The journey to modern silviculture systems

The second day of the Silviculture 4.0: Smart Technology from Nursery to Field conference moved from focusing on nurseries to the nitty gritty of getting the plants into the prepared soil and ensuring their survival as cost- effectively as possible.

The three-day event was hosted by Nelson Mandela University (NMU’s) Forsilvitech, represented by Ellepot South Africa’s Shaun Biggs and Dr Muedanyi Ramantswana of NMU.

Modernisation and automation of silviculture operations, global trends, soil preparation for planting, planting systems, weeding, fertilising, remotely piloted aircraft systems (RPAS) and productivity were the main topics under the microscope.

MONDI

A regular speaker at precision forestry events, Dr Dean Da Costa from Mondi described the background to Mondi’s journey in modernising its silviculture operations since 2012. He said the drivers are safety considerations such as ergonomics, productivity, quality, social responsibility and cost savings.

Dean said Mondi’s strategic modernisation goal was to “Optimise timber volumes by growing the correct tree species on a sustainable basis through planned and documented processes”.

The technical aspect focuses on overcoming steep slope and rough terrain challenges, integrating pitting, planting, and fertilising technologies, and considering the costs of mechanised and semi-mechanised operations on productivity and quality improvements.

The move from manual to motor-manual or mechanised silviculture improves working conditions, eliminates safety risks, upskills the workforce and improves productivity.

Dean emphasised the need for a clear silviculture strategy because it impacts the company’s value chain. Mondi has and continues to invest in research site genotype matching, residue management, site preparation, planting, blanking, coppicing, plant maintenance and forest protection.

Sibusiso Sibanyoni presented Mondi’s modern pre-canopy weeding operations. The company has embraced technologies including various boom sprayers, tracked John Deere and New Holland tractors, Remotely Piloted Aircraft Systems (RPAS) (commonly known as drones), boom sprayers with lances or dribble bards and manual tools.

Sibusiso said the next step is enhancing data analysis capabilities using digital tools, integrating systems, partnerships with machinery and herbicide manufacturers, and standardising operations.

GLOBAL TRENDS

Dr Muedanyi Ramantswana from NMU spoke about the global modern silviculture trends. The change drivers are health and safety, escalating costs, quality and productivity improvements, social challenges, environmental issues and better adherence to certification body requirements.

Muedanyi said that globally, in 2035, most silviculture operations will still be manual; however, technology will influence them. Companies must be well informed about the latest technologies, have a clear silviculture strategy, constantly gather and analyse data from their operations, and adapt and improve.

MULCHING

Dr Jacob Crous from Sappi Forest’s land management research programme spoke about the benefits  and disadvantages of mulching on early tree growth. Soil fertility is a concern because the treatments impact soil’s chemical, physical and biological properties.

Sappi’s research found that mulching improves soil moisture in dry conditions and conserves organic matter and nutrients. The survival rate of trees planted in burnt soil was 79.8% compared with 88.9% in mulched soil.

Jacob acknowledged there are downsides to mulching apart from its expense. However, “mulching should be the preferred slash-management practice. More research is needed to understand why not all sites respond positively to mulching, find ways to reduce mulching costs and find equipment that can work on steep slopes”.

MECHANISED PLANTING

Dr Rafael Ribeiro Soler from Bracke Forest’s presentation was about flat, moderate, and steep terrain planting technologies. He introduced the Bracke planters for excavators, which feature a slow-release fertiliser applicator and irrigation options.

• Bracke P11.b for 14 and 20-ton excavators can plant up to 300 seedlings per hour. It holds seedling containers with a standard capacity of 196 seedlings (60mm) and an option for 100 seedlings (75mm).
• Bracke P12.b for 20 to 24 tons excavators plants up to 250 seedlings per hour.
• Bracke P22.b is designed forexcavators weighing 24 tons and planting up to 600 seedlings per hour, with a similar container plant capacity to the P11.b and P12.b.
• The D61 planter is coupled to the Komatsu D61 bulldozer for application on flat terrain. The planting unit weighs 950kg and can plant up to 900 seedlings per hour. It has georeferencing capabilities for accurate planting.

Fanie Viljoen from Novelquip Forestry shared insights on the company’s journey towards a mechanised planter where the focus is on quality before quantity.

In 2021, Novelquip partnered with Ponsse and Epec to develop the world’s first forwarder-based planter. The concept machine has been tested in South Africa and by Suzano in Brazil. It consists of a four-head planter built on the Ponsse Buffalo forwarder featuring four self-contained planting units.

The fully automatic machine feeds seedlings from cassettes to the planting heads that make the pits, place the seedlings, firm the soil, irrigate and restart. It has two planting modes:

• Plant only achieves 1100 seedlings per hour
• Pit and plant achieve 640 seedlings per hour.

The machine operates for 95 minutes before it needs to be replenished in the field in a process that takes about 12 minutes.

Fanie said the present planting quality achieved with the concept machine is 90%; however, they are pushing for 98%.

DATA-DRIVEN TECHNOLOGY

Duncan Fryer from Stihl continued the emphasis on technology. He spoke about the Stihl Smart Connector, a cloud-based system that captures the machines’ usage data and transmits it via Bluetooth to the STIHL Connected App on a smartphone or tablet within range. The App stores and submits the data to the Stihl cloud via Wi-Fi or mobile network.

The portal allows for easy management of fleet performance and management data.
Roedolf Nieuwenhuis from Cropwatch Africa discussed using advanced data-driven technology for pest and disease detection. High-resolution satellite imagery enables large-scale monitoring of forest areas. Drones with multispectral or thermal sensors enhance this data by conducting aerial surveillance. Geographic information system (GIS) mapping integrates the data to identify pest hotspots and disease-prone zones.

Ground-based sensors and weather stations provide critical real-time data on local microclimates. Roedolf said modern forest managers should combine advanced technologies and AI for a holistic, data-driven approach to early detection, precision interventions, sustainable practices, and adaptive management of pests and diseases.

Santiago Ferrando from Uruguay spoke about the benefits of using the STA logger system. It is an integrated data logging attachment that fits certain knapsack and boom sprayer brands.

It records the location, time, herbicide application events, and area sprayed and categorises data into groups (like weed types).

Data is uploaded to the cloud, processed and delivered to his desktop or mobile device. It assists decision-making, letting his company achieve 95% traceability in planting, replanting, and replacement operations.

CHEMICAL APPLICATIONS

Sean McKenzie from Silvix spoke about the operational productivity of infield equipment and ergonomic standards for operator comfort and efficiency. He highlighted a few of the company’s products:

• The motorised 15-litre knapsack is equipped with a 3m aluminiumboom with different nozzles and application rates
• The ergonomic FAKA Plenty planting tool and the 18-litre Squam backpack.
• The Bendi Bar for direct application of glyphosate without drift

Sean introduced the company’s latest product, the Nutree Bag, a precise fertiliser application. One bag in the hole while planting contains enough controlled-release fertiliser for a year.

Matt Houghting from PACSys said the benefits of using drones (RPAS) in silviculture operations are invaluable. Drones can be programmed to deliver precise amounts of pesticide in specified areas. There is limited spray drift because it is as low as 3m above the plants.

It is productive, fuel-efficient and safe. He put the 40-litre drone through its paces on the field day in a demonstration that impressed the attendees.

COMPARISONS

NMU MSc student Mduduzi Junior Khoza discussed his research comparing the operational productivity and quality of manual and semi-mechanised planting methods. It compared manual planting tubes (pitless) and semi-mechanised high-pressure planting methods on burnt areas with different slash loads.

The results found higher productivity for the manual method (50 and 60% higher) across the different slash conditions. Regarding planting quality, both methods achieved high planting success rates (90%), with manual planting having a slight edge (+3%). Junior concluded that while manual planting methods continue to be productive, there is significant potential for semi-mechanised approaches in certain conditions, supporting ongoing initiatives to modernise planting techniques.

Aphelele Angel Goldsmith from Stellenbosch University said his research aimed to assess the effectiveness of slash burning and disc harrowing on fuel load and stand productivity of Eucalypts in Mpumalanga.

Angel found disc harrowing played a crucial role in fire management by breaking the horizontal continuity of fuel, which reduces the fire spread rate and fuel loading, thereby lowering fire intensity. However, the study noted a lack of quantified evidence regarding the long-term effects of these practices.

The study highlighted that repeated disc harrowing and prescribed burning influence root distribution patterns, significantly affecting the overall growth of Eucalyptus grandis × nitens, tree stand density, volume, and biomass production.

The last speaker of the event was Thembinkosi Zulu from NMU. He compared the operational productivity of pitting machine operators on burnt and mulched sites while also assessing the quality of the pits they produced in depth and diameter.

Using an M-PAT single-head pitting machine mounted on a Volvo EC55B compact excavator, data was collected from two compartments with similar terrain and soil types but different residue statuses (90% burnt versus 80% mulched). Each operator was assigned 10 plots, with 160 pits per plot, and productivity and pit quality were recorded.

The results showed that mulched sites had higher productivity (158 pits/plot) than burnt sites (136 pits/plot). More experienced operators consistently outperformed others, with productivity ranging from 200 to 600 pits per hour. Pit quality was strongly linked to operator experience rather than the specific site conditions, with more experienced operators producing a higher proportion of good-quality pits.

Thembinkosi concluded that operator experience significantly impacts productivity and pit quality and that marking planting positions on mulched sites increased efficiency.

Written By: Joy Crane & Justin Nyakudanga

Source: WoodBiz / SA Forestry Magazine – October 2024 (Pages 20 – 26)

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