality of cones, seeds and kernels, but did not increase cone to seed or kernel yields. However, fertilization increased type II seed damage by 45.4% and 18.9% in 2020 and 2021, respectively. The results obtained in this research may help producers adopt cultural practices to boost pine nut production.
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    Effect of thinning on growth and shape of Castanea sativa adult tree plantations for timber production in Chile
    (2023) Benedetti-Ruiz, Susana; Loewe-Munoz, Veronica; Del Rio, Rodrigo; Delard, Claudia; Barrales, Luis; Balzarini, Monica
    Chestnut (Castanea sativa Mill.) is an interesting species for high-quality timber production. It is well known that the species responds to early thinning, but there is no information on the impact of late interventions. The objective of this study was to assess the effect of a late thinning on the performance of unmanaged adult chestnut plantations in Chile. Future-tree selective thinning and control were compared in adult plantations using a randomized complete block design with three replicates at three sites, Minas, Pillo-Pillo and Pumillahue. Tree growth was evaluated periodically during the first 7 years after thinning in all plantations. Additionally, almost 20 years after the intervention, the Pumillahue plantation was measured for growth and tree shape variables. In this case study, the effect of thinning on tree growth decreased considerably after 5 years, with a maximum DBH increment in the third year after the intervention (45.8 %, 68.6 %, and 42.2 % in Minas, Pillo-Pillo and Pum-illahue, respectively). In all plantations, basal area was smaller in the thinned plots in the first years after the intervention, but in Pumillahue, 19 years after thinning, no differences were found among treatments. Height was statistically greater under thinning seven years after the intervention; this effect was also found in Pum-illahue plantation 19 years after thinning. Most trees showed high vigor, and were straight and healthy, even in control plots. Late effect of thinning was observed 19 years after thinning on tree shape, with a reduction in the proportion of bifurcated trees from 16 % to 8 %. The results suggest that late thinning is an effective silvicultural intervention to produce high-quality chestnut timber in unmanaged adult plantations. Progressive and frequent thinning should be used to increase growth and improve timber production in chestnut.
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    Effects of Tuber borchii inoculation on Pinus pinea 3 years after establishment along a latitudinal gradient in the Southern Hemisphere
    (2024) Loewe-Munoz, Veronica; Delard, Claudia; del Rio, Rodrigo; Gregori, Gianluigi; Balzarini, Monica
    Stone pine (Pinus pinea) produces a highly demanded dried fruit, the pine nuts; Tuber borchii produces a well-known commercialized truffle. Thus, the co-culture of P. pinea and T. borchii may represents an interesting productive option. This work evaluated the effect of T. borchii inoculation on stone pine tree growth, survival, health, entry into cone production, and mycorrhization level during the first 3 years after establishment along a 2000 km gradient in Chile. We tested two treatments (inoculation and non-inoculation) in a multi-environment trial (MET) involving seven sites along Chile. Plantations were repeatedly measured during 3 years after establishment. In all environments, inoculation enhanced tree height, root collar diameter (RCD) and crown diameter (6.9, 10 and 8.3% higher for inoculated than for non-inoculated plants). Vigor was also favored (14.1% more vigorous trees). Stone pine performance was enhanced in all sites, but mainly in those with extreme environmental conditions. T. borchii mycorrhizae were abundant (over 60% of mycorrhized root apexes) 3 years after establishment. The truffle-host plant combination was not previously evaluated in Chile. The results showed high root colonization levels and the persistence of mycorrhization 3 years after establishment, and an enhanced effect of mycorrhization on tree growth and vigor under different soil and climate conditions, confirming the high plasticity of both species.
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    Effects of climate and soil properties on growth of Pinus pinea young plantations
    (2024) Loewe-Munoz, Veronica; Bonomelli, Claudia; del Rio, Rodrigo; Delard, Claudia; Balzarini, Monica
    Background and aims Growth of Pinus pinea forests and plantations in native countries is known to be affected by soil and climate characteristics. However, edaphoclimatic drivers of growth and fruiting have been scarcely studied outside the species' native range; in addition, the role of soil nutrients, particularly in juvenile trees' development, has been poorly explored. Methods Relationships between edaphoclimatic variables and the performance of 54 young plantations were studied in Chile. Vegetative growth and fruiting were measured in 100 randomly selected trees per plantation. Composite soil samples were taken from each site to analyze soil chemical characteristics and texture. A principal component analysis was performed including climatic, soil data, and growth and fruiting variables. Results Annual growth was 1.3 cm year(-1) for stem diameter, 28.3 cm year(-1) for crown diameter, and 38.9 cm year(-1) for height; cone production per crown area was 0.07 cones m(-2). Negative correlation of height growth, crown growth and cone production with EC, Na, and pH were found, along with positive correlations with OM, PP and the index PP x AT. Stem diameter growth was favored by less acidic soils with high sand content, and showed no correlation with cone production. Furthermore, vegetative growth was positively correlated with N, P, Mg and clay content. In young plantations, vegetative growth was higher than in the species' native habitat. Conclusion Soil properties, in particular low EC and Na were identified as favorable for growth of young stone pine trees, along with high content of soil N, P and Mg, and PP.
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    Mixed Castanea sativa plantations including arboreal companion species enhance chestnut growth and high-quality timber production
    (2023) Loewe-Munoz, Veronica; Delard, Claudia; del Rio, Rodrigo; Barrales, Luis; Balzarini, Monica
    Context: Chestnut (Castanea sativa Mill.) is an important tree species for its timber, which is widely used for multiple purposes, including the veneer industry. The species has an interesting productive potential in Chile and requires specific management strategies to produce valuable, high-quality logs. Although mixed plantations including companion species usually enhance timber quality of several trees, the performance of chestnut under different associations is not well known. Aims: The objective of this study was to assess growth, survival, health, and timber quality of chestnut trees in several plantation types, including monoculture and mixtures with other companion trees and/or shrub. Methods: Growth and survival measurements were taken periodically in pure chestnut and mixed plantations established in southern Chile for a 20-year period after planting. The mixed plantations tested were: a main forest species mixture (Castanea sativa Mill., Quercus rubra L., Quercus robur L. and Prunus avium L.); three mixtures including main forest species plus one arboreal companion species (Alnus glutinosa L., Gevuina avellana Mol. or Embothrium coccineum J.R. Forst. & G. Forst.); one including main forest species plus one shrub nurse species (Fabiana imbricata Ruiz & Pav.); and three mixtures including one of the arboreal companion species and the shrub. Timber quality variables were assessed at age 20, and health status was recorded at ages 7 and 20 in all plantations. Growth variables were analyzed using linear mixed models to assess plantation effect over time. Kaplan-Meier survival analysis and Log Rank Test were used to compare chestnut tree survival among plantation types. Quality timber variables were analyzed with a chi 2 test. Results: Chestnut trees associated with arboreal main species (P. avium, Q. rubra, Q. robur) (Mix1) showed the best performance, with 10.1 % and 8.3 % higher height than average values of the other mixtures and the monoculture, respectively, and 19.1 % and 12.8 % higher diameter growth than across plantation types and monoculture average values, respectively. Mix1 had the highest average volume per tree (0.34 m(-3)), at least 30 % higher than the average volume of pure and other mixed plantations. This mixture including only main species also exhibited the highest percentage of trees with high trunk length values of all plantation types. No pest or diseases were recorded on chestnut trees, and survival was high in all plantation types. Conclusion: The impact of mixed plantations on growth and timber quality was evidenced at age 20. In particular, the association including arboreal companion species enhanced chestnut tree performance.
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    Recommendations for increasing yield of the edible Pinus pinea L. pine nuts
    (2024) Loewe-Munoz, Veronica; Delard, Claudia; del Rio, Rodrigo; Balzarini, Monica
    In Pinus pinea, cone to pine nut yield (total pine nut weight expressed as percentage of cone weight), an important crop trait, is decreasing worldwide. This phenomenon is of great concern, since the nuts of this species are highly demanded. Cone weight, seed and pine nut morphometry, and pine nut yield were monitored in a non-native area in Chile for 10 years. For this purpose, 560 cones, and the seeds and pine nuts contained in them, were counted, measured and weighed in a multi-environment study involving seven plantations. Seed and pine nut damage was evaluated. Two contrasting categories of cone weight (heavy/light) were defined. Cone to pine nut yield (PY) and other traits were calculated and compared between categories using a mixed linear model. Regression trees were used to explain PY variability. Cone weight was higher than in the species' native range (474 g vs 300 g on average). Pine nut number per cone and PY were significantly higher in the heavy cone category than in the light cone category (125 vs 89 units, and 4.05 vs 3.62%, respectively), The percentage of damaged seeds was lower in heavy than in light cones (9.0% vs 15.9%). Thus, PY depended on seed and pine nut morphometry as well as on seed health. Management practices, such as fertilization and irrigation, could be used to boost production of heavy cones and consequently increase PY.
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    Resilience of Pinus pinea L. Trees to Drought in Central Chile Based on Tree Radial Growth Methods
    (2024) Loewe-Munoz, Veronica; Del Rio, Rodrigo; Delard, Claudia; Cachinero-Vivar, Antonio M.; Camarero, J. Julio; Navarro-Cerrillo, Rafael; Balzarini, Monica
    The increasing occurrence of dry and hot summers generates chronic water deficits that negatively affect tree radial growth. This phenomenon has been widely studied in natural stands of native species but not in commercial plantations of exotic tree species. In central Chile, where the species is increasingly planted, the dynamics of stone pine (Pinus pinea L.) growth under drought have been little explored. We studied the impact of drought on four stone pine plantations growing in central Chile. We sampled and cross-dated a total of 112 trees from four sites, measured their tree-ring width (RWL) series, and obtained detrended series of ring width indices (RWIs). Then, we calculated three resilience indices during dry years (Rt, resistance; Rc, recovery; and Rs, resilience), and the correlations between the RWI series and seasonal climate variables. We found the lowest growth rate (1.94 mm) in the driest site (Pe & ntilde;uelas). Wet conditions in the previous winter and current spring favored growth. In the wettest site (Pastene), the growth rates were high (4.87 mm) and growth also increased in response to spring thermal amplitude. Overall, fast-growing trees were less resilient than slow-growing trees. Drought reduced stone pine stem growth and affected tree resilience to hydric deficit. At the stand level, growth rates and resistance were driven by winter and spring precipitation. Fast-growing trees were more resistant but showed less capacity to recover after a drought. In general, stone pine showed a high post-drought resilience due to a high recovery after drought events. The fact that we found high resilience in non-native habitats, opens new perspectives for stone pine cropping, revealing that it is possible to explore new areas to establish the species. We conclude that stone pine shows a good acclimation in non-native, seasonally dry environments.
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    Spatial Patterns of Productivity and Human Development Potentials for Pinus pinea L.
    (2024) Loewe-Munoz, Veronica; Del Rio, Rodrigo; Delard, Claudia; Gonzalez, Ricardo; Balzarini, Monica
    Pinus pinea (stone pine), a Mediterranean species, is valued for its highly nutritious pine nuts and its ability to adapt to different environmental conditions. The species has been increasingly planted in Chile, where its main ecological requirements are met across a vast area. However, new plantations are established without considering social dimensions. Policymakers can regulate private decisions on tree planting through the appropriate design of economic incentives to foster social well-being. The objective of this work was to describe spatial patterns of potential areas for the cultivation of the exotic nut-bearing conifer P. pinea in central Chile and the possible correlation of those patterns with human development indices. Spatial data layers of the municipality development index (MDI), elevation, edaphoclimatic variables, and stone pine nut's productive potential were overlapped at the municipality scale along 1225 km in central Chile. A spatial principal component analysis (sPCA) was used to integrate multiple dimensions, summarizing covariation structures, and identifying spatial patterns in the study area. Key results showed that spatial patterns of the potential productive index (PPI) were strongly regulated by the spatial pattern of climate and soil variables, whereas the spatial pattern of MDI showed a cryptic pattern and that the three dimensions of MDI-welfare, economy, and education-showed a different spatial movement, especially education and welfare. The results allow us to recommend that public policies boost municipality development through the promotion of P. pinea plantations and should target areas with a high productive potential and low MDI to generate socio-economic improvements. These findings are useful for the strategic spatial planning of the species cropping in Chile.