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Investigation into the heterogeneous nature of the impregnability of some poplar hybrids
1995 - IRG/WP 95-40052
Retention figures of some poplar hybrids are very heterogeneous when pressure impregnated. This makes it hard to prescribe impregnation processes for fast grown poplars that make it suitable for higher hazard uses. In order to gain fundamental knowledge in their variability in impregnation properties two trees were selected for a detailed investigation. Both trees originate from the same plantation and represent the genetically very similar clones Populus trichocarpa x deltoides 'Beaupre' and 'Boelare'. From the lower part of each stem a log was cut into over 80 samples measuring 5 x 5 x 100 cm³. After air-drying and conditioning they were CCA impregnated using a Lowry cycle. The mean retention levels for both trees are identical but their distribution in uptake figures is totally different. In the inner heart part of the 'Beaupre' tree the preservative liquid uptake of some samples was even lower than 90 kg/m³ while 'Boelare' samples at the corresponding location showed retentions of over 450 kg/m³. The differences in impregnation pattern are not related to the in-tree distribution of moisture content, density, radial/tangential sawing nor to the presence of tension wood. The hypothesis that parameters at the anatomical level affect the impregnability is examined and related to the specific type of heartwood present in poplar.
J Van Acker, M Stevens


Influence of clonal variability on the impregnability of poplar hybrids. (+ correction document of 23 April 1990)
1990 - IRG/WP 3614
The new Western European poplar clones (Populus nigra x deltoides and Populus trichocarpa x deltoides) were compared with the reference clone 'Robusta' and some old hybrids. Samples (5x5x50 cm³) with pure tangential/radial surfaces were sawn, including the transition zone between heartwood and sapwood. Treatment by a standard vacuum-pressure impregnation cycle with CCA showed a range of retentions from 2 to 10 kg/m³ for the 23 poplar clones studied. Only minor differences in impregnability were observed between samples of different trees belonging to the same hybrid. Although the new poplar clones in general show no substantial differences in uptake compared to the reference clone "Robusta" and the older poplar hybrids, the penetration of Cu and As was lower. No relation between wood density and impregnability was found. The radial and tangential penetrations were identical. Cu penetration in sapwood was significantly better than in heartwood. Samples of 1 m length revealed a poor longitudinal penetration.
J Van Acker Van, M Stevens, C De Haas


A comparative study of some anti-splitting devices, using Eucalyptus saligna and hybrids of Eucalyptus saligna X Eucalyptus spp poles
1983 - IRG/WP 3251
It is commom for some Brazilian wood pole users to require devices such as banding steel, to avoid or reduce splits at the end of Eucalyptus treated poles. On other hand users and manufacturers do not have data to confirm the effectiveness of the banding steel types normally used such as galvanized "Steel-Belt" and galvanized "Wire-Belt". For this reason a comparative study was carried out including in addition to the above, "Steel-Plates" (Gang-Nail type) and the "Kerfing" procedure. These devices were tried out on Eucalyptus saligna hybrids, species which present a strong tendency to split. Based on the results obtained in four bimonthly inspections of 80 poles (including a control series) and based on the statistical analysis, it was noted that the "Steel-Plates" (Gang-Nail type) contributed to reduce splits in the ends of Eucalyptus poles.
F C Geraldo, J A C Sodré


On the species problem in Nicobium castaneum (Col., Anobiidae)
1975 - IRG/WP 134
Nicobium castaneum (Oliv.) is one of the most important wood and book worms of the Mediterranean area (eg Portugal) and South Russian. It also occurs in the USA and Japan. A previous paper (Cymorek 1972) left open the question: is Nicobium castaneum one or two species? Nicobium castaneum is currently regarded as forming two varieties or sub-species - sub-specific taxa which are rarely well defined in the Coleoptera. When dealing with an insect of economic relevance, the exact determination of its status is necessary for the best application of control measures. The subject is also of interest for the taxonomy and systematics of the Anobiidae. First cross breeding results lead to the impression that probably a single species was concerned. Trials of the fertility of hybrid populations were planned to test this opinion. Results are given below.
S Cymorek