GROWTH STATISTICS

The rates of growth vary considerably on the quality of site as well as the location of the species. It
grows poorly in areas with kankar pan and in ‘usar’ soils. In one trial carried out at Banthra, District
Lucknow, Uttar Pradesh, during 1990, the growth from 2-8 years was a under.
Age of        Crop        Basal        Number        Biomass Production (Tonnes/ha)

Measure-        height        area        of        Green weight        Oven dry weight        Total m.a.i.        
ment        m        (BA)        tress/ha        (Tonnes/ha)        (Tonnes/ha)        Tonnes/ha/yr
m/ha
        Stem        Branch        Leaves        Total        Stem        Branch        Leaves        Total        Green        Dry

2        1.6        0.6        4650        0.80        0.20        0.02        1.02        0.32        0.08        0.01        0.41        0.51        0.21
3        1.7        0.9        4600        1.18        0.30        0.05        1.53        0.48        0.12        0.03        0.62        0.51        0.21
4        2.7        1.9        4425        3.18        0.84        0.12        4.14        1.29        0.34        0.04        1.67        1.04        0.42
6        2.5        2.5        4400        4.80        1.27        0.17        6.24        1.94        0.52        0.06        2.52        1.25        0.50
7        2.7        3.5        4450        7.35        1.95        0.26        9.56        2.98        0.80        0.08        3.86        1.59        0.67
8        3.1        4.8        4400        14.76        3.13        1.40        15.29        4.76        1.29        0.13        6.18        1.91        0.77
It is seen that the mean annual increment (m.a.i.) is going up in the 8th year. The maximum rate of
growth is not likely to take place earlier than 15 years. Benge15 states that 66% of the total growth of
the tree occurs in the first three years. The biomass yield is reported to vary between 10 to 100 tons
par ha per year. About 50% of the biomass is statedly contained in the leaves, about 25% in the fruit
and 25% in wood. All these statements are not corroborated by observations in India. These need a
critical reappraisal. The distribution of biomass in a tree between crown and stem can’t be expected
to occur in the ratios as indicated in the above reference.
Little reliable data on growth of neem at advanced age are available. A plantation of 44 years in
Motipur in Behraich district of Uttar Pradesh was found to have an average height of 10.7 m and girth
of 81 cm. This plantation had not been regularly tended and most of the trees were badly grown.
In areas where the species is harvested for timber, the rotation of harvest are 40-50 years and girth of
100 cm is expected. The species shows distinct growth rings but most of these rings are false. The
growth rings are not an indicator of age.