The influences of boiling and drying treatments on the behaviors of tension wood with gelatinous layers in <Emphasis Type="Italic">Zelkova serrata</Emphasis>

This study examined how boiling and drying treatments influenced various physical properties of the tension wood with gelatinous fibers (G-fibers) of a 29-yearold Zelkova branch. By boiling treatment, tension wood with numerous G-fibers contracted considerably in the longitudinal direction and the longitudinal Young’s modulus decreased in spite of the water-saturated condition. The drying treatment caused green tension wood and boiled tension wood with numerous G-fibers to shrink longitudinally and increased their longitudinal Young’s moduli. These specific behaviors in tension wood were highly correlated with the proportion of G-fibers in a specimen and were probably caused by the microscopic behavior of cellulose microfibril (CMF) in the gelatinous layers (G-layers). The longitudinal shrinkage of tension wood due to drying suggests the existence of a hygro-sensible, noncrystalline region in the CMF, which is abundant in the G-layer. Furthermore, the noncrystalline region in the CMF softens during boiling treatment, resulting in the reduction of the longitudinal Young’s modulus in tension wood. The longitudinal contraction of tension wood with G-fibers by boiling might be caused by the tensile growth stress remaining in green G-layers. However, no changes were detected in the 004 d-spacing of cellulose crystal in tension wood from the boiling and drying treatments, regardless of the proportion of G-fibers.     

Effects of different ecological and silvicultural factors on beetle catches in the Turkish fir (<Emphasis Type="Italic">Abies bornmülleriana</Emphasis> Mattf.) ecosystems

To study the bark beetle attacks on Turkish fir stands and to determine the principle site and stand factors influencing beetle attacks, trap log method was used in the Western Black Sea Region of Turkey. The study was carried out in ten different locations prior to flying time in February 2003. On each experimental plot, three healthy fir trees with 30–50 cm diameter and 200 m apart were cut down with a chainsaw. From each sampling tree, needles were sub-sampled for determination of specific leaf-area and macro-nutrient concentrations. In addition, on each experimental plot, crown closure, basal-area, and stand density were measured. To determine the bulk density and nutrient concentrations of the soil, samples were taken around trees on each plot. The relationship between measured stand variables, the number of beetle species and beetle populations were evaluated using correlation and stepwise multiple regression procedure. Eight different species belonging to four different families from Coleoptera were identified in examining the trap logs. Six of these eight species (Pissodes piceae Illig., Pissodes notatus Fabr., Cryphalus piceae Ratz., Pityophthorus pityographus Ratz., Xyloterus lineatus Oliv., Pityokteines curvidens Germ.) were identified as harmful beetles (HB). The other two (Thanasimus formicarius L. and Rhizophagus dispar Payk.) were identified as predator species. The analysis showed that the total number of HB increased as the site’s slope and needle specific leaf area increased. However, as needle N concentrations increased, HB population decreased. Increased Ca concentration in fir needle reduced total insect attack.     

Structure-function relationships during secondary phloem development in an angiosperm tree,Aesculus hippocastanum: microtubules and cell walls

We studied the dynamics of the cortical microtubule (CMT) cytoskeleton during differentiation of axial secondary phloem elements in taproots and epicotyls of Aesculus hippocastanum L. (horse-chestnut) saplings. Indirect immunofluorescence microscopy of alpha-tubulin and transmission electron microscopy revealed that fusiform cambial cells possessed a reticulum of CMTs in which individual microtubules were randomly arranged. During differentiation of these cambial cell derivatives into secondary phloem cells, the CMTs were rearranged to become helically oriented, regardless of phloem cell type. Although helical CMTs were a persistent feature of all axial elements of the secondary phloem (sieve elements, companion cells, phloem parenchyma, and fiber-sclereids), some modifications of this arrangement occurred as cells differentiated. Thus, at late stages of cell differentiation, sieve elements possessed nearly transverse CMTs, pronounced bundling of CMTs was seen in phloem parenchyma, and the density of CMTs in the helical arrays of fibers increased markedly. Additionally, phloem parenchyma possessed rings of CMTs in association with developing pit areas. Aspects of the development and chemistry of cell walls were also examined during phloem cytodifferentiation.     

Parasitoid Wasps as Flower Visitors in the Canadian High Arctic

Summary Collections and observations were made in 1963 and 1967 on insects visiting flowers at Hazen Camp and Gilman Camp on Ellesmere Jsland, N. W. T. Canada. The results giving the species of parasitoid Hymenoptera, the flowers visited, and their activity, are shown in this paper (Table 1).18 species with 50 specimens of 13 genera are listed. Most of them could be found feeding in the nectar of flowers and carrying pollen.The attractiveness of white blooms to parasitoid wasps, observed in different regions, also holds in the High Arctic, whereStellaria longipes visitors account for 35 in 7 genera out of a total of 41 in 13 genera.

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Zusammenfassung Parasitische Schlupfwespen als Blütenbesucher im kanadischen hohen Norden Im Sommer 1963 und 1967 wurden im Hazen Camp und Gilmann Camp auf der hochnordischen Ellesmere-Insel Beobachtungen und Sammlungen bezüglich Blüten besuchender Insekten durchgeführt. In der vorliegenden Arbeit sind in Tabelle 1 die gefundenen parasitischen Hymenopteren zusammengestellt.18 Arten mit 50 Individuen aus 13 Gattungen wurden gefunden, und zwar aus den Familien Chalcididae (3 Arten), Eulophidae (1), Pteromalidae (1), Braconidae (3), Ichneumonidae (9) und undeterm. (1). Am häufigsten war mit 22 Individuen die IchneumonideStenomacrus spec. anStellara-, Saxifraga- undDryas- Blüten vertreten. Es scheint, daß alle Ichneumoniden-Arten Nektar als Betriebsstoff für ihren Flug aufnehmen. Aber auch je eine Chalcididen-, Eulophiden- und Pteromaliden-Art wurden als Nektarfresser festgestellt.Von jeder beobachteten und anschließend gefangenen Schlupfwespe wird die Tätigkeit an der Pflanze skizziert. Am Körper der meisten Arten fanden sich Pollenkörper. Die in der Literatur aus anderen Gebieten der Erde berichtete besondere Attraktivität weißer Blüten auf parasitische Hymenopteren. wurde auch im Hohen Norden beobachtet: an den weißen Blüten vonStellaria longipes wurden 35 von 41 einzeln registrierten Individuen aus 7 Gattungen angetroffen.

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Contribution No. 920,Plant Research Institute of Agriculture, Canada Department, Ottawa, Canada.     

Distribution of boron in wood treated with aqueous and methanolic boric acid solutions

The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)₃] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)₃ was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution. PGA confirmed that B(OH)₃ was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than the methanolic solution. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281     

Effect of thermo-mechanical refining on properties of MDF made from black spruce bark

The effects of thermo-mechanical refining conditions on the properties of medium density fiberboard (MDF) made from black spruce (Picea mariana) bark were evaluated. The bark chips were refined in the MDF pilot plant of Forintek Canada Corporation under nine different refining conditions in which preheating retention time was adjusted from 3 to 5 to 7 min and steam pressure was set at either 0.6, 0.9 or 1.2 MPa. The resulting bark fibers were blended with 12% UF resin (based on oven-dry fiber weight) using a mechanical blender. The resinated fibers were manually formed into fiber mats and hot-pressed into MDF panels using consistent parameters. Two panels for each refining condition were produced, resulting in a total of 18 panels. Analysis of variance (ANOVA) was used to analyze the significance of factors. Regression coefficients and 3D contour plots were used to quantify the relationship between panel properties and the two test factors. The results from this study indicated that the preheating retention time was a significant factor for both modulus of rupture (MOR) and modulus of elasticity (MOE), the steam pressure was a significant factor for internal bond strength (IB), MOR and MOE, whereas both factors were insignificant for thickness swelling, water absorption and linear expansion. The properties of MDF panels were quadratic functions of retention time and steam pressure. Compared to the ANSI standard for 120-grade MDF, most panels with a nominal density of 950 kg/m³ had very high IB (>1 MPa) and acceptable MOR, MOE and dimension stabilities. These results suggest that black spruce bark residues can be considered as a potentially suitable raw material for manufacturing MDF products.     

The role of land tenure in conservation of tree and shrub species diversity in miombo woodlands of southern Malawi

Biodiversity is declining throughout southern African miombo woodlands due to poor land use practices that are detrimental to soil, vegetation and habitat. We aimed at examining tree and shrub species diversity and distribution in Uapaca kirkiana-dominated woodlands under three land tenure types; forest reserves, customary and leasehold land. The study was conducted at different forest sites within similar agroecological zone in southern Malawi. Study sites were located at a range of altitudes between 900 and 1,200 m a.s.l. Three circular plots each with 32.60 m radius were established at each study site to sample tree and shrub species composition, structure and distribution under three land tenure types. We found that forest reserves had higher species diversity with an average of 16 tree families, 27 genera and 34 species as compared to only 10 tree families, 6 genera and 6 species on customary forest lands. Comparisons of diameter at breast height size class distributions showed that customary land had significantly low numbers of small (5.0–10.0 cm) and very large (≥30 cm) diameter classes suggesting lower levels of regeneration and high rate of anthropogenic activities. The high species diversity and richness in forest reserves and leasehold land indicate high potential for protected lands to restore tree species diversity. It is concluded that levels of human activities as influenced by land tenure type reduce tree species diversity, composition and distribution at the different sites, and this confirms the hypothesis that open access lands are not compatible with conservation of tree and shrub species diversity because of high anthropogenic activities.     

Adaptation of Asia-Pacific forests to climate change

Climate change is a threat to the stability and productivity of forest ecosystems throughout the Asia-Pacific region. The loss of forests due to climate-induced stress will have extensive adverse impacts on biodiversity and an array of ecosystem services that are essential for the maintenance of local economies and public health. Despite their importance, there is a lack of decision-support tools required to evaluate the potential effects of climate change on Asia-Pacific ecosystems and economies and to aid in the development of regionally appropriate adaptation and mitigation strategies. The project Adaptation of Asia-Pacific Forests to Climate Change, summarized herein, aims to address this lack of knowledge and tools and to provide support for regional managers to develop effective policy to increase the adaptive capacity of Asia-Pacific forest ecosystems. This objective has been achieved through the following activities: (1) development of a high-resolution climate downscaling model, ClimateAP, applicable to any location in the region; (2) development of climate niche models to evaluate how climate change might affect the distribution of suitable climatic conditions for regionally important tree species; (3) development and application of forest models to assess alternative management strategies in the context of management objectives and the projected impacts of climate change; (4) evaluation of models to assess forest fire risk and the relationship between forest fire and climate change; (5) development of a technique to assess ecosystem carbon storage using LiDAR; and (6) evaluation of how vegetation dynamics respond to climate change using remote sensing technology. All project outputs were developed with a focus on communication and extension to facilitate the dissemination of results to regional forest resource managers to support the development of effective mitigation and adaptation policy.     

Antimicrobial flavonoids from the stem bark of Erythrina burttii

The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed against fungi and Gram(+) bacteria, but the Gram(-) bacteria Escherichia coli was resistant.