Looking at the levels of exploitation and regeneration potential of various species, some of the important timber species can be described to be under "threat" (see appendix 5). The major species under threat is Baikiaea plurijuga (mukusi). Although its population is still abundant (i.e. greater than 10 000 individuals), there is no successful regeneration taking place. The species takes about 100 years to grow to merchantable timber size but destruction through logging, fires and other damaging agents are taking a higher toll.
Assessments conducted in 1998 have shown a pathetic situation in some forest reserves of Baikiaea plurijuga in Sesheke and Senanga districts. For example, no seedlings were obtained in the Watembo Forest in Senanga on five plots which were established there. The plots were of 50 meters x 30 meters in size. Details of diameter distribution in each forest reserve assessed are shown in table 8.
TABLE 8: STOCKING AND DIAMETER DISTRIBUTION OF BAIKIAEA PLURIJUGA IN SIKUBINGWA, MALAVWE AND WATEMBO FOREST RESERVES
|
DBH* Class (cm) |
Stems per hectare |
||
|
Sikubingwa Forest reserve |
Malavwe Forest reserve |
Watembo Forest reserve |
|
|
Seedlings/saplings< 5.0 cm |
83 |
53 |
0 |
|
5.0 - 9.9 |
7 |
10 |
0 |
|
10.0 - 14.9 |
20 |
27 |
4 |
|
15.0 - 19.9 |
60 |
9 |
2 |
|
20.0 - 24.9 |
26 |
10 |
2 |
|
25.0 - 29.9 |
27 |
16 |
2 |
|
30.0 - 34.9 |
27 |
13 |
4 |
|
35.0 - 39.9 |
20 |
17 |
9 |
|
40.0 - 44.9 |
7 |
12 |
7 |
|
45.0 - 49.9 |
13 |
7 |
2 |
|
50.0 - 54.9 |
13 |
6 |
2 |
|
55.0 - 59.9 |
0 |
2 |
11 |
|
60.0 - 64.9 |
0 |
3 |
2 |
|
65.0 - 69.9 |
0 |
1 |
2 |
|
70.0 - 74.9 |
0 |
1 |
0 |
|
75.0 - 79.9 |
0 |
0 |
2 |
|
Total (excluding seedlings) |
220 |
143 |
51 |
|
Merchantable stems (30 cm DBH*) |
80 |
62 |
41 |
* DBH: Diameter Breast HeightPterocarpus angolensis (mukwa) is another species which is under threat due to the high demand for its timber. Although, its population is still high, it is being reduced at a very fast rate. Assessments conducted in 1996 in a heavily exploited area and a partially exploited area rich in Pterocarpus angolensis showed that nearly all the big trees were removed in Lualaba National Forest without leaving seed trees. Most of the stumps were killed by fire or got rotten, hence very little regeneration was observed. Details of the diameter distribution are given in table 9.
TABLE 9: STOCKING AND DIAMETER DISTRIBUTION OF PTEROCARPUS ANGOLENSIS IN LUALABA NATIONAL FOREST AND PETAUKE LOCAL FOREST
|
DBH* Classes (cm) |
Stems per hectare |
|
|
Lualaba national forest (heavily exploited) |
Petauke local forest (partially exploited) |
|
|
Seedlings/saplings, < 5.0 cm |
12 |
1 |
|
5.0 - 9.9 |
14 |
0 |
|
10.0 - 14.9 |
7 |
1 |
|
15.0 - 19.9 |
2 |
0 |
|
20.0 - 24.9 |
2 |
5 |
|
25.0 - 29.9 |
0 |
7 |
|
30.0 - 34.9 |
1 |
11 |
|
35.0 - 39.9 |
0 |
10 |
|
40.0 - 44.9 |
1 |
13 |
|
45.0 - 49.9 |
0 |
10 |
|
50.0 - 54.9 |
0 |
6 |
|
55.0 - 59.9 |
0 |
5 |
|
60.0 - 64.9 |
0 |
7 |
|
65.0 - 69.9 |
0 |
6 |
|
70.0 - 74.9 |
0 |
0 |
|
75.0 - 79.9 |
0 |
2 |
|
Total (excluding seedlings) |
27 |
83 |
|
Merchantable stems (30 cm DBH*) |
2 |
70 |
* DBH: Diameter Breast HeightThe other threatened species is Dalbergia melanoxylon because of its high demand for making carvings. The endangered species include Podocarpus milanjianus, which has been heavily exploited for making canoes, mortars and other hand tools, and Encepharlotos goetzi, which is now less than 100 individuals. The species has disappeared drastically because of its use as food and beverage. The other endangered species are Pancrantium triunthium and Oreobambos buchwaldi
