**1. Introduction**

The Elgon teak, *Olea welwitschii* (Knobl) Gilg. & Schelleneb is a canopy emergent tree in the family Oleacea [1]. This tree species is indigenous to sub-Saharan Africa ranging from Cameroon in the west to Ethiopia and Kenya in the east, and south to Angola, Zambia, and Mozambique [2]. It is typically a forest tree species, that grows from lowland tropical rainforests to evergreen montane forests [3]. The tree can grow to a height of 25 m with a straight bole and a small crown. It has a pale gray to white bark, that is grooved vertically. The flowers are small and white, in sprays to 8 cm long. The fruits are narrow, oval, and have small drupes. Its wood is extremely good, and stable with esthetic timber used in shipbuilding. It is also used to make fine furniture, door and window frames, and any other applications that require strong, durable, and stable wood. It is termite resistant and its branches are also used for firewood while its bark is medicinal. This species dominates the western Kenya forests, especially the Kakamega and Mt. Elgon forests. In these forests, *Olea welwitschii* does not show notable evidence of natural regeneration under the parent crowns [4]. This paper examines the factors that may be responsible for the lack of apparent natural regeneration in the Kakamega forest, Kenya.

The family Oleacea has been prized since the dawn of civilization. For instance, its most famous member, the olive (Olea Europa L.) was cultivated 3000 years B.C [5]. Today, in a large part of the world, the olive still represents life and plenty in the minds of men. The European ash (*Fraxinus excelsior*), another member of the Oleacea, was used by Greeks to make cupid bows. The most familiar members of the family are the jasmine species (*Jasminum* spp.) which have been favorites in home gardens for centuries [2].

Three Oleacea genera -*Schrebera*, *Olea,* and *Linociera*, occur in Africa [6]. Of these, *Olea* is by far the most common and widespread. In Kenya, it is represented by five species -*Olea africana* Milla, *Olea hochstetteri* Baker, the East African olive, *Olea kilimandscharica* Knobl, *Olea mildbraedii* (Gill & Schelleneb) and *Olea welwitschii*.

*Olea welwitschii* is typically a rainforest tree species endemic to Mt. Elgon [7, 8]. It also occurs in Kakamega, North, and South Nandi forests which appear to be its easternmost limit. Information on the pollination ecology of this species is scant. In Kakamega and the neighboring Kisere forests, Olea welwitschii is canopy dominant comprising some 7.5 and 49 percent respectively of the total volume of merchantable species [9]. Prior to 1966, this species comprised 69% of the total utilizable timber in the Kakamega forest and by 1980, this percentage had dropped to a mere 7.5% due to uncontrolled harvesting by commercial loggers.

In the Kakamega forest, it grows in localized patches of very few senescing adults -except for those in enrichment plantations. Kisere forest dominates the canopy but shows a skewed population distribution in the 500-ha forest [10]. For instance, it occurs in an almost pure stand in the south, east and north-eastern parts of this forest, and in neither forest does Olea welwitschii exhibit any apparent natural regeneration.

### **2. Study sites and methods**

#### **2.1 Study sites**

Three study sites were selected from different parts of the forest. Two sites were selected in the southern part of the forest while another site was in the northern part of the forest (**Figure 1**). Each of the three sites was contiguous with forest glades (grassy areas that are surrounded by forest). The northern study site was located in the Kisere forest which is part of the National Reserve and a long-time nature reserve. The southern study sites were located in the newly established Kakamega Forest National Reserve and at the Kakamega Forest Station. All three study sites had large mature *O. capensis* adults. The southern study sites have been logged selectively in the 1970s and early 1980s. During logging, many large *O. capensis* adults were selectively harvested [9].

*Regeneration Dynamics of an African Tropical Forest Canopy Dominant Tree Species DOI: http://dx.doi.org/10.5772/intechopen.110238*

**Figure 1.** *Map of the Kakamega forest complex. Source: [9].*
