Australia is the sole developed nation labelled a 'deforestation hotspot.' This crisis has economic ramifications, elevating living costs due to supply chain disruption, loss of jobs in rural areas, and increased reliance on >$3.5B in imports. Ecologically, forest loss endangers >700 plant and animal species, releases billions of tonnes of greenhouse gases, and jeopardises world heritage areas. To address this urgent challenge, we have been working with Australian forestry companies to develop innovative approaches that establish forests faster, and more sustainably. By studying how symbiotic mycorrhizal fungi use signalling to colonise and promote tree health, we are harnessing Australian symbiotic mycorrhizal fungi to develop strategies that aid reforestation. I will cover our recent work seeking to understand how mycorrhizal fungi use small secreted proteins to manipulate both their host immune function, but also the establishment of plant pathogens in newly established seedlings. I will cover how the outcomes of this work extend beyond applications within forestry and are now being used to develop new means of identifying and controlling plant diseases in a wide range of applications from forestry to agriculture.