It is now clear that forestry carbon offsets are resilient features of Australian climate change policies. To partic­ipate in such markets, farmers must be able to adequately measure, and verify the mitigation achieved (The CRC for Greenhouse Accounting & Tony Beck Consulting Services Pty Ltd, 2003). Forestry plantations that include some rotational harvesting for biochar or bioenergy will require more sophisticated carbon accounting than a simple revegetation project (Indepen­dent Pricing and Regulatory Tribunal, 2008). The estab­lishment of tree fodder plantations has long offered a significant productivity option for some farmers (Sanford et al., 2003). Deferring the early grazing of annual pastures and reduce dry season hand-feeding has long generated interest (Patabendige et al., 1992; Cleugh et al., 2002), and perennial fodder tree planta­tions offer another source to supplement stock feed in the summer/autumn period (Sanford et al., 2003). Deep-rooted perennials are well known to use available water when annual pastures are dead, recover nutrients from deeper soils, reduce soil acidification, minimize erosion, and some leguminous species also fix nitrogen (Patabendige et al., 1992; Cransberg and McFarlane, 1994; Hatton and Nulsen, 1999; Wise and Cacho, 1999; Valzano et al., 2005). Adding value to these conventional applications in such regions is the use of tree woody wastes to produce biochar as a feed additive which may improve ruminant growth when fed on the trees (which may be of lower grade and/or be a "high tannin" content), and in the process sequester carbon in the soil (McHenry, 2010). The mechanism for this improvement is generally known as "detannification", and may enable the use of potentially large resources of high-tannin fod­der species (such as Acacia sp.) by increasing the avail­ability of leaf protein (Van et al., 2006; Blackwell et al.,

2009) . Acacia sp. fodder plantations require annual prun­ing of the higher branches to provide fodder for grazing animals. Animals eat the leaves from the branches on the ground, leaving the inedible woody waste components in the paddock to dry and be collected as a potential source of biomass for biochar manufacture. The improved digestibility of some high-tannin fodder trees with biochar feed additives may expand their utility within agricultural production systems (McHenry,

2010) . In particular, if an Acacia sp. biochar feed additive is effective in Australian semiarid production systems (such as the West Midlands), this might provide a further incentive to revegetate semiarid sandy soils suit­able to many native Acacia sp. to attain a combination of positive benefits (Graetz and Skjemstad, 2003; Antle et al., 2007). These options are currently based on a

12- week experiment by Van et al. (2006) comparing goat growth rates fed on tannin-rich Acacia sp. fodder. The goats were either fed biochar (produced from bamboo) at a feed rate of <1 g per day per kilo of live weight, or no biochar for the control group. The experi­mental group exhibited notably higher growth rates (~ 20%) than the control goats that received no biochar feed additive on the same feed regime. Over the 12 weeks the experimental goats fed biochar weighed 5.2% heavier than their controls (Van et al., 2006). This may be a sufficient commercial incentive to drive de­mand and subsequent biomass conversion technology investment without a carbon price (McHenry, 2010). The work by Van et al. (2006) also presents a mechanism (via animal excreta) that may be assessed for efficacy when avoiding relatively expensive biochar soil applica­tion options such as deep banding, broadcasting, seeding application, topdressing, aerial delivery, or pre­cision application to ailing plants (Blackwell et al., 2009). In addition to researching the efficacy of small biochar additions to the diet of grazing animals, the opportunity arises to simultaneously investigate the reported capacity and magnitude of numerous other biochar benefits (McHenry, 2010), including the ecologi­cally delivered biochar to biosequester C; biologically immobilize inorganic N; retain soil N; increase soil pH; adsorb dissolved ammonium, nitrates, phosphate, as well as hydrophobic organic soil pollutants such as polycyclic aromatic hydrocarbons (Beaton et al., 1960; Gustafsson et al., 1997; Accardi-Dey and Gschwend, 2002; Lehmann et al., 2003). The remaining levels of bio­char in the animal excreta would also determine the car­bon fractions that survive the digestive system to determine the maximum available long-lived carbon species fractions to be sequestered in soils via the ecolog­ical delivery method (McHenry, 2010). Long-term soil testing may also be able to detect the stable fraction of the ecologically delivered biochar after being exposed to the soil environment. However, there is clearly
much research required to verify a number of assertions and assumptions to provide a level of certainty accept­able to farmers and investors who collectively command much of Australia’s productive capacity (Intergovern­mental Panel on Climate Change, 2000; Barker et al., 2007).