Silviculture of important Indian trees

In short

This topic covers the species-wise silviculture of India's commercially and ecologically important trees - the silvicultural characters (light demand, coppicing power, frost and drought hardiness), the regeneration method, nursery and planting technique, tending and thinning schedule, rotation and expected yield of each. It converts the general principles of silviculture into prescriptions that a working plan or a farm-forestry project can actually execute, species by species and locality by locality. It is examined heavily in B.Sc/M.Sc Forestry papers, in the Indian Forest Service (Forestry Paper II) and in state forest-service and ICFRE/FRI entrance tests. On the job it is used by State Forest Departments, FDCs, ICFRE institutes (FRI Dehradun, IWST Bengaluru, IFGTB Coimbatore), and by farm-forestry wings of ITC-PSPD, JK Paper, WIMCO/Yamunanagar plywood cluster, Greenply and Century Plyboards.

Explained

How a species' silviculture is described (the standard template)

• Silvicultural characters: light requirement (strong light demander, moderate shade bearer, shade tolerant), frost/drought/fire hardiness, coppicing and pollarding power, root-sucker habit, response to browsing.
• Phenology and seed: flowering and fruiting season, seed year/periodicity, seed weight (seeds per kg), viability period, pre-treatment (soaking, alternate wetting and drying, scarification, hot-water).
• Regeneration: natural (seedling, coppice, root sucker) versus artificial (direct sowing, nursery-raised entire plant, polypot, stump/ETP, clonal ramet).
• Silvicultural system: clear-felling with artificial regeneration, uniform/shelterwood, selection, coppice, coppice-with-reserve, taungya.
• Tending: weeding, cleaning, climber cutting, thinning grade (A to D of the British grades still used in Indian working plans), pruning.
• Rotation and yield: rotation of maximum volume production (where MAI = CAI), MAI in m³/ha/yr, site quality class from the yield table.

Hardwoods of the moist and dry deciduous forests

• Teak (*Tectona grandis*, Verbenaceae/Lamiaceae): strong light demander, frost-tender, good coppicer, needs well-drained deep soil with free lime; fails on waterlogged or acidic lateritic sites. Fruit is a drupe (~1,000-2,000 fruits/kg, varies by provenance), pre-treated by alternate wetting and drying (soak 12 h, dry 12 h, 7-14 cycles) or by charring/pit burning. Raised as stumps (ETP) or polypots, planted 2 × 2 m (2,500/ha) or 3 × 3 m; regenerated by clear-felling with artificial regeneration and classically by taungya (Chittagong/Nilambur method, Brandis). Thinnings at about 5, 10, 15, 20 years; rotation 50-60 years in South India (Nilambur, Konni), 60-80 in Central India; MAI roughly 3-8 m³/ha/yr by quality class; teak clonal seed orchards and TCP (tissue-culture teak) are now standard for farm forestry.
• Sal (*Shorea robusta*, Dipterocarpaceae): gregarious, light-demanding as a pole but seedlings need overhead shade initially; seed is recalcitrant - viability a few weeks only, so sown fresh at the onset of monsoon. The sal regeneration problem: abundant seedlings appear but die back repeatedly from weed competition (especially *Chromolaena/Eupatorium*), drought, fire, grazing and frost. Treatments tried and prescribed in working plans: controlled burning, soil working, weeding and cleaning, Behar method of regeneration improvement felling, canopy opening in steps (uniform/shelterwood with secondary and final fellings), and protection from fire and grazing. Coppices well when young; rotation 80-120 years.
• Shisham (*Dalbergia sissoo*): light demander, reproduces vigorously by root suckers on river-alluvium (khadir) and by seed; raised from pods (depulped) or stumps; a leading agroforestry/bund species in Punjab, Haryana and UP; rotation 25-40 years for timber, 8-12 for small timber. Dieback/wilt (*Fusarium solani*, *Ganoderma*) has caused widespread mortality - avoid waterlogging, use resistant provenances, do not plant in paddy-irrigated fields.
• Khair (*Acacia catechu*): dry riverain and Siwalik species, strong light demander; heartwood yields katha and cutch; 15-25 year rotation; felling and transit are tightly regulated in most states because of illicit katha trade.
• Babul (*Acacia nilotica* ssp. *indica*/*cupressiformis*): drought and salinity hardy, nitrogen fixing, coppices and pollards; used in rab, fuelwood, agricultural implements and tannin; irrigated plantations (Gujarat, Rajasthan) on 15-30 year rotation; "Ramkathi" and "Vedi" are the recognised types.
• Neem (*Azadirachta indica*): hardy dry-zone species, seed is short-lived (sow within 2-3 weeks), raised in polybags; valued for azadirachtin, oil cake and timber; planted widely in avenue and wasteland schemes.

Conifers of the Himalaya

• Deodar (*Cedrus deodara*): moderate shade bearer in youth, frost hardy, 1,700-2,700 m; cones ripen in autumn, seed winged, short-lived (sow the same season). Regenerated under the uniform (shelterwood) system with preparatory, seeding and final fellings, or by patch clear-felling and planting; rotation 100-150 years; does not coppice.
• Chir pine (*Pinus roxburghii*): strong light demander, extremely fire-hardy as a pole (thick bark, needle-cast fires), 450-2,000 m in the Siwaliks and outer Himalaya. Regenerated by seeding fellings/clear-felling with artificial regeneration; raised in polybags for mycorrhizal inoculation. Resin tapping by the improved rill method with CHIR (chemical hormone-induced resin) - acid paste (sulphuric/citric) on shallow rills, which gives higher yield and far less damage than the old blaze/cup-and-lip method; minimum girth, number of blazes per tree, rest years and tapping height are fixed by state resin rules.
• Blue pine (*P. wallichiana*), spruce (*Picea smithiana*) and silver fir (*Abies pindrow*): spruce and fir are shade bearers regenerated under selection or group selection in the moist temperate forests; regeneration is slow and browsing-sensitive.
• Sal-conifer contrast worth stating in exams: deodar and spruce tolerate shade and suit shelterwood/selection; chir pine and teak demand full light and suit clear-felling with artificial regeneration.

Fast-growing industrial and agroforestry species

• Eucalyptus (*E. tereticornis*, *E. camaldulensis*, *E. grandis* hybrids): raised from seed in root-trainers or as clonal ramets (ITC-PSPD, IFGTB clones); planted 2 × 2 m to 3 × 3 m; coppice rotation of 5-8 years, usually two coppice crops after the seedling crop; pulpwood and poles. Criticised for water use and allelopathy - prescribe it on farm bunds and non-moisture-limited sites, not on shallow drought-prone catchments.
• Poplar (*Populus deltoides*): deciduous, light demanding, frost hardy; ETP (entire transplant) of one-year-old nursery plants, planted January-February at 5 × 4 m (500/ha) or 5 × 5 m in agri-silviculture with wheat, sugarcane, turmeric and fodder between rows; 6-8 year rotation for plywood/matchwood (WIMCO clones G-48, S7C15, Udai, Kranti). Clones are propagated from one-node cuttings and can be registered under the Protection of Plant Varieties and Farmers' Rights Act, 2001.
• Casuarina (*C. equisetifolia*, *C. junghuhniana*): coastal sand-binder, fixes nitrogen through Frankia nodules, salt-spray and wind hardy; nursery raised or clonal, planted 1 × 1 m to 2 × 2 m; rotation 4-7 years for pulp, poles and scaffolding - the backbone of Tamil Nadu and Andhra Pradesh farm forestry.
• Melia dubia, Gmelina arborea, Acacia mangium/auriculiformis, Ailanthus excelsa, Leucaena leucocephala: short-rotation (4-10 year) plywood, pulp and matchwood species now dominating agroforestry supply to Perundurai, Yamunanagar and Hyderabad plywood clusters.
• Rubberwood and mango/jackfruit from homesteads supply a large share of Kerala's sawn wood - a reminder that much of India's industrial wood comes from trees outside forests (TOF), about a quarter to a third of the country's growing stock as reported in the FSI *India State of Forest Report*.

Special-value and multipurpose species

• Sandalwood (*Santalum album*): a root hemiparasite - its roots form haustoria on host roots; needs a pot host (e.g. *Cajanus cajan*) in the nursery and long-term hosts (*Casuarina*, *Pongamia*, *Melia*) in the field; heartwood formation starts at 10-15 years, harvest at 15-30 years; seed needs GA₃ treatment to break dormancy; spike disease is caused by a phytoplasma spread by insect vectors, with no cure - infected trees are removed. Karnataka and Tamil Nadu amended their forest laws in the early 2000s so that growers own the trees on their land; transit and sale rules still differ by state, so confirm the current state rule before advising a farmer.
• Bamboos (*Bambusa bambos*, *B. balcooa*, *Dendrocalamus strictus*, *Melocanna baccifera*): grasses, not trees; propagated by offsets, rhizome, culm cuttings and increasingly tissue culture; harvest only culms 3 years and older, cut 15-30 cm above ground just above a node, in the dry season (post-monsoon to pre-monsoon), retaining enough mature culms and all current-year culms - a 3-4 year felling cycle; gregarious flowering is followed by clump death (*Melocanna* mast flowering and "mautam" in Mizoram). Under the Indian Forest (Amendment) Act, 2017 bamboo grown on non-forest land is not a "tree", so no felling or transit permit is needed for it - bamboo on forest land remains regulated.
• Mangroves (*Rhizophora*, *Avicennia*): viviparous propagules planted directly in fishbone-channel sites; raised under CRZ and state coastal plantation programmes.

The legal and procedural frame in India

• Indian Forest Act, 1927 (reserved/protected/village forests, transit of forest produce); state Forest Produce Transit Rules and Tree Preservation/Felling Acts govern felling and movement of timber.
• Van (Sanrakshan Evam Samvardhan) Adhiniyam, 1980 - the renamed Forest (Conservation) Act, 1980 (renamed by the 2023 amendment); diversion of forest land needs central approval and compensatory afforestation, funded through the CAMPA mechanism under the Compensatory Afforestation Fund Act, 2016.
• Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006 - community forest resource rights affect silvicultural prescriptions and NTFP harvest.
• National Working Plan Code (2023 edition, MoEFCC) prescribes how working plans - and therefore species-wise prescriptions, felling series and yield regulation - are prepared; National Forest Policy, 1988 fixed the 33%/goal and barred clear-felling of natural forests for industrial plantations.
• Biological Diversity Act, 2002 (amended 2023) for access to genetic material; PPV&FR Act, 2001 for registering tree varieties; Seeds Act, 1966 certification does not cover most forest tree seed - quality is handled through ICFRE/state seed-source certification, which is largely voluntary.
• For trees on farmland, MoEFCC issued Model Rules for Felling of Trees on Agricultural Lands (2025) with a national timber-management portal to ease permits; adoption is by each state, so the operative rule is the state's notification.

Key points

• Light demander - needs full overhead light (teak, chir pine, shisham, poplar); regenerate by clear-felling or seeding fellings.
• Shade bearer - tolerates overhead cover (spruce, fir, deodar in youth); suits shelterwood or selection systems.
• Taungya - raising a plantation (classically teak) along with agricultural crops for the first 2-3 years.
• Sal regeneration problem - repeated seedling dieback despite heavy seed fall; cured by weeding, soil working, fire and grazing protection, gradual canopy opening.
• Recalcitrant seed - cannot be dried and stored (sal, neem, Hopea); sow fresh.
• Teak seed pre-treatment - alternate wetting and drying for 7-14 cycles to break the stony endocarp.
• ETP/stump planting - one-year nursery plant with shoot and root cut back; standard for teak and poplar.
• Coppice rotation - eucalyptus and casuarina regrow from stools; usually two coppice crops before replanting.
• Root suckers - shisham's main natural regeneration mode on alluvium.
• Frankia - actinomycete fixing nitrogen in casuarina root nodules (rhizobia fix in acacias and *Dalbergia*).
• Haustoria - sandalwood's parasitic root connections to hosts; spike disease is phytoplasma-caused and incurable.
• Rill method with CHIR - improved chir pine resin tapping, higher yield and less tree damage than the blaze method.
• Rotation of maximum volume production - the age of maximum MAI, where the falling CAI crosses and drops below MAI (CAI = MAI at that age).
• Site quality class - site productivity read from a yield table using top height at a reference age.
• Bamboo on non-forest land - excluded from the definition of "tree" by the Indian Forest (Amendment) Act, 2017.
• Compensatory afforestation - mandatory for forest-land diversion under the Van (Sanrakshan Evam Samvardhan) Adhiniyam, 1980, funded via CAMPA.
• TOF (trees outside forests) - farm and homestead trees that supply most of India's industrial wood, measured by FSI in the ISFR.

Formulas and examples

Example 1 - teak spacing, survival and thinning. Teak planted at 2 × 2 m on 4 ha.

• N per ha = 10,000 / (2 × 2) = 2,500/ha; total = 2,500 × 4 = 10,000 plants.
• First-year survival 88% → 8,800 alive; casualty replacement needed = 10,000 − 8,800 = 1,200 plants.
• Mechanical thinning at year 5 removing every alternate row (50%) leaves 1,250/ha; a second thinning at year 10 at 40% leaves 1,250 × 0.60 = 750/ha.

Example 2 - nursery seed requirement. 20,000 teak plantable seedlings are needed; past records show plant percent 35% and about 1,500 fruits/kg.

• Fruits to sow = 20,000 / 0.35 = 57,143 fruits.
• Weight = 57,143 / 1,500 ≈ 38 kg of teak fruit (add ~10% margin → about 42 kg). Seeds per kg varies widely with provenance, so always use the local seed-source figure.

Example 3 - single-tree volume, form factor versus quarter girth. A teak tree has DBH 45 cm and bole height 22 m, form factor 0.5.

• BA = π × 0.45² / 4 = 3.1416 × 0.2025 / 4 = 0.1590 m².
• V = 0.1590 × 22 × 0.5 = 1.75 m³ (true volume).
• By Hoppus with girth = π × 0.45 = 1.4137 m: (1.4137/4)² × 22 = 0.3534² × 22 = 0.1249 × 22 = 2.75 m³ - this is 78.5% of the full cylinder (3.50 m³), the classical 21.5% under-measure that customary timber trade accepts.

Example 4 - clonal eucalyptus yield and farm return. Clonal eucalyptus at 2.5 × 2.5 m, survival 90%, mean tree volume 0.090 m³ at 7 years, wood density 0.65 t/m³, mill gate price ₹4,500/t.

• N = 10,000 / 6.25 = 1,600/ha; surviving = 1,600 × 0.90 = 1,440 trees/ha.
• Volume = 1,440 × 0.090 = 129.6 m³/ha; MAI = 129.6 / 7 = 18.5 m³/ha/yr.
• Weight = 129.6 × 0.65 = 84.2 t/ha; gross revenue = 84.2 × 4,500 ≈ ₹3.79 lakh/ha over 7 years (before establishment, harvesting and transport costs; prices are indicative and move with the pulp market).

Example 5 - rotation of maximum volume production (teak, quality II).

• MAI is highest at 50 years (5.80) and the falling CAI crosses it just after, so the rotation of maximum volume production is about 50 years; a timber rotation would be longer because girth and heartwood quality, not volume, set the felling age.

Where it is used

• State Forest Departments and FDCs: writing and executing working plans, plantation journals, thinning and felling prescriptions, resin and NTFP leases, CAMPA plantations.
• Pulp, paper and panel industry farm forestry: ITC-PSPD and JK Paper clonal eucalyptus and subabul in Andhra/Telangana, Greenply and Century Plyboards poplar and melia supply chains, matchwood for WIMCO in Haryana-UP.
• Agroforestry and extension: poplar-wheat and eucalyptus-bund systems in Punjab, Haryana and UP; casuarina on the Coromandel coast; melia and sandalwood in Karnataka and Tamil Nadu farms.
• Research and tree improvement: ICFRE institutes (FRI, IFGTB, IWST, TFRI, AFRI) on provenance trials, clonal multiplication, spike and wilt management.
• Job roles: IFS and state forest officers, range officers and foresters, plantation and nursery managers, farm-forestry extension officers, forest certification auditors (FSC/PEFC group certification of farm woodlots), carbon-project MRV staff.
• Carbon and restoration projects: species selection and MAI estimates for Green India Mission, Nagar Van and corporate afforestation under CSR.

Interview questions

• Q: Why is teak seed given alternate wetting and drying? A: The drupe has a hard, stony endocarp; repeated swelling and shrinking cracks it and raises germination, which is otherwise low and spread over months.
• Q: What exactly is the sal regeneration problem? A: Sal produces abundant seed and seedlings, but the seedlings die back repeatedly from weed competition, drought, fire, frost and grazing, so recruitment to the pole stage fails; the cure is weeding, soil working, protection and phased canopy opening.
• Q: Why is deodar regenerated under a shelterwood system while chir pine is clear-felled? A: Deodar seedlings tolerate and even need some overhead shade, whereas chir pine is a strong light demander that establishes best in full light.
• Q: How does sandalwood get its nutrition? A: It is a root hemiparasite - it photosynthesises but draws water and minerals from host roots through haustoria, so pot and field hosts are essential.
• Q: What is the rill method with CHIR? A: An improved chir pine resin-tapping technique using shallow rills with an acid stimulant paste; it yields more resin and causes much less stem damage than the old blaze/cup-and-lip method.
• Q: Is a felling permit needed for bamboo grown on a farm? A: No - the Indian Forest (Amendment) Act, 2017 removed bamboo on non-forest land from the definition of "tree"; bamboo on forest land is still regulated.
• Q: Why is poplar planted as ETP in January-February? A: It is deciduous and leafless then, so a one-year-old entire transplant can be lifted and planted with minimum transpiration stress and flushes with the spring.
• Q: What causes shisham mortality in Punjab and Haryana? A: Dieback and wilt associated with *Fusarium solani* and *Ganoderma*, aggravated by waterlogging and planting in irrigated field conditions.
• Q: Which nitrogen-fixing symbiont does casuarina have? A: *Frankia*, an actinomycete - unlike legumes such as *Acacia* and *Dalbergia*, which host rhizobia.
• Q: How do you decide the rotation of a eucalyptus pulpwood plantation? A: Economically - the age that maximises net present value or MAI in the mill's wood-supply plan, typically 5-8 years, with coppice crops following rather than the much longer timber rotation.
• Q: Why does the timber trade's quarter-girth measurement differ from cubic volume? A: Hoppus measure uses (girth/4)² × length, which gives about 78.5% of the true cylindrical volume, allowing roughly for slabbing waste in squaring a round log.
• Q: A proposal needs 10 ha of reserved forest for a road. What silvicultural obligation follows? A: Approval under the Van (Sanrakshan Evam Samvardhan) Adhiniyam, 1980 with compensatory afforestation (and NPV) deposited through CAMPA, and a plantation plan with species, spacing and maintenance schedule.

Common mistakes

• Treating teak as site-indifferent - it fails on waterlogged, acidic and shallow soils even if rainfall is adequate.
• Calling sal a pure shade bearer or a pure light demander; its requirement changes with age, which is the whole basis of its regeneration prescription.
• Dividing spacing wrongly: forgetting that N = 10,000/(a × b) and quoting plants per acre as plants per hectare.
• Mixing up form-factor volume with Hoppus volume, or applying a bole form factor to total tree volume.
• Prescribing a coppice rotation for species that do not coppice (deodar, chir pine and most conifers).
• Storing sal or neem seed like teak seed - both are short-lived and must be sown fresh.
• Planting sandalwood without hosts, or expecting harvestable heartwood in under 10-12 years.
• Quoting old felling and transit exemptions as current - these are state rules that change; verify the state notification before advising.

Related topics

Silviculture: principles and practices · Forest nursery and plantation forestry · Tree improvement and forest genetics · Plant taxonomy · Ecology and ecosystems · Forest mensuration and working plans.