Growth and Establishment of Seedlings of Indigenous Species Inside Plantations and the Adjacent Natural Forest
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Date
2004-02
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Addis Ababa Universty
Abstract
Eucalyptus and Pill/IS plantations and adjacent natural forest in Shashemene-Munessa State
Forest were studied to investigate growth and establishment of seedlings of three indigenous
species: Podocarpus falcatus, Bersallla abyssillica and Crotoll lIlacrostachyus. Density, distance
from individual plantation trees, seedling architecture, transpiration and photosynthetic
performance of understory indigenous plants were measured in order to investigate the nursing
effect of plantation trees for the development of indigenous flora under their canopies.
Examination of growth and establishment of study plants exhibited variations not only between
plantations and adjacent natural forest but also between plantations themselves. Based on the
results from measurements of density, distance from plantation trees and architecture of
regenerated study species, plantations supported higher natural regeneration development (stem!
ha) of indigenous species than adjacent natural forest (1950 vs 1260). P.falcatus was found to be
the most successfully regenerated species in both plantations and adjacent natural forest. More
regeneration (stem!ha) and closer establishment to individual trees of plantation species of
understory plants were found in Eucalyptus plantation indicating its better nursing effect than
Pinus plantation. All study species had large number of individuals along the edge of Eucalyptus
plantation. The seedling population of P. falcatus in Eucalyptus plantation had a density
distribution inversely related with distance from seed source: with large number of individuals
near the seed source and few individuals at further distance away from the seed source. Seedlings
of P. fttlcatus and B. abyssillica exhibited differences in architecture in the two stands. Seedlings
of both species in Eucalyptus plantation had more biomass distribution to branches and/or leaves
to increase lateral growth than those in Pin liS plantation. These differences in seedling architectllre (stem growth and later,t1 growth) would probably reveal more need of silvicultural
treatments for growth and establishment of indigenous plants in Pill liS than Ellca/)'p/lls stand.
Analysis of fluorescence parameters in the leaves of study specics showed no significant
difference in the level of FvlFm, L'lF/F",', ETR and NPQ among species developed inside
plantations and adjaecnt natural forest. In Ellca/yp/lls plantation seedlings of 1'. ./ii/ca/lls and E.
saligl/a had similar photoS)~lthetic performance. From measurements of transpiration
considerable variation was found bctween indigenous species and plantation species. Seedlings of
E. saliglla lose much more water through their leaves than those .. of P./aica/lis and B. a/Jyssillica
with increasing vapor pressure deficit (VPD), Most impoFtantly, large difference in watcr relation
of E. saliglla and P./a/callis was recorded which indicates its better water usc. Comparison of
photosynthetic performancc and water relations of seedlings of P. /aica/lis with E. sa/iglla
indicated the potential of p, Pi/CO/liS to grow inside Fllcalyp/lls plantation. The study supported
the suggestion that plantations had nursing effects for growth and establishment of indigenous
flora under their canopies. Furthermore, the importance of seed availability and overstory species
composition on the natural regeneration development of study species was also evident in the
study
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Keywords
Establishment of Seedlings