TITLE:
Silvicultural Systems for Restoration of Mahogany in Degraded Landscapes in Africa: Influence of Mixed Rainforest Plantation on Growth and Pest Damage
AUTHORS:
Emmanuel Opuni-Frimpong, Nana Yaa Nyarko-Duah, Ebenezer J. D. Belford, Andrew J. Storer
KEYWORDS:
African Mahogany, Hypsipyla robusta, Mixed Plantation, Planting Density, Khaya Species
JOURNAL NAME:
Open Journal of Forestry,
Vol.4 No.4,
July
31,
2014
ABSTRACT: African
mahogany, one of the world’s most valuable timber species is threatened by
over-exploitation in natural forests and failure of plantations due to attacks
by the shoot borer Hypsipyla robusta. Mixed-species plantations has been
reported to be an effective component of integrated pest management of major
pest in other crops; but there is very limited empirical data on its use for
managing Hypsipyla in mahogany mixed
stands in West Africa. The aim of this study was to assess the effect of
mixed-species stands as management intervention, on the growth of Khaya grandifoliola and Khaya ivorensis in relation to Hypsipyla robusta attack in a 10 ha
experimental plantation in the wet evergreen forest type in Ghana. Khaya grandifoliola recorded faster
growth than Khaya ivorensis in this
forest type though the later naturally grow in this forest type while the
former is introduced from the dry forest. Two years after planting, diameter and height growth were greater in the
mixed-species stand than the pure stands for K. grandifoliola and K.
ivorensis. Hypsipyla damage was
less in the mixed stands of both K.
grandifoliola and K. ivorensis compared
to the pure stands, with the 20% and 10% Khaya mixed stand recording the lowest attack in both species. It can be recommended
that mixed stands of the two Khaya species at 20% or lower Khaya density
might be ideal for reducing the levels of Hypsipyla attack in this type of forest.