Bwa-yo - Société Audubon Haiti

6 Bayawonn
Table 1.1 Proximate analysis (% dry weight) of P. juliflora, after Gohl(l975).
COMPONENT CRUDE CRUDE CRUDE CARBO- ASH Ca P
PROTEIN FIBER FAT HYDRATES
Fresh leaves (Sudan) 19.0 ' 21.6 2.9 48.0 8.5 2.1 0.2
Fresh flowers (Sudan) 21.0 15.5 3.2 50.3 10.0 1.0 0.4
Pods (South Africa) 13.9 27.7 3.0 50.6 4.8
Fruit pulp 7.7 12.0 0.6 77.4 2.3
Seed (Sudan) 65.2 2.8 7.8 19.0 5.2
Pod husks 4.3 54.3 0.6 37.4 3.4
15 cm x 30 cm, have been used successfully on an experimental basis in Haiti (Dupuis,
1986a; Lee et aI., 1992). The major drawback is the cost involved in preparing the deep
holes properly to avoid J-rooting. Furthermore, complete weed control one season prior
to field establishment is recommended to build up soil moisture reserves on arid sites.
No serious pests are associated with the species in containerized nurseries (Josiah,
1989). Two-year-old stumps, with basal diameters 1.5-2.5 cm and roots 25 cm long,
also have been used in aridzones (Lamprecht, 1989).
Vegetative methods for the species have been employed successfully in Haiti. A
solar-powered mist system to root cuttings was experimented at Thomazeau with over
90% rooting success (Wojtusik et aI., 1994). Grafting techniques have been successful
utilizing a cleft graft with scion material selected and transported from Haiti to Texas
(Wojtusik and Felker, 1993; Wojtusik et aI., 1993). The rootstock selected for grafting
was R alba because of its vigor and influence on scion growth under greenhouse conditions
in Texas. Five clones, selected for desirable traits, achieved a 100% success rate.
Biomass Studies: Regression equations were determined to estimate the amount of
total dry biomass, wood, and pole volume ofR juliflora as a function of stem diameter.
One set of equations was developed from a sample of harvested trees at two sites near
Cabaret and Ganthier (Ehrlich, 1985). A separate set of equations was determined for
coppice stands near Bon Repos (Timyan, 1987). These equations are provided in Table
1.2.
Growth Performance: R juliflora has been tested in several trials throughout Haiti, in
most cases being compared to other species. The slow initial growth, thorny nature, and
prostrate form of the local variety have discouraged a wider selection of the species in
trials. It appears that the tree devotes its early years to establishing an extensive root system
with the aboveground portion ofbiomass developing slowly. Table 1.3 summarizes
the growth parameters for this species in Haiti. The Oxford Forestry Institute trials were
established with a variety originating in Honduras that survived and grew very poorly
in Haiti, confirming the wide genetic variability found in the species. Figure 1.4 compares
the height growth ofR juliflora across several sites in Haiti. Annual height increments
do not exceed 0.8 m yr- 1 , even on the best sites and provenances. This level of
growth amounts to very low yields ofwood for the estimates based on basal diameters
and regression equations developed in Haiti. The values cited in Wojtusik et aI. (1993)