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Ash BarkBeetle Damage

Ash BarkBeetle Damage Workshop and Production Section AIRCRAFT ENGINEERING August, 1943 An Alarming but Unimportant Type of Insect Attack in Ash By R. C. Fisher, B.Sc., Ph.D.* HROUGHOU T the summer and early logs, stumps of felled trees, or converted timber far as insect attack is concerned, there is no autumn , small piles of white bore dust on with bark still on th e edges. The dust, ex ­ justification for discarding such timber or for th e surface of the bark of ash, English or pelled by the beetles from their tunnels, col­ classifying it as unsuitable for us e in aircraft imported, are a common sight in timber yards lects in small heaps on the surface of the bark, construction or for other purposes where rigid an d dispersal sites. As th e Forest Products bu t it ma y fall on to board s beneath (Fig. 1), specifications demand the absence of defects Research Laboratory receives a number of also giving the impression that these are in ­ which might affect the strengt h and dura­ inquiries every year on this type of insect fested and thus causing confusion with th e more bility of th e wood. The following table sum­ attack , the following information may be useful serious type of damage caused by Lyctus marizes briefly distinguishing features of infest­ t o all who may be alarmed by its presence i n powder-post beetles. ation by th e ash bark-beetle and by Lyctus their stock. powder-post beetles:— Th e ash bark-beetle lays its eggs between the Th e ash bark-beetle (Hylesinus fraxini), bar k and the surface of th e wood, and the grubs Ash Bark-beetles Lyctus Powder-post Beetles which is responsible for this dust, is quit e un­ which hatch from these bore and feed in th e bark, just grazing the sapwood. On completing 1. Damage confined to bark with 1. Damage throughout sapwood importan t as a wood-boring insect since i t does superficial scoring of "outer which may become severely their development, they tur n into beetles which no t affect the timber of infested logs, planks, surface of sapwood which is powdered; bark not affected, boards, etc. Occasionally, a tunnel may bore their way out of th e bark in August and not powdered. 2. Bore dust falls from bark 2. Bore dust from sapwood. penetrate the sapwood, but the damage is no t September, leaving it riddled with exit holes only. (Fig. 1.) serious an d ther e is n o danger of i t continuing or abou t ⅛ inch in diameter . If th e bark is re ­ 3 . Bore dust coarse, granular in 3. Bore dust fine, flour-like in spreading throughout the wood. By removing moved the syste m of tunnels made by the texture. texture. th e bar k and trimming the edges of sapwood all beetles and their grubs can be seen on the 4. System of tunnels on surface of sapwood of regular and 4. A regular system of tunnels traces of the insect can be eliminated. The sapwood, forming a characteristic pattern characteristic pattern . (Fig. 2) absent. dust is caused by the beetles, which are about (Fig. 2), typical of th e workings of this insect. ⅛ inch in length, oval in shape and dark brown Instances have been brought to the notice of I n cases of doub t as t o th e cause and com­ or ashy grey in colour, boring into the bark of th e Laboratory, of timbe r inspectors rejecting parativ e importance of an y typ e of defect in ash ash showing evidence of ash bark-beetle activity or other timber, the advice of th e Laboratory * Of the Department of Scientific and Industrial Research, Forest on the grounds tha t the timber is affected. So is available to inquirers. Products Research Laboratory, Princes Risborough. A Universal Bevel Protractor E. R. Watts & Son, Ltd., 123 Camberwell Road. The Watts universal bevel protractor (Fig. 1 convenient measurement of angles. The prin­ London, S.E.5. and 2) is a high class engineer's tool for the cipal feature is that the circular scale is on a glass annuhis accurately divided and mounted within the protractor head. The circular scale graduations are read by means of a high power magnifier. The blades are of hardened steel. The sliding blade is locked against the protractor head by an eccentric, operated by a lever extending from the centre (see Fig. 1). The protractor angles are locked by the large knurled ring surrounding the protractor head. The angles are conveniently read when looking through the eyepiece. The sliding blade is interchangeable and may be either 12 in. or 6 in. long. The instruments will measure to 5 min. The dimensions are:— Length 6½ in. (when using 6 in. sliding blade). Width 2⅜ in. Depth 1¾ in . Further details can be obtained from the makers. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

Ash BarkBeetle Damage

Fisher, R.C.
Aircraft Engineering and Aerospace Technology , Volume 15 (8): 1 – Aug 1, 1943
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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb031047
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Abstract

Workshop and Production Section AIRCRAFT ENGINEERING August, 1943 An Alarming but Unimportant Type of Insect Attack in Ash By R. C. Fisher, B.Sc., Ph.D.* HROUGHOU T the summer and early logs, stumps of felled trees, or converted timber far as insect attack is concerned, there is no autumn , small piles of white bore dust on with bark still on th e edges. The dust, ex ­ justification for discarding such timber or for th e surface of the bark of ash, English or pelled by the beetles from their tunnels, col­ classifying it as unsuitable for us e in aircraft imported, are a common sight in timber yards lects in small heaps on the surface of the bark, construction or for other purposes where rigid an d dispersal sites. As th e Forest Products bu t it ma y fall on to board s beneath (Fig. 1), specifications demand the absence of defects Research Laboratory receives a number of also giving the impression that these are in ­ which might affect the strengt h and dura­ inquiries every year on this type of insect fested and thus causing confusion with th e more bility of th e wood. The following table sum­ attack , the following information may be useful serious type of damage caused by Lyctus marizes briefly distinguishing features of infest­ t o all who may be alarmed by its presence i n powder-post beetles. ation by th e ash bark-beetle and by Lyctus their stock. powder-post beetles:— Th e ash bark-beetle lays its eggs between the Th e ash bark-beetle (Hylesinus fraxini), bar k and the surface of th e wood, and the grubs Ash Bark-beetles Lyctus Powder-post Beetles which is responsible for this dust, is quit e un­ which hatch from these bore and feed in th e bark, just grazing the sapwood. On completing 1. Damage confined to bark with 1. Damage throughout sapwood importan t as a wood-boring insect since i t does superficial scoring of "outer which may become severely their development, they tur n into beetles which no t affect the timber of infested logs, planks, surface of sapwood which is powdered; bark not affected, boards, etc. Occasionally, a tunnel may bore their way out of th e bark in August and not powdered. 2. Bore dust falls from bark 2. Bore dust from sapwood. penetrate the sapwood, but the damage is no t September, leaving it riddled with exit holes only. (Fig. 1.) serious an d ther e is n o danger of i t continuing or abou t ⅛ inch in diameter . If th e bark is re ­ 3 . Bore dust coarse, granular in 3. Bore dust fine, flour-like in spreading throughout the wood. By removing moved the syste m of tunnels made by the texture. texture. th e bar k and trimming the edges of sapwood all beetles and their grubs can be seen on the 4. System of tunnels on surface of sapwood of regular and 4. A regular system of tunnels traces of the insect can be eliminated. The sapwood, forming a characteristic pattern characteristic pattern . (Fig. 2) absent. dust is caused by the beetles, which are about (Fig. 2), typical of th e workings of this insect. ⅛ inch in length, oval in shape and dark brown Instances have been brought to the notice of I n cases of doub t as t o th e cause and com­ or ashy grey in colour, boring into the bark of th e Laboratory, of timbe r inspectors rejecting parativ e importance of an y typ e of defect in ash ash showing evidence of ash bark-beetle activity or other timber, the advice of th e Laboratory * Of the Department of Scientific and Industrial Research, Forest on the grounds tha t the timber is affected. So is available to inquirers. Products Research Laboratory, Princes Risborough. A Universal Bevel Protractor E. R. Watts & Son, Ltd., 123 Camberwell Road. The Watts universal bevel protractor (Fig. 1 convenient measurement of angles. The prin­ London, S.E.5. and 2) is a high class engineer's tool for the cipal feature is that the circular scale is on a glass annuhis accurately divided and mounted within the protractor head. The circular scale graduations are read by means of a high power magnifier. The blades are of hardened steel. The sliding blade is locked against the protractor head by an eccentric, operated by a lever extending from the centre (see Fig. 1). The protractor angles are locked by the large knurled ring surrounding the protractor head. The angles are conveniently read when looking through the eyepiece. The sliding blade is interchangeable and may be either 12 in. or 6 in. long. The instruments will measure to 5 min. The dimensions are:— Length 6½ in. (when using 6 in. sliding blade). Width 2⅜ in. Depth 1¾ in . Further details can be obtained from the makers.

Journal

Aircraft Engineering and Aerospace Technology – Emerald Publishing

Published: Aug 1, 1943

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