Pinus merkusii Jungh. & de Vriese

Pinaceae

Distributed in Sumatera and the Philippines where over-exploitation, habitat degradation and overgrazing has caused fragmentation.

Description

Taxonomic Notes

In this assessment Pinus merkusii is regarded as endemic to Sumatera and the Philippines: populations on the Indochinese mainland are assigned to Pinus latteri Mason. The differences between the two taxa primarily involve a grass-like stage in the mainland subpopulations that is absent in the insular populations.

Distribution

Distributed in Indonesia (Sumatera) and Philippines.
Indonesia: restricted to Sumatera where there are three subpopulations: Aceh, Tapanuli and Kerinici. The largest is in Aceh in the north. In the 1960s it was estimated to cover an area of about 200,000ha: this has since declined due to logging and forest conversion (Hardayanto, 2001, Siregar & Hattemer, 1999). The Tapanuli subpopulation covered about 3500ha in the early 1990s. It too has significantly declined due to logging. The Kerinici subpopulation is estimated to cover less than 500ha. Each subpopulation is now severely fragmented (Hardayanto, 2001). The total current area of occupancy is less than 130,000ha (Siregar & Hattemer, 1999).
Philippines: it is restricted to Paragpagan/Kabilayan Barangay Pinagturilan, Sta. Cruz, Occidental Mindoro and Sta Cruz, Masinloc, Candelaria, Zambales. Both localites are small and degraded (Razal, 2005)

Habitat and Ecology

Pinus merkusii occurs in mountainous regions and forms more or less open pine woods or pine savannas influenced by periodic grass fires. This ecosystem is much influenced by man and may even have been created by people over thousands of years of occupation. In Sumatera, this is the only pine that crosses the equator into the southern hemisphere. The altitude range, 300 - 1300 meters, is from herbarium specimen labels and may be incomplete. It should be considered indicative only.

Human Uses

Merkus pine has been extensively planted throughout Indonesia (where it is only indigenous in northern Sumatera) by the Dutch in colonial times. Indonesian foresters have continued this practice as it is the country's most important producer of pine resin. Young planted trees are better for tapping than 'old growth' trees in natural stands. Indonesia is a major producer of turpentines distilled from this resin. In the Philippines, this species is tapped together with P. kesiya, which is indigenous on these islands, but not in Indonesia. When trees have grown beyond good yield of resin, their wood is harvested for the pulp industry to manufacture paper, a process which allows final extraction of the resin in the wood. If well managed, these plantations are a renewable resource and can assist in the preservation of the natural stands of P. merkusii. The wood of higher grade is also used in house construction, panelling and furniture making.

Conservation Status

Global status and rationale

Vulnerable B2ab(ii,iii,v)

Although the rate of decline past and present is unknown, continued exploitation of natural stands and deforestation in the Philippines and Indonesia are putting this species at risk. It is unknown to what extent natural stands are being replaced by pine plantations, if this occurs even with the same species it cannot substitute for natural pine forest. The extent of occurrence (EOO) is beyond a threatened category mainly due to the disparate distribution. However the area of occupancy is estimated to be less than 2000km². Subpopulations are severely fragemented and there is an ongoing decline due to deforestation and logging. On this basis, Pinus merkusii is assessed as Vulnerable under the B2 criteria.

Global threats

Throughout its range, Pinus merkusii is threatened by over-exploitation, habitat degradation and an increase in the frequency of fires. On Mindoro in the Philippines, mining is an additional threat (Razal, 2005). Around Lake Toba in northern Sumatera historical decline has fragmented the population and exploitation has progressed to the northeast from there. In the Philippines the much smaller populations are now also fragmented.

Conservation Actions

In the Philippines this species is recorded from at least one protected area (Mt Paragpagan Forest Reserve) while in Sumatera it is recorded from several protected areas such as Dolok Saut Nature Reserve and Kerinci National Park. Ex-situ collections have been established that represent the Sumateran provenances.