A review of tree domestication principles, practices and case studies illustrates the importance of a methodological approach to domestication. Domestication of new species involves of the entire value chain from identification of candidate species, through production and management, to uptake by communities and markets. Efforts to domesticate forest trees have often neglected the final step of adoption, with the result that many projects have resulted in mature trees without markets. Ensuring adoption and marketability is important for the success of any domestication effort, but especially in small island nations where local markets may be small, transport limited and transaction costs high.

Valuable timber trees in accessible sites in Vanuatu have been mostly removed by logging. There are large areas where plantations would likely be successful. Yet plantation establishment among landholders in Vanuatu has been limited to date, even with considerable extension support. There has been little systematic investigation of why this has occurred. The purpose of this research was to identify constraints to whitewood (Endospermum medullosum) plantation development. A participatory social research approach was used on Espiritu Santo Island to look for trends in attitudes toward plantations. This was achieved through the use of mixed methods social research to survey 139 local landholders from 42 villages. Most landholders on Santo Island were not convinced that there are good reasons to plant whitewood, at least not in large extensions. Future efforts should be focused on the development of local capacity for plantation establishment, maintenance, processing and export marketing, at a variety of scales.

Site and soil characteristics associated with existing plantings of whitewood (Endospermum medullosum Euphorbiaceae) were characterised across Espiritu Santo Island in Vanuatu. Two hundred, generally small (most commonly around 0.5 ha), plantations dominated by whitewood have been planted across the eastern side of the island. These plantations range up to 20 years in age and provide a guide to the expected growth rates of whitewood in plantation in those areas. Site and growth data collected from a range of those plots were used to determine the characteristics associated with the most productive plantations. This association of site variables with growth was correlated with pre-existing resource mapping to estimate the area and locations of land suitable (in terms of sustainable productivity) for whitewood plantation on the island. Some of the characteristics used in that estimation included soil depth, drainage, soil erodibility, slope and existing land use. Using this method it was estimated that around 33 000 ha of land on Espiritu Santo, currently not used or native forest, is highly suitable for whitewood development.

The development of plantations with a new species, such as is occurring with the endemic tree Endospermum medullosum (whitewood) in Vanuatu, requires the resolution of appropriate establishment techniques. Site preparation, fertilisation and weed control have a very large impact on plantation productivity and represent major risks to plantation success. Establishment techniques for tropical species are reviewed and preliminary site preparation and fertilisation trials for whitewood reported. Trials were established at a site on Espiritu Santo island using available general purpose fertiliser with and without micronutrients at two rates. There was no effect of fertiliser over various rates of complete fertiliser with and without micronutrients, designed to provide adequate phosphorus in volcanic ash soils. Ripping had no significant effect on growth, however insufficient hand clearing of vegetation resulted in lower growth due to competition and complete machine clearing of vines results in high temperatures and decreased survival. A serious issue for whitewood establishment in single species plantations is weed management, especially vine control (Merremia spp). The time needed for weed control is influenced by initial planting density and spacing. When inter-planted with mixed gardens of food crops, weed control is not an issue due to more regular tending.

This paper investigates the early growth response, branching and stem quality of Endospermum medullosum (whitewood) at different spacings. Whitewood plantings were established at stockings of 400–833 trees per hectare and early growth, tree stem quality and branching were quantified up to age 3 years. Growth, number of live branches and branch size were negatively correlated with stocking. The stocking of trees of acceptable quality had high spatial variation. Initial spacing in whitewood plantations can be used to manipulate branch size, crown rise and stem size; all of which are important for development of pruning and thinning regimes to produce high quality logs. If unimproved whitewood stock is used, to ensure that there are 300 stems per hectare of acceptable quality to produce sawlogs, more than 600 trees per hectare should be established at planting.

Whitewood (Endospermum medullosum) is a tree species that shows promise for plantation timber production in Vanuatu, but few growth data are available to inform yield forecasts. Three simple relationships summarizing stand dynamics, namely height-age, diameter-height-stocking, and mortality-basal area relationships, were calibrated with data from 15 plots to form the basis of a model for silvicultural and management decisions. Despite the simplicity of the model, it offers predictions consistent with independent data. The model suggests that the optimal silviculture involves planting 635 stems/ha, thinning at 20 and 26 years, and clearfelling at age 36 when trees have a diameter of 55 cm dbh. However, many options offer a net present value within 5% of this nominal optimum. The flexibility to vary the timing and intensity of harvests over a wide range while maintaining good financial returns, coupled with good growth and timber properties, suggests that whitewood warrants further domestication and promotion in Vanuatu.

Vanuatu whitewood (Endospermum medullosum L.S. Smith) is an economically important timber species for Vanuatu. Inter- and intraprovenance genetic parameters for stem diameter at breast height, basic density and radial variation in density, were estimated for two provenances selected from a 12.4-year-old open-pollinated seed orchard on Espiritu Santo Island, Vanuatu. Kole provenance exhibited the highest mean basic density, greatest mean diameter and greatest radial variation in density across the stem.

Mean basic density at breast height was 345±2 kg/m³. Growth rings were not visually discernable and colour was homogenous across all samples. For radial variation determination, each pith-bark core was sectioned into four equi-length subcores (A–D). Subcore density increased consistently and significantly from pith to bark, with mean basic density of 308±3, 327±3, 343±3 and 359±3 kg/m³ for cores A–D respectively.

The narrow-sense heritability estimate () was low (0.26±0.2) for diameter, with a moderate coefficient of additive genetic variation (CV_A= 17.61%). Estimated for density was moderate (0.49±0.24), with a low coefficient of additive genetic variation (CV_A= 5.39%). Though the precision of these estimates is modest, reflective of the small sample size, indications are that the heritable genetic variation in both growth and quality traits will result in economic gain from a recurrent selection and breeding program.

A breeding program aimed at increasing economic value of whitewood plantations in Vanuatu and conserving declining genetic resources will take direction from the results of this study. Genetic parameters for stem diameter breast height over bark (DBHOB), straightness and branching were estimated in an 11.4-year-old whitewood breeding population on Espiritu Santo Island. Wood density variation in one subpopulation was also studied. Trees with the fastest growth and best form were from Espiritu Santo. Growth and form trait heritability estimates ( = 0.10–0.16) were low to moderate, with moderate phenotypic variation (CV_P = 17–36%). DBHOB at 11.4-years and 4-years were very closely genetically correlated (r_A = 1.00 ± 0.17). Mean unextracted wood basic density at breast height was 330 (SD±21) kg/m³, or similar to mature-tree densities. Economic gain in growth traits can be expected from a recurrent selection and breeding program given the heritable genetic variation indicated in this study. Conserving genetic diversity in this species is a high priority.

Whitewood (Endospermum medullosum) is a useful timber species, previously sourced from native forests and now available from plantations in Vanuatu. However, plantation-grown whitewood will have about 30% more knotty wood than previously experienced in logs from native forest. This will impact on the economics of growing and processing whitewood, and on potential uses of the timber. Opportunities to add value to knotty wood are to produce large section structural lumber, to recover short lengths of clear wood for furniture, and to treat heartwood with preservative chemicals to enable structural use in exposed and in-ground applications.

A series of trials examining fertilizer-shading interactions on the island of Leyte (Philippines, 11°N) revealed that the endemic dipterocarp mayapis (Shorea palosapis) benefits from shade trees, either directly above or to the east, during the early stages of plantation establishment. Although it can attain 2 cm/year diameter increment in plantations, mayapis exhibits poor growth and survival under wide spacing, when waterlogged and in exposed bare soil. Indications that early growth can be hampered by high soil temperatures warrant further research and development of practical planting techniques for smallholders.