January 8, 2018 - No Comments
When the forestry industry started to diversify into eucalypts back in the 1960s, many of us found ourselves in unknown territory. At the time, commercial nurseries were virtually non-existent; we set up our own on the plantations. This is what they were like:
Pine bark medium was yet to come; top-soil for making seed beds and filling plastic seedling packets was used, gleaned from wherever it was available (often the wattle plantations, seed and all), mixed with sub-soil and sifted manually using a builder’s sieve.
Eucalyptus seed was sown, using a pepper pot, and seedlings were ‘pricked out’ of the seed bed using a dibbler, also called a dibber (a stick the same size and shape as a pencil, used to lift individual seedlings, and drill a cavity for them in the soil in the plastic bag). It was used in agriculture as long as 2000 years ago. Plastic bags came a bit later.
The bags rested on the ground until the seedlings were ready for planting. If the roots grew through the drainage holes at the bottom of the packets, we severed them by drawing a thin wire under the neat rows, which left the seedlings looking like an army platoon on the way back from the pub.
We made boxes from wayne-edge pine to hold 10 seedlings. It was an achievement to get 7 000 seedlings onto an eight-ton lorry fitted with additional tiers. Packed in planter flats, that’s a mere bakkie load.
Non-biodegradable plastic bags
The first bags were of clear, 100% non-biodegradable plastic, but soon gave way to cheaper, black, biodegradable ones. Hard to believe today, but we planted bag and all! The tap, or main root, we assumed in our ignorance, would find its way out through the drainage holes, so the black ones were a fortuitous change; they rotted and the trees simply burst them out of the way. That tough little clear plastic bag was going to last for 100 years; it turned the root system into something akin to a knobkerrie, and left plantations liberally interspersed with scraggly stalks.
There’s an adage that says one week is the difference between a good farmer and a bad one. Timing in sylviculture isn’t cut as fine, but missing the moment can have long-term effects.
• Blanking more than three weeks after planting is a waste of everything – the trees will never catch up.
• Late coppicing ruins tree form and reduces yields
• Soil temperature a few centimetres down on a hot day can be as high as 45 degrees C. Rather wait for a cooler day.
• Planting the roots horizontally or pointing upwards in a ‘J’ causes mortality or stunted growth. Clustered tiny leaves on stunted plants, the ‘tea bush’ effect, are a certain sign of this.
• Spring and summer are not the only seasons for planting. Winter planting using polymers on frost-free sites gives the young trees a head start in spring.
• A planting depth of 200mm is ideal, not least because everyone carries this measure – it’s the distance between the tip of your little finger and the tip of your thumb, and it pre-dates the axe.
*First published in SA Forestry magazine, Dec 2017