Bwa-yo - Société Audubon Haiti

Bavawonn 7
Table 1.2 Equations used to estimate biomass components (kg dry weight) of P. juliflora in
Haiti.
COMPONENT REGRESSION EQUATION 1 R 2
DIAMETER SITE
RANGE (em)
Total aboveground biomass 00408(DBH)2 0.97 1.2-10.8 Cabaret & Ganthier
Usable wood weight 0.304(DBH)2 0.99 1.2-10.8 Cabaret & Ganthier
Usable wood weight 0.195(sd)2 0.97 1.5-13.5 Cabaret & Ganthier
Coppice biomass 0.158S(sd)/ + 0.163 0.97 2.4-18.3 Bon Repos
Usable coppice wood weight 0.123S(sd)n 2 + 0.013 0.98 204-18.3 Bon Repos
I DBH =Stem diameter at 1.3 m above ground level, in em. sd =Stump diameter at 0.10 m above ground level, in em. n
= Number of stems at 0.10 m above ground.
for total biomass yields, corrected in Table 1.3 by a factor of 0.75 for estimated wood
yields, are derived from regressions developed under different growing conditions and
may be overestimates oflocal wood yields.
Tree Improvement: The trial at Thomazeau is a genetic screening trial, established by
Texas A & I University in 1987, and managed by the Convention Baptiste d'Haiti. A
total of 70 Prosopis accessions, including 44 Haitian accessions, 12 Peruvian accessions,
and several other Prosopis species from Nprth America, Chile, and Argentina are
being assessed for economically important traits: biomass production, form and pod
production. The early results indicate that the seed lots from Peru are a significant
improvement in form, being more erect and achieving greater height growth than the
Haitian accessions. Figures 1.5 and 1.6 compare the height and aboveground biomass
growth ofthe top 15 accessions, which are dominated by the Peruvian accessions. The
differences in the habit ofthe Haitian and introduced Peruvian types are significant (see
Fig. 1.7 and Fig. 1.8). Among the Haitian selections, no geographic trends are evident
in height or biomass yield, nor is there a significant correlation between the size ofthe
parent tree and the growth rate of the progeny. Individual selections based on progeny
testing would be appropriate for continued improvement ofthe local variety. The combination
ofsuperior genetic quality and proper silvicultural management is necessary to
develop trees for high-value wood production (Fig. 1.9).
Table 1.3 Site and growth parameters of Prosopis juliflora trials in Haiti. Dry wood yields for
the Thomazeau site were estimated from Wojtusik et al. (1993).
SITE ELEVAnON ANNUAL AGE SURVIVAL HEIGHT
(m) RAINFALL (yr) (%) M.A.I. I
(mm) (m)
d 2
M.A.I.
(em)
DRY WOOD
YIELD
(kg tree· I )
Nan Marron 450 600 3.3 28 0.2 0.2 0.1
Mare Grand Bois 20 1200 3.5 58 0.6
Bekin 100 1397 3.5 96 0.8
Thomazeau (Peru) 25 970 3.8 89 0.8
Thomazeau (Haiti) 25 970 3.8 94 0.6
Fond-des-Blancs 250 1335 4.0 58 0.2
Cabaret 80 900 6.9 72 0.3
1 M.A.I. =Mean annual increment. 2d =Stem diameter at 0.3 m above ground level.
0.9 1.9
0.7 1.2
5.0
4.1
0.2 0.1
0.4 1.5