Eucalyptus planting: good technique means good establishment

Achieving high survival rates and encouraging the highest growth rate possible during first years is necessary to reduce the length of timber production cycles in eucalypt plantations. This can be addressed successfuly by selecting the most appropriate soil preparation methodology for each particular case, making sure soil porosity is favourable to encourage a quick development of root systems and thus prevent leaning and/or windthrow; by selecting an appropriate planting stock both from genetic and vegetative standpoints to make sure available resources are efficiently transformed into timber; by ammending soil in the area in which young seedlings will start their adaption to a new environment with the addition of the right type and amount of fertilizers according to current nutritional status of superficial layers; and by a good control of competition for light, water and nutrients caused by pioneer understorey plants that must last until the new trees are able to outgrow and control them on their own. Sometimes plant protection is necessary during the first growing seasons for defense against herbivores, being risk higher in areas and times of the year where alternative food supply is scarce.

For the particular case pictured above, seedlings reached up to two meters in their first growing season. This was achieved on acidic soils with a favourable slope after a deep scarification followed by a mix of the superficial layer and debris from previous vegetation clearing to encourage nutrient availability from fresh organic matter; by the addition of gradual release mineral fertilizers with a reduced proportion of nitrogen and enough phosphate and potassium to encourage lignification of young stems as soon as possible; and by regular monitoring growth of both planted seedlings and understorey.


Tree spacing is a choice that should depend on the desired final product (the end) and the silvicultural regime (the means) that could be applied to the growing plantation to achieve it . For fast growing eucalypts two main regimes can be considered depending on final dimensions desired for harvested logs and other restrictions linked to the possible industrial processing destination. Pulpwood regimes aim for higher tree stocking per hectare to maximise tonnage, but those logs must have minimum dimensions to be marketable. Solid wood regimes aim for high initial tree stocking per hectare which will be reduced gradually by thinnings after canopy closure to diminish competition for light among the remaining trees and encourage diameter growth over height growth in those that will be standing by the end of production cycle. To make sure the knotty core is as reduced as possible an early low pruning must be performed, preferably on alive branches with calipers smaller than 3 cm. Further high pruning operations should be considered to increase the number of high quality logs produced per tree.

For the particular case pictured above saplings grew from two to seven meters height during their second and third growth seasons thanks to the effect of remaining fertiliser and natural nutrients now widely available for well spread root systems. It was during this third growth season when the definitive decission of applying pulpwood or solid wood silvicultural regimes should have been made, and the associated operations for any of the choices should have started. Switching for a moment from eucalypt forestry to eucalypt gardening, this is also the moment in which the decision of letting your sapling become a big sized tree or pollarding and pruning your plant to keep it at a reasonable size for future management in small garden spaces must be taken. Sooner better than later.

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© 2006 Gustavo Iglesias Trabado / GIT Forestry Consulting