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Title: Improving tree selection for felling and retention in natural forest in Amazonia through spatial control and targeted seed tree retention : a case study of a forest management project in Amazonas State, Brazil
Author: De Freitas, Joberto Veloso
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2004
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An important aspect of forest management is the promotion of natural regeneration of commercial timber species.  To explore the potential of tree selection processes that consider species requirements for regeneration, I developed an approach to select trees to be retained as seed trees and to be felled alternative to a conventional system.  The commercial species were characterised for attributes relevant to tree selection.  The alternative approach developed to retain seed trees consisted in to retain 10-30% regarding to seven ecological attributes.  The conventional consisted of 10% retention regardless species characteristics.  I compared the % of retention per species of conventional and alternative approaches in blocks of 100 ha.  The two methods selected a similar proportion of seed trees (17%), yet the alternative approach retained relatively more seed trees for species with more limitations for regeneration.  Shade bearing species were responsible for 87% of commercial species group basal area, suggesting that gap reduction and damage control on advanced regeneration as a silvicultural strategy.  The alternative approach to select trees for felling included a harvest map designed to facilitate the protection of seed trees and potential crop trees.  A field rule was introduced to control the spatial variation in harvest intensity.  I compared impacts of treatments on residual stand conditions and timber production. The area in logging gaps was reduced from 28% to 15% with the introduction of the alternative approach, the impacts on ground level, from 52% to 32% and on damage on potential crop trees from 13% to 6%.  Timber production from the conventional approach was on average 45.5 m3 ha-1 and from the alternative was 24.4 m3 ha-1.  However, the proportion of volume of high valued species increased from 57.5% to 72.7% with the alternative approach.  This study suggests that a compromise between timber production and impact reduction is required to achieve sustainable forest management.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available