Type A: Parashorea malaanonan Forest

 

The following is an excerpt of JED Fox's PhD thesis. The article stays fairly true to the original with minor changes. Most measurements are changed to the Metric System.

Quick Jump    Mt. Silam    Lormalong    Timbun Mata    Mull Hill    Silabukan FR    Banggi Is    Last words

 

Coastal areas of Darvel Bay contained a high proportion of this species with few other trees growing as emergents. The Mostyn area, cleared in the early 1950s for the establishment of oil palm plantations, where porous loamy soils are developed on volcanic basalt lava, had a timber stand exceeding 2000 cu. ft/acre (130 cu. m/ha) with 80% being P. malaanonan (FDAR 1952). Further north on hilly ground in the Silam area with soils derived from the Basement Complex, coastal areas yielded 9098% of the type species (Walton 1955).

 

The Forest in Mt. Silam, Lahad Datu

Stocking data for plots totalling 3.4 acre (1.4 ha) enumerated from 12 ins girth (10 cm diam) in the Silam area showed that P. malaanonan the most abundant large tree with 38% of trees over 6 ft and 54% of those over 9 ft. girth. Other emergent species are typically Shorea guiso (SB) and Hopea sangal (though this species is often small) with the Rubroshorea species such as S. leprosula, S. parvifolia and S. johorensis.

 

Eusideroxylon zwageri is absent in the Silam area and the most common species of the main canopy are Hopea sangal, Cynometra elmeri, small trees of the emergent species, large Diospyros spp., Eugenia [Syzygium] spp., Meiogyne viragata, Sympetalandra borneensis, and Dialium platysepalum. In the lower canopies, the genus Diospyros is well represented, and Aglaia, Dillenia, Hydnocarpus, Meiogyne, Paranephelium, and Teijsmanniodendron are also frequent.  Individual large trees occur of 912 ft girth (90120 cm diameter) and 160 ft (50 m) or more in height. Dryobalanops lanceolata, Dipterocarpus spp. and Koompassia excelsa are scarce.

 

The unfelled forest just above the sea at Silam is almost pure S. guiso  as are some of the other Darvel Bay areas [see also here].

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The Forest at Lormalong Settlement Scheme, Mostyn, Kunak

The Lormalong Settlement Scheme near Mostyn where the chert spilite is adjacent to basalt carried a similar forest on low lying land with P. malaanonan, S. guiso, and H. sangal. Other large tree species in this area were the dipterocarpsS. parvifolia, S. leprosula, S. seminis (SB), H. nervosa, also Barringtonia anacardifolia, Eniscosanthum grandifolium, Alangium griffithii and Plachonia valida. The lower Tingkayu River area, passing through the Chert Spilite Formation and felled over in late 1960s had - in addition to P. malaanonan - S. argentifolia, S. seminis, D. caudiferus and Koordersiodendron pinnatum, Dracontomelon puberulum and Planchonia. Higher up the Tingkayu on the alluvium, Eusideroxylon zwageri was a constituent of an essentially similar forest with the following other non-dipterocarps as trees of the main canopy: Ganua kingii, Irvingia malayana, Castanopsis sp., Beilschmiedia tawahense and Mallotus penangensis.

 

Plots laid down in the Mostyn area on different soils (A.R.R.B. 1960) showed that there were few specific differences but Dipterocarpus was absent on the volcanic soil. More details work on the only remaining forest on basalt (Madai FR) in the are showed the preponderance of Parashorea malaanonan. A relascope survey of 158 acres (64 ha) gave a total basal area as 139 sq. ft./acre with stem 5.8 stems over 8 ft girth of basal area 53 sq.ft.  P. malaanonan comprised 31% of all stems and 62% of those over 8 ft girth gave the following stocking values for stems over 12 ins. girth.

 

A complete stand table for 2 plots totalling 5 acres (2 ha) of this forest showed that, as on the Chert Spilite, Eusideroxylon is absent and Dr. lanceolata occurs mainly as smaller trees. Shorea pauciflora, at least locally, is the commonest emergent associate of P. malaanonan.

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The Forest of Timbun Mata Island

The forest of Timbun Mata Island on Chert Spilite Formation also belong mainly to this type. P. malaanonan is locally gregarious on steep slopes with S. guiso, Cynometra elmeri, Pterocymbium tinctorum and Pterospermum stapfianum (the two latter seral species suggesting frequent windfalls), also with palms and liana abundant. On less steep slopes, though still the predominant species, P. malaanonan is found in association with Rubroshorea species S. johorensis, S. leprosula, S. smithiana, and S. ovalis and, infrequently Dr. lanceolata and D. caudiferus. Local occurrence of Drypetes /Cynometra /Dialium on dry, rounded hills with P. malaanonan absent may represent late secondary forest following fire. Diospyros macrophylla is the commonest species of the genus on Timbun Mata, and in the Darvel Bay area generally where perhaps the genus reaches its greatest abundance in both species and density in Sabah. This species was one of the most abundant species of non-dipterocarps recorded in RP 233 at Silam, which covered 30 acres (12 ha) along with Koordensiodendron pinnatum, Phoebe macrophylla, Nephelium mutabile, Neonauclea bernardoi, Lophopetalum javanicum and Dillenia excelsa.

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The Forest of Mull Hill, Tawau

The olivine basalts of the Tawau area have different types, e.g. Type C on the flatter areas, Type E on steep slopes marginal with Type F. All are deficient in Dipterocarpus however, and in this respect similar to the Madai forests. In contrast the forest on Mull Hill, a basic intrusion in the Tawau area, is floristically similar to Madai basalt.  

P. malaanonan  and S. pauciflora  are the commonest larger species, S. guiso,  and Drypetes kikir (cf Drypetes on Timbun Mata), are present and nearby are Scaphium longipetiolatum, Shorea symingtonii (An) and  S. superba (SB).

 

Data from 4 plots of 1 acre (1.6 ha) for the forest at Tangah Nipah, east of Lahad Datu on the Tabanak Conglomerate Formation, showed that the genera  Dipterocarpus, Dryobalanops  and Eusideroxylon were all absent in this area where Shorea guiso, Cynometra elmeri, Koordersiodendron pinnatum and Sympetalandra borneensis  were present as associates of P. malaanonan,  with several Rubroshorea species present, including S. argentifolia locally abundant. North of Lahad Datu, across the Segama River, on Labang Formation, Type A merges with Type B. In the area felled 196768 by Timber Producers of Sabah part contained Type A species. P. malaanonan, Hopea sangal, Cynometra elmeri, and P. tomentella, Eusideroxylon zwageri, Dryobalanops lanceolata with Dipterocarpus spp. occurred in another part.

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The Forest in Silabukan FR, Lahad Datu

Further east of Lahad Datu in Silabukan FR, the P. malaanonan type is represented in the Bakapit Catchment area. A relascope survey in Block 11 covering 173 acres (70 ha) of V.J.R. No. 14 (A.R.R.B. 1964) gave total basal area over 12 ins as 119 sq. ft/acre with 3.5 stems over 8 ft. girth of basal area 29 sq. ft. The geology of this area is rather mixed being described as the Tungku Formation, with P. malaanonan  forests occurring on volcanic breccia. P. malaanonan  does not occurs on the carbonaceous sandstones and clays with conglomerates, further east and north in Silabukan FR, while in the hills of the Bagahak Range, Type E is predominant. Type A reappears on Togopoi Formation at the end of the Dent Peninsula.

 

East of Silabukan FR coastal forests on podsols at Sabahat are similar to, but taller than, those on ultrabasic at Malawali Island with presence of the Anthoshorea species S. bracteolata and S. gratissima. These are similar to forests in coastal Pahang described by Beveridge (1953). They occur as emergents to 30 m above a low scrub tangle on white sands just behind the Casuarina equisetifolia fringe at Sabahat, whereas on Malawali they found on slopes (where Gymnostoma nobile is absent) with Eugenia (Syzygium) alcine in a low forest to 20 m. Shorea bracteolata is also present elsewhere on the northern islands under Gymnostoma with Callophyllum obliquinervium, Santiria laevigata, Eugenia (Syzygium) and Tristania (Tristaniopsis).

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The Forest in Banggi Island

The lowland forest on Banggi Island has affinities with Darvel Bay P. malaanonan forest. This species and S. guiso, Hopea sangal and Koordersiodendron pinnatum are all present, but the most characteristic tree is Dipterocarpus warburgii (elsewhere a tree of riverine swamps, see here), and D. gracilis is also common. Coastal limestone forests also have affinities (see here). One further forest requiring mention is the coastal association at Kampong Sibumbong, Banggi Island, of S. guiso, S. bracteolata, Cynometra elmeri, Koordersiodendron pinnatum, Dipterocarpus gracilis and Semeocarpus sp. as large trees. This merges inland with an ultrabasic forests with dipterocarps Cotylelobium melanoxylon, Vatica papuana and V. umbonata present as small trees under an emergent canopy of Gymnostoma nobile.  

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Last words

The P. malaanonan type of dipterocarp forest is probably the most commercially valuable. The main areas of managed forest containing this type are parts of Silabukan FR, Silam Extension and Ulu Segama FR and parts of Tingkayu FR. The main occurrence is coastal and is association with comparatively good soils and low rainfall.

 

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