Portable sawmills provide a relatively low-cost entry into sawmilling. They are well suited to processing alternative species (also called specialty species) grown in farm woodlots and small plantations.
Portable sawmills have been used in New Zealand since the late 1800s, when bush sawmills were first used in native forests.
Today, some portable mills can be towed to site, and others can break down for transport on a trailer. In most cases, they can be set up to saw timber on farm or in the forest in less than an hour.
There are larger commercial models designed for semi-permanent on-site use. A loader, forklift, or farm tractor is needed to move, stack, and load out logs and timber.
Portable sawmilling has many advantages.
There’s a big demand for timber in New Zealand and internationally. New Zealand imports some high value specialty timber to meet demand for things like decorative timbers, flooring, wood panelling, and furniture.
Some of this demand is met by locally grown and milled timber.
Macrocarpa (Cupressus macrocarpa), Mexican cypress (C. lusitanica), redwood (Sequoia sempervirens) and various eucalypts are the most popular and widely produced New Zealand-grown timbers milled by portable sawmillers.
The success of a portable sawmilling business depends on things like:
Good roads and access tracks are important. Good access allows easier harvesting with smaller machines that have less impact on soils. Smaller machines also have lower running costs and emissions.
One large milling site is often the preferred option, with logs brought to it from the forest. Preferably the site has all-weather road access and is large enough to lay everything out.
The site should have enough flat land for the sawmilling operation, including an area for:
Log making is a critical step as the lengths of the logs need to match the standard lengths of timber for sale, and preferably the highest value by grade.
Additional logs need to be stacked nearby, and timber stacked ready to be trucked out or moved to a storage area. This needs a circular area about 20 to 30 metres wide depending on the sawmill type and the number of logs to mill.
This amount of area can be difficult in steep country. If there are more than a few trees to mill, it’s a good idea to excavate and level the site well in advance of sawmilling.
You’ll need extra flat land if drying and storing sawn timber on site.
Wooden bearers are needed to stack the logs on to keep them off the ground and allow airflow around them. Timber packs need to be covered with corrugated iron or stored in a large open drying shed for final seasoning. Some commercial operators using on-site mills invest in kilns for drying, including solar kilns.
Larger forests on a large farm could have multiple sites to decrease the distance of felled trees to the mill site.
You can buy a variety of locally manufactured or imported portable sawmills.
In 2020, small manual models range in price from around $6,000 to $12,000.
At the top end of the range, commercial multi-saw models with power feed and computer headworks cost around $20,000 to $25,000 (2020 prices).
Commercial bandsaw models with power feed, computer headworks, and hydraulic log handling can cost between $60,000 to $120,000, depending on the model and whether you buy locally or import (2020 prices).
The amount of sawn timber you get from a log depends on the type of sawmill and the quality and dimensions of logs.
If you're sawing a log larger than 50cm in diameter then conversion from log to sawn timber is likely to be:
Multi-blade (quarter saw) and swing-blade sawmills are efficient for sawing large logs of medium to low grade. They're particularly suited to sawing large softwood logs including cypresses and redwoods.
Advantages of multi-blade saws include:
Disadvantages of multi-blade saws include:
Bandsaws offer greater flexibility. They saw any alternative species (including hardwoods). They can produce high quality boards from good quality pruned and knotty logs of high value species. This increases the value of the sawn timber output.
Advantages of bandsaws include:
Disadvantages of bandsaws include:
A suitable machine is essential for moving logs and loading packets of timber.
For smaller blocks you can use a farm tractor to load logs into the mill. Stack sawn timber directly on to a trailer. Or fillet stack, strap and lift with a front-end loader and move to a storage area.
For high value native and exotic timber some parts of New Zealand use heli-logging (helicopter logging). This can be flying the mill into the forest and the packets of timber out, or flying the logs to a central mill site.
It might be hard to find a small logging crew prepared to work at the scale and rate to suit portable milling operations.
Options available to farm foresters or forest growers include:
There is no specific licensing or regulation of commercial portable sawmillers except for native timber milling. Temporary portable sawmilling operations on a farm or in a forest may be undertaken within a rural zone as a 'permitted activity'. Get advice from your local district or regional authority before you start.
Any permanently set up mills need to follow local government-permitted activities for the zone they plan to operate in or will need a resource consent.
This fact sheet is based on research from Specialty Wood Products Research Partnership and the Marlborough Research Centre, prepared for the Hawke’s Bay Regional Council and the Hawkes Bay Regional Investment Company.
This was funded by the One Billion Trees Partnership Fund, Te Uru Rākau - New Zealand Forest Service/Ministry for Primary Industries.
Read the report: Portable sawmilling of locally grown alternative timber species: A report on the potential for a sustainable small-scale regional industry in Hawke’s Bay Region on the Ministry for Primary Industries' website.
This work was completed in 2019. Since then, devastating weather events have affected the North Island in 2023. The Government is doing more work on species for erodible land in this region, so this material may no longer be accurate or up to date.