Species choice, density, and paddock configuration important when planting trees

While that is an interesting story, I feel to plant at that density is not for everyone, and extremes of too many or too few trees often have some productivity and environmental consequences to consider.

Like most farmers, we appreciate the value of trees for shade and wind protection for livestock, and for bird and other native wildlife habitats.

A starting point for what might be a desirable level of trees on any property is what might have been the number and configuration prior to European arrival.

It is impossible to be entirely sure as to what number of trees were present on a given farm.

Some authors have attempted to assess likely situations for many areas from records kept by early explorers such as Oxley.

For example, in our area, noted environmental author and local farmer, the late Eric Rolls, in his book A Million Wild Acres based on Oxley's records, described the now dense Pilliga Forest as having one to two trees per acre with adjoining areas often open grazing country.

Much of the Pilliga is now set aside in conservation areas and is so thick with trees that native understudy-like grasses are often totally shaded out.

Dense trees in this environment impact their ability to flower and seed, which is important for biodiversity.

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Growing up on a farm in the central west Greenethorpe area, my father and grandfather believed our property had always been low in tree numbers, with their personal knowledge relevant to around 1900 onwards.

Older farmers in our area (east of Coonabarabran) believe our farm falls into this category.

In mainly clumps, we have 2.5 trees/ha on an overall average, but with significant areas open for cropping.

It's a fair guess that is at least as many trees as might have been here more than 200 years ago.

So our approach to trees has not aimed to establish forests or rings around paddocks.

We have established small blocks in paddocks with few trees to help ensure good shade should the current, mainly relatively scattered trees, die.

These are mainly 10 years old and beginning to provide useful shade as well as habitat for birds and other wildlife.

I think a lot of animal species, like magpies, suit scattered tree clumps, and there are lots of nearby, more or less continuous lines of trees, on adjoining roads.

Since European-era settlement, we have established infrastructure across our farms, which means we carry a lot more wildlife today than was present more than 200 years ago.

Regular water via troughs and dams and feed from often far more vigorous pastures and grain crops helps ensure a strong remnant population, even into extended drought.

In pre-European times, droughts would have meant no water for large distances.

Big area plantations may be part of carbon programs on some properties.

Part of such developments will need to have insurance schemes to cover possible major fire events.

Many timber programs for carbon capture will be lengthy ones and will require legal aspects, as land transfer will commonly be a big possibility.

With a strong emphasis today, not just on carbon capture but also on biodiversity, it is important to appreciate that well-managed pastures can be as diverse as non-improved ones.

For example, a study published in the Rangeland Journal, titled 'A Botanical Study of Two Native Grazing Options on a Commercial Cattle Property', noted that species diversity was greater in fertilised native pasture compared to unfertilised ones.

The author was Bob McGufficke, then NSW DPI Inverell district agronomist.

High farm tree numbers are a focus often promoted by conservation and media interests.

Important aspects include species choice, density, and paddock configuration, as well as positive and negative impacts on productivity.

In my DPI days, where I was involved with colleagues with many research experiments, it was important not to establish them within 30 metres of a tree to avoid plot yield loss when close to a tree.

I have seen some plantations where tree deaths begin after around 15 years if the wrong species have been chosen. Too dense, and trees struggle to flower and set seed.

They need care to ensure they are not a haven for feral animals and need fire protection strategies.

And I feel they need to fit in beneficially with the district environment.

Next week: Strategy to minimise stripe rust next year.