Antifungal effect of bark extracts from some European tree species

The inhibitory effect of methanol bark extracts from six deciduous and three coniferous European tree species were bioassayed against eight fungi from the different damage categories, brown rot, white rot, canker and blue-stain. This is the first report providing data on the antifungal activity of several Europaen tree species against fungi within these damage categories. Generally the decay fungi were more inhibited by the bark extracts than the blue-stain fungi, while the lowest inhibition was found among the cancer fungi. The main pattern found between the fungal groups in relation to the bark extracts in this study is believed to be caused by the route of ingress. Acer platanoides bark extract proved to be the most efficient bark extract tested, significantly reducing the growth rate of all tested fungi. Betula pubescens bark extract generally gave the weakest reduction in growth rate. In this study, the conifer bark extracts were in general more active against the canker and blue stain ascomycete fungi than the deciduous trees extracts.     

南岳树木园木兰科树种物候特征观察研究

通过对39种木兰科树种进行物候观察,弄清了各物候期时间:树液流动始期集中在2月下旬,萌芽集中在3月和4月初,幼叶的生长集中在3~4月,花期集中在3~5月,果熟期集中在9~10月。并根据当地气候,求算出积温生长指标,弄清了这39种木兰科树种生物学零度为5.0~10.0℃,各物候期所需积温分别为:展叶活动积温192.4~1 364.0℃,有效积温变幅在55.9~759.2℃之间,开花活动积温75.0~1 121.9℃,有效积温23.0~591.8℃,果成熟活动积温4 023.9~5 436.7℃,有效积温变幅在2 457.9~3 821.2℃之间。分析了各积温的标准差和变异系数,开花物候期变异较大,果成熟和生长停止期的变异较小,为引种驯化栽培提供参考。     

Generalized allometric volume and biomass equations for some tree species in Europe

Since biomass is one of the key variables in ecosystem studies, widespread effort has aimed to facilitating its estimation. Numerous stand-specific volume and biomass equations are available, but these cannot be used for scaling up biomass to the regional level where several age-classes and structural types of stands coexist. Therefore simplified generalized volume and biomass equations are needed. In the present study, generalized biomass and volume regression equations were developed for the main tree species in Europe. These equations were based on data compiled from several published studies and are syntheses of the published equations. The results show that these generalized equations explain 64–99% of the variation in values predicted by the original published equations, with higher values for stem than for crown components.

Studies on root distribution of five multipurpose tree species in Doon Valley,India

Observations on the growth performance, rooting behaviour and distribution of fine roots of five tree species viz., Bauhinia purpurea, Grewia optiva, Eucalyptus tereticornis, Leucaena leucocephala and Ougeinia oojeinensis (Family: Papilionaceae) are being presented here. Roots were exposed at the time of planting, 6 months, 16 months, and 28 months after planting. Total root weight and root volume were highest in Eucalyptus tereticornis and lowest in Bauhinia purpurea. Major part of the root system confined within 90–120 cm soil depth in case of Bauhinia purpurea, Grewia optiva and Leucaena leucocephala but Eucalyptus tereticornis and Ougeinia oojeinensis strike their roots to deeper depths. Bauhinia purpurea had its roots evenly distributed down to 120 cm. In general, the vertical distribution of fine roots (< 2 mm in diameter) of the five species indicate that more the depth, fewer the number of roots. The observations on soil binding capacity, indicated that Ougeinia oojeinensis had the maximum and Eucalyptus tereticornis had the minimum binding value. Due to leaf shading and other litter fall significant increase of nutrient components in soils under the tree canopies has been observed. The study indicates that bulk of the roots of the five tree species are found near the surface, but observation on soil moisture and nutrient content does not indicate variation under the tree canopies and in open, hence there may not be root competition in initial years of plantation.Authorised for publication by the Institute as contribution No.3311/239/89.     

一些竹种在不同季节不定根诱导的形式

考察了季节和植物激素、非植物激素生长调节剂对不定根形成的影响,以进行黄竹、孝顺竹、马甲竹和龙竹无性繁殖。在冬天,夏天和雨季的3个生长季节,将成熟秆截取成单节扦插方式,并用IAA,IBA、NAA、硼酸和水进行24h处理。之后,将扦插秆水平放置,盖上沙子,在喷雾箱中放2个月。     

Wood specific gravity of some tree species in the Garhwal Himalayas,India

Estimation of terrestrial biomass depends critically on reliable information about wood specific gravity of forest trees. In recent years, wood specific gravity has become more important when exploring the universality of functional traits of plants and estimating their global carbon stocks. To estimate their specific gravity, wood samples were collected from a total of 34 tree species, 30 from lower elevations and 4 from upper elevations in the Garhwal Himalayas, India. The results show that the average wood specific gravity was 0.631 (ranging between 0.275 ± 0.01 and 0.845 ± 0.03) for the species at lower elevations and 0.727 (ranging between 0.628 ± 0.02 and 0.865 ± 0.02) for the upper elevations. The average wood specific gravity for the upper elevation species was 9.6% greater than that for the species at lower elevations. Aegle marmelos among the lower elevation species and Quercus leucotrichophora among the upper elevation species had the highest wood specific gravity, which were 0.845 ± 0.03 and 0.865 ± 0.02, respectively.     

Structural root form and fine root distribution of some woody species evaluated for agroforestry systems

Fine root distribution and structural root characteristics of four-years-old multipurpose woody species with potential for use in agroforestry systems were investigated on an Alfisol in the forest savanna transition zone of south-western Nigeria. Rooting patterns of woody species studied differed considerably. Lonchocarpus sericeus had the lowest percentage (21%) of total fine roots confined to the upper (0 to 30 cm) soil layer, compared to 84% with Tetrapleura tetraptera. Despite the superior tap root system of Enterolobium cyclocarpum and the fine root form of Nauchlea latifolia however, their extensive distribution and very large lateral woody root volume density may pose a major problem for seedbed preparation and tillage operations in simultaneous agroforestry systems. Lonchocarpus sericeus appears to have the most desirable structural and fine root architecture among the species studied for simultaneous agroforestry systems. The total root density below the underlying distal soil layers was linearly related to the sum of square of tap root diameter and the corresponding soil depths. This revised version was published online in June 2006 with corrections to the Cover Date.     

Biomass prediction using generalized allometric regressions for some northeast tree species

Generalized allometric equations for several tree species were developed to assess the feasibility of using such equations for sites other than those for which they were developed. Regressions relating weight of stem, branch, and total above ground biomass to DBH (diameter at breast height, 1.3 m) were compiled for six species from the literature and used to generate new generalized regressions by species and plant part. Mean differences between values predicted by the generalized regressions and estimates from original regressions for total above ground weight were generally within the range of errors of estimate reported for individual regressions. The generalized regressions do not introduce bias into the results with increasing dbh. Differences between the generalized regressions and the original regressions for stem and branch weights of all species were considerably higher. Tests of generalized regressions against field data for sugar maple and aspen indicate excellent prediction by a generalized maple regressions but somewhat less accurate predictions by generalized aspen regressions.     

Topology, scaling relations and Leonardo's rule in root systems from African tree species

Aspects of root architecture, including topology, link length, diameter and scaling relations, were analyzed in excavated coarse root systems of three field-grown fruit tree species (Strychnos cocculoides Bak., Strychnos spinosa Lam. and Vangueria infausta Burch) and the fruit-bearing shrub Grewia flava DC. We investigated the root systems using semi-automatic digitizing and computer-based 3-D reconstruction techniques. Topological analysis was carried out to investigate branching patterns as basic determinants of root architecture. New topological indices were developed and revealed significant differences among the species. The different architectural strategies can be explained in terms of cost-benefit relations and efficiency in soil resource exploration and exploitation. In addition, some well-known hypotheses about geometry and scaling, most of them previously unverified by empirical observations on root systems, were tested. For practical applications, the main emphasis is on the relationship between proximal root diameter, an easily determined parameter, and several parameters describing the size of the whole root system. We also tested the "pipe stem" theory, essentially dating back to Leonardo da Vinci, which underlies many models and which we found conformed to our measurement data with reasonable accuracy. A physiological consequence of the "constant cross-sectional area rule" may be a certain homogeneity of hydraulic architecture throughout root systems.     

Differences in transpiration between a forest and an agroforestry tree species in the Sudanian belt

Average population growth in the African Sudanian belt is 3 % per year. This leads to a significant increase in cultivated areas at the expense of fallows and forests. For centuries, rural populations have been practicing agroforestry dominated by Vitellaria paradoxa parklands. We wanted to know whether agroforestry can improve local rainfall recycling as well as forest. We compared transpiration and its seasonal variations between Vitellaria paradoxa, the dominant species in fallows, and Isoberlinia doka, the dominant species in dry forests in the Sudanian belt. The fallow and dry forest we studied are located in northwestern Benin, where average annual rainfall is 1200 mm. Sap flow density (SFD) was measured by transient thermal dissipation, from which tree transpiration was deduced. Transpiration of five trees per species was estimated by taking into account the radial profile of SFD. The effect of the species and of the season on transpiration was tested with a generalized linear mixed model. Over the three-year study period, daily transpiration of the agroforestry trees, V. paradoxa (diameters 8–38 cm) ranged between 4.4 and 26.8 L day^?1 while that of the forest trees, I. doka, (diameters 20–38 cm) ranged from 9.8 to 92.6 L day^?1. Daily transpiration of V. paradoxa was significantly lower (15 %) in the dry season than in the rainy season, whereas daily transpiration by I. doka was significantly higher (13 %) in the dry season than in the rainy season. Our results indicate that the woody cover of agroforestry systems is less efficient in recycling local rainfall than forest cover, not only due to lower tree density but also to species composition.     

6种生防真菌、细菌防治牡丹根腐病的研究

6种生防菌对牡丹根腐病病原菌Fusarium solani的室内抑菌测定表明，6种生防菌均有一定抑菌效果，以康宁木霉菌Trichoderma koningii(TK1)和枯草芽孢杆菌Bacillus subtilis的两个菌株(BA31、BXN)抑菌效果最好，均达80％以上；6种生防菌制剂的田间药效试验结果表明，BA31和TK1效果最好，每株2g，一个生长季节施药4次，防治效果均达到70％以上。     

Patterns of root respiration rates and morphological traits in 13 tree species in a tropical forest

The root systems of forest trees are composed of different diameters and heterogeneous physiological traits. However, the pattern of root respiration rates from finer and coarser roots across various tropical species remains unknown. To clarify how respiration is related to the morphological traits of roots, we evaluated specific root respiration and its relationships to mean root diameter (D) of various diameter and root tissue density (RTD; root mass per unit root volume; gcm(-3)) and specific root length (SRL; root length per unit root mass; mg(-1)) of the fine roots among and within 14 trees of 13 species from a primary tropical rainforest in the Pasoh Forest Reserve in Peninsular Malaysia. Coarse root (2-269mm) respiration rates increased with decreasing D, resulting in significant relationships between root respiration and diameter across species. A model based on a radial gradient of respiration rates of coarse roots simulated the exponential decrease in respiration with diameter. The respiration rate of fine roots (<2mm) was much higher and more variable than those of larger diameter roots. For fine roots, the mean respiration rates for each species increased with decreasing D. The respiration rates of fine roots declined markedly with increasing RTD and increased with increasing SRL, which explained a significant portion of the variation in the respiration among the 14 trees from 13 species examined. Our results indicate that coarse root respiration in tree species follows a basic relationship with D across species and that most of the variation in fine root respiration among species is explained by D, RTD and SRL. We found that the relationship between root respiration and morphological traits provides a quantitative basis for separating fine roots from coarse roots and that the pattern holds across different species.     

Differences in leaf gas exchange and water relations among species and tree sizes in an Arizona pine-oak forest

We compared leaf gas exchange and water potential among the dominant tree species and major size classes of trees in an upland, pine-oak forest in northern Arizona. The study included old-growth Gambel oak (Quercus gambelii Nutt.), and sapling, pole, and old-growth ponderosa pines (Pinus ponderosa var. scopulorum Dougl. ex Laws.). Old-growth oak had higher predawn leaf water potential (Psi(leaf)) than old-growth pine, indicating greater avoidance of soil water stress by oak. Old-growth oak had higher stomatal conductance (G(w)), net photosynthetic rate (P(n)), and leaf nitrogen concentration, and lower daytime Psi(leaf) than old-growth pine. Stomatal closure started at a daytime Psi(leaf) of about -1.9 MPa for pine, whereas old-growth oak showed no obvious reduction in G(w) at Psi(leaf) values greater than -2.5 MPa. In ponderosa pine, P(n) and G(w) were highly sensitive to seasonal and diurnal variations in vapor pressure deficit (VPD), with similar sensitivity for sapling, pole, and old-growth trees. In contrast, P(n) and G(w) were less sensitive to VPD in Gambel oak than in ponderosa pine, suggesting greater tolerance of oak to atmospheric water stress. Compared with sapling pine, old-growth pine had lower morning and afternoon P(n) and G(w), predawn Psi(leaf), daytime Psi(leaf), and soil-to-leaf hydraulic conductance (K(l)), and higher foliar nitrogen concentration. Pole pine values were intermediate between sapling and old-growth pine values for morning G(w) and daytime Psi(leaf), similar to sapling pine for predawn Psi(leaf), and similar to old-growth pine for morning and afternoon P(n), afternoon G(w), K(l), and foliar nitrogen concentration. For the pines, low predawn Psi(leaf), daytime Psi(leaf), and K(l) were associated with low P(n) and G(w). Our data suggest that hydraulic limitations are important in reducing P(n) in old-growth ponderosa pine in northern Arizona, and indicate greater avoidance of soil water stress and greater tolerance of atmospheric water stress by old-growth Gambel oak than by old-growth ponderosa pine.     

Response of five tree species to salinity and waterlogging: shoot and root biomass and relationships with leaf and root ion concentrations

Unproductive saline and waterlogged (WT) wastelands could be beneficially transformed into agroforestry systems using trees tolerant to these stresses. We studied the salinity and waterlogging tolerance of five Australian tree species (Acacia salicina, Casuarina glauca, Casuarina obesa, Eucalyptus camaldulensis and Eucalyptus occidentalis) during seedling stage and their relationships with root and leaf ion concentrations. 8-month old plants were exposed for 5 months to five irrigation water salinity treatments (EC values between 2 and 22 dS m^?1) and two waterlogging treatments (drained or WT). The salinity tolerance of the five species was high, although decreased in WT conditions. Irrespective of salinity, the two Casuarina species were more tolerant and the other three species were less tolerant to WT than drained conditions. In all species, salinity and waterlogging increased leaf Cl^? and Na⁺ and decreased leaf Ca²⁺, but not leaf K⁺. Root Cl^? and Na⁺ increased with salinity but not with waterlogging. Salinity tolerance was negatively correlated with Cl^? and Na⁺ leaf accumulation rates per unit increase in salinity. Waterlogging reduced the ability of the seedlings to exclude Cl^? and Na⁺ from the leaves. The two most salt tolerant Casuarina species under both drained and WT conditions showed the highest leaf Cl^? and Na⁺ exclusion and the highest root Cl^? and Na⁺ accumulation, suggesting that sequestration of these toxic ions in their roots was a significant salt-tolerant mechanism. Revegetation of saline and WT wastelands with these tolerant Casuarina species could be profitably used for biomass, biofuel and renewable energy production.     

Growth characteristics of some native tree species used in silvopastoral systems in the humid lowlands of Costa Rica

Research for developing silvopastoral systems includes tree species selection and management, and interactions of trees with pastures. In the Caribbean humid lowlands of Costa Rica, total height, diameters at breast height (DBH), survival, basal area and bole volume were compared among three plantations with four species each, in pure stands as well as in the mixture of the four species. In Plantation 1, at 86 months old the pure plantations of Jacaranda copaia and Vochysia guatemalensis, and the mixed plantations (Jacaranda copaia + Vochysia guatemalensis + Calophyllum brasiliense + Stryphnodendron microstachyum) had the largest DBH. Vochysia guatemalensis is one of the most preferred species in the region for reforestation of degraded pastures, while Jacaranda copaia is not preferred because it has low local economic value. In Plantation 2, at 81 months, the greatest DBH was found in Virola koschnyi, Terminalia amazonia and the mixed plantations (Virola koschnyi + Terminalia amazonia + Dipteryx panamensis + Pseudosamanea guachapele). Dipteryx panamensis has good economic value and has a relatively open canopy that produces moderate shade. Virola koschnyi and Terminalia amazonia have denser canopies, are preferred by farmers, and they could be planted in low density in silvopastoral systems. In Plantation 3, at 70 months, the greatest DBH was found in Vochysia ferruginea, Hieronyma alchorneoides and the mixed plantation (Vochysia ferruginea + Hieronyma alchorneoides + Genipa americana + Balizia elegans). Most of these species are currently used in silvopastoral systems in the region. Mixed plantations may combine beneficial effects of the different species' characteristics, with the additional advantage of product diversification. This revised version was published online in June 2006 with corrections to the Cover Date.     

Planning tree species diversification in Kenya based on differences in tree species composition between farms. I. Analysis of tree uses

Concerns exist about the limited diversity of tree species in agricultural landscapes. Complete tree inventories were carried out on 201 farms from four villages in western Kenya to establish whether significant differences in tree species composition existed between farms, and if so their magnitude and implications for new introductions and plantings. Tree species composition was interpreted to encompass elements of both tree identity and abundance. Tree identity was viewed from both taxonomic and function (e.g. fruit, timber, medicine) perspectives. Novel types of ordination using the Hellinger ecological distance and polynomial Redundancy Analysis indicated wide heterogeneity between farms with respect to tree species composition. For the 12 most prevalent functions of trees, the analyses showed significant differences (p<0.05). Partitioning of variance identified that village location explained much of the differences between farms suggesting that farmers share tree species within villages more than between villages. Differences between farms were assessed on two-dimensional ordination graphs. For five important tree functions, including beverage, charcoal, construction, fodder and medicine, two species dominated the compositional differences. For these functions, diversification can be achieved by village-to-village sharing even in the absence of any new species introductions. A general process to determine the degree of tree diversity at farm and landscape levels and steps to increase it are discussed.     

Influence of Armillaria root rot on the foliar nutrients and growth of some coniferous species

Armillaria root rot induces a reduction in the concentrations of N, P, K, Mg and Na; an increase in the levels of Ca, Mn, Fe and Zn; and a decrease in the annual height growth of the diseased trees of four coniferous species. The data indicates that these changes are caused by interferences in the metabolism of the infected host.     

水盐胁迫对上海常见4种绿化树种根系生长的影响

试验选取了上海较为常见的4种绿化树种,落羽杉、乌桕、栾树、喜树,针对上海泥质海岸沿海防护林的建设需要,对其进行了模拟海水的耐盐、耐水淹交叉胁迫处理。结果表明,栾树和喜树的根系在水盐胁迫环境中受到的影响比乌桕和落羽杉大,从根系表面积、长度、体积、平均直径来看,栾树和喜树的敏感程度比较大,均出现早期上升,中后期下降的情况。落羽杉和乌桕根系对环境的表现则不是那么明显。     

Planning tree species diversification in Kenya based on differences in tree species composition between farms. II. Analysis of tree niches.

Concerns exist about the limited diversity of tree species in agricultural landscapes. Complete tree inventories were carried out on 201 farms from four villages in western Kenya to establish whether significant differences in tree species composition existed between farms, and if so their magnitude and implications for new introductions and plantings. Novel types of ordination using the Hellinger ecological distance and polynomial Redundancy Analysis indicated wide heterogeneity between farms with respect to tree species composition of five niches, including homestead, cropland, fallow, woodlot, and external boundary (p ≤ 0.05). Multiple regression analysis confirmed the ordination results using the abundance of dominant species as the response variable. The relationship between location and species composition differed with those of two previous surveys. Methodological differences in sampling intensity, locations and time of sampling between these surveys could have caused the difference. The maps of spatial distribution of compositional types provided in the previous surveys were not confirmed, whereas villages were found to contain several farms with a species composition that was not typical of their village. Meaningful results about the species composition of a landscape should include several farms per village and use a sampling grid finer than 5×5 km².