What Is Slenderness Ratio?

Slender borneol (scientific name: Dipterocarpus gracilis Bl.) Is a borneol plant of the genus Bornaceae, a large tree, about 40 meters high, with aromatic resin; the bark is gray-white, longitudinally cracked, exfoliating in blocks, and the surface often Pi hole. Leaves leathery, oblong or oblong-oval, about 15 cm long and 10 cm wide, apex acuminate or short pointed, base round or wedge-shaped. Racemes axillary, stellate hairy; pedicels stout, short, sparsely hairy. Petals white or pink. Flowering from June to July, fruit from December to January. ^[1]

Slender borneol grows on slopes and gully forests below 240-800 meters above sea level. ^[1]

Distributed in India, Myanmar, Thailand, Vietnam, Laos, Malaysia, Indonesia, and China; in China in western Yunnan (Yingjiang Nabang Dam, Jieyang River). ^[1]

The slender borneol is the fruit ripening period from February to April, and it is stored and transported by using fresh moss interlayer seeding method. The seeds do not have a dormant period, and will germinate in about one month in a normal humid environment. The seed life is about 50 days, which is a short-lived seed. After the seeds germinate and grow into seedlings. Usually placed in seedling bags every 10-20 days. Seedlings need to be watered and weeded in a shaded environment, so that the seedlings grow well. After 3-5 months, select 5 seedlings to observe the growth. The average monthly high growth of 0.5 year old seedlings is 0.01 meters, and the average monthly growth of 0.05 cm. Semi-annual seedlings can be planted as high as 30-40 cm. ^[4]

Planting began one week after the rainy season (the rainy season in early May in Lulun, Yunnan, China). Select deep soil layers, fertile and loose, and good water retention in shady slopes. The row spacing of the plants is 4 meters × 4 meters. After planting, the root water is poured through once, which helps the seedlings to adapt quickly and recover. Within six months after planting, manual management needs to be strengthened, weeds next to the seedlings, shovel ponds, and loose soil are often removed. In the dry season, it is best to leave some weeds higher than the seedlings 20-30 cm away from the seedlings, and block the sun to avoid burning the leaves of the seedlings in the hot sun and affect the growth. ^[4]

The trunk is straight and round, the wood is less knotted, and the yield is high. Loose wood, heartwood and sapwood are clearly distinguished, sapwood is yellowish white, heartwood is brown. Medium to slightly coarse structure, straight texture, medium specific gravity, slightly soft material, medium mechanical strength. The radial shrinkage of the chord is relatively large, and it is easy to warp and crack due to improper drying. The trunk is rich in resin and the wood is resistant to decay and is used in construction in Myanmar. According to its material properties, it can be used as materials for construction, bridges, carriages, flooring, interior decoration, and can be used for rotary cutting sheets, making furniture, boxes, etc. This tree species can produce resin, which is made by opening holes in the trunk or by distillation from wood for paint and various industrial uses. ^[2]

Species status: China's national third-level protected plants, rare species. Only within 30 square kilometers of Yingjiang, Yunnan, China, there are sporadic distributions. Due to the long-term deforestation and reclamation, the forest area has been continuously reduced, and the habitat of the production area has deteriorated, which seriously threatens the survival of the tree species. ^[5]

Protective measures: The Yingjiang distribution area in Yunnan , China has planned to establish a nature reserve, which needs to be implemented as soon as possible to strengthen protection. Relevant units should conduct introduction and breeding experiments. ^[5]