Silvopasture - integrating trees, forage and livestock - could be a win-win-win for livestock, the environment and farmers' pockets.
Silvopasture is a land management practice that integrates trees, forage and grazing livestock on a single unit of land to achieve several mutually beneficial effects. It differs from wooded livestock paddocks in that silvopastoral systems are carefully managed to ensure a sustainable ecosystem. Silvopastoral systems can positively impact animal welfare, farm finances and ecosystem services.
As the world becomes hotter, livestock become more vulnerable to heat stress. Heat stress makes livestock less productive and, in extreme cases, can cause organ damage and even death (MLA n.d.). Providing livestock with adequate shade is vital to their continued productivity and wellbeing. This is where silvopasture comes in. Trees are often a better source of shade than man-made structures. Cattle prefer natural shade, evapotranspiration (the movement of water from the earth's surface and through plants into the atmosphere) creates a cool microclimate, and barns or sheds can have poor airflow (USDA NAC 2013). Besides this, systems with even cover keep livestock shaded during various activities and stop them from grazing in a concentrated area (USDA NAC 2013).
This shade can also enhance forage quality and yield depending on species and management. Producers in the United States reported that they produced high-quality forage in silvopasture and increased their yield during summer months and in times of drought (Smith et al. 2022). Further, leaf fodder and mast (i.e., fruit and nuts) dropped by trees can provide livestock with an alternative feedstock and a more varied diet (Smith et al. 2022). In turn, and when managed properly, livestock grazing on this leaf fodder reduces fuel load and wildfire risk (Smith et al. 2022).
Smith et al. (2022) found that shade was one of the most common reasons producers gave for adopting silvopasture; the other was income diversification. Predictive modelling by Francis et al. (2022) found that softwood silvopastures have higher net present values (NPVs) than either grazing alone or timber alone. They cite several other studies that support this outcome (Francis et al. 2022).
Lewis et al. (2022) suggest converting degraded or regrowth forest on private land into silvopasture as a win-win for Australia and graziers. Australia faces a decreasing supply of plantation forest, the phasing out of harvesting and a growing demand for timber. Converting private forest to silvopasture would relieve Australia's timber shortage without harming biodiversity. It would also provide an additional income stream for graziers and make farms more resilient to the economic unpredictability caused by climate change.
Smith et al. (2022) note several other economic benefits mentioned by producers, including that converting marginal land to silvopasture increased the utility and value of the land. This also allowed producers to expand their contiguous grazing land without the expense of buying and paying additional property taxes on new land. In addition, marginal or wooded pasture that can be converted to silvopasture is a less expensive alternative for beginner farmers who cannot afford to buy 'prime' farmland. Effective silvopastoral systems can also save producers costs like feed (which can be provided by trees), weed management and fertiliser (which can be done and produced by livestock).
As well as the economic benefits, silvopasture can provide several ecosystem services. Compared to open pasture, silvopasture has higher soil and biomass carbon sequestration (i.e., it stores carbon rather than releases it into the atmosphere; Smith et al. 2022). Lewis et al. (2022) calculate that even at low densities (50 stems ha−1 with 50 cm diameter trunks at breast height), native regrowth eucalypt forest could sequester 280 tonnes of CO2 equivalent ha−1. Even if trees are harvested for construction or biochar, the carbon they store will remain locked up (Raskin 2019).
Soil in silvopasture is also improved in various ways; it has enhanced nutrient cycling and water retention (Amorim et al. 2023). Silvopasture is also an effective way to prevent soil erosion (Amorim et al. 2023), phosphorus loss and nitrate leaching (Smith et al. 2022). Other ecosystem services include increased biodiversity (compared to open pastures; Francis et al. 2022; Smith et al. 2022) and habitat for wildlife, such as birds and insects (Amorim et al. 2023).
Despite the many benefits of silvopasture, adoption of the practice in Australia is slow (Lewis et al. 2022). One of the biggest barriers is the knowledge gap; while farmers are highly knowledgeable in their area of specialisation, few have the forestry expertise to implement and manage silvopastures without guidance (Lewis et al. 2022; Raskin 2019).
Many producers in Smith et al. (2022) worked with foresters and other natural resource professionals to implement their silvopastoral systems. However, they also noted that some foresters were reluctant to embrace silvopasture as they confused it with unmanaged woodland grazing. Additionally, Lewis et al. (2022) conclude that further research is required to determine best practices for silvopasture in Australia's various climates.
Another barrier is economic. Studies show that silvopasture is more profitable in the long term than timber or grazing alone. However, the upfront costs and the long payback periods (at least 15-20 years) mean many landowners, understandably, choose to continue high-grading or clearing forests, which provides a higher annual income in the short term (Francis et al. 2022; Lewis et al. 2022).
In Queensland, there is also the risk that, allowed to grow, non-remnant ecosystems will revert to remnant ecosystems under the Vegetation Management Act 1999, which means that they cannot legally be harvested (Francis et al. 2022; Lewis et al. 2022).
Overcoming these barriers will likely require government intervention. A scheme that recognises silvopasture as a carbon-sequestering activity and compensates landowners accordingly could help cover the investment cost. Lewis et al. cite (2022) the success of such incentives in Central and South American countries. In Queensland, there needs to be a guarantee that landowners will be allowed to harvest the timber from silvopasture on their properties.
Despite the barriers, silvopasture is a practice that should be explored further. Given the rate at which climate change is worsening, discovering what works best in the Australian context cannot come soon enough.
