Bondability of tropical fast-growing tree species I: Indonesian wood species

To estimate the potential bonding performance of bonded wood products from tropical fast-growing tree species, a study on the bondability of Paraserianthes falcataria L. Nielsen, Pinus merkusii Jungh et. De. Vriese, and Acacia mangium Willd from Indonesia was conducted. Two-ply laminations were produced using polyvinyl acetate emulsion (PVAc), urea formaldehyde (UF), resorcinol formaldehyde (RF), and water-based polymer isocyanate (API) adhesives. In order to determine the bonding performance, the block-shear test was applied according to the Japanese Agricultural Standard for structural glued laminated timber under normal conditions and after accelerated-aging treatments. To support this study, the wettability of each wood species was also investigated through contact-angle measurement. The results showed that the bonding performance of low-density P. falcataria was better than that of medium-density P. merkusii and medium-density A. mangium, while the bonding performance of medium-density P. merkusii was better than that of medium-density A. mangium. Furthermore, compared with A. mangium, the small contact angle and good wettability in P. falcataria and P. merkusii result in better adhesion and more intimate contact between the wood surfaces and adhesive.     

5种典型热带引种园林植物幼苗抗寒性研究

选取广州地区5种常见引种园林植物的苗木,包括凤凰木、塞楝、大叶榄仁Terminalia catappa、马占相思、铁刀木作为材料,采用人工气候箱进行1℃、9℃、17℃、25℃连续18 d的不同程度冷冻处理,研究了低温胁迫下树苗生长发育有关的生理生化指标的变化与抗冻害的关系。结果表明:随着处理温度的降低,各树种叶片的相对电导率呈上升趋势,塞楝和马占相思上升比凤凰木、铁刀木、大叶榄仁慢;低温胁迫的各种苗木叶片内的脯氨酸大于对照组,其中马占相思的脯氨酸增加率最大;除塞楝外各种苗木POD活性先是缓慢升高,然后随低温胁迫程度加快升高;相对电导率结合Logistic方程推算塞楝和马占相思的半致死温度(LT50),分别为8.99℃、7.62℃。抗寒性综合评价表明,5种苗木的抗寒能力排序为马占相思>塞楝>铁刀木>凤凰木、大叶榄仁。     

Physiological responses of seedlings of two oak species to flooding stress

The physiological responses of 2-year-old seedlings of Nuttall＇s oak （Quercus nuttallii） and Southern red oak （Q.falcata） with two treatments i.e., deep-drowning and shallow-drowning, were studied. Taxodium distichum was selected as a control. The survival rates of seedlings were calculated, the photosynthetic indices were detected by Licor-6400 photosynthetic system instrument, and the root activities of seedlings were tested by the method of triphenyltetrazolium chloride （TTC）. Results showed that： 1） By experiencing flooding for 76 d and recovering for 60 d after water was drained off, all seedlings survived under the shallow-drowning treatment. None of Q. falcata seedlings died in the deep-drowning treatment until the 49th day. The survival rate of Q. falcata in the deep-drowning treatment was 30%. 2） Within 61 d of waterlogging treatments, the net photosynthetic rate （Pn）, stomatal conductance （gs） and transpiration rate （Tr） showed a tendency of declining, but intercellular concentration of CO2 （Ci） increased. With the prolongation of flooding stress, the extents of variation for all indices under deep-drowning treatment were larger than those under the shallow-drowning treatment. The variation of Q. falcata in flooding stress was larger than that of Q. nuttallii. 3） The root vigor and alcohol dehydrogenase （ADH） activities were detected at the 61st day in flooding stress. Waterlogging obviously inhibited root activities. Shallow-drowning made root vigor of Q. nuttallii decreased by 11.7%, and for Q. falcata, by 51.88%. Shallow-drowning treatment had no remarkable effects on ADH activities of seedlings, but deep-drowning increased those of Q. nuttallii seedlings by 227.24%, and decreased those of Q. falcata seedlings by 59.22% in the meantime. We conclude that Q. nuttallii had a stronger waterlogging resistance than Q. falcata, but weaker than T. distichum.     

Effects of landscape patterns on species density and abundance of trees in a tropical subdeciduous forest of the Yucatan Peninsula

Most studies of the effects of fragmentation and landscape patterns on plant communities focus on particular patches and on local species richness (α-diversity), while few studies examine different patch-types at the whole landscape level and address effects on abundance and composition of species or functional groups. The present study aims to identify and characterize relationships between patch-type metrics and species density and abundance of trees using four tropical subdeciduous forest landscapes in the Yucatan Peninsula considering the entire landscape as the unit of study. Species density and abundance of different groups of tree species resulting from hierarchical clustering were related to landscape patterns of patch-types (area, edge, shape, similarity and contrast) using regression analysis and Akaike Information Criterion (AIC). The abundance of tree species in the oldest stages of succession was associated with percentage of land of a patch-type. Total area may favor the establishment of shade-tolerant tree species in the study area because as the area of forest patches increases, the area of forest interior conditions also increases. Conversely, the abundance of species at early and intermediate stages was related to total edge contrast and edge density, respectively. Fragmentation increases the proportion of edge zones of a patch-type, creating contrasting microclimate conditions that could promote the establishment of pioneer and light-demanding species. Thus, the combined effect of total area and edge length of a patch-type may enhance total tree species richness in the study area by favoring species with different life-history strategies. The appearance of area, shape, edge and contrast in most of the regression models suggests that some generalization can be made about the effects of spatial geometry of patch-types on species composition and abundance of tropical trees. Understanding associations between landscape metrics and species density and abundance of objectively derived groups or guilds of species can provide important insights on the effects of fragmentation and landscape pattern on these guilds and on overall α-diversity, as well as guidelines for their conservation and management.     

The critical stress in various stress levels of bending member on fire exposure for mechanical graded lumber

This study focused on the relationship between stress level and the fire resistance of structural lumber. The 210 samples were prepared from 15-year-old trees of Acacia mangium from the Forest Estate Plantation, Indonesia. Specimens were 20 ® × 20 (T) × 500mm (L) and were air-dried. Sixty samples were tested under four-point bending stress to obtain the modulus of elasticity (MOE) and the modulus of rupture (MOR) for classifying the stress grades of the remaining 150 samples. The tests were performed using a four-point load bending position at various stress level while the specimens were exposed to fire along the shear-free region. Time to failure was affected by the stress levels in an exponential trend. Despite changes in stress level, charring rate, and time to failure, the critical stress of a member from the same species was similar. The fire performance under applied load could be predicted by using simplified fire-testing methods. The developed testing apparatus is valid for evaluating the small-scale fire resistant behavior of structural lumber in bending.     

Changes in surface properties of tropical wood species exposed to the Indonesian climate in relation to mold colonies

Changes in mold populations and genera on the exposed surfaces of tropical hardwoods — albizia (Paraserianthes falcata), kapur (Dryobalanop lanceolata), mahoni (Switenia macrophylla), nangka (Artocarpus heterophyllus), puspa (Schima wallchii) — were investigated. The wood specimens were exposed to the Indonesian climate for 32 weeks. Properties including mass loss, wettability, mold growth (colony-forming units), and mold genera were evaluated. The change in properties after exposure was significantly affected by the wood species, but there was no clear relation between mass loss and the initial chemical components or between wettability and wood density. The number of mold populations was different by exposure period and wood species, but there was no significant effect of climate conditions, such as rainfall and ultraviolet radiation. Of the genera identified,Aureobasidium, Cladosporium, andPenicillium were dominant molds on the exposed wood surfaces.     

干旱胁迫对5种园林绿化植物生理生化的影响

为给抗旱性较强的城市园林绿化植物的筛选提供依据,以5种园林绿化植物蛇莓、蛇莓萎陵菜、东北玉簪、紫萼玉簪和大萼铁线莲为试材,在持续干旱条件下,研究了园林绿化植物的渗透调节和抗氧化酶活性的响应特性。结果表明,持续15d干旱降低了土壤田间持水量,5种植物叶片水势和净光合速率随之下降。但是,蛇莓叶片水势和净光合速率降低的幅度比其它4种植物降低幅度小。干旱胁迫提高了叶片的丙二醛含量,细胞膜脂发生了过氧化。在持续15d干旱过程中,蛇莓和蛇莓萎陵菜叶片SOD活性增强。因此,蛇莓和蛇莓萎陵菜在干旱胁迫下能保持相对较高的光合速率,并利用酶促和非酶促系统清除氧自由基,表现出较强的抗旱能力。     

淹水胁迫对落羽杉等4个树种苗木生长的影响

采用人工控制模拟大田淹水,研究了淹水胁迫下乌桕、落羽杉、山核桃、水松4个树种在生长和形态特征上的响应。结果表明:(1)水松、落羽杉表现出较适应淹水的典型反应,在淹水茎部产生皮孔的膨大和不定根,试验结束时水松、落羽杉受淹的根系表现正常;乌桕、山核桃则表现出淹水胁迫下受到明显的伤害,叶片变小、叶片数量减少,叶片萎蔫、失绿、坏死、脱落;乌桕受淹根系部分腐烂,而山核桃受淹根系大部分腐烂,腐烂程度较乌桕严重。(2)涝处理不同程度地抑制了树种的苗高、地径、生物量、根干质量的积累,涝害指数、叶面积指数能够在一定程度上反映树种的耐涝性。(3)4个供试树种耐涝性可分为3个等级,抗涝型为水松、落羽杉,中等抗涝型为乌桕,不抗涝型为山核桃。     

铅胁迫对4种行道树生长的影响

在湖南省林业科学院林场苗圃内选择香樟、深山含笑、栾树、鹅掌揪等4个树种的1年生幼苗为试材,对其进行Pb2+胁迫试验,设定Pb2+浓度为0 mg/L(对照)、50 mg/L、400 mg/L、800 ng/L、1 600 mg/L 5个水平,每1个处理重复3次,研究不同pb2+浓度对4种行道树生长的影响.结果表明:低浓度...     

Impact of selective logging on genetic diversity of two tropical tree species with contrasting breeding systems using direct comparison and simulation methods

The impact of selective logging on genetic diversity of two tropical tree species with contrasting breeding systems was examined using direct comparison and simulation methods. Shorea leprosula is a diploid and predominantly outcrossed species, whereas Shorea ovalis ssp. sericea is an autotetraploid species with apomictic mode of reproduction. Direct comparison of adjacent natural and logged-over stands showed reduction of genetic diversity of S. leprosula, but not of S. ovalis ssp. sericea. These results clearly demonstrated that a single logging event would cause the genetic erosion of S. leprosula. However, the apomictic mechanisms and the effects of tetrasomic inheritance of S. ovalis ssp. sericea might be a way of maintaining the level of genetic diversity. These results clearly implied that outcrossing species might be more susceptible to the negative impact of logging on genetic diversity than apomictic species. Simulation studies were conducted using three approaches: (1) simulated-removal of individuals based on diameter size classes; (2) simulated-removal of individuals at random; and (3) simulated-removal of individuals in clump. The simulation study based on the first approach showed that the loss of genetic diversity was higher for the Malayan Uniform System (MUS) compared with the Selective Management System (SMS). This might suggest that SMS is more orientated towards the conservation of genetic diversity. In addition, the simulation study showed that to conserve 100% of the total number of alleles, the tolerable cutting limits of S. leprosula in the 50-ha plot of Pasoh FR should be >85 cm diameter at breast height (dbh). Comparison of simulation studies based on the second and third approaches showed that the loss of genetic diversity was more rigorous if logging activities were anticipated through extraction of trees in clump rather than to extract trees at random. Implications of the studies for conserving and managing the tropical forests are discussed.     

树木抗旱生理及造林技术研究进展

阐述了抗旱性结构、抗旱生理及抗旱造林措施方面的研究进展。在抗旱性结构方面，树木靠减少叶量和叶面积、增加根系，及叶、茎、根的旱生化结构来提高抗旱能力。在抗旱性生理方面，光合作用与蒸腾作用、酶活性、根系活力及水分参数均随着树木抗旱能力的强弱而发生变化。通过树种选择、提前整地、覆盖造林和使用保水剂等造林措施的实施，均可提高树木的抗旱能力。     

华南18个景观树种抗NO2能力研究

为探讨18个华南景观树种抗NO2污染能力,以2～3 a生实生苗为材料,通过人工气候室的盆栽试验,在NO2质量体积浓度为2.05 mg/m3的胁迫处理下,测定了叶片表观伤害症状、叶片气体交换参数及相对叶绿素含量等生理生态指标。采用隶属函数法及系统聚类分析法对其抗NO2污染能力进行了综合评价。结果表明,复羽叶栾树(Koelreuteria bipinnata)、穗花棋盘脚(Barringtonia racemosa)和广宁红山茶(Ca-mellia chekiangoleosa)抗NO2污染能力强;大花紫薇(Lagerstroemia speciosa)、紫薇(Lagerstroemia indica)、木棉(Bombax ceiba)、杜鹃红山茶(Camellia azalea)、深山含笑(Michelia maudiae)和澳洲火焰木(Brachychiton acer-ifolius)抗NO2污染能力较强;腊肠树(Cassia fistula)、仪花(Lysidice rhodostegia)和红花荷(Rhodoleia champio-nii)抗NO2污染能力中等;火焰木(Spathodea campanulata)、蓝花风铃木(Tabebuia pentaphylla)、樱花(Prunusserrulata)、红花羊蹄甲(Bauhinia blakeana)和美丽异木棉(Chorisia speciosa)抗NO2污染能力较弱,蓝花楹(Jacaranda mimosifolia)抗NO2污染能力弱。研究结果为华南重度酸污染地区景观树种选择提供参考。     

Early seedling establishment of two tropical montane cloud forest tree species: The role of native and exotic grasses

Tropical montane cloud forest has been undergoing a drastic reduction because of its widespread conversion to pastures. Once these forests have been cleared exotic grasses are deliberately introduced for forage production. Exotic grass species commonly form monodominant stands and produce more biomass than native grass species, resulting in the inhibition of secondary succession and tree regeneration. The purpose of this study was to assess the effect of native vs. exotic grass species on the early establishment of two native tree seedlings (Mexican alder, Alnus acuminata and Jalapa oak, Quercus xalapensis) on an abandoned farm in central Veracruz, Mexico. Seedling survival and growth were monitored (over 46 weeks) in relation to grass cover and height, and available photosynthetic active radiation (PAR). More seedlings survived in the presence of the native grass Panicum glutinosum than those growing with the exotic grass Cynodon plectostachyus (92% vs. 48%). The causes of seedling mortality varied between species; Q. xalapensis was affected by herbivory by voles but mainly in the exotic grass-dominated stands, whereas A. acuminata seedlings died due to competition with the exotic grass. A. acuminata seedlings increased more in height in the exotic grass-dominated stands (102 ± 7.8 cm) compared to native grass-dominated stands (51 ± 4.7 cm). Grass layer height, cover and available PAR were correlated (Pearson; p < 0.05). In the exotic grass dominated plots, grass layer height was correlated with the relative height growth rates of Q. xalapensis (Pearson; p < 0.05). These results indicate that the exotic grass may be affecting tree regeneration directly (grass competition) and indirectly (higher herbivory). Passive restoration may occur once P. glutinosum dominated pastures are abandoned. However, when C. plectostachyus dominates, introduction of early and mid successional tree seedlings protected against vole damage is needed.     

印度西部5种热带干落叶林中凋落物中生物元素和返回到绿叶中的季节性变化(英文)

本文对印度西部5种热带干落叶林中凋落物里生物元素的季节性变化和它们返回到新鲜叶中季节性变化进行研究。对5个树种:阿拉伯金合欢(Acacia nilotica L.)、金合欢(Acacia leucophloea Roxb.)、柚木(Tectonagrandis L.f.)、绒毛野独活(Miliusa tomentosa Roxb.)和紫矿(Butea mono-sperma Lain.)中凋落物的成熟叶、枝和再生部分的N、P、Ca、Mg、K和Na的浓度,以及老叶和幼叶中浓度间的关系进行调查。对这些树种的总干物质进行记录,并分析它们所含的N、P、Ca、Mg、K和Na的含量。其中阿拉伯金合欢叶子中N的含量最高,而金合欢的叶子里Ca和Mg含量最高。叶中含P最多的是阿托伯金合欢、金合欢和紫矿,而含P最少的是柚木和绒毛野独活。K和Na含量在这些树种中没有明显的区别。观察发现,N、P和K的浓度随季节变化大,但Ca和Mg则不然。唯有钾在所有树种中都是最稳定的,吸收N和P可以用于来年新叶的生长。从老叶和凋落物中吸收的营养会支持新叶的生长,并增加土壤的肥力。图1表4参30。     

高温胁迫下21个山茶种质的生理生化响应

为给山茶属植物的资源评价及进一步开发利用提供科学依据,以21个山茶种质为材料,研究了高温胁迫条件下的相对电导率、叶绿素含量、丙二醛含量和SOD活性变化情况。结果表明,随着温度的升高,21个山茶种质的相对电导率升高,且呈"S"型曲线,XSC14等5个种质的半致死高温均达60℃以上。高温胁迫促使21个山茶种质的叶绿素含量均有不同程度的下降。结合MDA含量和SOD活性测定结果,发现XSC20、XSC14耐热性较强,而XSC4耐热性较差。     

7种(品种)冬青属植物对苯气体胁迫的反应

用移液枪在密封仓中分别注入10μL、20μL、40μL和80μL的苯溶液对7种(品种)冬青属植物进行胁迫处理.结果表明:7种(品种)冬青树种净化苯污染的能力存在显著差异.7种(品种)冬青净化苯污染能力依次是:钝齿冬青、'金宝石'冬青、'蓝少女'冬青、全缘冬青、大别山冬青、刺叶冬青、冬青.生理指标测定表明,7种(品种)冬青树种耐苯胁迫的能力也存在显著差异,其中大别山冬青和刺叶冬青耐苯胁迫能力较强;'蓝少女'冬青、钝齿冬青和全缘冬青耐苯胁迫能力一般;冬青和'金宝石'冬青耐苯胁迫能力相对较差.     

云南13种乡土绿化树种对SO2、NO2气体反应的研究

采用人工模拟熏气的方法,研究了13种云南乡土绿化树种对城市SO2、NO2有害气体的反应.结果表明云南红豆杉、长梗润楠、翠柏、滇润楠、麻栗坡含笑、南亚含笑、山玉兰对SO2气体的抗性弱,而云南含笑、脉叶虎皮楠、川滇三角枫对SO2气体的抗性最强,灯台树、川滇三角枫净化SO2的能力较强,其净化量分别为300mg·kg-1、700 mg·kg-1.NO2浓度为1.0 mg·m-3时,长梗润楠、云南含笑、云南拟单性木兰、云南红豆杉、麻栗坡含笑、灯台树叶片的N净化量依次为2 000 mg·kg-1、1 100 mg·kg-1、1 700 mg·kg-1、2 300 mg·kg-1、1 200 mg·kg-1、13 100 mg·kg-1.经综合比较川滇三角枫对SO2气体具有较好的抗性和净化能力,而对NO2气体具有较好的抗性;云南含笑、云南拟单性木兰、脉叶虎皮楠等树种对SO2、NO2气体具有较好的抗性和净化能力.     

Responses of the seedlings of five dominant tree species in Changbai Mountain to soil water stress

Soil water stress was studied on the potted seedlings of five dominant tree species (Pinus koraienes Sieb.et Zucc.,Fraxinus mandshurica Rupr., Juglans mandshurica Maxim, Tilia amurensis Rupr. and Quercus mongolica Fisch.ex Turcz) from the broadleaved/Korean pine forest in Changbai Mountain. Leaf growth, water transpiration and photosynthesis were compared for each species under three soil moisture conditions: 85%-100% (high water, CK), 65%-85% (Medium water, MW) and 45%-65% (low water, LW) of 37.4% water-holding capacity in field. The results showed that the characteristic of typical drought-resistance of the leaves is significantly developed. The net photosynthetic rate and water use efficiency of Fraxinus mandshurica were higher in MW than those in CK. But for the other four species, the net photosynthetic rate and water use efficiency in CK were lower than those in MW and LW. The transpiration rate responding to soil moistures varied from species to soecies.     

水杨梅等5个树种造林耐水性比较试验

在太湖滩地采用水杨梅、光蜡树、水杉、池杉和柳树（对照）进行耐水性比较试验,结果表明：（1）在淹水深度10.0～30.0 cm、连续淹水时间40 d,水杨梅和柳树（对照）的成活率分别为100%和99.5%,光蜡树、水杉和池杉的成活率分别为19.5%,30.2%和31.1%。（2）水杨梅的耐淹水能力略高于柳树（对照）,水杨梅的生长势和生长量一切正常,且叶色翠绿。     

4种地被植物干旱胁迫下的生理响应及抗旱性评价

为了丰富关中地区园林地被植物种类,让园林企业在合理选择和应用地被植物有可靠的理论依据,以关中地区引种栽培的顶花板凳果、大吴风草、迷迭香和蜘蛛抱蛋4种常绿地被植物2年生盆栽苗为试材,采用人工控水模拟水分胁迫的方法,研究其在不同程度下的植株形态变化,并测定4种植物的萎蔫系数及叶片的游离脯氨酸、MDA、SOD、POD、CAT、可溶性蛋白以及可溶性糖等生理生化指标的变化,由此来综合评价其抗旱性。结果表明:1)从干旱临界值来看,迷迭香的最低,达到3.01%;2)从叶片游离脯氨酸含量变化来看,顶花板凳果、大吴风草及迷迭香随着干旱胁迫程度的增加呈现增长趋势,到了重度干旱胁迫,其含量分别达到对照的7.09倍、11.73倍、18.59倍;3)从MDA含量变化来看,大吴风草和迷迭香叶片中的含量同干旱胁迫程度呈正相关,蜘蛛抱蛋、顶花板凳果则整体呈现缓慢的下降趋势;4)随着干旱胁迫程度的增加,4种植物叶片可溶性蛋白含量变化均有所增加,但差异不显著。可溶性糖的含量只有蜘蛛抱蛋呈现先升后降的趋势,其余3种均呈现显著连续下降趋势;5)从叶片保护酶活性分析,干旱胁迫条件下SOD、POD和CAT均有所增加。其中顶花板凳果、大吴风草及蜘蛛抱蛋的CAT含量显著增加,增长率分别达159.28%、239.31%和200.97%;6)利用隶属函数分析4种常绿地被植物的抗旱性强弱,其顺序为:迷迭香>顶花板凳果>蜘蛛抱蛋>大吴风草,这一结果与盆栽干旱试验的形态表现一致。