The labour-intensive task of lifting bare-rooted seedlings from nursery beds is ripe for mechanisation. An innovative ‘block-lifting’ tree lifter has been developed by Jonathan Sudano at Tree Nursery NZ in partnership with FGR’s Precision Silviculture programme.
The block lifter, which attaches to the rear plough arms of a small tractor and is controlled by the tractor’s GPS, can gently lift a one-metre-length block of 8 -10 rows of trees at a time – around 120-150 trees. It can lift at least 20,000 seedlings an hour – the equivalent ten people working flat out. Tree roots are mechanically trimmed, and trees then placed in a bin which holds 8,000-10,000 trees. Bins are lifted onto a trailer towed by the tractor and delivered to an indoor grading and packing line.
“The system involves minimal soil disturbance – it only requires one pass of the tractor,” says Jonathan. “The roots and mycorrhizae are returned to the bed, keeping the organic matter there, and the site is left clean and ready for replanting.”
While Jonathan stresses he has a good team of manual lifters at the moment, he envisages productivity gains once the system is fully operational, likely to be in the 2024 lifting season. “We’re going to do some more tests later this year on some spring onions we’ve got growing here – which are actually quite similar to pine seedlings,” says Jonathan, who has been helped with the machine design by local agricultural design and technical engineers.
Automated seedling grading and packing is the next obvious step, and another project to develop artificial intelligence-based tools to grade trees is on-going. Trials have shown that an AI system can be trained to select seedlings according to specific quality criteria, enabling rapid and consistent grading of stock. Initially designed for an in-shed conveyor system, the potential exists to embed this technology directly into a seedling-lifting machine, which would increase efficiency even further.
Collaborators: Tree Nursery NZ; Timberlands Ltd; University of Canterbury; Contempo Lab.
