JOURNAL OF FOREST PRODUCTS & INDUSTRIES, 2012, 1(2), 26-34 26 Abstract— The objective of the study was to determine whether the A.seyal variety seyal (A.seyal) is able to produce healthy wood (rebellious to A.seyal borer), suitable to be used in building poles, firewood and charcoal when applying particular type of felling process, in particular period. The study confirmed the possibility, of producing endurable amount of A.seyal wood, not infested by A.seyal borer, when felled during April and June using charcoal felling process, and October and January when girdling process was used. The study also revealed that, the moisture content in A.seyal wood has noticeable effect; on the revival of the insect activity i.e. A.seyal borer was active only when the moisture content was in the range of 27-30% in the wood which seldom occurred in autumn due to rainfall frequency. Index Terms— Acacia seyal, Felling process, Endurable A.seyal wood, Revival of the insect activity, A.seyal borer I. INTRODUCTION cacia seyal predominantly a tree of the cracking clay soil found in large almost pure stands or mixed with A. senegal and Balanites aegyptiaca under rainfalls of 250 to 1000 mm. under low rainfalls on water- receiving sites and depressions. Confined in the Flood Region to low elevation intermittently flooded by rain. It is also found in depressions on sandy soils derived from Nubian Sandstone under rainfalls of 200 mm or above. It occurs in northern Sudan fringing the flood plains of rivers and in basins at the upper edge of Acacia nilotica forests. It tolerates high pH and salinity [1]. Acacia seyal is considered as tree number one in Sudan, as reported by [2] that has potential never been fully explored, but they are promising. The global demand for A.seyal gum is to be noted. The species is an important multipurpose tree for the rural population. In Sudan, the tree varieties occur naturally in the low rainfall savannah zone and extend from Gadarif, Blue Nile and White Nile to the clay plains around Nuba Mountains and the Darfur Region. In the savannah * corresponding author region of Sudan Acacia seyal has been subjected to large scale deforestation from mechanized farming, over grazing, fires and other human factors [3; 4]. It produces a gum arabic known as “talha”, which is of inferior quality to that produced by A. senegal making about 10% of Sudan’s gum arabic exports. The gum is produced from cracks or wounds caused by drought, fire, insects or wounds. Pods and bark contain about 20% tannin and smoke from the wood is a good insect repellent. Women use the aromatic smoke to tan and perfume their skin. The tree does not respond to tapping, and the gum is collected from natural exudation. There are numerous medicinal uses, mainly bark, and leaves [1 and 5]. A.seyal poles were widely used for telegraph poles during the war II era. The Forest and Plant Protection Authorities resorted to submerging poles in the river instantaneously after felling to leach as much carbohydrates as possible. The limited research and studies which were subsequently investigated the varies ways of seasoning, for protecting A.seyal wood against damage by A.seyal borer. [6, 7]. The susceptibility of A.seyal wood insect borer required more considerable efforts [2]. A.seyal borer (Sinoxylon senegalense ) infects A.seyal wood immediately after felling , turning it into powder in short time in such a manner that render it useless, even for firewood or charcoal, let alone to building poles. The borer also infested sap wood of most wood species and bamboo. The most destructive agents to forests and their products are insects, particularly of the orders Coleoptera, Isoptera and Thoptera which affect growth of trees, quality and quantity of wood products [2]. Over 40 species of insects are reported associated with A. seyal. These include 10 species of bruchid beetles which may damage high proportion of stored seeds. The relationship between the wood moisture content and the insect attack was investigated by [8] who stated that, there are two types of pests, one lives only in green timber, but other do not appear until the wood is at least seasoned to 30% moisture content. In case of the first type of insect who live in green timber its activity feeble as the wood dries out. Wood seasoned below 30% moisture content is less susceptible to insect attack. Assessing the Effect of Timing and Felling Techniques on the Susceptibility of Acacia seyal (Del) to Wood Borers. Mohamed T. A. Eltayb¹ and Talaat D. Abdel Magid*² ¹ Forest National Corporation Sinnar State E-mail: [email protected]² University of Bahri, College of Natural Resources and Environmental Studies, E-mail: [email protected](Received: October 15,2012, Accepted: November 6, 2012) A
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JOURNAL OF FOREST PRODUCTS & INDUSTRIES, 2012, 1(2), 26-34
26
Abstract— The objective of the study was to determine whether
the A.seyal variety seyal (A.seyal) is able to produce healthy wood
(rebellious to A.seyal borer), suitable to be used in building poles,
firewood and charcoal when applying particular type of felling
process, in particular period. The study confirmed the possibility,
of producing endurable amount of A.seyal wood, not infested by
A.seyal borer, when felled during April and June using charcoal
felling process, and October and January when girdling process
was used. The study also revealed that, the moisture content in
A.seyal wood has noticeable effect; on the revival of the insect
activity i.e. A.seyal borer was active only when the moisture
content was in the range of 27-30% in the wood which seldom
occurred in autumn due to rainfall frequency.
Index Terms— Acacia seyal, Felling process, Endurable A.seyal
wood, Revival of the insect activity, A.seyal borer
I. INTRODUCTION
cacia seyal predominantly a tree of the cracking clay soil
found in large almost pure stands or mixed with A.
senegal and Balanites aegyptiaca under rainfalls of 250
to 1000 mm. under low rainfalls on water- receiving sites and
depressions. Confined in the Flood Region to low elevation
intermittently flooded by rain. It is also found in depressions
on sandy soils derived from Nubian Sandstone under rainfalls
of 200 mm or above. It occurs in northern Sudan fringing the
flood plains of rivers and in basins at the upper edge of Acacia
nilotica forests. It tolerates high pH and salinity [1].
Acacia seyal is considered as tree number one in Sudan, as
reported by [2] that has potential never been fully explored,
but they are promising. The global demand for A.seyal gum is
to be noted. The species is an important multipurpose tree for
the rural population. In Sudan, the tree varieties occur
naturally in the low rainfall savannah zone and extend from
Gadarif, Blue Nile and White Nile to the clay plains around
Nuba Mountains and the Darfur Region. In the savannah
* corresponding author
region of Sudan Acacia seyal has been subjected to large scale
deforestation from mechanized farming, over grazing, fires
and other human factors [3; 4]. It produces a gum arabic
known as “talha”, which is of inferior quality to that produced
by A. senegal making about 10% of Sudan’s gum arabic
exports. The gum is produced from cracks or wounds caused
by drought, fire, insects or wounds. Pods and bark contain
about 20% tannin and smoke from the wood is a good insect
repellent. Women use the aromatic smoke to tan and perfume
their skin. The tree does not respond to tapping, and the gum
is collected from natural exudation. There are numerous
medicinal uses, mainly bark, and leaves [1 and 5].
A.seyal poles were widely used for telegraph poles during the
war II era. The Forest and Plant Protection Authorities
resorted to submerging poles in the river instantaneously after
felling to leach as much carbohydrates as possible.
The limited research and studies which were subsequently
investigated the varies ways of seasoning, for protecting
A.seyal wood against damage by A.seyal borer. [6, 7]. The
susceptibility of A.seyal wood insect borer required more