Sandalwood inventory

• Department of Forests, Vanuatu

Continued high demand and over-exploitation of the natural resource base of sandalwood (Santalum) species has led to a shortage of sandalwood oil on the international market. Recent field studies in Vanuatu and Cape York Australia have discovered that a small proportion of trees (3-4%) in local sandalwood populations possess exceptional oil qualities, even better than Indian sandalwood. This new discovery opens the prospect for local communities to produce highest quality sandalwood oil. There are currently limitations on sandalwood harvest in Vanuatu, but the Vanuatu government is concerned that wild stocks may be exploited. Characterising sandalwood (Santalum austrocaledonicum) abundance in Vanuatu is challenging due to the broad, discontinuous yet highly modified distribution of sandalwood and the lack of systematic historical inventories or detailed harvest documentation. This study undertook a rough census of the country's wild sandalwood stocks to provide scientific underpinning for a conservation strategy.

The preliminary distribution had been estimated from anecdotal ranges provided by the Vanuatu Department of Forests (VDoF), GIS spatial analyses and recorded sandalwood locations collected during an Oil Quality Survey in 2005, and during the 2007 sandalwood inventory survey conducted for this project.

Historic densities have been estimated from anecdotal descriptions and harvest data records. Current densities are based on the 2007 field survey of sandalwood populations on four Vanuatu islands. The surveys were conducted in regions of known sandalwood populations. The low aggregated density (0.4 trees/ha) of commercially sized trees found in these surveyed populations is a cause for concern. The survey scientists recommended extending the current survey to Tanna and perhaps northern Santo islands.

Based on the field data, they estimated that the current resource on the four islands surveyed is approximately 210 tonnes, with another 80 tonnes on other islands of Vanuatu. At current harvest rates this resource may be quickly depleted and there would be a shortfall until plantation sandalwood is available in 10-15 years. They believed that the quota for wild sandalwood harvest needed reducing to a sustainable level. This would entail implementing two purchase registers that clearly record purchases of heartwood and sapwood as separate products. The further development of this monitoring system may be a suitable activity for government or overseas assistance.

There is a need for accurate and ongoing sandalwood growth and yield data, based on several islands to cover the range of genetic types present. Ideally these growth data should be collected annually at permanent quadrats. Measurements of tree height, diameter at breast height (DBH), basal area at 10-cm height and identification of host species should be made using standard forestry techniques.

There is also a need for systematic recording and archiving of harvest data within the VDoF. Ideally this would be regularly sourced from the buyers and recorded on a standard proforma. The data could be stored both electronically and in hard copy, and analysed regularly with some form of reporting.

The survey scientists supported the initiatives of the VDoF and industry to promote plantation establishment on several islands. This will also take harvest pressure away from wild populations of sandalwood, which currently need protection from over-harvesting and from damage by cattle grazing and trampling. They found that size class distribution over the entire survey area was skewed towards very small seedlings/suckers and saplings. Even at the best sandalwood sites there was a lack of mature trees and the distribution of stem sizes was likewise heavily skewed. The remaining trees occurred in small clusters and density per hectare was very low.

They suggested that the sandalwood genetic resource should be conserved using ex-situ seed conservation techniques. This might be carried out in the private sector as an adjunct to the wider establishment of sandalwood plantations. They also recommended that VDoF investigate the feasibility of establishing an effective network of sandalwood conservation agreements to conserve representative populations and genetic resources over the species' range in Vanuatu. This might be in exchange for support for plantation establishment.

The implementation of a planted resource survey, to quantify the extent and maturity of both small holder and investment plantings, would help determine the most appropriate planting models for different economic objectives. The scientists recommended the establishment of sandalwood growth plots in conjunction with progressive sandalwood farmers, to quantify the long-term productivity of different planting models across different climatic and edaphic zones.

They also saw opportunity for further refinement to map suitable sandalwood habitat across Vanuatu that accommodates both climatic variables and environmental tolerances. Variables such as proximity to transport corridors and ports should also be considered when determining areas suitable for more significant investment in planting sandalwood.