main reasons for the shift from indigenous to exotic trees.
Later on ecologists and policy makers were divided as to tree performance and the ecological
effects of E. tereticornis. Shiva and Bnadyopad- hyay 1987 discussed its negative impact on water
resources, soil, air and human skin. In promoting wide-scale cultivation of E. tereticornis only its
wood productivity has been emphasised, while other non-wood products and ecological effects
have generally been ignored. This has led to inap- propriate assessment of the potential of exotic
versus indigenous trees. Indigenous species such as Dalbergia sissoo, although having a long gesta-
tion period, fetch a better price for their wood, in addition to various intangible products such as
fodder and ash which are commonly used by locals.
The claimed fast growth rate and projected returns of E. tereticornis over indigenous trees
such as D. sissoo have led us to investigate the ecological and economic potential of both tree
species at 6 – 8 years and 19 – 21 years, correspond- ing to the maturation age of the respective trees.
2. Methodology
Two sets of tree plantations E. tereticornis and D. sissoo, in triplicate, 6 – 8 and 19 – 21 years old,
respectively, were selected in the territory of Chandigarh, North India 30°42 N, 76°54 E, 333
msl, at
sites with
similar edapho-climatic
conditions.
2
.
1
. Measurement of growth parameters The data were collected on 20 randomly se-
lected, duly marked trees at each site from 1995 to 1998. The spatial arrangement of trees is shown in
Table 1. The measurements were made in terms of bole, crown and marketable heights using Re-
laskop, and diameter at breast height using a measuring tape. The bole, crown and marketable
volumes were calculated following Philip 1994:
Bole and marketable volume = pr
2
h0.5 and
Crown volume = pd
2
hf4 where r is mean tree radius, h is tree height, d is
crown diameter, and f is form factor for crown volume taken as 0.33 for E. tereticornis and 0.5
for D. sissoo.
The growth performance for all the observed parameters was been analysed in terms of annual
growth rate AGR and relative growth rate RGR as follows:
Annual growth rate AGR =
Final reading − initial reading time period in years
and Relative growth rate RGR
= log
n
final reading − log
n
initial reading time period in years
The data were statistically analysed employing Student’s t-test using Ecostat software to ob-
Table 1 Site details of 6–8- and 19–21-year-old mono-culture plantations
Site E. tereticornis
D. sissoo Spacing of trees
Number of trees per hectare Spacing of trees
Number of trees per hectare
6
–
8
-Year-old plantations 892
3.3×3.3 1287
i 2.5–3.0×2.5–3.0
2.3–2.8×2.3–2.8 1492
ii 3.4×3.4
842 2.7×2.7
1301 3.2–3.5×3.2–3.5
iii 853
19
–
21
-Year-old plantations i
2.5×2.5 1579
3.2×3.2 906
2.3×2.3 1605
3.4×3.4 821
ii 2.4×2.4
1594 3.3×3.3
852 iii
serve the level of significant difference for each parameter between the two populations i.e. tree
species, and discriminant analysis using stato- graphic software to compare all the parameters
of one site of one species with the corresponding site of another species, to obtain an overall con-
clusion about tree performance.
2
.
2
. Measurement of economically important parameters
The economic viability of both tree plantations was analysed in terms of five components, i.e.
timber, fuel-wood, eucalypt oil, fodder and ash content at the 8th and 21st years of growth.
2
.
2
.
1
. Timber The timber volume was calculated from the
marketable tree height and mean girth for 20 randomly selected trees following Philip 1994:
Timber volume m
3
= pr
2
h0.00015 The monetary returns were estimated according
to the market price available in the local timber market.
2
.
2
.
2
. Fuel-wood The quantity of fuel-wood was measured from
previously felled trees in young and old planta- tions at each site. This was necessary as the felling
of the trees was prohibited at all sites. The mone- tary value was estimated with respect to market
price.
2
.
2
.
3
. Eucalypt oil The mean amount of eucalypt oil per unit leaf
fresh weight was estimated during spring, sum- mer, autumn and winter, at each of the E. tereti-
cornis sites. The monetary value was calculated according to the price assigned by the Forest
Department, Ooty, State of Karnatka, where eu- calypt oil is extracted on a commercial scale no
such industry existed around Chandigarh in or- der to calculate the entire potential value of E.
tereticornis as a standing crop.
2
.
2
.
4
. Fodder The mean amount of fresh leaves kgtree was
measured during the different seasons of the year spring, summer, autumn and winter for 20 sam-
pled trees of D. sissoo in each of young and old plantations. The measurements were based on
calculation of the number of leaves per quater- nary branch, per tertiary branch, and then per
secondary and primary branches. Accordingly to- tal fresh leaf weight per tree was calculated.
The monetary value of fodder was estimated from the shadow price assigned by locals, as these
leaves are browsed by their cattle and goats. Locals, who used to bring their animals into the
plantation areas, were asked how much they would have to spend if they did not use D. sissoo
leaves as fodder. As mentioned by Khan 1979 these leaves are highly nutritious for animals.
Unfortunately, no direct price was available for this particular usage.
The leaves of E. tereticornis have no value as fodder.
2
.
2
.
5
. Ash The ash obtained from simple burning of fuel-
wood is largely used by the locals in their house- holds
and for
enriching their
fields. The
calculations were done by simply burning the fuel-wood of both types and ages of trees. The
content of ash produced per hectare was esti- mated and its monetary value was assigned by the
shadow price method, based on the local prefer- ence for spreading ash on fields rather than using
artificial fertilizers; the local women also use ash for barter and to clean utensils.
The total expected cost of inputs raising, car- ing, logging, felling and transportation was ob-
tained from the local timber merchants, at the current price index, as felling of the trees was
prohibited at the study sites we also wanted to follow a non-destructive method of estimation
regarding the age and site characteristics, during the market analysis for various inputs and out-
puts. The mean values were calculated for all collected data. The total net returns were esti-
mated after deducting input charges from total gains.
Table 2 Mean annual growth rate AGR myear and relative growth rate RGR of bole, crown, marketable heights and respective
volumes and diameter at breast height, in 6–8- and 19–21-year-old mono-cultures of E. tereticornis and D. sissoo plantations
a
Parameters 19–21-year-old plantations
6–8-year-old plantations E. tereticornis
D. sissoo E. tereticornis
D. sissoo 0.436
c
Bole height 0.798
c
1.060
b
1.701
b
0.140
b
0.114
b
0.070
c
0.168
b
Crown height 1.348
b
1.158
b
0.979
c
2.094
b
0.229
b
0.085
c
0.185
b
0.194
b
0.986
c
0.996
c
Marketable height 1.582
b
1.996
b
0.159
b
0.062
c
0.227
b
0.117
b
0.031
b
Bole volume 0.012
c
0.041
c
0.099
b
0.587
b
0.152
c
0.467
c
0.282
b
2.397
c
Crown volume 24.21
b
4.749
c
35.367
b
0.158
c
0.308
b
0.176
c
0.356
b
0.021
c
0.045
c
0.030
b
0.107
b
Marketable volume
0.647
b
0.179
c
0.291
b
0.488
c
0.097
b
0.043
c
0.069
c
0.058
b
Diameter at breast height
0.247
b
0.171
c
0.066
c
0.079
b a
Simple figures represent the values of annual growth rate AGR for the respective parameters. Figures in bold represent the respective values in terms of relative growth rate RGR. Similar superscripts in a row represent the insignificant values at P = 0.
05 level, after applying Student’s t-test.
The widely accepted 8-year rotation cycle of E. tereticornis
Thapliyal, 1986;
Rajan, 1987;
Niskanen et al., 1993; Saxena, 1994 led us to examine its monetary value from 8 to 21 years of
age, the latter being the minimum maturation age of D. sissoo. Foresters generally base their deci-
sions upon growth as well as monetary gain for these two tree species over a short period of time.
So, comparative analysis has been done in terms of growth performance and total returns in both
age groups of each plantation type.
3. Ecological viability of growth performance in E. tereticornis and D. sissoo plantations
