Supervisors:
Dr. R.S. Rawal GBPIHED, Kosi-Katarmal, Almora
Prof. Y.P.S. Pangtey, D.S.B. Campus, Kumaun University, Nainital
Summary:
All
through the history of vegetation studies, extent of diversity,
representativeness and uniqueness of Himalayan forests have attracted the
global attention. As a
result, gradual advance has been noticed in understanding structure and
function of these forests. In recent two decades, the quantum and quality
of data on ecological attributes of Himalayan forests, especially the
Kumaun - west Himalaya, has improved considerably. The available database
highlights peculiarities of these forests on a global scale. Such
reflections of uniqueness call for in-depth investigation, particularly to
understand the variations in pattern within and among forests. In this
context, studies on selected ecologically and economically important tree
species assume greater significance on account of the vital role played by
them in structuring the forest stands. Present study is one step forward
in this direction. The objective is to examine the pattern of Myrica
esculenta - an ecologically and economically important tree associate,
in forests of Kumaun Himalaya. The study specifically focuses on possible
influence of M. esculenta on
composition and regeneration of forest stands, particularly in view of
dioecious nature of this species. Scrutiny of literature indicates that no
such study has been conducted so far in this region.
The
target species, Myrica esculenta,
a dioecious, moderate sized, evergreen tree, is characteristic associate
of the forests between 1000 - 2200 m asl., especially in chir - pine (P.
roxburghii), banj - oak (Q.
leucotrichophora) and mixed broad leaf forests, in the region. The
species is well known for its edible fruits and as an income-generating
source. In addition, the species is useful in multiple ways. The bark is
used in several diseases and has commercial value as tanning and dyeing
material. The oil obtained from the flowers and seeds is used in the
preparation of tonic. The species is extensively used as fuel wood
throughout the hilly region and competes well in fuel wood value with
other priority species. The species exhibits microhabitat dependent
variations in distribution and shows colonization ability.
Present
thesis included 6 Chapters with special emphasis on: spatial
heterogeneity, natural regeneration & survival, and source dependent
germination variability. The results of various chapters are discussed to
find out implications for regional forests. Also, the management
considerations of target species are dealt with.
Studies
on Spatial
Heterogeneity revealed variations in compositional features across
the sites / habitats and canopy condition (intact and disturbed).
Following information was generated during present investigation:
(i)
Considering the canopy conditions (i.e.
intact and disturbed), under each habitat type, mean tree density,
sapling, & seedling density and total basal area was low in disturbed
habitat conditions.
(ii)
The mean forest tree density (775 - 963 ind. ha-1,
intact; 518 - 650 ind. ha-1, disturbed) of M.
esculenta stands was comparable with the values (350 - 590, chir -
pine; 320 - 150, banj - oak; 440 - 1180 ind ha-1, mixed
forests) reported for similar forests in Kumaun. This suggests that the
overall tree stocking remains unaffected by the presence of M.
esculenta in forests of Kumaun Himalaya.
(iii)
The density of forest seedling (intact 2944 - 3427; disturbed
2775-3329 seed. ha-1) and saplings (intact 6236
- 7448; disturbed 5616 - 7117 sap. ha-1) in M. esculenta stands was considerably higher than the reported range
(seedling 712 - 1768, sapling 156 - 420 ind. ha-1) in the
Kumaun forests. This indicates that Myrica
dominant stands exhibit high recruitment compared to Myrica diffused stands.
(iv)
The increased seedling and sapling density in Myrica
stands was due to higher contribution of M.
esculenta and dominant species (49 - 73% seedling;
68 - 76% sapling) in these sites.
(v)
There was a strong male - biased sex ratio for M.
esculenta in all cases (intact: c2
= 12.58 chir - pine, 16.62 banj - oak, 11.56 mixed, p<0.01; disturbed: c2
= 12.25 chir - pine, 6.41 banj - oak, 8.09 mixed, p<0.05), suggesting
overall resource - limited harsh or marginal habitat conditions.
(vi)
Across different sites frequency of femaleness increased towards
the higher elevational sites (male / female: intact 1.83 lowest site, 1.34
highest site; disturbed 2.44 lowest side, 1.28 highest site) suggesting
overall favourableness of these sites.
(vii)
All the studied population structures revealed accumulation of Myrica individuals in sapling stage indicating availability rich Myrica
sapling banks.
The
information generated on patterns of Natural Regeneration and Survival revealed the following:
(i)
There was a sharp difference in M.
esculenta recruitment peak (September) from total forest and dominant
species recruitment peak (March and / or June), suggesting that M.
esculenta has differential regeneration strategies compared to
dominant and other species.
(ii)
There were no fixed trends of survival / mortality in case of M. esculenta.
(iii)
The survival percentage of seedling varied among habitats. On an
average the contribution of Myrica seedling
was high in chir - pine habitat and proportional contribution was higher
under disturbed canopy condition. However, the disturbed canopy conditions
of other two forests Quercus and
mixed, exhibited a sharp reduction in average seedling density.
(iv)
Considering the Myrica
sapling density, under all habitats the intact canopy conditions towards
high altitude sites were favourable for establishment of rich sapling
banks.
Analyses
of data obtained from the experiments on Seed
Dormancy and Germination across different source environment
exhibited the following:
(i)
Germination responses of M.
esculenta varied significantly for seed obtained from populations
(sites) at different altitudes. For untreated seeds, germination was
significantly high (40.3%) for seeds obtained from highest altitude as
compared to the seeds from lowest altitude (20.8%).
(ii)
Prechilling (20d, 4°C)
improved germination significantly for seeds from all the sources.
However, the mean germination (78.3%) for high altitude population was
significantly better than the responses under all other treatments.
(iii)
Among habitats, the seeds from chir - pine and mixed forests
responded better than the Quercus
forest seeds. Also, the seeds obtained from small tree size class (<60
cm) responded poorly compared to seeds from larger trees (>61 cm).
The
wide ranging Ecological
Implications of the findings are discussed in the context of
regional forests. Attempts have been made to discuss and compare present
findings to find out the:
(i)
Implications for structural heterogeneity of forest stand in the region.
(ii)
Indicator value of Myrica
recruitment patterns for predicting the shifts in species boundaries.
(iii) Possibilities of including M. esculenta in restoration activities through forestry operations and structuring the management strategies.
Bhawana Pandey
Subject : Botany
Ph. D - Botany Kumaun University, Nainital
Correspondence Address:
, CBD/GBPIHED, Kosi-Katarmal, Almora,Uttaranchal-263 643
Work Title