Management of teak plantations in Bhutan - Mr. Chimi Dorji

Chimi Dorji
Divisional Forest Officer, Samtse Division, Bhutan

Green fruits of teak.

ABSTRACT

Teak was introduced into Bhutan plantations in the 1950s, using Indian seed. One-year-old nursery seedlings are stumped and pit stored under shelter in dry sand. Stumps are planted in the pre-monsoon rains; stored stumped plants are preferred as they are still dormant at planting time. Plantations are established with 2.5 × 2.5 m spacings, mixed with other species to prevent soil erosion. Weeding is carried out when necessary and thinning at age 5-7 years when the trees are 7-10 m high. MAI volume production is high - 16.5 m³ in a 30-year-old plantation, and the rotation on good sites is likely to be 70-80 years. The current Indian market price for produce is US$595/m³. Future plantation prospects are good in degraded land through national restoration and reclamation plans. The re-afforestation plan components are: afforestation, enrichment planting, community planting and rehabilitation of critical watersheds. Constraints to expansion are: the lack of technically trained manpower and experience in raising teak, and managing plantations while illicit tree felling is attracted by the high value.

Key words: Tectona grandis, Bhutan, teak plantations, stump storage, value.

INTRODUCTION

Teak (Tectona grandis) is not indigenous to Bhutan. It was introduced to the country in the early 1950s in plantations, mainly concentrated in the south, bordering the Indian states of Assam and West Bengal.

STATUS OF TEAK PLANTATIONS

Early plantations were raised as monocultures. The sites were selected on flat and gentle slopes between 200-500 m above the sea level (a.s.l.). On steep terrain, teak was mixed with sal (Shorea robusta), Terminalia spp., and Duabanga spp., which are also light-demanding species. Teak monoculture is no longer practiced since it was observed in older plantations that pure teak suppresses nearly all undergrowth and causes soil erosion during the rainy season. Teak is now planted with mixtures of other species, which also helps to protect the fragile ecosystem of the Himalayan foothills.

NURSERY AND PLANTING

In the past, teak seed was procured from India and seedlings were raised in local nurseries with stumps generally prepared from one-year-old seedlings. Seedlings are uprooted from nursery beds in February-March and made into stumps with 2 cm of stem and 13-15 cm of root. All secondary roots are scraped from the taproot and the stumps kept humid under a thin layer of dry sand in sheds. Stumps are field planted in April-May, before the first rains. Stored stumps are found to give better results than freshly lifted nursery stumps as the stored stumps are still dormant when planted, whereas plants from nursery beds have already begun to sprout new leaves and shoots.

The best time for planting stumps is during the pre-monsoon rains when the soil is wet to about 20 cm. The stored stumps are generally planted before the pre-monsoon rains are expected. Delaying planting until July would mean the loss of the first year’s growth season. Pre-planting soil working is a simple process in which holes just large enough to take the stumps are made with crowbars. The soil must be well firmed around the stump to avoid direct rain water penetration as the stumps rot. The preferred planting space is 2.5 × 2.5 m.

TENDING AND THINNING

Teak can withstand a certain amount of grass and weed competition, but tending operations such as climber cutting are necessary to prevent bending of shoots for the first two years. Teak planted at 2.5 × 2.5m can be first thinned at age 5-7 years, when the trees are about 7-10 m tall. In the first thinning, alternate trees are removed; subsequent thinnings are carried out at about 5-year intervals in the initial plantation years, and thereafter intervals are extended to 10 years as the plantation matures.

VOLUME PRODUCTION

Bhutan teak plantations have not yet reached rotation and harvesting age. Enumerations of 30-year-old plantations provide the data in Table 1.

Table 1. Plantation standing values at age 30 years

This growth data is equivalent to ‘Quality II’ of the Indian Yield Table for teak and, accordingly, the plantation growth rate is considered satisfactory. The rotation age for timber production on good sites is likely to be between 70-80 years, but on poorer sites the rotation may be longer.

PROSPECTS FOR DEVELOPMENT OF TEAK PLANTATIONS

There are good prospects for the future development of teak plantations as a timber resource since the country has adequate degraded areas suitable for raising teak with other species. The existing natural forests are suffering under human pressure for fuelwood, fodder, and timber for construction. Bhutan has an estimated forest land area of 2.3 million ha, which constitutes more than 60% of the total land area below the forest limit. The annual rate of degradation is estimated at 0.5%, and some 0.1% of this falls in subtropical deciduous forest where teak can be planted. Because of increasing and conflicting demands for forest products, the country has pursued a policy of restoration and reclamation of degraded lands with re-afforestation and watershed development programmes, including community/private forestry, to maintain Bhutan’s forest cover on a sustainable basis. The following components of the re-afforestation programme have been implemented:

• Afforestation (normal plantations);

• Enrichment planting;

• Community / private forestry; and

• Rehabilitation of critical watersheds.

Teak is considered a promising species for private forestry, judging from its value in the local Indian market where it can fetch Indian Rs. 500 per cu. ft. or US$17 per cu. ft., which is equivalent to Rs.19,250 /m³ or US$595/m³.

PROBLEMS AND CONSTRAINTS IN THE MANAGEMENT OF EXISTING TEAK PLANTATIONS

The main constraint in the management of teak plantations is the lack of technically trained manpower. A social aspect is the illicit felling of teak because of the high value attached to the timber in the market. Lack of technical know-how and scarce in-country experience in raising and managing teak plantations are further limitations.