People often ask why we don’t plant all year round and why our tree planting season has such a narrow window. It all has to do with best conditions for the new trees.
In the southern states of Australia, the winter months are the best times to plant trees, with the season extending into late autumn and early spring if rainfall has been good. In the northern states, the season is longer due to the wetter summer season.
Plants tend to be dormant in winter, and so by planting them then, we don’t interrupt their growth cycle. As temperatures drop, a plant’s metabolism slows down. This is largely due to the enzymes that drive these biochemical reactions, they don’t work so well in the cold.
However, while the stem, branches and leaves in winter are mostly inactive, the roots are still performing the essential life processes. This means, when we plant in winter, the roots begin slowly spreading and expanding in search of water and nutrients. By the arrival of spring and warmer weather, the newly planted trees will have grown a substantial root network. This will help them cope with the oncoming acceleration of growth. In the wetter months, the soil is moist and rich in nutrients that are not as abundant in the dryer months. Perfect conditions for an expanding root system.
Winter is also beneficial because our trees will not be competing against lots of weeds. In spring and summer these fast-growing competitors will aggressively steal the water and nutrients our new trees need. And new trees are particularly vulnerable to competing plants in their first year. But in winter most of these weeds are absent, so our trees can start to grow their roots freely. Once they are established, our trees can hold their own against weeds more effectively.
Tree planting is also better for the planters too! The ground is moist and so digging is much easier. It is hard work planting trees, you really work up a real sweat, and so it is easier to work in the cooler months with cloud cover (often rain) and lower temperatures than under a hot sky in the warmer months.
If the trees are planted in the correct season, the survival rate is up at around 75 – 80% which is a great outcome. The plants also get a good watering on the rainy days, and quite often so do we!
And that is why dear friends, we plant in winter!
Writer; Colleen Filippa | Founding Director | Fifteen Trees
Colleen’s background is in environmental education. In 2009, after 20 years in primary, secondary and tertiary institutions, Colleen left the classroom to start Fifteen Trees. Fifteen Trees is a social enterprise that assists individuals and companies to reduce their carbon footprint through the support of community groups such as landcare, environmental networks and friends groups.