An intra-stand approach to identify intra-annual growth responses to climate in Pinus nigra subsp. laricio Poiret trees from southern Italy

Survival of forest tree species in semi-arid environments such as the Mediterranean area is threatened by the increase in harsh drought conditions. Therefore, better knowledge of the eco-physiology of Mediterranean species and their growth responses to climatic factors is needed to develop strategies for sustainable management.The studies of cambial activity and wood formation can provide information on tree growth and physiological responses to variations in intra-annual climatic parameters, helping to answer questions related to tree performance and plasticity under changing environmental conditions.Our aim was to investigate cambium production in holm oak (Quercus ilex L.) as one of the most widespread evergreen oaks in Southern Italy. We studied the response of cambium activity throughout the particularly dry year 2017. We collected tissues from tree stems every two weeks by sampling microcores containing phloem, cambium and xylem. For the analyses, thin cross sections of the microcores were analysed under a light microscope to identify the timing of cambial production, xylogenesis and phloem formation. We detected the period in which the cambium was active, as well as the period in which the cambium was not productive. We interpreted the cambial response to climatic conditions at the site during the period of observation.The observed pattern of xylogenesis differed from the expected bi-modal pattern typical for Mediterranean species which usually results in Intra-annual Density Fluctuations (IADFs) in tree-rings. In Q. ilex we observed only one peak of cambial activity, likely due to the low water availability during the year 2017.The obtained results provide useful information supporting the forecasting of the wood-growth responses to expected climate change. Moreover, we gained technical experience on optimal preparation of thin sections of problematic tissues, which is especially challenging in Q.ilex due to high hardness of the peculiar wood structure making the investigations of xylogenesis very challenging in this species.

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Western juniper and ponderosa pine ecotonal climate–growth relationships across landscape gradients in southern Oregon

Canadian Journal of Forest Research ◽

10.1139/x08-142 ◽

2008 ◽

Vol 38 (12) ◽

pp. 3021-3032 ◽

Cited By ~ 22

Author(s):

Kevin C. Knutson ◽

David A. Pyke

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Radial Growth ◽

Winter Precipitation ◽

Forest Growth ◽

Annual Growth ◽

Growth Responses ◽

Climate Fluctuations ◽

Western Juniper ◽

Tree Ring Data

Forecasts of climate change for the Pacific northwestern United States predict warmer temperatures, increased winter precipitation, and drier summers. Prediction of forest growth responses to these climate fluctuations requires identification of climatic variables limiting tree growth, particularly at limits of tree species distributions. We addressed this problem at the pine–woodland ecotone using tree-ring data for western juniper ( Juniperus occidentalis var. occidentalis Hook.) and ponderosa pine ( Pinus ponderosa Dougl. ex Loud.) from southern Oregon. Annual growth chronologies for 1950–2000 were developed for each species at 17 locations. Correlation and linear regression of climate–growth relationships revealed that radial growth in both species is highly dependent on October–June precipitation events that recharge growing season soil water. Mean annual radial growth for the nine driest years suggests that annual growth in both species is more sensitive to drought at lower elevations and sites with steeper slopes and sandy or rocky soils. Future increases in winter precipitation could increase productivity in both species at the pine–woodland ecotone. Growth responses, however, will also likely vary across landscape features, and our findings suggest that heightened sensitivity to future drought periods and increased temperatures in the two species will predominantly occur at lower elevation sites with poor water-holding capacities.

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Differential growth responses in Pinus nigra, P. pinaster and P. sylvestris to the main patterns of climatic variability in the western Mediterranean

Forest Ecology and Management ◽

10.1016/j.foreco.2021.118921 ◽

2021 ◽

Vol 483 ◽

pp. 118921

Author(s):

Héctor Hernández-Alonso ◽

Jaime Madrigal-González ◽

Fernando Silla

Keyword(s):

Climatic Variability ◽

Pinus Nigra ◽

Western Mediterranean ◽

Growth Responses ◽

Differential Growth

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Growth responses of West-Mediterranean Pinus nigra to climate change are modulated by competition and productivity: Past trends and future perspectives

Forest Ecology and Management ◽

10.1016/j.foreco.2011.05.038 ◽

2011 ◽

Vol 262 (6) ◽

pp. 1030-1040 ◽

Cited By ~ 67

Author(s):

Dario Martin-Benito ◽

Vincent Kint ◽

Miren del Río ◽

Bart Muys ◽

Isabel Cañellas

Keyword(s):

Climate Change ◽

Pinus Nigra ◽

Growth Responses ◽

Future Perspectives

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A new mechanistic understanding of ecophysiological patterns in a widespread alpine dwarf shrub – Refining climate-growth relationships

10.5194/bg-2021-99 ◽

2021 ◽

Author(s):

Svenja Dobbert ◽

Roland Pape ◽

Jörg Löffler

Keyword(s):

Thermal Conditions ◽

Frost Damage ◽

Growth Patterns ◽

Environmental Data ◽

Annual Growth ◽

Dwarf Shrub ◽

Environmental Drivers ◽

Growth Responses ◽

Evergreen Species ◽

Early Season

Abstract. Considering the recent widespread greening associated with dwarf shrubs in arctic and alpine ecosystems, further understanding of how these shrubs respond to environmental conditions is of crucial importance. Here we present novel insights and propose a new method to monitor shrub growth, using high-precision point dendrometers. We analyzed intra- and inter-annual growth patterns of a common evergreen species (Empetrum nigrum ssp. hermaphroditum) by measuring its hourly radial stem variability at a micrometer scale over four successive years on exposed ridge positions and along a steep elevational gradient. With the same temporal resolution, we collected near-ground micro-environmental data and identified environmental drivers controlling growth behaviour. Overall, we found high inter-plant variability in growth-defining parameters, but high similarities in growth responses to the micro-environment. Early-season radial growth in spring exhibited high sensitivity to winter thermal conditions and prolonged ground-freezing in spring, suggesting that the evergreen species E. hermaphroditum remains photosynthetically active during the snow-free period, which increases carbohydrate accumulation for early season physiological activities. We discovered a phase of radial stem shrinkage during the winter months, which can be attributed to an active cell water reduction to protect the plant from frost damage. We present the first fine-scale intra-annual growth curves for an alpine dwarf shrub and identify soil moisture availability and winter freezing conditions as the main drivers of radial stem variability, thus forwarding the ongoing debate on the functional mechanisms of greening and browning in arctic and alpine regions.

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Tree Growth Response to Low-Intensity Prescribed Burning in Pinus nigra Stands: Effects of Burn Season and Fire Severity

Applied Sciences ◽

10.3390/app11167462 ◽

2021 ◽

Vol 11 (16) ◽

pp. 7462

Author(s):

Juncal Espinosa ◽

Dario Martin-Benito ◽

Óscar Rodríguez de Rivera ◽

Carmen Hernando ◽

Mercedes Guijarro ◽

...

Keyword(s):

Tree Growth ◽

Prescribed Burning ◽

Fire Severity ◽

Pinus Nigra ◽

Fire Season ◽

Pure Stand ◽

Growth Responses ◽

Individual Tree ◽

Tree Characteristics ◽

Significant Factors

The study of the short-term post-burn tree growth in a mixed stand of Pinus nigra and Pinus pinaster and in a pure stand of P. nigra in the Cuenca Mountains (Spain) will enable us to determine the disturbance of prescribed burning conducted in two seasons. Dendrochronological methods and mixed modelling were used to investigate whether tree growth responses are influenced by stand and tree characteristics, fire season and fire severity variables. The findings revealed that prescribed burning scarcely affected tree growth. The type of stand (mixed or pure) was not critical for tree growth. The individual tree characteristics were significant factors in all the scenarios studied. The inclusion of some fire severity variables for the first time in tree growth models showed that the maximum scorch height determined a main part of the variability of tree growth. The time during which the temperature was above 60 °C in the cambium region and temperature was above 300 °C in the bark surface were only significant factors after spring burnings. The litterfall one year after the prescribed burning was not a significant factor in any of the models. Overall, the findings confirm the characteristic resistance of P. nigra to surface fires and favor the potential application of prescribed burning programs for this species in the Mediterranean Basin.

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