About half the CO2 being stored is as organic carbon in the soil and half is in the wood of the branches, trunk and roots. Tagasaste typically yields roughly 1 ton of edible material per 100mm of rain per hectare per year. The potential of tagasaste as a Spanish fodder was identified by Dr Perez, a medical practitioner, based on La Palma island in the Canary Islands in the 1870s, and Spanish cattle farmers. He wrote to the Spanish authorities promoting tagasaste as a fodder shrub but could not get them interested. He then sent seed to Kew Gardens in England. Kew Gardens tested tagasaste and then sent seed to all its colonies around the world. In Australia, tagasaste's potential was promoted by a number of individuals over the next century (e.g. Dr Schomburge in South Australia and Dr Laurie Snook in Western Australia) but was not adopted on a large scale until the 1980s in Western Australia. The first 2 ha of tagasaste in the West Midlands was planted by John Cook on his farm near Dandaragan in 1982. The success of this small paddock excited the interest of local farmers and researchers. Before this the farming systems in the region were totally based on annual pastures and crops. The region has strongly winter dominant rainfall, with up to eight months without rain over some summers. Until the development of tagasaste it was believed it was not possible to grow perennial pastures in this region. In 1984 the Martindale Research Project was started by the University of Western Australia with a large grant from Sir James McCusker. This project encouraged the participation of local farmers and the Western Australia Department of Agriculture in research and development. Farmers such as John Cook and Bob Wilson at Lancelin developed seeding and mechanical cutting equipment that allowed tagasaste to be sown and managed cheaply by farmers on a broadacre scale. The Martindale Research Project resolved many issues relating to agronomy, animal production and economics that resulted in a reliable package that farmers could adopt with confidence. The Western Australia Department of Agriculture also conducted trials on their Badgingarra Research Station and at Bob Wilson's farm at Lancelin. Local farmers and researchers formed the West Midlands Fodder Shrub Improvement Group. This evolved into the Evergreen Group, which expanded its interests to include a range of other shrubs, grasses and perennial legumes. There are now about 100,000 ha of tagasaste in Western Australia. In Western Australia it is mostly grown on deep, infertile sands in regions nearer the coast with 350 to 600 mm rainfall.