This study investigated the potential for Melaleuca rhaphiophylla bark to be made into a sustainable engineered wood product. Boards were manufactured from M. rhaphiophylla bark by hot pressing them without the use of any additional binders or other chemical treatments. Sheets of bark were pressed for 20 min at temperatures of 90 °C, 120 °C, 150 °C, 180 °C and 195 °C and pressures of 1, 2 and 3 MPa. Samples of the boards underwent three-point bending, water absorption and impedance tube testing to determine their Modulus of Rupture (MoR), Modulus of Elasticity (MoE), thickness swelling, water absorption and sound absorption potential. Linear mixed effects (LME) models were used to identify correlations between the condition of the bark and hot-pressing parameters with the properties of the final boards. The MoR, MoE and thickness swelling properties of the boards were found to be similar or superior to other bark-based alternatives. Water absorption was similar to commercially available plywood and medium density fibreboard (MDF) control materials, sound absorption was higher, but MoR and MoE were lower. M. rhaphiophylla bark boards show potential to be suitable alternatives for medium density fibreboard and plywood including uses in cabinetry or veneers with further development.

Flash flaming has shown promise as a seed enhancement technology that improves the handling properties of bulky or irregularly shaped seed material, which in turn benefits logistical and ecological aspects of large-scale direct seeding. To date, only a small number of grass species, that possess similar morphological characteristics, have been tested. This paper describes the application of flash flaming to diaspores (i.e. the dispersal unit comprising the seed and any surrounding or attached tissues) of 19 diverse dryland species from the Amaranthaceae, Asteraceae, Chenopodiaceae and Poaceae critical to ecological restoration in the mining intensive Pilbara region of Western Australia. Flash flaming parameters for each species were tested to identify and maximise volume and mass reduction, reduce particle cohesiveness and maximise flow through a mechanical seeding device, whilst maximising germination. Flaming of all species resulted in reductions in batch volume and mass, and improvements to flow characteristics. For 17 species, flaming either benefited or did not impact on germinability. For two species in the Amaranthaceae, flaming with the settings tested here resulted in a reduction in germinability; however, flaming enabled the diaspores to pass through a mechanical seeding device enabling mechanical distribution which is critical if the species are to be used in large scale restoration.

We posit that a better meshing of traditional engineering disciplines and ecological restoration science is central to achieving environmental repair at the scale and pace required to combat globally ever-growing, human caused, land degradation and biodiversity loss. Ecological restoration is an increasingly vibrant endeavour supported by diverse fields of research. But there is a rapidly emerging role for traditional engineering disciplines to design and deploy solutions to the challenges regularly encountered in returning biodiverse plant communities across degraded landscapes of varying characteristics. In order for large-scale restoration to be feasible, increased efficiencies throughout all stages of the restoration process are required. We argue for increased investment into the development of engineered tools and techniques guided by ecology, able to enhance our ability to cheaply, quickly, and effectively restore ecosystems. By conceptualising the overlap between ecosystem service value, traditional economic outcomes and successional land use we seek to explore how investment in new restoration technologies can lead to a net benefit for society and businesses alike. Using terrestrial mining as an example, we highlight engineering issues faced in large-scale restoration and outline how these may be overcome to maximise both economic and ecological outcomes with a particular focus on restorative earthworks and technologies for the direct return of plants.

We aimed to understand the influence of differing soil rock content on seedling emergence of a dominant arid zone grass critical to mine restoration (Triodia pungens R.Br.). We assessed whether emergence mortality resulting from seedlings failing to navigate rocky soils contributes meaningfully to failed recruitment and the maximum emergence depth. Cleaned seeds and florets (the natural dispersal unit) were buried at discrete depths of 0, 5, 10, 15, 20, 30, and 40 mm in three soil-rock matrices of varying rock content (soil sieved to <5 mm, sieved to <25 mm, or left un-sieved). Rock content reduced emergence of seeds buried below 15 mm and truncated the maximum emergence depth. When seeds were buried at 5 mm; near the modelled 6.0 mm optimal depth, any failure to emerge was largely attributable to failed seed germination. However, when seeds were buried greater than 20 mm, failure of pre-emergent seedlings to reach the surface became the significant factor contributing to failed emergence. Florets failed to recruit under all scenarios. Soil rock content can influence critical seed germination and emergence life stages and therefore the optimal seed recruitment depth. Emergence of deeply (>20 mm) buried seeds is likely restricted by rocks imposing a physical barrier to recruitment.

Mine rehabilitation is not just earthworks.Mine rehabilitation is a complex, integrated process that involves multiple stakeholders, long-term commitment, and a comprehensive understanding of site-specific conditions.When it comes to the re-introduction of vegetation, increasing the likelihood of successful plant establishment requires the proper implementation of many components including growth media movement, land forming, seedbed preparation, and seed delivery.From a perspective of initiating plant recruitment, best practice use of native seeds is fundamental, and seed technologies can also be coupled with the invention, development and modification of the seeding equipment needed to deliver seeds at scale.Improving seed-use efficiency through seed-enhancement technologies is one approach that has gained recent attention in dryland rehabilitation.Techniques including precision flash flaming, priming, polymer-based seed coating, and extruded seed pelleting all aim to improve the germination and establishment potential of seeds under suboptimal conditions.Along with modifications to existing mechanical seeders or with new builds, these technologies are one potential solution to overcome inefficiencies in dryland seeding efforts.For instance, through the fabrication and engineering of new parts fitted to existing seed-coating equipment, 'flash flaming' is a technique that removes unwanted hairs and appendages off bulky and fluffy seed batches (e.g.spinifex or Triodia species).After removal, seed batch volume is significantly reduced, while the flow properties of seeds through cleaning equipment and mechanised seeders are vastly improved.

The methods used to distribute seeds influence the success of a restoration project. We surveyed 183 restoration practitioners from across the globe with the aim of identifying common limitations to the effective use of mechanical direct seeding in large‐scale restoration practice to highlight avenues for design improvement to mechanized seeding equipment. Results from this survey show that direct seeding methods are commonly used for ecological restoration and agree with other studies that suggest the method can achieve results much quicker and cheaper than the alternative of distributing nursery‐grown tube stock. However, this study indicates that current mechanical direct seeding methods lack adequate control of seed sowing depth and spatial distribution and highlight that the inability to sow seeds of varying morphology over complex topography are common limitations to direct seeding. To improve restoration success, engineering improvements to mechanical direct seeders used in large‐scale restoration should focus in particular on addressing issues of precision of delivery for diverse seed types and landscapes.

The ability to reliably and efficiently restore degraded ecosystems at scale is a major challenge.Restoration on a mine site typically consists of either the planting of cultivated nursery stock or the direct seeding of seed onto site to reinstate native plants and ecosystems.At scale, planting seedlings can be extremely costly and time consuming and therefore, restoration practitioners have moved towards mechanical direct seeding methods.In many circumstances, however, mechanical direct seeding is unreliable and most mechanisms lack the versatility needed to plant a variety of native species in a range of sowing environments.Results of a global survey of restoration practitioners uncovered that seeding depth precision and accuracy is extremely important when distributing many native seeds.In order to guide improvements to the design of native seeders that are used in the Pilbara region of Western Australia, we studied the maximum and optimal emergence depth of a species crucial to restoration in the region, Triodia pungens (soft spinifex).Results showed that the current practice of broadcasting seeds on the soil surface may be inadequate to facilitate germination, and that covering seeds to 5 mm yields optimal emergence.Seedling emergence dropped off considerably at 10 mm with almost no emergence occurring once seeds were sown to 30 mm.Most mechanical seeders currently in operation are unable to control depth to this level of precision, particularly on the rocky and uneven terrain associated with mine waste dumps.Future designs should focus on improving depth control in such conditions.