One report says that the plant is very tolerant of soil conditions. It is easily grown in a loamy soil but the plants are unable to withstand much frost. Requires a lime-free soil. The Tung tree is reported to tolerate an annual precipitation of 64 - 173cm, average temperatures ranging from 18.7 - 26.2°C, and a pH of 5.4 - 7.1. Tung trees are very exacting in climatic and soil requirements. They require long, hot summers with abundant moisture, with usually at least 112 cm of rainfall rather evenly distributed through the year. Trees require 350 - 400 hours in winter with temperatures 7.2°C or lower - without this cold requirement, trees tend to produce suckers from the main branches. Vigorous but not succulent growth is the most cold resistant - trees are susceptible to cold injury when in active growth. Production of tung is best where day and night temperatures are uniformly warm. Much variation reduces tree growth and fruit size. Trees grow best if planted on hilltops or slopes, as good air-drainage reduces losses from spring frosts. Contour-planting on high rolling land escapes frost damage. Tung makes its best growth on virgin land. Soils must be well-drained, deep aerated, and have a high moisture-holding capacity to be easily penetrated by the roots. Green manure crops and fertilizers may be needed. Dolomitic lime may be used to correct excessive acidity; pH 6.0 - 6.5 is best; liming is beneficial to most soils in the Tung Belt, the more acid soils requiring greater amounts of lime. Trees are not very cold hardy outdoors in Britain. Another report says that they are fairly hardy. A very ornamental tree, it is cultivated in China for the oil contained in its seed. There are some named varieties. Seedlings generally vary considerably from parent plants in growth and fruiting characters. Seedlings which have been self-pollinated for several generations give rather uniform plants. Only 1 out of 100 selected 'mother' tung trees will produce seedlings sufficiently uniform for commercial planting. Usually seedling trees outgrow budded trees, but budded trees produce larger crops and are more uniform in production, oil content and date of fruit maturity.
Seed. There are no more details but the report should be treated with caution since the oil from the seed is said to be poisonous.
Seed - sow March/April in a warm greenhouse. When large enough to handle, prick the seedlings out into individual pots and grow them on for at least the first winter in a greenhouse. Plant out in early summer and give the plants some protection from the cold for their first winter outdoors. Tung seed are normally short-lived and must be planted during the season following harvest. Seeds are best hulled before planting, as hulls retard germination. Hulled seed may be planted dry, but soaking in water for 5 - 7 days hastens germination. Stratification, cold treatment or chemical treatment of seeds brings about more rapid and uniform germination. Dry-stored seed should be planted no later than February; stratified seed by mid-March; cold-treated and chemical treated seed by early April. Cuttings of mature wood in a frame. Most successful budding is done in late August, by the simple shield method, requiring piece of budstock bark, including a bud, that will fit into a cut in the rootstock bar. A T-shaped cut is made in bark of rootstock at point 5 - 7.5 cm above ground level, the flaps of bark loosened, shield-bud slipped inside flaps and the flaps tied tightly over the transplanted bud with rubber budding stripe, 12 cm long, 0.6 cm wide, 0.002 thick. After about 7 days, rubber stripe is cut to prevent binding. As newly set buds are susceptible to cold injury, soil is mounded over them for winter. When growth starts in spring, soil is pulled back and each stock cut back to within 3.5 cm of the dormant bud. Later, care consists of keeping all suckers removed and the trees well-cultivated. Spring budding is done only as a last resort if necessary trees are not propagated the previous fall.
Base of foothills esp. in rocky places, to 1000 metres in W. China. Montane sparse forests at elevations of 200-1500, occasionallyto 2000 metres.
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