Tree Farming

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In 1992, I bought about 160 acres (65 hectares) of farmland South of Perth in an area with a reasonable annual rainfall. The land had been cleared many years ago, and had been grazed extensively by both cattle and sheep. An intensive feed-lot farming operation had been in place until the time of my purchase. The land had been well fertilised on a regular basis, but the clearing of trees over many years, and the rising water table, had resulted in the first evidence showing of salt damage in the SouthWest corner of the block.

The planting of farmland back to trees had been increasing in the surrounding districts for a few years, with the aims of both helping to reduce salt degradation by lowering the water table again, and providing income from a crop of timber to be used either as pulp for paper production, or sawlogs for the hardwood timber industry. Advice from colleagues undertaking these activities, and contractual assistance from a private forester led to the establishment of a Tasmanian Blue-gum (Eucalyptus globulus subsp. globulus) plantation on the block. Blue-gums grow up to 70m tall in forests with a long straight trunk. Their early foliage has quite a blue colouration, hence their name, which is replaced by mature green leaves as the trees grow. About 140 acres were prepared by deep ripping and mounding along contours with 4 metres between rows, and then about 70,000 tree seedlings were planted by hand 2 metres apart in each mounded row (1250 stems per hectare).

I have prepared an extensive gallery of pictures showing some of the differences between the early period in 1992/3 and more recent times in mid 1999. (Note: Being mainly pictures, the gallery may load quite slowly, depending on your computer and the bandwidth to which you have access ...)

Once the trees are 10 years old, they will be clear-felled for pulp to make paper, or thinned out to allow the best to continue growing into saw-logs for timber. The story will not end there, however. After felling the trunks, the root systems of the trees will remain intact, and each stump will sprout a number of shoots forming a coppice. With careful, labour-intensive pruning of this coppice, one or two of these sprouts on each stump will be encouraged to grow into new trees. In about 8 more years the block will again look like it does today because the regrowth trees will grow faster with mature root systems than they were able to do the first time, and a second crop can be taken then. The third crop will be taken about 7 years after that again.

There has been a wide variation in growth rates seen over the block. Those trees on the hilly NorthEast end ('Red Hill') with red gravelly soil have grown best, while those adjacent to the worst salt-affected area at the other end have been very slow to improve. After nearly 8 years, however, and with a significant drop of 1-2 metres in the level of the water table, the slow trees are now starting to grow taller more quickly and to display healthy-looking crowns. They do seem to respond also to hugging <g>. Apart from the lower water table, it is the first evidence I have seen first-hand that the battle against salt encroachment can be won. Plant some trees yourself some day, and watch them grow. It's a great feeling.

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