Urban forests are widely recognised as a nature-based solution to mitigate the effects of climate change; however, urban forests are also vulnerable to climate change. Therefore, there is a need to improve species selection to ensure the delivery of ecosystem services by urban forests now and in the future. Research on the impacts of climate change on urban forests requires investigation to capture the complexities associated with species identity and growing conditions. Yet, such studies remain rare in urban contexts, highlighting the need for expanding collaborative research in cities. Here, we present a nation-wide urban trial network established across four states in Australia, showcasing stakeholder collaboration aimed at advancing urban forest research. The network consists of 11 standardised plantings of tree and/or shrub species aimed at testing species' growth and performance (i.e., stress tolerance) in cities across a range of climatic conditions. To test these differences, we measured height and diameter relative growth rates (RGR) and leaf damage caused by stress at each site one month after planting (2018-2020) and at the end of the austral summer in 2024. We used generalised linear mixed-effects models for RGR and ordinal logistic regressions for leaf damage to test the effects of annual maximum temperature (TMAX) and the Pinna Combinative Index (IP, a climate-drought index). By 2024, across all sites, we found 23 % of the originally planted individuals had died or were missing. We recorded significant differences in height and diameter RGR and leaf damage among sites, and IP was significantly and negatively related to both RGR and leaf damage. The network serves as an example of how stakeholder collaboration can broaden the scope of urban forest research that evaluates plant growth and performance across regions and environmental conditions.

Tropospheric ozone (O3) threatens agroecosystems, yet its long-term effects on intricate plant-microbe-soil interactions remain overlooked. This study employed two soybean genotypes of contrasting O3-sensitivity grown in field plots exposed elevated O3 (eO3) and evaluated cause-effect relationships with their associated soil microbiomes and soil quality. Results revealed long-term eO3 effects on belowground soil microbiomes and soil health surpass damage visible on plants. Elevated O3 significantly disrupted belowground bacteria-fungi interactions, reduced fungal diversity, and altered fungal community assembly by impacting soybean physiological properties. Particularly, eO3 impacts on plant performance were significantly associated with arbuscular mycorrhizal fungi, undermining their contribution to plants, whereas eO3 increased fungal saprotroph proliferation, accelerating soil organic matter decomposition and soil carbon pool depletion. Free-living diazotrophs exhibited remarkable acclimation under eO3, improving plant performance by enhancing nitrogen fixation. However, overarching detrimental consequences of eO3 negated this benefit. Overall, this study demonstrated long-term eO3 profoundly governed negative impacts on plant-soil-microbiota interactions, pointing to a potential crisis for agroecosystems. These findings highlight urgent needs to develop adaptive strategies to navigate future eO3 scenarios. Soybean, a global staple crop, is used in rotation practices worldwide to decrease fertilizer use due to its symbiotic relationship with soil nitrogen fixation microbes. Soybean, however, is vulnerable to ozone pollution, leading to low performance and yield. As ozone pollution is projected to increase, a crucial task is understanding how ozone damages soybean and soil microbes, which could reveal a crisis in underground ecosystems. This study demonstrates how long-term ozone pollution profoundly degrades plant and soil health by altering plant-microbe-soil interactions. The findings highlight the urgency for adaptive strategies against future food and economic losses resulting from ozone damage.image

Plastic mulch is widely utilized for weed control, temperature regulation, soil erosion prevention, disease management, and soil structure improvement, ultimately enhancing crop quality and yield. However, a significant issue with conventional plastic mulches is their low recycling rates, which can cause plastic residue to build up, thereby damaging soil quality and reducing crop yield. The emergence of biodegradable films offers a promising solution to mitigate this issue and reduce soil pollution. However, its potential effects on soil properties and plant performance remain unclear. In this study, low-density polyethylene (LDPE) and poly (butylene succinate-co-butylene adipate) (PBSA) were used to observe the effect of plastic mulch residues on soil properties and plant growth performance via potting experiment. Additionally, the interaction effects of compost and biochar as soil amendments with plastic mulch residues were also evaluated. The result of this study revealed that the type of plastic significantly affected the total nitrogen and magnesium uptake; however, the morphological traits of the tested plant (Japanese mustard spinach) were not significantly affected. The addition of compost and biochar led to a significant increase in both shoot and total dry weight of the plant, indicating a positive effect on its growth. The results of the two-way ANOVA indicated a significant influence of plastic type on dissolved phosphate (PO43- ) levels and soil dehydrogenase activity (DHA). The interaction effect (plastic type with soil amendment) was statistically significant only for soil DHA. Neither plastic mulch residues nor soil amendments significantly affected other soil chemical properties. However, long-term experiments to systematically investigate the long-term effects of plastic residues are necessary.