If you're propagating native trees, running a revegetation project, or producing seedlings for farm planting, you've likely heard experienced growers mention forestry tubes. These specialised containers have become the standard for commercial and serious hobby propagators across Australia, and for good reason: they produce healthier root systems than conventional pots.
This guide explains what forestry tubes are, how air pruning technology works, and why tube pots might be the missing piece in your propagation setup.
What Are Forestry Tubes?
Forestry tubes, also called tube pots or hiko trays, are tall, narrow cylindrical containers designed specifically for growing tree seedlings. Unlike standard nursery pots that are wider and shorter, forestry tubes are typically 50mm in diameter and range from 80mm to 150mm in height, depending on the species and growing timeframe.
The key feature that sets forestry tubes apart is their open bottom design. Rather than having a solid base with drainage holes, forestry tubes have a completely open or heavily ventilated bottom that exposes roots to air.
This design isn't just about drainage. It's about controlling root development through a process called air pruning.
The Science Behind Air Pruning
When a seedling grows in a standard pot, roots eventually reach the container walls and bottom. Unable to penetrate the barrier, roots begin circling around the inside of the pot. This is called root circling or root spiralling, and it creates several problems:
- Structural weakness: Circled roots never develop proper radial structure, making transplanted trees prone to wind throw
- Restricted growth: Circling roots continue this pattern even after transplanting, eventually strangling the tree
- Poor establishment: Root-bound seedlings struggle to break out of their growth pattern and establish in the ground
- Increased mortality: Severe root circling can lead to long-term decline or death years after planting
Air pruning solves this problem through a simple but elegant mechanism. When a root tip reaches the open bottom of a forestry tube and encounters air, the tip desiccates and stops growing. This process, called air pruning, triggers the plant's natural response: produce more lateral roots.
Rather than one long circling root, you get dozens of shorter, fibrous lateral roots throughout the tube. This creates a dense, healthy root ball with radial structure that transplants successfully and establishes quickly in the ground.
The benefits are measurable. Studies on native tree propagation show air-pruned seedlings establish 30-50% faster than pot-bound seedlings and have significantly higher survival rates in field conditions.
Forestry Tubes vs Standard Pots: Real-World Differences
If you've grown seedlings in both systems, the difference is obvious when you tip out the tubes at planting time.
Standard pot seedlings often slide out as a solid root-bound mass, with roots coiled against every surface. These take longer to establish, and some species never fully recover from the circling pattern.
Forestry tube seedlings, in contrast, have a dense fibrous root ball that breaks apart easily at the edges. Roots are evenly distributed throughout the tube depth, and there's no circling at the bottom. These transplant cleanly and begin establishing new roots within days.
The taller, narrower shape also mimics the natural taproot development of many Australian native species. Eucalypts, acacias, and casuarinas all benefit from the deeper root zone that forestry tubes provide compared to squat nursery pots.
Standard Sizing: Why 50mm Forestry Tubes Are Industry Standard
While forestry tubes come in various diameters, the 50mm tube has become the Australian industry standard for native tree production. This size strikes the right balance between several factors:
- Adequate growing volume: 50mm diameter with 100-120mm height provides enough media for 8-12 weeks of growth
- Efficient spacing: Standard 40-cell trays fit perfectly on nursery benches and in hardening-off areas
- Transplanting ease: 50mm tubes produce a root ball that's easy to handle but substantial enough to survive field conditions
- Cost efficiency: Smaller than traditional tube stock but large enough for quality results
Commercial forestry operations and revegetation contractors have standardised around 50mm for these reasons. Unless you're growing particularly fast species or need extended growing time, 50mm forestry tubes will suit most native tree propagation needs.
Forestry Tube Tray Systems: Why the Tray Matters
Forestry tubes are almost always used in tray systems rather than as individual units. A standard 40-cell forestry tube tray holds 40 tubes in a rigid plastic frame that keeps tubes upright and organised.
The tray serves several important functions:
Stability and organisation: Individual tubes would tip over constantly. The tray keeps everything vertical and makes moving batches of seedlings straightforward.
Air gap management: Quality tray systems suspend tubes slightly above the bench surface, ensuring proper air circulation beneath for effective air pruning. If tubes sit directly on a solid surface, you lose the air pruning benefit.
Root training: The tray grid spacing prevents roots from adjacent tubes growing together, which can happen if tubes touch.
Bench efficiency: Standard tray dimensions fit nursery bench layouts, making efficient use of growing space. A 40-cell tray typically measures around 540mm x 280mm, and you can calculate exactly how many trays fit your available space.
Handling efficiency: Moving 40 seedlings at once rather than individually saves enormous amounts of time when watering, hardening off, or transporting to planting sites.
When purchasing forestry tubes, buying a complete tray system rather than individual tubes is almost always more practical. The 40-cell forestry tube tray with 50mm pots has become the standard unit for Australian native propagation for good reason.
Using Forestry Tubes for Native Tree Propagation
Australian natives are particularly well-suited to forestry tube production. Many species, especially eucalypts, acacias, and natives from drier regions, develop strong taproots early. The depth and air pruning of forestry tubes supports this natural growth pattern better than shallow pots.
Here's a typical workflow for native propagation in forestry tubes:
Filling and sowing: Use a quality seed-raising or native plant mix. Fill tubes to about 10mm below the rim, firm lightly, sow seeds, and cover to appropriate depth. Water gently from above or set trays in shallow water to bottom-water.
Germination: Keep media consistently moist until germination. Many natives germinate better with some air circulation, so avoid covering trays with plastic unless required for specific species.
Early growth: Once seedlings emerge, begin reducing watering frequency but increase volume per watering. This encourages deeper root growth. Fertilise lightly with a native-specific or low-phosphorus fertiliser once true leaves develop.
Root training phase: From 4-8 weeks, roots begin reaching the tube bottom. You'll notice white root tips appearing at the base of tubes. This is when air pruning begins working. Don't be alarmed by these visible roots; this is the system functioning correctly.
Hardening off: Before transplanting, gradually expose seedlings to full sun and reduce watering frequency. This hardens tissue and prepares seedlings for field conditions. Well-hardened seedlings in forestry tubes can handle surprisingly tough conditions.
Transplanting: Seedlings are typically ready to transplant when roots are visible throughout the tube but haven't become overly dense. For most natives, this is 8-14 weeks from sowing, depending on species and growing conditions. Simply push up from the bottom of the tube to remove the seedling with its intact root ball.
The key advantage throughout this process is that you're not fighting root circling. The plant puts energy into producing fibrous lateral roots rather than wrapping roots around the container.
Commercial Growing vs Hobby Propagation
Forestry tubes make sense for both commercial operations and home gardeners, but the scale and approach differ.
Commercial growers producing thousands of seedlings for revegetation contracts or farm forestry rely on forestry tubes for efficiency and results. When you're growing 10,000+ seedlings, the difference in establishment rate and survival between air-pruned and root-bound stock directly impacts profitability. Commercial operations typically work in batches of multiple pallets (40-80 trays at a time) and have dedicated hardening areas with shade cloth and irrigation systems.
Hobby propagators might start with a single 40-cell tray system, which is perfect for a home garden revegetation project or ongoing propagation for property planting. One or two trays fit easily on a small bench or in a shadehouse corner. The investment is modest compared to buying advanced trees from a nursery, and you gain control over species selection and genetic diversity.
The workflow is essentially the same at both scales. The advantage of forestry tubes is that the system scales efficiently: whether you're managing 40 seedlings or 40,000, the fundamentals of air pruning, root development, and transplanting remain consistent.
Beyond Transplanting: Tree Guards for Long-Term Success
After successfully propagating seedlings in forestry tubes and transplanting them to their final positions, protection during establishment is crucial. Young trees face threats from browsing animals, wind, and harsh sun, particularly in the first 12-24 months.
This is where tree guards become essential. A quality tree guard creates a protective microclimate around the young tree, shielding it from wind and herbivores while allowing light and rain through. Many revegetation projects see 40-60% losses in unprotected plantings, compared to under 10% with proper tree guard protection.
Tree guard systems that include support stakes are particularly effective. The guard prevents wallabies and rabbits from browsing tender growth, while the stake provides stability in wind. For commercial plantings or larger property revegetation, buying tree guards in bulk sets (25-75 guards with stakes) makes economic sense.
The effort you've invested in propagating quality seedlings with healthy root systems deserves protection during the vulnerable establishment phase. Tree guards are a modest additional cost compared to the alternative of losing plants and replanting.
Choosing Quality Forestry Tube Systems
Not all forestry tube systems are equal. When selecting tubes and trays, consider:
Tube thickness: Thicker plastic tubes hold their shape better and last longer if you're reusing them. Thin tubes can collapse or tear when handled.
Tray rigidity: The tray frame should be sturdy enough to support 40 tubes filled with wet potting mix without flexing excessively. Flimsy trays make handling difficult and increase the risk of dropped seedlings.
Air gap design: Check how the tray suspends tubes above the surface. Some designs simply have legs that elevate the entire tray. Others have individual tube supports. Either works, but there must be adequate air circulation beneath.
Drainage: While the open bottom is the defining feature, some designs have better side ventilation than others. More air circulation generally improves root pruning.
Reusability: If you plan to propagate regularly, invest in quality trays that will last multiple seasons. Clean tubes thoroughly between batches with dilute bleach solution to prevent disease transmission.
Complete tray systems (tray plus tubes) are more cost-effective than buying components separately and ensure compatibility.
Getting Started with Forestry Tubes
The barrier to entry for forestry tube propagation is lower than many assume. A single 40-cell tray system costs less than buying 40 advanced trees from a nursery, yet allows you to produce seedlings indefinitely.
Start with:
- A 40-cell forestry tube tray system with 50mm pots
- Quality seed-raising or native potting mix
- Seeds or cuttings of your chosen species
- A protected growing area (shadehouse, covered bench, or similar)
- Basic watering equipment
If you're propagating for your own property, one or two trays will produce more seedlings than most home gardeners can use in a season. For commercial operations or larger revegetation projects, calculate needs based on planting numbers plus 20% extra for losses and culls.
The learning curve is gentle. Native propagation has its challenges, but the forestry tube system itself is forgiving. You're working with the plant's natural growth patterns rather than fighting root circling issues that plague standard pot production.
Why Air Pruning Matters for Australian Conditions
Australian native trees evolved in harsh, competitive conditions. Many species naturally develop extensive root systems to access deep water and nutrients. When we restrict these species to containers, we risk compromising the very characteristics that make them resilient.
Air pruning technology in forestry tubes allows us to produce containerised seedlings without sacrificing root quality. The result is trees that establish faster, grow more vigorously, and survive better in field conditions.
For revegetation projects, this translates to better outcomes with less maintenance. For farm forestry, it means healthier timber stands. For home gardeners, it means successful plantings that don't struggle for years before establishing.
The difference might not be obvious in the first growing season, but after three to five years, the gap between air-pruned and root-bound seedlings becomes dramatic. Trees propagated in forestry tubes develop proper structure from the beginning and never need to overcome early root defects.
Ready to Upgrade Your Propagation Setup?
If you're serious about native tree propagation, revegetation, or seedling production, forestry tubes with air pruning technology represent a significant step up from standard pot production.
The 40-cell forestry tube tray system with 50mm pots has become the industry standard for good reason: it balances growing efficiency, root quality, and handling practicality at a scale that suits both commercial and hobby growers.
At Harwood's Garden Supplies, we stock complete forestry tube tray systems designed for Australian conditions, plus the growing media and propagation supplies you need to succeed. All orders ship free Australia-wide.
Browse our range of forestry tubes, propagation systems, and tree protection products at www.harwoodsgardensupplies.com.au/products, or view the 40-cell forestry tube tray at www.harwoodsgardensupplies.com.au/products/40-cell-forestry-tube-tray-with-50mm-square-native-forestry-tube-stock-pots.
Start propagating healthier seedlings today.