Elsevier

Agricultural Systems

Volume 186, January 2021, 102982
Agricultural Systems

Short Communication
Climate change impacts on phenology and yield of hazelnut in Australia

https://doi.org/10.1016/j.agsy.2020.102982Get rights and content

Highlights

  • This study projects hazelnut yield for future using process-based modelling.

  • Climate projections from various GCMs are used as input for the simulations.

  • Australian temperatures are predicted to increase, while changes in rainfall is uncertain.

  • Hazelnut yield is projected to increase in southeastern Australia in future climate.

  • For remaining areas, future changes in yield and production are climate model-dependent.

Abstract

The growing demand for nuts and the required diversification of supply are urging to identify additional zones for hazelnut tree cultivation around the world. Given the long-term nature of the investment needed to establish new orchards, an ex-ante evaluation of the future production trends due to global changes is critical to support stakeholders and decision makers. With this motivation, we investigate the physiological response and the attainable yield of hazelnut in Australia, using a process-based model. Simulations examined phenological development, hazelnut growth processes and yield in recent past and near-future climate conditions, using an ensemble of regional climate models bounded by four global climate models (GCMs). While the entire domain of analysis will warm up in the next twenty years, the precipitation patterns are rather erratic across GCMs. The effect of climate change on hazelnut farming is variable across agro-climatic zones, except in the southeasternmost part of Australia, where all simulations agree in predicting a yield increase ranging from 18 to 52%. Elsewhere the hazelnut production potential varies, with some GCMs projecting yield increase and others estimating reductions or no significant changes. Yield increase is associated mainly with higher gross assimilation rates, whereas decrease is related to a delay in chilling requirements fulfilment, caused by the projected increase in minimum temperatures and to sub-optimal conditions for the photosynthetic process. Despite the need of additional field trials to further validate the model, these results may be used by private and public bodies to support new investment plans, and promote legislative measures aimed at encouraging hazelnut cultivation in Australia.

Introduction

European hazelnut (Corylus avellana L.) is a deciduous tree belonging to the Birch family. It has been commercially cultivated in temperate maritime climate regions in Turkey, Italy, Spain, Azerbaijan, Oregon (USA), China and Georgia (FAO, 2018).

Despite its wide range of natural distribution, commercial orchards are concentrated in few locations worldwide. Turkey is the leading producing country, contributing to more than half of the global production of in-shell hazelnuts, followed by Italy, Oregon and Azerbaijan (FAO, 2018). After 2007–2008, the global hazelnut supply has not increased proportionally to the largely growing demand from the chocolate and pastry industry. In Australia, hazelnuts import has increased from 1400 t in 1992 to 2300 t in 2015 (Baldwin, 2015), requiring to enlarge domestic production through the establishment of new hazelnut plantations. More importantly, freshly cracked hazelnut kernels available from the Australian growers have a major competitive advantage over imported products due to their freshness quality (Baldwin, 2010). Hazelnuts are grown mainly in the temperate regions of southeastern Australia, and in few scattered patches of South and Western Australia. In southeastern Australia, the main production zones are the central Tablelands of New South Wales around Orange, northeast Victoria around Myrtleford, central and eastern Victoria and in northern Tasmania (NutsForLife, 2019; PlantHealthAustralia, 2020). Various studies and experimental field trials have indeed demonstrated that some Australian areas such as the New South Wales, Victoria and Tasmania, meet the thermal and water requirements of hazelnut trees, and can be suited for hazelnut cultivation (Baldwin, 2004; Baldwin, 2009; Baldwin, 2015; Baldwin et al., 2003; Baldwin and Guisard, 2014). The main cultivation areas are characterized by Mediterranean maritime climate (mild humid winters and cool summers) with average maximum temperatures between 25 and 30 °C, average minimum temperatures between 0 and 5 °C and average annual rainfall between 500 and 1000 mm (Baldwin, 2015). Available studies, however, are limited to few locations and refer to current climatic conditions, despite the long-term nature of the investment connected to hazelnut cultivation (around 10 years after planting before full production). Hence, the identification of new territories suitable for hazelnut farming should be based on the expected trends of the impacts of thermal and precipitation regimes on hazelnut growth and development.

Various studies have documented the impact of changes in temperature and precipitation on hazelnut. Available studies report that an increase in the number of days with maximum temperature (Tmax) higher than 35 °C and relative humidity (RH) lower than 70% caused a severe water stress leading to yield decline and shortened vegetative growth, combined with a reduction in kernel filling (Bignami and Natali, 1997; Thompson, 1981; Tombesi, 1994). Similarly, an increase in minimum temperature (Tmin) during the cold season could limit the accumulation of chilling hours required to break dormancy of vegetative buds, and to trigger pollen shed and female anthesis (Mehlenbacher et al., 1991). Unlike water stress, which can be reduced with irrigation, the negative effects of temperature increase on chill hours and leaf burning cannot be easily mitigated. Similarly, the increase in temperature can hasten vegetative growth, reducing the duration of kernel filling and kernel weight (Asseng et al., 2015).

Nevertheless, temperature increase can also have beneficial effects on hazelnut production. The damages to catkins, female flowers and early leaves from severe winter temperature (Duke, 1989; Germain, 1986; Schuster et al., 1944; Thompson, 1981) are expected to be less frequent in the future. Temperature increase can also have positive effects on pollen fertilization, kernel filling and in preventing the damages to the newly emerged shoots. For instance, daily maximum temperature below 21 °C during ovary growth and grain filling may lead to blank nuts and reductions in nuts weight (Silva et al., 1996). Also, temperature below −3 °C could damage small shoots (Bergoughoux et al., 1978).

The effect of temperature increases on hazelnut production is not simple to assess. For instance, the intra-seasonal distribution of temperature matters more than the average increase (Materia et al., 2020), as extreme cold hours could be more frequent in the future despite the increase in mean temperature. This is further complicated by the possible negative impacts of temperature increase on crop yield under changing climatic conditions, related to the decrease in stomatal conductance (Allen et al., 2011; Rosenzweig et al., 2014). Moreover, depending on whether the increase in atmospheric carbon dioxide (CO2) concentration was accounted for or not, the differences in simulated yield could be as high as 60% toward the end of century (Degener, 2015).

A few studies already pointed out the influence of climate change on hazelnut tree cultivation. An et al. (2020) projected that the hazelnut yield will decrease up to 13% in around half of the actual production areas using multiple regressions between yield and climatic variables. However, the study did not investigate the physiological reasons behind the decrease, which might help farmers/managers to implement proper adaptation strategies. Process-based simulation provides a mean to reproduce the effects of the variability of soil properties and weather conditions on hazelnut physiological processes, and to gain more insights on the system behavior (Korzukhin et al., 1996). It is a viable methodology to analyze the complex interactions between the genotype, the environment and crop management (Cuddington et al., 2013). The main advantage provided by such modelling approach is its capability to dynamically reproduce the non-linear interactions between crop physiological processes and agro-pedo-climatic conditions (Archontoulis and Miguez, 2013; Singh, 1994), and extrapolate reliable assessments beyond observed conditions. On the other hand, the use of a process-based model for climate change scenario analysis requires a proper calibration, aimed at proving its adequacy in reproducing experimental field data (Angulo et al., 2013).

In our knowledge, there is no literature yet regarding the impacts of climate change on hazelnut phenology and yield in Australia. The objectives of this study are (1) the evaluation of the projected impacts of climate change on hazelnut yield and production in a vast area of Australia, and (2) the identification of the main sources and degree of uncertainty in the projection of future hazelnut yield trends. Since it takes around 10 years to establish a hazelnut orchard before it comes into commercial production, the model-based information can be used to design experimental trials with controlled environmental conditions on specific locations for further investigation.

Section snippets

Study workflow

Our study is based on the application of a process-based hazelnut simulation model (HAZEL, Bregaglio et al., 2016) to estimate changes in phenology, growth and yield considering future climate and baseline conditions (Fig. 1). HAZEL simulates the effects of environmental conditions on the growth dynamics of a single hazelnut plant at full production. Further information on HAZEL is available in section 2.1 of the Supplementary Material (SM 2.1).

Model calibration

Before the spatially-distributed application, the

Future change in climate

The climatic conditions of the recent past climate are presented in section SM 3.2 (Fig. S2). There is no agreement among climate models regarding the future changes in precipitation. The simulations forced by CSIRO-MK3.0 and ECHAM5 are projecting drier conditions over most southeast Australia, while the other two models are projecting an increase in precipitation (Fig. 2a-d; SM 3.2).

Unlike precipitation, all climate models agree in projecting an increase in Tmax and Tmin, however the rate of

Discussion

This study investigates the potential for hazelnut cultivation in Australia in the recent past and near future, accounting for the expected future changes in climatic conditions.

The NARCLiM climate forcing was chosen because it provides high-resolution data (0.11° longitude × 0.09° latitude), needed to represent realistic climate-topography interactions in the study area, and includes different climate modelling instances to represent projection uncertainties. In order to investigate the impact

Conclusion

The impact of climate change on hazelnut yield in Australia is rather controversial, due to the lack of agreement among climate models on the future changes in precipitation and the degree of temperature increase. While the warming is somewhat certain for both minimum and maximum temperatures, its intensity will play an important role on the change of potential hazelnut production. Moreover, models show an erratic signal in future precipitation amounts and patterns, and this uncertainty is

Declaration of Competing Interest

None.

Acknowledgements

The authors would like to thank Dr. Basil Baldwin for providing access to field trial data from Australian locations for HAZEL calibration. The research was carried out with the cooperation and contribution of the Hazelnut company division of Ferrero Group. This research received support from the AgriDigit-Agromodelli Project (DM n. 36502 of 20/12/2018), funded by the Italian Ministry of Agricultural, Food and Forestry Policies and Tourism.

References (42)

  • B. Baldwin
  • B. Baldwin

    Hazelnuts: Variety Assessment for South-eastern Australia

    (2010)
  • B. Baldwin

    The Growth and Productivity of Hazelnut Cultivars

    (2015)
  • B. Baldwin et al.

    The Status and Future Challenges for the Austrlian Hazelnut Industry International Society for Horticultural Science (ISHS), Leuven, Belgium

    (2014)
  • B. Baldwin et al.

    Hazelnut Variety Assessment for South-eastern Australia, Canberra

    (2003)
  • F. Bergoughoux et al.

    Le Noisetier, Production et Culture

    (1978)
  • C. Bignami et al.

    Influence of irrigation on the growth and production of young hazelnuts

    Acta Hortic.

    (1997)
  • K. Cuddington et al.

    Process-based models are required to manage ecological systems in a changing world

    Ecosphere

    (2013)
  • R. Darbyshire et al.

    Impact of future warming on winter chilling in Australia

    Int. J. Biometeorol.

    (2013)
  • J. Degener

    Atmospheric CO2 fertilization effects on biomass yields of 10 crops in northern Germany

    Front. Environ. Sci.

    (2015)
  • J.A. Duke

    Corylus avellana L. (BETULACEAE) – European Filbert, Cobnuts Hazelnuts Barcelona Nuts, Handbook of Nut

    (1989)
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