Resistance of larches to bark stripping by sika deer in Hokkaido,northern Japan

Resistance of the Japanese larch (Larix kaempferi) (Lk), the Kurile larch (L. gmelinii var. japonica) (Lg), and their F₁ hybrid (Lg × Lk) to bark stripping by sika deer (Cervus nippon yesoensis) were studied in a forest in Hokkaido by cafeteria tests. Several sets of logs prepared from Lk, Lg, and Lg × Lk were fed to the deer. The stripped areas of logs significantly differed between the Lk/Lg set and the Lk/Lg × Lk set (P 0.05). The resistances of Lg and Lg × Lk to bark stripping was stronger than Lk. This result was similar to those of previous studies on gray-sided voles and mountain hares in Hokkaido.     

Lignin characteristics of bast fiber and core in kenaf, bark and wood of paper mulberry and mulberry

The structural features of bast fiber and core lignins in kenaf (Hibiscus cannabinus), bark and wood lignin of paper mulberry (Broussonetia papyrifera (L.) Vent × Broussonetia kazinoki Sieb.) and mulberry (Morus bombycis) were characterized by alkaline nitrobenzene oxidation, ozonation and methoxyl group determination. Bj?rkman lignins were isolated from bast fiber and core, and bark and wood fractions of the plant samples, and structural characteristics were investigated by ¹H NMR and ¹³C NMR spectroscopies. Kenaf bast fiber gave very high molar ratio of syringaldehyde to vanillin (S/V) of alkaline nitrobenzene oxidation products, while methoxyl content was about the same as that of the core fraction. Results of ¹H NMR and ¹³C NMR of Bj?rkman lignin suggested the presence of aliphatic fragments in lignins isolated from paper mulberry and mulberry bark, but not in kenaf bast fiber. The lower yield of alkaline nitrobenzene oxidation products from bast fiber and bark might be due to the higher content of condensed structure of lignin compared to core fraction. Total yield of erythronic (E) and threonic (T) acids of ozonation products and the molar ratio of erythronic acid to threonic acid (E/T) of the bast fibers and bark were lower than the corresponding core and wood fractions, suggesting that the contents of arylglycerol-β-aryl ether intermonomer linkages in the bast fiber and bark lignin were lower than those of the core and wood fractions. Methoxyl content of bark lignin was lower than the corresponding wood lignin. The methoxyl content of the extract-free kenaf bast fiber was similar to that of the core fraction, while the values of paper mulberry and mulberry bark were about one-half of the corresponding wood fractions, respectively. In bark lignins, the methoxyl contents of Klason lignin and Bj?rkman lignin from bark were lower than those of the extract-free barks. This result suggests that the purity of Klason lignin and Bj?rkman lignins of bark may be rather low.     

Development of a method for forest cafeteria tests for evaluating chemical deterrents against bark stripping by sika deer (Cervus nippon yesoensis)

Damage caused by sika deer (Cervus nippon yesoensis) is a serious problem in commercial and environmental (non-harvested) forests in Hokkaido, northern Japan. Cafeteria tests in forests may be useful for evaluating the efficacy of chemical deterrents against bark stripping by deer. To develop a method for forest cafeteria tests in the continuous snow cover period, two experiments were carried out. In the experiments, logs were produced from tree trunks, and used as carriers of chemical deterrents. Carriers were installed in forests and fed to deer. The first experiment was to find suitable sites and installation methods for carriers. Criteria for the local suitability and the installation methods were as follows: a) Sites where deer are active should be selected; b) Carriers should be installed along actively used deer trails; c) Installation sites of carriers should be changed in response to deer movement; d) Carriers should be produced from tree species that deer naturally prefer; and e) Each carrier should be partially buried in the snow. The second experiment evaluated the feasibility of a cafeteria test method based on the results of the first experiment. The method was used for 13 sets of the cafeteria test, in which the deterrent effectiveness of 5 chemicals (wood tar, rosin, wood vinegar, and 2 pyroligneous liquors) was examined. We obtained results from all the sets. The chemicals tested did not deter bark stripping by deer. Nevertheless, the method used in the present study was practical for the cafeteria tests.     

The influence of heterogeneous habitats on the germination ofAcanthopanax senticosus seeds and the dynamics of its seed pool

Differences in germination ofA. Senticosus, an important shrub under the Korean Pine broad-leavd forest and its secondary forest in heterogeneous habitats and the dynamics of its seed pool have been studied by observations in location. The results showed that transformation rates from seeds to seedlings were in the following order: 16.8% in Larch plantations, 4.1% in Mongolian oak forests, 2.7% in Birch forests, 1.8% in Korean Pine plantations, and 0.5% in hard wood forests. The life-span of seeds was determined to be four years in the simulating seed pool under Larch plantations. The percentage of the seedling output was, 14.5% in the 2nd year, 10.1% in the 3rd year, and 1.8% in the 4th year. Other types of the seed output were those: decayed 33.1%, senescent, 22.3%, predated by mice 14.1%, which was variable due to the variation in the number of mouse, and only 1.17% were eaten by insects and ofher soil animals. The project was supported by National Science Foud of China     

Antibacterial and antifungal activities of Angiopteris evecta

The leaves, stem bark, stem heart wood, root and tubers of Angiopteris evecta were successively extracted with petrol, dichloromethane, ethyl acetate, butanol and methanol. All the fractions exhibited a wider spectrum of antibacterial activity. The dichloromethane and ethyl acetate fractions of the leaves and stem bark were particularly good and were the only fractions exhibiting antifungal activity. All fractions of the tuber with the exception of petrol, exhibited very good antibacterial activity.     

Wood properties of <Emphasis Type="Italic">Pericopsis mooniana</Emphasis> grown in a plantation in Indonesia

The relationships between growth characteristics and wood properties were investigated for a threatened species, Pericopsis mooniana, to promote the establishment of plantations of this species in the tropics. Growth characteristics (diameter and height) and stress-wave velocity (SWV) of trees were measured for 22-year-old P. mooniana trees planted in Indonesia. The trees were categorized into three groups, fast-growing, middle-growing, and slow-growing trees, to investigate the effect of growth rate on the wood properties. In addition, radial variation of anatomical characteristics and wood properties were determined. No significant correlation was found between growth characteristics and SWV. The values for the vessel diameter, cell wall thickness of wood fibers, wood fiber length, basic density, modulus of elasticity, and modulus of rupture from wood at the bark side were higher than those at the pith side. On the other hand, vessel frequency gradually decreased from pith to bark. These results suggested that low-quality wood, such as juvenile wood, existed near the pith area.     

Herbizideinsatz und Mäuse in Forstkulturen

Application of herbizides and voles in forest plantations Two areas in different spruce plantations were treated with Gramoxone® (Paraquat). Changes of the density of small mammals especially of the Field Vole(Microtus agrestis) and the Common Vole(Microtus arvalis) were observed. Residues of Paraquat in the excretions of marked individuals in the treated area were not detected with few exception. The problem of debarking young trees by starving voles and food scarcity caused by the weedkiller is discussed.     

35年生大花序桉生材性质研究

为研究大径级大花序桉人工林的基本木材性质,采用排水法对35年生大花序桉人工林木材的生材密度、基本密度、树皮率、心材率以及生材含水率等指标进行了测试。结果表明:35年生大花序桉的树皮体积百分率为8.92%,树皮质量百分率为12.35%,生材密度为1.12g·cm^-3,基本密度为0.76g·cm^-3,生材含水率为44.79%。各部位含水率差别不大,各指标表现都很好。     

Antibacterial and antifungal activities of Breynia cernua

The Breynia cernua leaves, stem and root barks and heart-woods extracted with petrol, dichloromethane, ethyl acetate, butanol and methanol gave fractions with varied level of antimicrobial activity. The best activity was exhibited by the methanol extract of the root bark followed by its butanol fraction. These were the only fractions exhibiting a good level of antifungal activity as compared to the standard. The dichloromethane fraction of the stem bark also demonstrated good activity.     

Screening of extracts of Japanese woods for melanin biosynthesis inhibition

The effects of 120 methanol extracts prepared from bark and heartwood of 69 types of Japanese wood on the melanin production of B16 melanoma cells were examined. The melanin content of B16 melanoma cells was determined spectrophotometrically at 405nm. The extracts were also examined for their effects on cell viability. We found that the methanol extracts of Fagus crenata (buna, wood, 100μg/ml), Sapium sebiferum (Nankinhaze, wood, bark, 10μg/ml), and Zelkova serrata (keyaki, wood, 10μg/ml) greatly inhibited the melanin production of B16 melanoma cells without significant cytotoxicity. However, these extracts did not inhibit tyrosinase activity at the concentration of 100μg/ml. These findings indicate that the depigmenting mechanism of these extracts involves the suppression of some pigmenting signals in stimulating melanogenesis rather than the inhibition of tyrosinase activity. Part of this study was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, Japan, March 2003     

Possibility of improvement in fundamental properties of wood of acacia hybrids by artificial hybridization

Growth, specific gravity, and wood fiber length of Acacia mangium, Acacia auriculiformis, artificial acacia hybrid clones, and combinations, which were planted in a trial forest in Bavi, Vietnam, in July 2001, were examined. The radial variations from pith to bark were investigated to clarify the effect of genetic factors on these traits. Superiority of hybrids over their parents ranged from 36.3% to 41.6% for diameter, from 20.0% to 25.3% for height, from 6.9% to 20.7% for specific gravity, and from 6.1% to 12.8% for wood fiber length. The hybrid possessed heterosis in diameter, height, specific gravity, and wood fiber length regardless of whether the female parent was A. mangium or A. auriculiformis. The profiles of wood fiber length and specific gravity in the radial direction were similar for all the trees investigated. Wood fiber length was initially 0.5–0.6 mm near the pith and then increased slowly, finally reaching 1.0–1.2 mm near the bark. The specific gravity of acacia increased from 0.49–0.58 near the pith to 0.63–0.74 near the bark. From a relative distance of 30% from the pith, the specific gravity increased slightly and seemed to be stable. The relations among tree diameter, specific gravity, and wood fiber length were fair and could be represented by positive linear regression formulas. Hybrids for which A. auriculiformis was the female parent and A. mangium was the male parent had a faster growth rate and longer wood fibers than the inverse hybrids. Part of this report was presented at the 6th Pacific Regional Wood Anatomy Conference, Kyoto, Japan, December 2005     

异叶南洋杉人工林木材生材性质研究

为合理利用异叶南洋杉人工林木材,通过排水法、质量法和数值法对异叶南洋杉人工林的生材性质展开研究,结果表明,异叶南洋杉人工林木材树皮体积百分率、质量百分率、生材密度、基本密度和生材含水率的平均值分别为11.39%、13.78%、0.842 g/cm³、0.394 g/cm³和121.43%。随异叶南洋杉树高的增加,树皮体积百分率和质量百分率总体呈增大趋势;生材密度和基本密度总体呈下降趋势;生材含水率总体呈先升高后降低的趋势。以期为异叶南洋杉人工林木材的合理利用提供数据支持和理论支撑。     

Antibacterial and antifungal activities of Euroschinus papuanus

The crude methanolic extracts of the leaves, stem bark, stem heart wood, root bark and root heart wood of Euroschinus papuanus and the fractions obtained on partitioning with petrol, dichloromethane (D), ethyl acetate (E) and butanol (B), exhibited a broad spectrum antibacterial activity. Fractionation drastically enhanced the activity. Excellent activity was demonstrated by the E fractions of stem heart wood, D of root bark, and E of root heart wood. Antifungal activity was exhibited by the B fractions of leaves, stem heartwood and root bark.     

Lignification and peroxidase in tension wood ofEucalyptus viminalis seedlings

Seedlings ofEucalyptus viminalis were grown for 50 days with their stems bent so tension wood would form. Every 10 days the lignin content, monomeric composition, and peroxidase activity in the tension wood were compared with those in the lower side (opposite wood) and in vertically grown controls. The lignin content in the developing tension wood started to decrease after 10 days of bending and kept decreasing for 50 days, whereas those in control plants and opposite wood remained almost unchanged. The yields of syringaldehyde from tension wood by nitrobenzene oxidation increased, and consequently the syringyl/ guaiacyl ratio of the lignin was higher in tension wood than in opposite wood and control plants. The peroxidase ionically bound to the cell walls (IPO) catalyzed oxidation of guaiacol and syringaldazine. The syringaldazineoxidizing activity of IPO from tension wood increased, whereas the activities of IPO from opposite wood and control plants did not show any marked change. In tension wood the increase in syringaldazine-oxidizing activity of IPO was consistent with an increase in the syringaldehyde yield. This suggests that IPO contributes to syringyl lignin deposition as other enzymes involved in the monolignol biosynthesis do in tension wood formation.This study was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

Effects of bark stripping by sika deer, Cervus nippon, on wind damage to coniferous trees in subalpine forest of central Japan

We evaluated the effect of bark stripping by sika deer (Cervus nippon), and subsequent wood decay, on tree fall in a coniferous forest on Mt Ohdaigahara in central Japan from July to September 2006. This valuable primeval coniferous forest is declining because of bark stripping. Broken trunks of Abies homolepis and Picea jezoensis var. hondoensis had more serious decay and larger bark-stripping wounds on the trunk than standing trees, suggesting that bark stripping causes trunk decay and results in broken trunks and uprooting by typhoons.     

南京地区黑翅土白蚁饵料筛选与取食记忆研究

通过不同林分黑翅土白蚁采食工蚁的饵料筛选结果,分析白蚁取食经历对食物选择的影响。结果表明:来自不同林分的黑翅土白蚁喜食树种最佳为鹅掌楸树皮粉,其工蚁数量、泥被覆盖率和饵料被食率均较高,泥被出现时间在所有饵料中也相对较早。筛选出的辅食饵料最佳比例为15%小米粉和5%蔗糖,高糖分对黑翅土白蚁仅有短暂的诱食作用,一段时间后,高糖分诱食作用减退。白蚁采食工蚁存在取食记忆现象,取食记忆的持续时间与原取食材料在食物资源中的嗜食序列有关。若原取食材料属于食物选择试验中最嗜食物质,取食记忆可持续存在;否则,一定时间后发生食物选择的改变。试验筛选出最佳饵料配方为80%鹅掌楸树皮粉+15%小米粉+5%蔗糖,采食工蚁对不同树种树皮粉的取食选择可能与化学成分有关。     

Bark stripping by moose on young Pinus sylvestris in south‐central Sweden

Bark stripping by moose (Alces alces L.) on young Scots pine (Pinus sylvestris L.) was studied at the Grimsö Wildlife Research Area in south‐central Sweden. The investigation was launched to attempt to elucidate the underlying mechanism(s) for this behaviour. To document the seasonal pattern of bark stripping by moose, four young Scots pine plantations were observed between August 1988 and November 1989. In addition, pine bark samples were collected systematically throughout the study period, and the composition of various nutrients, minerals, and fibre fractions and their digestibility were determined. The occurrence of bark stripping was significantly higher in April and May, coinciding with an increase in fibre, K, starch and total carbohydrate concentrations, and decreasing crude protein, P and Mg content. Results are discussed with respect to the potential relationship between bark stripping and nutrient deficiencies in moose and the potential mechanisms inducing bark stripping.     

桉树木材皱缩形成机制与调控研究进展

文章综述了近年来国内外学者对桉树木材皱缩形成机制的研究进展, 分析了可有效防止木材皱缩的后期调湿处理、热处理、加压或拉伸处理以及预冻处理等主要预处理方法对减少木材皱缩的作用, 展望了今后木材皱缩研究的发展趋势, 以期为我国桉树人工林资源高附加值利用提供参考。     

The effect of bark decortication for hiwada production on xylem and phloem formation in Chamaecyparis obtusa

Of all plant materials used to cover the roofs of traditional Japanese buildings, Japanese cypress (Chamaecyparis obtusa) bark, hiwada, has the longest service life and has been used from ancient times. However, wood and bark properties after hiwada harvest have not been evaluated in detail. We studied whether decortication for hiwada production in winter affected xylem and phloem formation. Decorticated trees still preserved all inner bark and part of the outer bark, and both decorticated and control trees had similar annual ring structures at all stem heights in the xylem and phloem. In both xylem and inner bark, no significant difference in ring width at any stem height was found between annual rings before and after decortication. Thus, this study revealed that the decortication of bark for hiwada production does not affect the formation of xylem and the inner and outer bark if decortication is carried out by highly skilled workers in winter.     

Walnut hoarding by the Japanese wood mouse,Apodemus speciosus Temminck

Walnuts,Juglans ailantifolia Carriere, are large and the shell is difficult to open. Thus, seed predators in Japan are restricted mainly to the Japanese squirrel (Sciurus lis Temminck) and the wood mouse (Apodemus speciosus Temminck), which can shave away the hard shells with their sharp incisors. Previous work indicated that the squirrels are not only predators, but also disperse walnuts. In this study, 95 walnuts in Period1 (September 1996–February 1997) and 80 walnuts in Period 2 (September 1999–February 2000) each attached to a miniature radio transmitter, were placed in a feeding box, and 93 and 53 of them were transported by free-living wood mice in the respective periods. Most of the walnuts provided from September to November were scatter-hoarded in the litter layer, while from December to February, the mice fed immediately and seldom scatter-hoarded on the ground surface. In all, 66 walnuts were hoarded and 80 were eaten soon after discovery, although walnuts were eaten more frequently in Period 1 than in Period 2, which may be related to annual differences in seed crop size in the study site. The mean transport distance of hoarded seeds was 6.2 ± 5.0 m (mean ± SD,n=66). The fate of hoarded walnuts was followed from September 1996 to May 1997; 21 (75%) of the scatter-hoarded walnuts were recovered, but 7 (25%) were left uneaten. Consequently, the Japanese wood mouse also plays a role in seed-dispersion of the walnut, but the transport distance for mice was shorter than that for squirrels.