Pterocarpus santalinus

Plant Profile

Pterocarpus santalinus

Therapeutic uses

• The heartwood of red sanders is used as an astringent and tonic, and is bitter, sweet, cooling, analgesic, anti-inflammatory, and febrifuge.
• Its decoction is given in chronic dysentery.
• It is also useful in vitiated conditions of pitta, burning sensation, vomiting, skin diseases, leprosy, ulcers, fistula, and haemorrhages.

Morphological characteristics

• Lal chandan is a moderate-sized deciduous tree with clear trunk and dense rounded crown.
• It attains a height of 10 m and a girth of 0.9–1.5 m under favourable growing conditions. The blackish-brown bark is fissured and resembles crocodile skin.
• The inner bark, when injured or cut, oozes red coloured ‘santolin’ dye.
• The wood is extremely hard and dark red in colour, with a specific gravity of 1.109.
• The leaves are imparipinnate, petiolate, and alternate.
• They are simple at seedling stage but trifoliate or rarely pentafoliate later.

Floral characteristics

• The flowers of the species are yellow, densely arranged in simple or sparingly branched racemes.
• Flowering occurs from February to April, after new leaves sprout.
• Pods are formed rapidly but get ripened in next February–March.
• Pods are oblilquely orbicular, 3–4 cm in diameter, including the wing, and gradually narrow down into a short stipe.
• There is only one seed per pod, which is 1–1.5 cm in length and red- dish brown in colour.

Distribution

• The Pterocarpus species is distributed in peninsular India and Sri Lanka.
• It occurs gregariously in patches in tropical dry deciduous forests, towards south eastern Ghats.

Pterocarpus santalinus - tree

Climate and soil

• Well-drained red soils with gravelled loam are suitable for the cultivation of lal chandan species.
• It regenerates well in dry hot climate and requires rainfall ranging from 800 mm to 1000 mm annually for good growth.

Varieties

• In nature, two types of rakta chandan trees are observed—wavy grained and straight.
• The wavy grained wood is more in demand in trade and is preferred for commercial plantation.
• No commercially released varieties are available.

Propagation material

• The seeds retain their viability for about one year under normal storage conditions and are the best propagation material.
• Fruits are collected in March for the extraction of seeds.
• Seedlings or stumps prepared from two-year-old nursery seedlings are used for planting in the field.

Agro-technique

Nursery technique

Raising propagules

• March, April or May months are suitable for raising nursery from seeds.
• Mature and healthy pods are chosen to collect the seeds; these are sown in raised nursery beds.
• It takes 10–15 days for the germination to complete.
• Pretreated seeds (10–12 kg) are sown per bed (10 m × 1 m) of sandy loam or loamy soil in April and covered with a thin layer of soil or hay.
• After one year, stumps can be prepared, which are planted in polybags in February to March, to be utilized after four to five months as stump-sprouted seedlings.

Propagule rate and pretreatment

• About 1 kg seeds are needed to raise seedlings for 1 hectare of plantation.
• Seeds show only about 50%–60% germination and about 40% plant survival.
• Seed treatment with GA₃ (gibberellic acid) + BA (benzyladenine) @ 250 PPM (parts per million) helps in early and optimum germination.
• Alternatively, seeds can be soaked in cold water for 72 hours or in cow dung slurry for 72 hours.

Pterocarpus santalinus - crop

Planting in the field

Land preparation and fertilizer application

• The land is ploughed and harrowed repeatedly and soil is brought to a fine tilth.
• Pits of size 45 cm × 45 cm  × 45 cm are dug at a spacing of 4 m × 4 m.
• The pits are filled with topsoil mixed thoroughly with 10–15 kg FYM (farm yard manure) and 10 g lindane dust to protect the planting stock from soil-borne fungi.

Transplanting and optimum spacing

• The best time for planting the crop in the field is end of May to June, that is, onset of rainy season.
• Generally, the stump-raised seedlings or stumps obtained from two-year-old nursery plants are transplanted.
• A plant population of about 600 per hectare is recommended with a spacing of 4 m × 4 m.

Intercropping system

• No particular intercropping system has so far been studied in this crop; however, herbaceous rhizomatous species may be grown as an intercrop in inter-row spaces.

Interculture and maintenance practices

• About 10–15 kg FYM per plant per year and 150:100:100 g NPK (nitrogen, phosphorus, and potassium) per plant per year are required for at least five years.
• Fertilizer should be applied in 15–20-cm-deep circular trenches dug around the plant at a distance of 60 cm.
• Full dose of P and K along with one-third N should be applied at the end of February. The remaining N should be applied in two split doses during June–July and October–November.
• Application of inorganic fertilizers should always be followed by irrigation.
• Gap filling is done one month after planting. Weeding is done manually as and when necessary and particularly just before manuring.
• The soil around the basin is loosened frequently by hoeing.

Irrigation practices

• The plants are irrigated immediately after transplantation.
• Thereafter, irrigation is done on alternate days up to 15 days.
• After the seedlings get established, irrigation may be done at an interval of 10–15 days, depending on the weather conditions.

Disease and pest control

• Leaf-eating caterpillars have been found to damage the crop during April–May.
• These can be controlled by prophylactic spray twice at weekly intervals.

Pterocarpus santalinus - bark

Harvest management

Crop maturity and harvesting

• The fruits require almost 11 months to mature.
• Twenty- to twenty-five-year-old trees are used for the extraction of bark and wood.
• The bark may be extracted selectively by strip technique and the tree may be allowed to stand.
• The tree has to be felled for extraction of wood.

Chemical constituents

• Bark, heartwood, and sapwood contain santalin A and B, isopterocarpolone, pterrocarptriol, isipterocarpene, pterocarpdiolone, pterocarpol, acyl olealonic aldehyde, and acetyloleanolic acid.

Yield

• Pod yield from 15-year-old trees is 30 tonnes per hectare.
• Heartwood yield per tree after felling is 250 kg.
• Thus, 150 tonnes per hectare of heartwood is expected after 15–20 years.

Source : Agro-techniques of selected medicinal plants.