Cost minimization through the use of taungya system in pulpwood plantation establishment

The costs and benefits of the use of three labour alternatives: direct permanent, direct casual and taungya labour in Gmelina arborea pulpwood plantation establishment in Nigeria were investigated. Results show that cost per hectare is lowest with taungya labour and highest with permanent labour with savings in cost of as much as 30% and 47% by taungya labour over casual and permanent labour respectively. The net present value per hectare of investment is highest when taungya labour is used and lowest and negative with permanent labour. Also, the internal rate of return of investment is highest with taungya labour and lowest with permanent labour. The net present values and internal rates of return for Gmelina plantations calculated for the three pulp and paper mills in Nigeria show the same trend in favour of taungya labour.     

Kebon tatangkalan: a disappearing agroforest in the Upper Citarum Watershed,West Java,Indonesia

A comprehensive study was carried out on a typical indigenous agroforestry system, called kebon tatangkalan, in the changing agricultural landscape of the Upper Citarum Watershed, West Java, Indonesia. The main objectives of the study are to elucidate the structural patterns, multidimensional functions, and dynamics of this multi-layered agroforest. The study has identified 12 groups of different plant assemblages indicating that this type of agroforest contributes considerably to the heterogeneity of the agricultural landscape in the study area. Multivariate analysis suggests that elevation and slope are the biophysical factors that correlate most significantly with the distribution of plant species in kebon tatangkalan. The presence of this man-made vegetation is currently declining from the landscape due to population growth and rapid regional economic development. Serious effort to revitalize this traditional agroforest is needed to prevent its disappearance. Introduction of highly productive species and establishment of integrated policies in regional land-use planning and management are measures that should be taken into account in preserving this traditional agroforestry system.     

Reducing end groups in brich xylan and their alkaline degradation

Summary The structure of the reducing end group in xylan can be written: --D-Xylp-(14)--D-Xylp-(13)--L-Rhap-(12)---D-GalpA-(14)-D-XylIn alkaline media the reducing xylose group is easily isomerized and removed by a -elimination which leads to a reducing galacturonic acid end group. The 1, 2-linkage between rhamnose and the galacturonic acid explains the retarding effect on the alkaline peeling. Even under fairly mild conditions the galacturonic acid group is converted to other groups which are very stable in alkaline media. Model experiments permit the conclusion that OH-3 in the reducing group is subjected to -hydroxyelimination. The 3-deoxy-2-O--L-rhamnopyranosyl-D-threo-hex-2-enuronic acid group formed is unstable in acid medium and escapes observation by the techniques employed for determination of the end groups.Upon prolonged alkaline treatment and increased proportion of these groups is lost and a rapid peeling proceeds until a xylose group with a 4-O-methylglucuronic acid substituent is liberated. The consecutive reactions of this group are similar to those of the galacturonic acid groups.The formation of 3-deoxyaldonic acid end groups, an important stopping reaction in cellulose, is of minor importance in xylan.The financial support from the 1959 Års Fond för Teknisk och Skoglig Forskning samt Utbildning is gratefully acknowledged.     

Altitudinal and longitudinal variations in Pinus brutia (Ten.) of Crete Island,Greece: some needle,cone and seed traits under natural habitats

Four populations representing the entire natural distribution range of Pinus brutia (Ten.) in Crete (Greece) were sampled to determine: (1) Altitudinal variation within populations of Lassithi, Vorizia, Koustagerako, and Samaria, and; (2) Longitudinal variation among the four populations, based on morphological and anatomical differences in cone, needle and seed characteristics. Samples were collected from 10 trees per altitude, at three altitudes in each population. A total of 12 morphological and anatomical traits from needles, cones and seeds were analyzed to assess the altitudinal and longitudinal variations of the species in the island. The number of teeth per cm showed significant (P<0.01) differences between altitudes in Samaria, Vorizia and Lassithi, while needle length, width and the number of resin canals showed significant differences (P<0.01) between altitudes in Koustagerako. Cone width showed patterns of variation along the altitudinal gradient in Koustagerako, Samaria and Vorizia. Most traits had their highest means at the middle altitudes (650masl) in all the four populations. Overall, no clear altitudinal differentiation was detected, probably due to high rate of gene flow. Longitudinal variability showed a clear pattern of differentiation along the east–west climatic gradient. Needle length, width, sheath length, number of teeth per cm and the number of resin canals were the most useful traits for determining the climatic gradient clines.     

Data bank of rDNA-ITS sequences from building-rot fungi for their identification

Wood Science and Technology -     

Exotic plant species in the southern boreal forest of Saskatchewan

Exotic species possess abilities to harm the ecosystems they invade. This study assesses the density, frequency and cover of exotic plants in roadside right-of-ways, logged areas and wildfire sites within mixedwood sections of the southern boreal forest of Saskatchewan. A total of 23 exotic species were observed including nine species of Gramineae, seven species of Leguminosae and five species of Compositae. Average density of exotic species in areas recently disturbed by timber harvesting or wildfire was 0.2 stems m⁻² with a frequency of 72%. Exotic species adapted for wind dispersal were best represented including common dandelion (Taraxacum officinale), perennial sow thistle (Sonchus arvensis) and annual hawksbeard (Crepis tectorum). Only two exotic species, T. officinale and Canada bluegrass (Poa compressa), were observed in mature forest; both occurred with a frequency of 13% and an average density of 0.002 stems m⁻². A total of 22 exotic species was found in the right-of-ways quadrats with an average density of 117 stems m⁻² and a frequency of 94%. The most frequently observed exotic species in the roadside right-of-way areas were T. officinale, alsike clover (Trifolium hybridum), S. arvensis, creeping red fescue (Festuca rubra) and smooth brome grass (Bromus inermis). These species are either common agricultural weeds or were part of the original seed mixture used to establish a plant cover in the roadside right-of-ways.     

Intra-annual variations in climate influence growth and wood density of Norway spruce

Intra-annual radial growth variations of two Norway spruce trees (Picea abies (L.) Karst.) were monitored over 4 years, at four heights up the stem, by means of point-dendrometers. The trees were then felled and radial wood samples were cut from the radii that had been monitored by the dendrometers and analyzed for density. From the radial growth measurements recorded by the dendrometers, we related positions within the rings to dates, thus making possible investigation of the relationships between changes within the rings in wood density and fluctuations in climate or growth rate. Radial growth started in early April and ended, with large intra-annual differences, in August or September. Short-term variations in growth rate were related to fluctuations in climate parameters and soil water reserves. The sensitivity of radial growth to climate decreased with stem height. Wood density responded strongly to drought events, and a dry period in June 1996 induced false-ring formation. Wood density was relatively independent of growth rate and climatic conditions during the first part of the growing season, but increased with decreasing radial growth rate later in the growing season.     

Grazing and fertilizer management for establishment of Lotus uliginosus and Trifolium subterraneum under Pinus radiata in southern Chile

An experiment was conducted in southern Chile to study the effect of tree cover (0 or 200 stems of 13-year-old Pinus radiate/ha), grazing severity (8 or 12 cm height at commencement of grazing by sheep) and fertilizer application rate (low or high) on the establishment and growth of Lotus uliginosus and Trifolium subterraneum, when sown in conjunction with Festuca arundinacea. The establishment of both legumes was greater in the agroforestry than the open field, and the percentage of viable seeds that were established was greater for Trifolium than Lotus. Festuca established better when sown in conjunction with Lotus in the open field. During the two years after stand establishment there was a greater reduction in the ground cover and dry matter (DM) yield of both legumes, but in particular Trifolium, in the agroforestry than in the open field. In the second year of grazing Trifolium contributed less than 9% of total DM yield in the agroforestry, compared with 22% for Lotus. The ground cover of Lotus was increased by a tall grazing height in the agroforestry, whereas Trifolium increased its cover when the grazing height was short. Additional fertilizer at establishment had a greater effect in increasing herbage yield in the open field than in agroforestry. It is concluded that both Lotus and Trifolium establishments are greater in agroforestry than in an open field, but that in agroforestry there is a reduction in legume yield over time, particularly of Trifolium. This revised version was published online in June 2006 with corrections to the Cover Date.     

Raupen des MondvogelsPhalera bucephala L. (Lepid., Notodontidae) als Schädlinge an Obstgehölzen

Caterpillars of the buff-tip moth, Phalera bucephala L. (Lepid., Notodontidae) attacking cherry trees Observations were made on caterpillars of P. bucephala attacking cherry trees in 1972 near Schkopau (DDR). Informations are given about the symptoms of damage as well as about the food quantity needed by the pest larvae.     

Möglichkeiten,Grenzen und Aufgaben einer Kartierung von Pflanzenschädlingen

Ohne ZusammenfassungFür die Förderung der Arbeit danke ich Herrn Prof. Dr. H. v. Lengerken.