Bwa-yo - Société Audubon Haiti

Him 139
present in Haiti, genetic improvement can be made on azadirachtin levels in neem.
Azadirachtin levels ranged from 2.40-3.50 mg per dry gram seed kernel.
Silviculture: ODH experimented with the direct seeding ofneem and failed primarily
because the neem germinated too slowly and rotted in the field (Welle et aI., 1985).
Fruits, dried seed, and pre-soaked seed were tested. The latter had a germination rate of
25%, but failed to establish as seedlings. However, the transplanting oftop-pruned volunteers
planted during the same period exhibited 60% survival after a month ofonly 10
mm ofrainfall. Reid (1991) measured a 4% survival ofdirect-seeded neem after 1 year
at Cazeau.
Container and potting mix trials have shown mixed results in survival and early
height growth (Dupuis, 1986a; Reid, 1991). However, these studies have never been
continued beyond 2 years and should be considered with caution as to the real impact
that nursery treatments have on longer term field productivity.
Neem appears to be weed sensitive during the first year that the seedling is developing
a root system. Stunting ofthe tree has been observed by several foresters at trials
that were neglected, particularly under droughty site conditions. Subsequent weeding of
the trials generally does not exert a positive height-growth response.
The only pests that have been observed to attack mature trees are the stem borer
Apate monachus and a carpenter bee (Hymenoptera: Xylocopinae). A. monachus penetrates
deeply into the branches, forming galleries that retard growth and make the
branches susceptible to wind breakage (Knudson et aI., 1988). This same pest is known
to attack Casuarina equisetifolia, Swietenia mahagoni, S. macrophylla, and Melia
azedarach (CATIE, 1992). The carpenter bee attacks in a similar fashion, boring into
apical stems, and forming galleries that weaken the tree. It is likely that these pests are
only a problem when neem is under drought stress, since the observations were reported
in the drier regions of Haiti and the Dominican Republic.
Double rows of neem alternating with a single row ofL. leucocephala developed
more vigorously with less stem fluting, higher forking, and less canopy volume than
pure stands ofA. indica at an equivalent spacing and age. The use ofL. leucocephala as
a nurse crop maximizes the potential ofneem as a source ofpoles and lumber, always
of a higher value than fuelwood or charcoal in the urban area.
Pure stands ofneem at stocking densities ranging from 2000-2500 stems ha- 1 consistently
have yielded poor seed harvests, with any significant production occurring at
the stand edge. A neem stand, established in 1991 near Croix-des-Bouqets, produced
seed within 2 years at a density of 800 stems ha- 1 • This appears to be the optimal density
to maximize fruit yields.
Biomass and Volume Studies: Equations developed to estimate various components of
A. indica have been completed over the past decade. The first study was conducted to
estimate fuelwood volume based on stem diameters. This was done in 1983 on a 2-yearold
stand near Bon Repos (Timyan, 1983). Ehrlich (1985) conducted a biomass study
from a 4-year-old stand at Thomazeau and included pole volume tables. A third study
was completed in 1986 for a coppice stand and regression equations were analyzed to
estimate fuelwood and pole biomass separately (Timyan, 1987). The volume and biomass
equations from these studies are provided in Table 16.2. Because ofthe difference