Inventory parameters 1 Introduction

Quantification and enumeration of non-timber forests is not as straightforward as measuring the diameter, and then calculating the basal area of tree species (Philip,

1994). With non-timber products, in order to develop sustainable harvesting regimes, it is essential that the correct parameters are determined prior to the commencement of

an inventory or survey. These parameters depend on the life form of the plant as well as the plant part harvested. This is discussed in more detail by Peters (1996; 1999).

3.2.2.2 Taxonomy

It is essential to know which species are being enumerated and, in conjunction with studies of economic and ethnobotany, which species have potential utility. Without reference to a sound taxonomic base, an accurate assessment of the resource being enumerated is not possible. Where there is doubt surrounding the identification of a species, voucher specimens should be taken. This process need not be undertaken for each individual within a sample area, but representative samples can be taken for “morpho-species” (de Walt et al., 1999)’. In addition to providing crucial information about the resource base, knowledge of the taxonomy of the species concerned also provides invaluable information with regard to the relationship between the rattan flora and the wider vegetation.

A number of previous inventories in Africa that have included rattan have been somewhat constrained by a poor understanding of the taxonomic base (CRSFP, 1994; Wong, 1997), or have relied on local nomenclature that is not always congruent with western taxonomy (van Dijk, 1995; van Dijk, 1999). Unfortunately, in such cases the lack of a rigorous baseline reference means that such surveys have little application for the coherent management of the rattan resource.

3.2.2.3 Stem length vs harvestable length

Stem length, as well as the number of stems per unit area, are the most crucial

parameter for determining potential yield in rattans. However, there is some difference between total stem length and harvestable stem length (Bogh, 1996; Sunderland and Dransfield, in press). Rattan stems selected for harvesting are those mature stems without the lower leaves (i.e. where the leaf sheaths have sloughed off). It is usual that only the basal 10-20m is harvested. The upper “green” part of the cane is too soft and inflexible for transformation and is often left in the canopy. Hence, to ascertain the

' Individuals clearly o f the same (albeit unidentified) species within the sample area. Only a single representative voucher o f such taxa needs to be made.

true yield per hectare of a species, both total and harvestable stem lengths must be measured.

As Peters (1996) rightly points out, however, accurately measuring the length of a rattan stem that can climb up to 150m into the forest canopy is fraught with logistical problems. Actual measurement of stem length is almost impossible and “rough estimation” does not provide the accuracy required for inventory purposes (Nur supardi et a l, 1996). Shim (1989) and Lee (1993), in their studies of Calamus in Asia, found that the intemode length for most species of rattan is relatively constant. By calculating the mean internode length and multiplying by the number of intemodes on each stem, it is possible to determine the total stem length in a manner that is

relatively accurate.

Unfortunately, the mature (and harvestable) cane length is devoid of leaves and hence internodes, and cannot be measured in this way. However, as this represents the proximal portion of the stem, this portion can be more accurately measured by more conventional means such as with a tape or a calibrated stick. In applying a

combination of these two methods of stem measurement,proviëes-an extremely accurate means of determining stem length can be achieved.

3.2.2.4 Plot shape and size

Considerable discussion has surrounded the determination of plot shape and size with regard to forest mensuration and these have been reviewed in the rattan context by Stockdale and Wright (1994) and Nur Supardi (1999) and the wider NTFP context, including rattan, by Peters (1996). Stockdale and Wright (1994) conclude that

rectangular plots, oriented parallel to the direction of the slope, are more cost efficient, and within the desired level of precision, than square plots. However, Peters (1996) concluded that rectangular enumeration plots are prone to errors in boundary identification and area estimation, and advocates the use of square, or circular, research plots for NTFPs.

Beyond the fact that larger individual organisms require larger sample plots, there are, in general few guidelines that govern the selection of an appropriate plot size for

vegetation sampling. In the case of rattans, quite large sample sizes are needed if clustering species are to be included in the sample. Nur Supardi (1999) found that large, square plots were most effective at capturing not only the larger clustering individuals, but also up to 80% of the rattan species present within the sample area.

Bogh (1996) also found that lha square plots were sufficiently large enough to capture these large clustering individuals and provide a representative sample of the rattan flora of the area in Thailand he was studying. This lha square plot methodology has been widely implemented for many resource surveys and, if sited correctly, can

provide a representative and reasonably homogenous sample of variation in forest type (Boom, 1987; Prance et aL, 1987; Philips and Gentry, 1993; Philips et al., 1994; Wong, 1997; Graham et al., 1998; de Walt et al\ 1999; Sunderland and Comiskey, 2000). In this respect, such lha plots, when permanently demarcated, are also recommended as being suitable for long-term monitoring o f vegetation (Alder and Synnot, 1992).

For the purposes of this study, a series of lha permanent sample plots (PSPs) were established in three protected areas in Cameroon with the intention that they are permanently demarcated for long-term research. Aside from the initial baseline measurement, which is presented here, these plots will be monitored on a regular basis, which will allow, over time, the calculation of growth rates, mortality and recruitment. This, in turn, will enable the potential harvest, and sustainable extraction rates to be established for each species within the sample sites.

3 .3 . Re s e a r c h Sit e s

Three diverse protected areas, the Campo Ma’an Faunal Reserve, the Mokoko River Forest Reserve and the Takamanda Forest Reserve, were chosen for this survey. Site selection was based on known diversity and climatic variation (based on a review o f previous studies) and with regard to logistical feasibility. These sites were enumerated from February to April 1997 (Campo); October to December 1998 (Takamanda) and January to February 1999 (Mokoko).

F ig ure 81. M a p o f C a m e r o o n sh o w in g prote cted areas; the stu d y sites are h ighlig hted. M od ified from G a rtla n , 1989).

120 Km

Tchobal M babo R eserve forestière

be- to Rivtére -Ma wne R eserve fo re stiè re be Tal(amQnbQ ffé s e rv e forestière f^Wku Parc fJ a fm a l be f\/lbam e t D ierem be N fa Ati R eserve forestière b 'E ja g h o m P. N. be Korup I

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R éserve be Faune be Campo

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Forêt bu Lac L o b éké

3.3.1 Campo Ma^an Faunal Reserve

3.3.1.1 Introduction

The Cam po M a 'a n Faunal Reserve (2 °0 9 ’-2°53’N; 9°4 8 ’-1 0 °2 5 ’E) w as created by decree on the 19th N ovem ber 1932 and is situated in the South Province o f C am eroon (G artlan, 1989). The Reserve covers an area o f 271,160 ha and is bordered to the north by the Lobé R iver, to the south by the N tem River, w hich also m arks the political border w ith Equatorial G uinea, to the w est by the A tlantic O cean and to the east by the

3.3.1.2 Climate

The Campo Reserve has a typical equatorial climate with four distinct seasons: a long dry season from November to February, a mini rainy season from March to May, a shorter dry period from June to August followed by a protracted period of rain from mid-August to November. The average annual rainfall is 2,820mm and the mean annual temperature is 26.8°C.

3.3.1.3 Topography, geology and soil type

The Reserve is situated on inferior pre-Cambrian formations with varying relief. In the west of the area, the topography is relatively and consistently plain-like except for the Massif des Mamelles, which rises to 323m altitude. The east of the Reserve however, is quite mountainous with altitudes varying between 400-95Om. Mount Nkolenengue, at 969m, is the highest point in the Reserve (Thomas and Thomas, 1992).

The parent rock of the area is made up of micaschists, superior and inferior gneiss and undifferentiated gneiss. There are essentially two types of soil, ferric soils and

hydromorphic soils. The ferric soils are somewhat yellow in colour and are derived from the metamorphic rocks characteristic of the coastal plain. The hydromorphic soils develop in a distinct layer near to the soil surface in area of swamp and seasonal inundation.

3.3.1.4 Vegetation

The vegetation of the Campo region is defined by Letouzey (1985) as Atlantic Biafran forest rich in Caesalpiniaceae^. This vegetation type is widespread within 100km of the coast, from Nigeria to Equatorial Guinea. Campo is rich in Caesalpiniaceae; there are large numbers of individuals, high dominance and high levels o f diversity of this family. Although Letouzey (1985) described a single vegetation type covering the whole range, there is considerable variation in dominant species and species composition between localities, there are several sub-types in the area. These are characterised by indicator species such as Sacoglottis gabonensis (Humeriaceae) and Calpocalyx heitzii (Mimosaceae) (Sunderland et al., 1997).

^ I have maintained the continental nomenclature o f the Leguminosae, where the three sub-fam ilies are accorded family status, throughout this Chapter.

The vegetation of the sample sites and the surrounding area is classified as Atlantic Evergreen Biafran Forest with Caesalpiniaceae and Calpocalyx heitzii (Letouzey,

1985). This forest type covers a large area of the south of Cameroon and the northern regions of Equatorial Guinea. Unlike many areas within Cameroon, this forest

formation is somewhat unique in its homogeneity and is representative of a large forested area from southern Cameroon to northern Equatorial Guinea.

Along with numerous members of the Caesalpiniaceae, the characteristic species of this forest formation are Anthonotha macrophylla (Papillionaceae), Coula edulis (Olacaceae), Glossocalyx brevipes (Monimiaceae) Lophira alata (Ochnaceae) and Scyphocephalium mannii (Myristicaeae) Other indicator species are Hoplestigma klaineanum (Hoplestigmataceae), the abundant understorey tree Meiocarpidium lepidotum (Annonaceae) and Podococcus barteri, a slender understorey palm that forms dense, often monospecific, stands.

3.3.1.5 Forest exploitation

This forest type is highly prized for its timber resources and as such, is heavily logged, even within the boundaries of the Reserve. Hence, a substantial proportion of the study area supports an intricate mosaic of secondary regrowth vegetation. Non-timber forest products are also exploited, particularly for primary health care on which the majority of the local population relies, in the absence of formal medical services. Rattan is not harvested at levels beyond immediate household requirements.

3,3.2 Mokoko River Forest Reserve 3.3.2.1. Introduction

The Mokoko River Forest Reserve (4°2r-4°28’N; 8°59’-9°07’E) covers an area of 9,100ha and is situated to the north-west of the Bambuko Forest Reserve. The reserve is bordered to the south-east by the Onge River, to the north-east by the Meme River estuary, to the north by the Mokoko River and to the west by the River Boaba. The Mokoko FR was created in 1952 as a production forest and this legal status has remained unchanged by the successive Forestry Laws of 1983 and 1994. Currently, the

reserve has no management plan (Thomas, 1994; ERM, 1998; Sunderland and Tchouto, 1999).

33.2.2 Climate

Annual precipitation on the Western flank of Mount Cameroon varies between 3,000mm and 4,000mm and declines further east of Mokoko in a rain shadow caused by the Mount Cameroon massif. There is a single rainy season between March and October. December, January and February are all relatively dry months, often with no rain falling at all. The annual mean temperature is 27°C.

3.3.2.3 Topography, geology and soil type

The Mokoko FR is situated at an altitude between 120 to 360m, on the north west inferior slope of Mount Cameroon. The majority of the reserve is seated on ancient volcanic rocks, basalts and trachites. Nearer the sea, there are small areas o f more recent alluvial deposits. The soils that predominate within the reserve have been formed by an association between ancient and recent volcanic material with a small area of non-volcanic sedimentary sandstone-derived soil nearer to the Boa Plain (ERM, 1998).

3.3.2.4 Vegetation

The majority of the lowland forests in the hinterland of Mount Cameroon have been converted to industrial plantations, and the forests of the Mokoko area currently constitute the only pristine and most extensive forest formation in the region. As such, they are extremely important, both in terms of biodiversity value (Cable and Cheek,

1998) and for indigenous use and management (Sharpe, 1998; Sunderland and Tchouto, 1999).

The vegetation of the Mokoko Reserve was originally described by Letouzey (1985) as being of the “Atlantic Biafran evergreen forest with numerous Caesalpiniaceae”

formation. Whilst this general description certainly encompasses the general physiognomy of the area, Letouzey's classification, at 1:500,000 scale with limited ground-truthing, does not allow for more subtle variations in vegetation that are characteristic of the forests around Moimt Cameroon. As such, subsequent field-work

and observations have built upon Letouzey’s original classification (Gartlan, 1989; Thomas, 1994).

Based on preliminary Mount Cameroon Project inventory results, Thomas (1994) suggests that the vegetation of Mokoko is comprised of two forest types that inter­ grade completely. To the south, where the rainfall is higher is what Letouzey (1985) described as Atlantic Biafran Forest with Caesalpiniaceae with Oubangia alata (Scytopetalaceae) and other coastal indicators such as Protomegabaria stapfiana (Euphorbiaceae), Dichostemma glaucescens (Euphorbiaceae), Octoknema affinis (Octoknemataceae), Tapura africana (Dichapetalaceae) and many members of the Olacaceae.

Moving progressively northwards, the coastal forest grades into Atlantic Biafran forest with Caesalpiniaceae well represented by gregarious genera such as Didelotia,

Hymenostegia afzelii, Microberlinia bisulcata, Monopetalanthus, Plagiosiphon and Tetraberlinia bifoliolata. The Myristicaceae are also an important component of this forest, represented in particular by Coelocaryon preussii, Scyphocephalium mannii and Staudtia stipitata. The narrow endemic Medusandra richardsiana

(Medusandraceae) along with Oubangia alata (Scytopetalaceae) dominate the understorey along with Garcinia mannii (Guttiferae) and Lasianthera africana

(Icacinaceae), the latter of which are both important NTFP resources. The genera Cola (Sterculiaceae) and Diospyros (Ebenaceae) are also important components of the lowland forests of northern Mokoko. Cable and Cheek (1998) suggest that the forest types found in the northern Mokoko area exhibits clear affinities with the southern Korup area and, to a lesser extent, to the forests immediately south of the Sanaga.

The vegetation was also described by Gartlan (1989) as having certain semi-

deciduous elements at its western edge. These latter elements originate from the rain shadow present to the north of Mount Cameroon which has species communities present more often associated to those of the drier, eastern parts of Cameroon such as

Triplochiton (Sterculiaceae) Ceiba (Bombacaceae) and many other representatives of the Meliaceae and Sterculiaceae. The presence of these species more commonly

associated with drier forest, was confirmed by an inventory undertaken by the Mount Cameroon Project (Thomas, 1994).

Another interesting component to the flora of the Mokoko area is the presence of the sub-Sahelian palm, Borassus aethiopum, which is at the southern-most edge of its range. These ^ora^^w^’-dominated savannahs occur on deep ash soils, and are a highly unusual formation in what is, essentially, a forest zone (Sunderland and Tchouto,

1999).

3.3.2.5 Forest exploitation

The exploitation levels of timber and non-timber forest products in Mokoko is high (Sunderland and Tchouto, 1999). There is a thriving Nigerian-led cross-border trade in a number of high-value forest products such as chewstick {Garcinia mannii),

“vegetable” {Lasisanthera africana and Gnetum spp.) and the cattle-stick {Massularia acuminata). Rattan is also widely exploited and exported.

3.3.3 Takamanda Forest Reserve