SANDALWOOD is being considered for a potential alternative tree crop in Victoria, writes SANDRA GODWIN

Its discovery helped ensure the economic success of Perth during the early days of settlement in the 1800s and now sandalwood is now considered a valuable alternative tree crop in Victoria.

Prized for the essential oil extracted from the heartwood, the timber itself is a valuable commodity, much sought after in numerous cultures for ornaments.

Former West Australian researcher Ben Boxshall, now principal of agribusiness Spicatum Resources Australia which manages several large sandalwood plantations, said the most famous species was Indian sandalwood.

Traded globally for more than 4000 years, Ben said the first statue of Buddha was thought to have been carved from Indian sandalwood.

Australian sandalwood kicked off a 19th century rush in WA, which preceded any gold or other mineral rushes.

Ben said eastward exploration from the west coast by white settlers was largely driven by demand for sandalwood, "the fact they had a market and a very lucrative crop on their hands".

But the native population of sandalwood in WA became depleted by the clearing of the wheatbelt and non-stop export of the wild-harvested wood.

"At times over 50,000 tonnes a year was leaving for Asia," Ben said.

"There's still about 2000 tonnes a year being harvested.

"It's coming from very remote and arid country, generally. It's gone from the wheatbelt, much of the goldfields and become a plant that's in decline over huge areas of WA."

A growers group formed in 2003 and by last year the Kimberley region was home to the world's biggest plantation of 3500ha.

No plantation sandalwood has yet been harvested, but proponents claim the returns per hectare will be significantly higher than wheat over the long-term, the report said.

Several trial projects are under way in Victoria to assess whether the climate, soils and local native trees are suitable for the establishment of new plantations.

Defined as a hemi-parasitic plant, sandalwood cannot survive in the wild on its own. It attaches its shallow roots to the root system of nearby plants and draws water and nutrients from each of the host plants.

"While it has green leaves and can generate some of its own sugars, it can't thrive independently," Ben said.

"It is more dependent than a lot of other hemi-parasites in the Australian flora."

Sandalwood produces numerous fruit, each containing a large nut with a kernel that contains different oils to the heartwood.

Commercial yields of nuts are usually produced about three or four years after sowing.

The nuts, which fetch $20-$30/gram, are harvested after they fall to the ground in summer.

They are in demand from growers who want to expand their plantings and from the cosmetics industry, but high levels of trans-fats in the edible kernels make them unattractive to eat.

The most significant market for the heartwood chips is in perfumery.

"Seventy per cent of the world's perfumes including Chanel No. 5 contain some percentage of sandalwood oil," Ben said.

"A very good base or carrier oil, it is also used in personal care products such as soaps, shampoos, aromatherapy. Experimental uses include adding it to stockfeed to reduce methane emissions from animals in feedlots (and) incense is burned in the foyers of hotels across the Arab world."

Fruit: Sandalwood produces fruit containing a large nut with a kernel that has different oils to the heartwood. After being involved in projects in WA where sandalwood was established in systems incorporating large numbers of plant hosts, some sites with 17 different genera and 60 different species, Ben said a test site near Echuca was established in September 2006.

The aim was to test potential local host species to see whether they could be successfully parasitised by the sandalwood and how they would cope with it.

"Sandalwood is not a discriminant parasite," he said. "It will attach itself to anything - water pipe, eucalypt - it will have a crack, but it can really only take advantage of some species, particularly nitrogen-fixing species."

With acacia stenophylla as a primary host, the site was sown with sandalwood nuts next to the seedlings, before planting of secondary hosts in between.

"The sandalwood nuts cracked naturally with the right combination of moisture and temperature, and the seed germinated ... found the host root, attached and survived the first summer," Ben said.

He recommends sowing at 4kg of nuts/ha to give sufficient density, allowing for a 40 per cent germination success rate.

High density - 300 to 400 sandalwood/ha - and high diversity made the system more robust than one based on a single host species, by allowing shorter-lived host plants to naturally mature, die and regenerate without jeopardising the sandalwood.

This also has benefits for biodiversity, providing habitats for a larger variety of wildlife as was evident at the Echuca site where the plantation was abuzz with birds and numerous insects.

Ben said pruning and thinning of sandalwood was less rigorous because it was not harvested as saw logs.

This made the shape of the tree less important than the proportion of sapwood to valuable heartwood, which begins accumulating after about five years.

The most valuable part of the tree was the butt, with the highest oil levels found at ground level and in the major roots.

So, as well as picking up the nuts, harvest involves uprooting the entire plant after 15 to 20 years.

"After harvesting, there are generally some roots left behind and it can sucker," he said. "We've seen mass germination of sandalwood from nuts on the ground."

Five years on, Ben said the test site managed by the Northern United Forestry Group had evolved into a unique system.

"These sandalwood are well and truly attached to many different hosts," he said.

"The great strength of the system is the resilience, number and diversity of hosts ... if some drop out of the system as a result of water stress, a pest or pathogen, the sandalwood is not vulnerable because it's attached to a large number of other species."

While the sandalwood succeeded on all species "to an extent", Ben said the best results were observed on acacia stenophylla and acacia implexa.