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Ways to improve natural assets on a farm Protect and restore paddock trees

Scattered paddock trees are a familiar feature across rural Australia. These trees are important for maintaining agricultural productivity and are critically important for the conservation of wildlife. Many of these trees are being lost due to old age, stress and fire, but there are ways to protect and restore paddock trees.

Many paddock trees were the oldest, largest trees in the landscape at the time of clearing, so they can be hundreds of years old. We are rapidly losing these iconic trees due to old age, stress from agricultural production, fire, and a lack of continuous replacement. If current trends continue, it is possible that in as little as 40 years all scattered paddock trees across most of the south-eastern agricultural region will be gone.

By keeping scattered paddock trees in good condition, and ensuring that trees are recruited to replace lost trees, we can retain this valuable resource for the next generation of landholders as well as help to conserve our native wildlife.


Why are scattered trees important for farm productivity?

Scattered paddock trees are valuable assets that boost farm productivity and profitability.

The most recognised and well-understood value of trees on farms is providing shade and shelter from wind for livestock. Shade and shelter are necessary to reduce the heat and cold stress experienced by livestock. This allows livestock to dedicate less energy to self-maintenance, which can result in improved farm productivity.

Energy expended by livestock to maintain a regular body temperature diverts valuable energy away from desired production gains, such as live weight gain, milk production or wool growth.

  • Dairy cows have been shown to produce 17% more milk in paddocks with trees that provide shelter.
  • Less energy is required to maintain optimal body temperature in livestock, which can improve weight gain and lower livestock nutrient requirements. For example, sheltered off-shears wethers require approximately one third the amount of supplementary feed to maintain bodyweight compared to those that have no shelter.

Other benefits of large old trees

Production gains from shelter provided by paddock trees is not limited to livestock. Benefits to other parts of your farm include:

  • Improving soil structure and quality as wind and water erosion is reduced. Soil fertility also improves as leaf litter and animal droppings decompose, returning nutrients to the soil.
  • Salinity management as trees can reduce waterlogging and dryland salinity problems.
  • Scattered paddock trees have been shown to increase water infiltration in soils, helping retain moisture in the landscape.
  • Increased pasture growth and reduced desiccation in hot, dry periods, due to the shelter provided by paddock trees.
  • Paddock trees are associated with an increase in the abundance and diversity of insect pollinators and natural pest control agents. Native bats, lizards, and birds will prey on common farm pests, and many of these species use scattered paddock trees for roosting and foraging. The presence of these animals on farms can significantly reduce the number of insect pests.

 

Why are scattered trees important for biodiversity?

Scattered paddock trees are often the only remaining remnants of previously widespread vegetation communities, such as box-gum grassy woodlands. These trees are often hundreds of years old, and are incredibly important for native wildlife.

Not only do scattered paddock trees allow many species to persist on farms, they also influence biodiversity across the wider landscape. Scattered paddock trees are typically the oldest living features in the landscape, and provide essential and often critical wildlife resources.

Tree hollows are a prime example. Hollows that wildlife rely on can take over a century to form, and are critical for many species including threatened species such as the Superb Parrot and Squirrel Glider. Large old trees also tend to flower more prolifically than younger trees, providing essential resources for nectar-reliant species.

Features of scattered paddock trees that are important to wildlife include:

  • Tree hollows and large canopies. These are critical for the persistence of some wildlife and are difficult to replace as they can take many centuries to develop.
  • Connecting habitat between native vegetation patches and plantings by providing ‘stepping-stones’ for wildlife to move across the landscape. This increased connectivity helps increase biodiversity across the landscape.
  • Cracks and crevices in paddock trees provide habitat for small mammals and reptiles.
  • Paddock trees will often flower more heavily than other trees, providing important resources for wildlife, such as honeyeaters. In addition, a variety of tree species across the landscape ensures that species such as honeyeaters, sugar gliders and other animals that depend on nectar and pollen have a continuous supply of nectar.
  • Provide a source of natural regeneration for the next generation of paddock trees and a source of seeds for collection, storing and propagation.
  • The presence of paddock trees will have a positive influence on the biodiversity of other vegetation on farms, such as remnant patches or tree plantings. This applies whether the large old tree is within the vegetation patch or located nearby.

Dead trees or “stags”

Remember, dead trees are really important too! Large dead trees provide hollows that are essential nesting sites for wildlife. These sites are rapidly disappearing, meaning that every large dead tree, whether alone in a paddock or part of a vegetated patch, is valuable.

How to protect and restore scattered paddock trees

There is no single cause of the demise of scattered paddock trees. Contributing factors include increased stress caused by agricultural practices (e.g. spray drift, stock camps and stubble burns), changes in hydrology, drought, insect attack, clearing, and natural death due to old age.

As these veteran trees vanish from the landscape, there are no trees to replace them. Regrowth – a source of future paddock trees – has been suppressed over the last century by livestock grazing, clearing, fire and other land management activities.

But the good news is, there are many actions farmers can take to turn this situation around. The key is to arrest the decline of existing trees and ensure there is a succession plan of younger trees. These solutions will vary across different landscapes and for different production systems.

Photo by Cameron Odewahn, Walla Walla NSW.


Protecting paddock trees and creating a succession plan for new ones.

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Incorporate paddock trees into farm planning

Identify the main threats to paddock trees on your property, and then incorporate management of the trees into your farm plan.

Going through this process can often identify some obvious and easily achieved options, such as identifying scattered trees that could be protected by incorporating them into tree plantings. Or there may be paddocks where you wish to increase scattered paddock trees, creating a wooded pasture for extra livestock shelter and wildlife.

Reduce livestock pressure on paddock trees

Stock camps can cause major stress for scattered paddock trees. This occurs through physical damage to the root zone and the tree trunk, and increased nutrient loads in the surrounding soil.

Reducing or removing stock pressure directly under trees can help trees recover, prolong their life and encourage natural regeneration.

Fencing to exclude livestock access from just the tree’s dripline (the diameter of the tree’s canopy) still enables stock to utilise shade and shelter benefits without damaging the tree’s roots and trunk.

Rest paddocks to allow recruitment of new trees

Spelling paddocks on a regular basis (e.g. periods of grazing with recovery times of 3, 6 or 12 months) or by setting a paddock aside for a longer period (2-3 years) can promote regeneration of trees and allow existing scattered paddock trees time to recover. Note that results can vary due to climatic conditions during this period, nutrient loads and grass cover.

Incorporate paddock trees into plantings

Paddock trees can be protected and and are often maintained in reasonable condition when they are surrounded by other younger trees.

Incorporating paddock trees into new plantings will not only help protect them, but also give the new planting a 150-year “head start” in providing habitat to a range of animals.

Protect paddock trees from spray drift, fertiliser and fire

While trees often recover from many herbicides, the initial stress caused by herbicides does weaken trees. This makes them more vulnerable to insect attack, disease and wind damage.

Avoid exposing scattered paddock trees to fire, whether wildfire, burn off, or stubble fires. Old trees are particularly vulnerable.

Establish new paddock trees

In areas with few paddock trees or minimal opportunities to protect those that exist, planting and fencing off individual young trees will, in the long term, help re-establish the scattered spatial patterns of paddock trees on farms without having to take substantial areas of land out of production.

References and further reading

Fischer J, Stott J, Zerger A, Warren G, Sherren K & Forrester R. 2009. Reversing a tree regeneration crisis in an endangered ecoregion. Proceedings of the National Academy of Sciences of the USA, 106 (25): 10386-10391.

Fischer J, Stott J & Law BS. 2010. The disproportionate value of paddock trees. Biological Conservation, 143 (6): 1564-1567.

Gibbons P & Boak M. 2002. The value of paddock trees for regional conservation in an agricultural landscape. Ecological Management & Restoration, 3(3): 205-210.

Gibbons P, Lindenmayer DB, Fischer J, Manning AD, Weinberg A, Seddon J, Ryan P & Barrett G. 2008. The future of scattered trees in agricultural landscapesConservation Biology, 22 (5): 1309-1319.

Manning AD, Fischer J & Lindenmayer DB. 2005. Scattered trees are keystone structures: Implications for conservationBiological Conservation, 132 (2006): 311-321.

Manning AD, Gibbons P, Fischer J, Oliver DL & Lindenmayer DB. 2013. Hollow futures? Tree decline, lag effects and hollow-dependent species. Animal Conservation, 16 (4): 395-403.

NSW Government Local Land Services. 2014. Scattered Paddock Trees. Factsheet. December 2014. Available from: https://centralwest.lls.nsw.gov.au/__data/assets/pdf_file/0009/537597/Scattered-paddock-trees-web.pdf

Reid N & Landsberg J. 2000. Tree decline in agricultural landscapes: what we stand to lose. In: Hobbs RJ & Yates CJ (eds). Temperate Eucalypt Woodlands in Australia: Biology, Conservation, Management and Restoration. Surrey Beatty & Sons, Chipping Norton, NSW. Pp. 127-166.


Tips from John Baker, Hovells Creek Landcare Group, on how to plant new paddock trees. Click here to see more paddock tree resources from Hovells Creek Landcare Group.