Introduced <Emphasis Type="Italic">Eucalyptus</Emphasis> psyllids in Brazil

In the last 10 years, four species of psyllid were detected in Brazil on eucalypts: Ctenarytaina spatulata in 1994, Blastopsylla occidentalis in 1997, Ctenarytaina eucalypti in 1998 and Glycaspis brimblecombei in 2003. The latter two are serious pests in several countries. In Brazil, G. brimblecombei caused significant damage to the eucalypt plantations in the first years of its introduction. Now this pest is under control due to the programmes of integrated pest management, where the parasitoid is the principal control agent. The four eucalypt psyllid species introduced into Brazil are presented with information on distribution, hosts, biology and control.     

Distribution of solanesol in Nicotiana tabacum

Solanesol is an important secondary metabolite in Nicotiana tabacum. Distribution of solanesol in Nicotiana tabacum was investigated by High Performance Liquid Chromatography （HPLC） method. The quantitative distribution of solanesol in various organs and tissues of N. tabacum showed that solanesol content, obviously different in all organs, was 6.8, 18.3, 27.5, 45.8, and 68.0 times higher in leaves than that in the stalks, flowers, seeds, fruits and roots, respectively. The contents of solanesol in various parts of leaf, stalk and flower were determined. The content of solanesol in top leaf, middle leaf and bottom leaf gradually decreased （6.124, 5.813 and 5.687 mg.g^-1, respectively） and the content of solanesol in various leaf-parts （leaf apex, leaf middle and leaf base） also gradually decreased. The content of solanesol in top stalk was 1.19 times and 1.92 times higher than that in the middle stalk and the bottom stalk, respectively. The content of solanesol in various tissues of stalk （epidermis, cortex and stele） dramatically decreased. The sepal contained higher concentration of solanesol （1.192 mg·g^-1） compared to any other parts in flower. The study will provide the base data for the regulation and control of solanesol, moreover, it will provide the scientific evidences for the rational development and utilization of N. tabacum resources.     

Fine roots refilling process in an artificial gap in a Picea mongolica forest

Picea mongolica is an endemic but endangered species in China. The spruce forest is only found in sandy forest-steppe ecotones. In this study, we examined the initial response of the quantity and refilling process of fine roots in an artificial canopy gap with a diameter of 36 m in a P. mongolica forest. Under the canopy, the fine root length densities of trees, shrubs and herbs were 2,622, 864 and 3,086 m·m–2, respectively. The fine root biomass of trees, shrubs and herbs were 148, 62 and 65 g·m–2, respect...     

Dormancy release in male flowers of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

To clarify key characteristics of the process whereby dormancy is released in male flowers of Cryptomeria japonica, twigs with male flowers were collected every three days between December 1992 and February 1993. Half of the twigs collected on each date were chilled at 0°C for three days and the cumulative temperatures required by the chilled and non-chilled flowers for florescence were compared. There was no difference in the cumulative temperature required for florescence between chilled and non-chilled male flowers collected before 19 December. However, for samples collected between 21 December and 21 January, the cumulative temperature needed for the florescence of chilled male flowers was 8–68°C lower than that required for non-chilled male flowers. However, there was little difference again in the cumulative temperature required to induce the florescence of chilled and non-chilled male flowers for collection dates later than 24 January. These results suggest that the dormancy of male C. japonica flowers was gradually released by exposure to low temperature and the process was completed by 24 January. The cumulative temperature required for florescence and the sum of the mean daily temperatures between the date of collection and the date of natural pollen dispersal were almost equal after the dormancy of the male flowers was released. The exact day on which pollen will be released can be predicted using the dormancy characteristics of male flowers.     

Root biomass and distribution of a <Emphasis Type="Italic">Picea–Abies</Emphasis> stand and a <Emphasis Type="Italic">Larix–Betula</Emphasis> stand in pumiceous Entisols in Japan

Root biomass and root distribution were studied in Entisols derived from the thick deposition of volcanic pumice on Hokkaido Island, Japan, to examine the effect of soil conditions on tree root development. The soil had a thin (<10 cm) A horizon and thick coarse pumiceous gravel layers with low levels of available nutrients and water. Two stands were studied: a Picea glehnii–Abies sachalinensis stand (PA stand) and a Larix kaempferi–Betula platyphylla var. japonica stand (LB stand). The allometric relationships between diameter at breast height (DBH) and aboveground and belowground biomass of these species were obtained to estimate stand biomass. The belowground biomass was small: 30.6 Mg ha₋₁ for the PA stand and 24.3 Mg ha₋₁ for the LB stand. The trunk/root ratios of study stands were 4.8 for the PA stand and 4.3 for the LB stand, which were higher than those from previous studies in boreal and temperate forests. All species developed shallow root systems, and fine roots were spread densely in the shallow A horizon, suggesting that physical obstruction by the pumiceous layers and their low levels of available water and nutrients restricted downward root elongation. The high trunk/root ratios of the trees may also have resulted from the limited available rooting space in the study sites.     

Dynamics of non-structural carbohydrate reserves in pruned <Emphasis Type="Italic">Erythrina poeppigiana</Emphasis> and <Emphasis Type="Italic">Gliricidia sepium</Emphasis> trees

In alley cropping systems, fast growing leguminous trees are pruned to reduce competition with crops for light and to provide organic inputs for crop nutrition. Tree regrowth depends on non-structural carbohydrate reserves in the remaining tree parts. In this study, the dynamics of starch and soluble carbohydrates in roots and stems of completely pruned (all shoots removed), partially pruned (one branch retained on the pruned stump) and unpruned Erythrina poeppigiana (Walp.) O.F. Cook and Gliricidia sepium (Jacq.) Kunth ex Walp. trees were studied under humid tropical conditions in Turrialba, Costa Rica. Measurements on starch and soluble carbohydrates in roots and stems were made at 0, 2, 6 and 12 weeks after pruning during both a “rainy” and a “dry” season. In general, the dynamics of non-structural carbohydrates in roots and stems of pruned E. poeppigiana and G. sepium trees were similar. Starch concentration was highest in unpruned trees and higher in roots than in stems of pruned trees. The effect of pruning intensity was first observed in stems, and starch reserves were more depleted in stems than in roots, an effect more evident during the “dry” season. The critical tree regrowth stage for starch mobilisation was that of vigorous sprout development at six or four weeks after pruning particularly in completely pruned trees. At this time, fine root biomass and length and nodule biomass in pruned trees decreased. Survival of fine roots and nodules was greater in partially pruned than in completely pruned trees. Starch accumulation in roots recommenced at 12 weeks after pruning in G. sepium, and later than 12 weeks after pruning in E. poeppigiana roots. This study showed that E. poeppigiana responded better to pruning regimes than G. sepium. Recovery of trees after pruning is better when trees are partially pruned than when completely pruned.     

Research advances in allelopathy of Quercus L.

The term allelopathy refers to biochemical interaction between all types of plants including microorganisms through pro-duction of chemical compounds that escape into the environment and exist widely in Quercus L. The development of investigations into types of allelochemicals, their compounding and spreading pathways, as well as expression of allelopathy in Quercus L. are re-viewed in this paper. We have closely and systematically emphasized the functional mechanisms of allelopathy in forest plants for our next research project on allelopathy in Quercus L.     

Variations in bark thickness and sapwood density of <Emphasis Type="Italic">Calophyllum inophyllum</Emphasis> provenances in Australia and in Sri Lanka

Sapwood density and bark thickness of Calophyllum inophyllum L. (a multipurpose durable timber species) were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4-15 mature trees having girth at breast height over bark (GBHOB) at 100-150 cm were selected on the basis of the population size. Significant (p<0.05) hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.     

Characterization of sp<Superscript>2</Superscript>- and sp<Superscript>3</Superscript>-bonded carbon in wood charcoal

Japanese cedar (Cryptomeria japonica) preheated at 700°C was subsequently heated to 1800°C and characterized by electron microscopy, X-ray diffraction, and micro-Raman spectroscopy. The degree of disorder of carbon crystallites and the amount of amorphous phase decreased considerably with an increase in heat treatment temperature to 1400°C, while carbon crystallites clearly developed above this temperature, showing that the microstructure of carbonized wood undergoes drastic changes around 1400°C. Besides showing the bands for sp²-bonded carbon, the Raman spectra showed a shoulder near 1100 cm⁻¹ assigned to sp³-bonded carbon. With an increase of heat treatment temperature, the peak position of the Raman sp³ band shifted to a lower frequency from 1190 to 1120 cm⁻¹, which is due to the transformation of sp³-bonded carbon from an amorphous phase to a nanocrystalline phase. These data showed that the microstructure of carbonized wood from 700° to 1800°C consisted of the combination of sp²- and sp³-bonded carbon, which is probably due to the disordered microstructure of carbonized wood. It is suggested that the sp³-bonded carbon is transformed from an amorphous structure to a nanocrystalline structure with the growth of polyaromatic stacks at temperatures above 1400°C.     

Problems of using pines in <Emphasis Type="Italic">Tuber melanosporum</Emphasis> culture: soils and truffle harvest associated with <Emphasis Type="Italic">Pinus nigra</Emphasis> and <Emphasis Type="Italic">P. sylvestris</Emphasis>

In Mediterranean pine forests, truffles and mushrooms generate greater profits than any other woodland products. However, there are no studies on Tuber melanosporum Vittad. associated with pines. For this reason, we have carried out a study of this truffle in mountain woods with Pinus sylvestris L. and P. nigra Arnold subsp. salzmannii (Dunal) Franco, in central Spain. Two hundred and eight Tuber melanosporum burns were monitored for 7 years in five different habitats within the same geographical area. An ANOVA test confirmed significant differences in carpophore production. In higher producing habitats, pines were less abundant. We also confirmed that in 433 burns, T. melanosporum was always unequivocally associated with the root base of Quercus or Corylus trees. Similarly, 14 truffle collectors confirmed that they had never found a single burn with carpophore production associated exclusively with pines. Nevertheless, soil analyses indicated that the soil of these pine woods was very favourable to Tuber melanosporum. We therefore conclude that at present Pinus nigra salzmannii and P. sylvestris are of little interest to Tuber melanosporum culture, as they hinder carpophore production. However, this study has also confirmed that Pinus nigra salzmannii and P. sylvestris mycorrhize easily with Tuber melanosporum, both in the laboratory and in natural environments. On this basis, we propose that pines may act as transmitters of T. melanosporum, although they do not induce fruiting. As a result, the commercial cultivation of Pinus nigra salzmannii and P. sylvestris seedlings mycorrhized with Tuber melanosporum is not recommended in truffle culture at the present time.     

Growth and yield modelling of <Emphasis Type="Italic">Acacia mangium</Emphasis> in Colombia

To study the growth and yield of Acacia mangium in the Caribbean region of Colombia, allometric equations of total volume and aboveground plus coarse roots biomass were fitted as a function of the tree’s diameter at breast height (dbh). The von Bertalanffy’s growth model and 59, 0.1 ha plots (0.55–9.55 years old) were used to develop site index (SI) curves at 6 years base age. Then, using the state-space approach, stand growth and yield models were developed for basal area, volume and biomass. The results show that A. mangium is a very promising species for timber production, atmospheric carbon removal and soil restoration because it grows very fast even in mining degraded soils. On average sites it reaches 15 m in height in 3 years. However, early and reiterated thinning coupled with initial mortality by cattle invasion of the very young understocked plantations are producing relatively low yields.     

Wundfäule in Fichtenwaldungen mit alten Schälschäden

Wound decays in spruce stands following bark stripping . 2083 trees in 91 sample plots on four trial areas (24 ha) were examined for bark stripping and decay. Only 25% of trees showed no injury. Of the injured trees, 73% showed some degree of decay, 10% discoloration. and 17% neither decay nor discoloration. Of the wood destroying fungi isolated Fomes annosus was dominant and appeared to be the most important and widespread of the wound inhabiting fungi in the test area. Besides the Basidiomycetes a considerable number of other fungi was isolated. The most frequent was Cylindrocarpon cylindroides var. tenue.     

Phenotypic variation in thirteen native provenances of Lespedeza bicolor Turcz

Lespedeza bicolor Turcz is a native shrub in the temperate region of China. Thirteen provenances of L. bicolor were inves-tigated in our study. Morphological diversity among and within provenances were analyzed based on 19 phenotypic traits, including seven vegetative growth characteristics, nine floral traits and three pod characteristics. The coefficient of variation (CV) ranged from 6.4% to 65.4% and the phenotypic differentiation coefficient from 43.3% to 97.3%. Analyses of variance showed that there were extremely significant variations among and within provenances in pod length. Differences in plant height, inter-nodal length, number of branches, leaf width, leaf length and leaf area were not remarkable among provenance, but distinct within provenances. Other traits showed evidence of contrasts. Variation among provenances was the main part of phenotypic variation. Correlation analysis indicated that there were highly significant positive correlations between plant height and other vegetative growth characteristics. Floral traits were not associated with vegetative growth characteristics. The 13 provenances of L. bicolor investigated can be classi-fied into three groups according to a UPGMA cluster analysis.     

Soil water dynamics in cropping systems containing <Emphasis Type="Italic">Gliricidia sepium</Emphasis>, pigeonpea and maize in southern Malawi

The water dynamics of cropping systems containing mixtures of Gliricidia sepium (Jacq.) Walp trees with maize (Zea mays L.) and/or pigeonpea (Cajanus cajan L.) were examined during three consecutive cropping seasons. The trees were pruned before and during each cropping season, but were left unpruned after harvesting the maize; prunings were returned to the cropping area in all agroforestry systems to provide green leaf manure. The hypothesis was that regular severe pruning of the trees would minimise competition with crops for soil moisture and enhance their growth by providing additional nutrients. Neutron probe measurements were used to determine spatial and temporal changes in soil moisture content during the 1997/98, 1998/99 and 1999/00 cropping seasons for various cropping systems. These included gliricidia intercropped with maize, with and without pigeonpea, a maize + pigeonpea intercrop, sole maize, sole pigeonpea and sole gliricidia. Soil water content was measured to a depth of 150 cm in all treatments at 4–6 week intervals during the main cropping season and less frequently at other times. Competition for water was apparently not a critical factor in determining crop performance as rainfall exceeded potential evaporation during the cropping season in all years. The distribution of water in the soil profile was generally comparable in all cropping systems, implying there was no spatial complementarity in water abstraction by tree and crop roots. However, available soil water content at the beginning of the cropping season was generally lower in the tree-based systems, suggesting that the trees continued to deplete available soil water during the dry season. The results show that, under rainfall conditions typical of southern Malawi, the soil profile contains sufficient stored water during the dry season (ca. 75–125 mm) to support the growth of gliricidia and pigeonpea, and that gliricidia trees pruned before and during the cropping season did not deleteriously compete for water with associated crops. Water use efficiency also appeared to be higher in the tree-based systems than in the sole maize and maize + pigeonpea treatments, subject to the proviso that the calculations were based on changes in soil water content rather than absolute measurements of water uptake by the trees and crops.     

Problems of using rockroses in <Emphasis Type="Italic">Tuber melanosporum</Emphasis> culture: soil and truffle harvest associated with <Emphasis Type="Italic">Cistus laurifolius</Emphasis>

The Périgord black truffle (Tuber melanosporum Vittad.) can mycorrhize with rockroses (Cistus L.) in Mediterranean forests. These shrubs may be of interest for truffle cultivation as they produce early carpophores, collaborate in tree mycorrhization and in the survival of Tuber melanosporum mycelium. However, there are very few quantitative studies on truffle production associated with Cistus. For this reason, we have carried out a study on the natural production of Tuber melanosporum associated with Cistus laurifolius L. in central Spain. An Anova test confirmed the existence of significant differences in carpophore production in four habitats, with and without the presence of C. laurifolius. Twenty-one burns associated with C. laurifolius showed less significant production than the rest. We also confirmed that in 122 burns, Tuber melanosporum was always unequivocally associated with the root base of Quercus L. or Corylus L. trees. Similarly, five truffle-collectors confirmed that they had never found a single burn with carpophore production associated exclusively with rockroses. It has also been statistically verified that many Cistus die in Tuber melanosporum burns, whereas in old burns with minimum carpophore production, a new colonization of young Cistus has been observed. This study also confirms that C. laurifolius mycorrhizes easily with Tuber melanosporum. We propose that Cistus laurifolius may act as transmitters of Tuber melanosporum, although they do not induce fruiting. Consequently, the commercial cultivation of Cistus laurifolius mycorrhized with Tuber melanosporum for production is not recommended in truffle culture. The results reported substantiate the negative observations in cultivations of T. melanosporum with other Cistus species.     

Alkaloid variations in Catharanthus roseus seedlings treated by different temperatures in short term and long term

A study was conducted to investigate the effects of high temperature on variations of alkaloid metabolism in C. roseus seedlings in Key Laboratory of Forest Plant Ecology, Northeast Forestry University, Heilongiang, China. 60-day-old C. roseus seedlings with 3-4 pairs of leaves were incubated in chambers with temperature of 30℃ and 40℃for short-term heat shock experiment and 20℃, 25℃ and 35℃ for long-term experiment. The contents of vindoline, catharanthine, vinblastine and vincristine in C. roseus leaves and root were checked at different temperatures in short term （1-6 h） and long term （1-16 d）. Results showed that under short-term heat shock, the contents of vindoline, catharanthine and vinblastine in leaves of the seedlings were higher at 40℃ than at 30℃, but after 6 h treatment, the contents of vindoline and catharanthine under the two temperatures came to the same level. Catharanthine was exclusively distributed in C. roseus roots and its content was increased by 40% after two hours incubation at 40℃, while increased slowly at 30℃ incubation and reached the highest value at 6 h. In the Long-term experiment, concentrations of monomeric alkaloids catharanthine and vindoline were higher at 20℃ than at 25℃ and had a sharp increase under the condition of 35℃. While for dimeric alkaloid, it showed that the higher the temperature, the earlier the peak value of vinblastine content appears. Vincristine had a continuous enhancement and attained 0.027 mg.g^-1 at 16th day under 35℃ condition which was higher than those in the other conditions. It was concluded that high temperature could promote the accumulation of different alkaloids in C. roseus and the accumulation characteristic is highly related to treatment time.     

Differences in land cover interpretation in landscapes rich in cover gradients: reflections based on the <Emphasis Type="Italic">montado</Emphasis> of South Portugal

This paper contributes to the discussion on current issues in methodologies of mapping land cover in the agro-silvo-pastoral landscapes of the Mediterranean. These landscapes, characterized by intermixed land use and indefinite boundaries, require particular attention in applying the patch-corridor-matrix model when classifying patches and their delineation. In a case study area in southeast Portugal, mainly characterized by agro-silvo pastoral systems, the land cover for 1990 has been mapped. The paper discusses the consequences of the complexity of some Mediterranean land use systems for land cover mapping dealing with detailed landscape dynamics. Within this scope a land cover mapping project in a small case study area is compared with the mapping undertaken within a national land cover database. Both studies were carried out on the same scale and through visual interpretation of aerial photographs. Differences in land cover classification and allocation are explored using matrix with levels of agreement. Recommendations for future land cover mapping projects are: the application of fuzzy approaches to land cover mapping in agro-silvo-pastoral landscapes should be explored and land cover classifications should be standardized in order to enhance consistency between databases. On the other hand, the fuzziness of the boundaries in this kind of landscapes is inherent to the system and should be accepted as such. The accompanying uncertainties should be taken into account when undertaking landscape analysis on the basis of land cover data.     

Adaptation of herbaceous plant species in the understorey of <Emphasis Type="Italic">Pinus brutia</Emphasis>

Most of Pinus brutia (Ten.) Holmboe forests are grazed, as silvopastoralism is well adapted in the Mediterranean environment. However, little attention has been paid to the demographic dynamic of the understorey vegetation even though it is strongly affected by the absorbed radiation. The purpose of this study was to examine the adaptation of herbaceous plant species under a Pinus brutia canopy, in Northern Greece. Monocultures of four plant groups (annual and perennial grasses, annual and perennial legumes) were sown in experimental areas of 50%, 70% and 100% light intensity. The density of annual and perennial grasses and perennial legumes were decreased by the shade cast by the Pinus brutia canopy. Population density of the annual legumes was little affected by light intensity: the annual grasses Bromus mollis L. and Lolium rigidum Gaudin; the perennial grasses Dactylis glomerata L. var. palestine, Festuca arundinacea and Agropyron cristatum (L.) Gaertn; the perennial legume Medicago sativa L. var. romana; the annual legumes Medicago lupulina L. and all the tested varieties of Trifolium subterraneum adapted well to the 50% light intensity habitat.