Bwa-yo - Société Audubon Haiti

114 Kasva
Table 14.1 Proximate analysis of S. siamea (% dry weight basis), after Gohl (1975).
COMPONENT CRODE CRODE CRODE CARBO- ASH Ca P
PROTEIN FIBER FAT HYDRATES
Leaves
Fresh twigs
16.8
20.0
19.8
l6.5
11.2
56
46.8
52.6
5.4
5.3 l.l4 Ol4
and cheap, this technique is not recommended.
The growing of seedlings in containerized systems, such as the Rootrainer and
Winstrip, has been the principal propagation method used for S. siamea since the 1970s.
Seed germination, following immersion in hot water and soaking for a couple of days,
ranges from 65-80%. As with other Senna species, S. siamea seedlings are sensitive to
overwatering and precautions are required in the preparation of the potting medium. It
is highly susceptible to leaf spot diseases, particularly Cercospora, requiring a regular
schedule of foliar fertilizer and fungicide treatments (Fig. 14.5). Runion et al. (1990)
indicate at least 8 genera of fungi causing leaf spot, a single genus (Colletotrichum)
associated with anthracnose, and a powdery mildew that Tourigny (1987) attributed to
Oidium (Fig. 14.6). It takes approximately 14 weeks to prepare seedlings for outplanting
with the initial 3 weeks under shade and the final 4 weeks hardening off (Josiah,
1989). Seedlings do not respond well to top-pruning.
The growing of root suckers and the transplanting of volunteers and stumps are
low-input methods that are sometimes used. Stumps are left to grow to a I cm root col··
lar diameter in a deeply-dug nursery
bed at 15 cm x IS cm, and are prepared
by pruning the shoot to 10 cm
and the roots to 25-30 cm (Geilfus,
1989).
Figure 14.5 Cercospora leaf-spot on S. siamea
seedling.
Biomass and Volume Studies:
Ehrlich (1985) developed biomass
and pole volume tables from a stand
located in Limbe. In 1990, an additional
set of regression equations was
analyzed in a biomass study conducted
at the CARE trial near Nan
Marron. The equations in Table 14.2
can be utilized Lo estimate biomass
components based on stem and tree
height measurements.
Growth Performance: The fastest
early growth rate that has been
observed for S. siamea is 3.2 m yr- I
during the first 2 years at Cazeau
(Fig. 14.7). This site is well-drained
with a deep sandy loam and approximately
1200 mm rainfall that is sup-