Walnut | Chandler
Climate change offers opportunities and challenges to walnut growing in NSW, with some regions expected to decrease in climate suitability.
Walnuts in NSW
Australia’s walnut industry is its third-largest nut crop industry. The industry continues to grow, with new plantings established over the last 5 years. In NSW in 2021-22, 9,322 tonnes of walnuts were produced, with a value of $32.2 million, representing 65% of Australia’s production.
The Riverina region near Griffith is NSW’s primary walnut production area, with smaller orchards in the Southern Highlands and Central Tablelands. These areas are suitable for walnut production due to their cool winters. The map shows the nut growing regions in NSW, excluding macadamia and almonds. Darker colours represent higher numbers of trees of bearing age.
The key walnut phenophases assessed in this project are dormancy, budbreak, flowering and pollination, fruit set and growth, kernel development, and harvest.
What is the NSW DPI Climate Vulnerability Assessment? ⏷
Climate change is altering the growing conditions for many agricultural commodities across NSW. Primary producers need evidence-based information about the changing climate, and the risks and opportunities it may bring.
The NSW DPI Climate Vulnerability Assessments are enhancing the resilience of our primary industries by providing information and data to help the sector better plan for, and respond to, climate change. They have assessed climate change impacts for extensive livestock, broadacre and irrigated cropping, marine fisheries, forestry, horticulture and viticulture, and important biosecurity risks associated with these industries to inform sound planning, risk management and adaptation decisions.
How we assessed climate suitability ⏷
Climate projections were sourced from Climate Change in Australia’s ‘Application Ready Data’. This dataset is comprised of projections from an ensemble of 8 global climate models, each presenting a plausible future climate. The models differ in their projections, giving rise to uncertainty which is reflected in the confidence statements given in brackets. Care should be taken when interpreting these results.
The Climate Vulnerability Assessment is intended to highlight potential industry- or regional-level changes. Intermediate and high emissions scenarios were used in the assessments (RCP4.5 and RCP8.5), but these are not the only future scenarios possible. The inclusion of climate variables important to the commodities production was based on published research, expert knowledge and data quality and availability.
Learn more in the Climate Vulnerability Assessment Project Framework.
Climate impacts: what to expect
Climate change presents challenges and opportunities for walnut-growing regions in NSW, with both increases and decreases in climate suitability expected to occur by 2050 under both emissions scenarios.
Walnut vulnerabilities
- Irrigation water requirements are likely to increase for walnut growing regions in the future (low to moderate confidence). The increase is likely to be greatest under the high emissions scenario.
- There is likely to be a moderate decrease in accumulated chill portions (see call-out box, page 16) during dormancy across Bilpin, Dareton and Griffith (high confidence). This decrease can disrupt budbreak and flowering, reducing nut yield.
- Dareton and Griffith regions are likely to have increased maximum temperatures during fruit set and growth (over 38°C), kernel development (over 38°C) and harvest (over 32°C) (high-moderate confidence). This is likely to minimally to moderately decrease suitability in Griffith and Dareton (high confidence). The increase in the number of days experiencing temperatures greater than 38°C is also likely to minimally decrease quality attributes like kernel colour, shrivel and sunburn in Griffith and Dareton (high confidence).
Walnut opportunities
- Due to a decrease in days with temperatures below 0°C during flowering and pollination, there is likely to be an increase in suitability around the Bathurst growing region from highly suitable to very highly suitable (high confidence). The Sassafras region will also minimally increase in suitability, remaining very highly suitable (high confidence).
- All growing regions are likely to remain very highly suitable during the flowering and pollination phenophase (high to moderate confidence).
Adapting to the changing climate
Adapting to extreme heat
- An increase in the number of hot days is expected to affect kernel quality. Applying kaolin spray during kernel development could help protect the trees and nuts against high temperatures and sunburn. Consideration of walnut cultivars with greater heat resilience could also provide a buffer against increased hot days.
Adapting to increased irrigation water requirements
- The walnut industry may need to improve water efficiency through changing irrigation practices, upgrading water infrastructure or adopting new technologies.
Adapting to low accumulated chill portions
- Applying growth regulators before budburst may curtail the negative effects of insufficient accumulated chill portions. Planting low-chill walnut cultivars may be beneficial in regions with declining accumulated chill portions.
Where can I find the climate suitability maps?
Maps of historical and future climate suitability for horticultural commodities were produced to demonstrate where in the state a commodity is likely to thrive or else be limited by future climatic conditions. The maps are not provided on these webpages but can be found in the Climate Vulnerability Assessment Summary Report (PDF, 41425.92 KB).
Walnut Factsheet
(PDF, 383.57 KB)
Summary Report
(PDF, 41425.92 KB)
