Tree

Motivated by some recent research on the terminal (reduced) distance matrix, we consider the terminal Wiener index (T W ) of trees, equal to the sum of distances between all pairs of pendent vertices. A simple formula for computing T W is obtained and the trees with minimum and maximum T W are characterized.

In this note we show that the asymmetric Prover-Delayer game developed in [BGL10] for Parameterized Resolution is also applicable to other tree-like proof systems. In particular, we use this asymmetric Prover-Delayer game to show a lower bound of the form 2 Ω(log) for the pigeonhole principle in tree-like Resolution. This gives a new and simpler proof of the same lower bound established by Iwama and Miyazaki [IM99] and Dantchev and Riis [DR01].

We are interested in coloring the edges of a mixed graph, i.e., a graph containing unoriented and oriented edges. This problem is related to a communication problem in job-shop scheduling systems. In this paper we give general bounds on the number of required colors and analyze the complexity status of this problem. In particular, we provide N Pcompleteness results for the case of outerplanar graphs, as well as for 3-regular bipartite graphs (even when only 3 colors are allowed, or when 5 colors are allowed and the graph is fully oriented). Special cases admitting polynomial-time solutions are also discussed.

By allowing the estimation of forest structural and biophysical characteristics at different temporal and spatial scales, remote sensing may contribute to our understanding and monitoring of planted forests. Here, we studied 9-year time-series of the Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on a network of 16 stands in fast-growing Eucalyptus plantations in São Paulo State, Brazil. We aimed to examine the relationships between NDVI time-series spanning entire rotations and stand structural characteristics (volume, dominant height, mean annual increment) in these simple forest ecosystems. Our second objective was to examine spatial and temporal variations of light use efficiency for wood production, by comparing time-series of Absorbed Photosynthetically Active Radiation (APAR) with inventory data.

In the Mediterranean region the fruits of the strawberry tree (Arbutus unedo L.) may be fermented and distilled to produce a traditional beverage very much appreciated in Southern Europe. The aim of the present work was to study the diversity of the yeast population and the killer activity of the isolates identified as Saccharomyces cerevisiae, obtained during solid state industrial fermentations of the arbutus berries. The identification of the isolates was performed by the 5.8S rRNA-ITS region restriction analysis and by sequencing the D1/D2 region of the large subunit of the rRNA gene. At the start of the fermentations, various non-Saccharomyces species were detected including Aureobasidium pullulans, Dothichiza pithyophila, Dioszegia zsoltii, Hanseniaspora uvarum and yeasts belonging to the genera Metschnikowia, Cryptococcus and Rhodotorula. However, as the biological processes progressed the number of different species decreased with S. cerevisiae and Pichia membranaefaciens becoming dominant at advanced stages of the must fermentation that is characterized by high concentrations of ethanol. Forty three isolates identified as S. cerevisiae were tested for killer activity against two sensitive reference strains and Zygosaccharomyces bailii. Their killer sensitivity in relation to five killer referenced toxins (K2, K5, K8, K9 and K10) was also studied. Out of the isolates analyzed, 95.3% were sensitive and 4.7% were tolerant against the killer toxins tested. Only three isolates revealed killer activity against one sensitive strain and two of them against the spoiler yeast Z. bailii. The microbiota obtained revealed an interesting potential to be used as starter cultures to overcome unpredictable uncontrolled fermentations of the arbutus fruits as well as in other applications of biotechnological interest.

In this paper I explore the variation in symbolic value of Upper Palaeolithic art in Western Europe. Drawing inspiration from Jesus Altuna's demonstration of the complex relationship between animal frequencies in art and in animal bones, I summarise several of my studies based on analysis of the art and animal bones from Parpallo in Valencia. I show that the relationship between art and bones is more complex and varies regionally across western Europe. At Parpallo the relationship varied through time, and the major change in relationship corresponds with a change in the pattern of importance of plaquettes across the same region, and seems to suggest that the major change corresponds to the change archaeologists recognise between the Solutrean and Magdalenian industries. This suggests that the stone industry changes may really correspond to change in more comprehensive aspects of culture.

Early growth performance of six native and two introduced tree species was studied for seven years at 16 sites in the Southern region of Costa Rica. Selected study sites represent a wide environmental gradient that ranges from acid low fertility soils such as Ustic Haplohumults and Typic Haplustults to fertile soils such as Typic Hapludand and Fluventic Eutropepts. Mean annual precipitation ranges from 2600 to 4500 mm and length of dry season from none to more than three months each year. The experimental layout was a randomized complete block design nested within four eco-regions, with all plots on private farms. The size of the experimental plot was 11 Â 11 trees planted at a spacing of 3 Â 3 m with a sampling plot of 7 Â 7 trees. The species included in the initial trials were: Pinus caribaea Morelet var hondurensis (Barret y Golfari) and Gmelina arborea Roxb as the introduced species (from Honduras and southeast Asian regions, both of which benefit from genetic selection), and Terminalia amazonia (J. F. Gmelin) Exell, Vochysia ferruginea Mart., Vochysia guatemalensis Donn. Sm., Hieronyma alchorneoides Fr. Allemao, Calophyllum brasiliense Cambess and Schizolobium parahyba (Vell.) S. F. Blake (collected extensively in this project from indigenous populations from across the Southern region of Costa Rica). All plots were measured annually and data collected for tree height, DBH and mortality. Composited soil samples were taken at three depths in each site to characterize chemical and physical soil properties. In general, the native species were highly responsive to eco-regions, the introduced species much less so. The yield and dominant stand height of the introduced species were higher in acid soils with well defined dry season than the selected native species. As soil nutrient and water supply improved, the differences between introduced and native species decreased in mean stand height and yield. Two species (Calophyllum brasiliense and Schizolobium parabyba) had more than 80% mortality in almost all plots during the first two years of establishment. The results of this study contrasts with findings obtained in the Northern region of Costa Rica on acid Ultisols (Typic Tropohumult), where at least Vochysia guatemalensis and Vochysia ferruginea out-competed the best introduced species, Gmelina arborea and Pinus spp. Results are mainly attributed to the pronounced ustic moisture regime in the Southern region of Costa Rica that is able to be tolerated by Gmelina arborea and Pinus spp. but not by the selected native tree seedlings.

The objective of this study was to assess the impact of some processing parameters on moisture content, flowability, hygroscopicity and water solubility of spray dried acerola pomace extract using maltodextrin and cashew tree gum as drying aids. The experiment was conducted according to Response Surface Methodology, with the independent variables being: inlet temperature (170-200 C), drying aid/acerola ratio (2:1-5:1), and percent replacement of maltodextrin by cashew tree gum (0-100%). Higher inlet temperatures favored the desired physical properties of the powders, decreasing their moisture contents and hygroscopicity, and increasing flowability. The drying aids decreased the powder hygroscopicity, especially cashew tree gum (CTG), which also enhanced the powder flowability. The best processing conditions to obtain a free-flowing and least hygroscopic acerola pomace extract powder by spray drying were: inlet temperature above 194 C; drying aid/acerola solid ratio, 4:1; percent replacement of maltodextrin by CTG, at least 80%.

Two methods of estimating the lateral migration of a river channel have been proposed. The first method is based on Coarse Woody Debris (CWD) dating. The terraces of the Mala Panew River are mainly covered with plantations of Pinus sylvestris where individual trees grow at equal distances to each other. During times of high discharges trees fall onto the riverbed providing information on the extent of flood plain erosion. The ages of CWD and the surface of the eroded flood plain provide an estimation of the rate of lateral migration. The erosion rates measured at two sites in the Mala Panew River were between 0.24 and 0.36 m/year. Another way of reconstructing the rate of lateral migration is by dating trees growing on different-aged sandy meander bars. These levels are primarily covered with Alnus glutinosa and Alnus incana. The oldest trees growing on each level give information about the minimum age of that level, which allows us to reconstruct the rate of lateral migration. The lateral migration of the channel has also been estimated dating the oldest trees growing on mid-channel islands separated from the lateral banks. The values obtained for 10 sites of the Mala Panew channel oscillate between 0.07 and 1.83 m/year. Tree ring analyses also allow us to determine the impact of individual high discharges on the lateral migration rate of the Ma"a Panew channel. The lateral migration of the channel was most rapid in the years 1953-57 and 1966-68 as well as during the extraordinary flood in 1997.

Population viability risk management (PVRM) provides a framework for explicitly including qualitative information about the possible outcomes of a management decision with regard to the viability of an endangered population in conservation management. Multi-criteria decision-making (MCDM) techniques enables managers to select the most preferred choice of action in a context where several criteria apply simultaneously. In that context a combined approach of the PVRM concept and a MCDM technique is presented for the development, evaluation and finally ranking of the in situ conservation strategies. We discuss the concept based on a case study for the maintenance of a gene conservation forest of an English yew population (Taxus baccata L.) in Styria, Austria. As part of the PVRM the analytic hierarchy process (AHP) is used to evaluate six conservation strategies with regard to the viability of the yew population. The viability of the population is evaluated based on the results of an analysis of the current environmental, social and economical state and a characterization of the ecological parameters of its population. The most significant risk factors (illegal cutting, browsing by game, tree competition, light availability and genetic sustainability) are structured and prioritised according to their impact on the viability of the yew population applying the AHP. Effects of the six conservation strategies on the viability of the yew population are determined through a qualitative assessment of the probability of a decrease of the population along with four different environmental scenarios. In this context strategy IV combining selective thinning, protection measures, game control with public relation activities seems to be the most effective alternative. The benefits of the combined approach of the PVRM concept with the AHP for the rational analysis of conservation strategies for this endangered tree species are discussed.

Secondary habitats are increasing in importance in tropical countries due to ongoing destruction of pristine vegetation. In spite of the magnitude of current changes, our understanding of their effects on nontrees (e.g., nonvascular or vascular epiphytes) is still very patchy, particularly in lowland habitats. Here, we report a study with isolated pasture trees in southwest Panama. The 4 800 studied trees, which belonged to 4 100 different species, harbored almost 27,000 epiphytes of 83 species. Orchidaceae was the most species-rich family, with almost 60 percent of all species, while Bromeliaceae were most abundant. A rainfall gradient in the study region from ca 1000 to 4 3000 mm explained more of the variation in species abundance and richness than host characteristics (e.g., species identity, tree size). The unexpectedly large number of epiphytes in these pastures still represents a substantial change relative to a natural setting, which is suggested by a comparison with a forest inventory under similar climatic conditions. In pastures, species richness was lower as deduced from individual-based rarefaction curves, a larger proportion of species and individuals showed crassulacean acid metabolism, and the relationship of epiphyte abundance/species richness and tree diameter was much less steep. Even the already reduced diversity, however, may be only transient in secondary habitats-the long-term persistence of epiphyte populations in pastures is an open question and has to be addressed by repeated monitoring to fully evaluate the significance of pasture trees for the conservation of vascular epiphytes in tropical lowlands.

Solid biofuels such as wood chips are common fuels in many heating plants. The fuels are by nature heterogeneous and the fuel particles can form a stable structure across openings, which may stop the fuel ow in the feeding systems of heating plants. This phenomenon is known as bridging and in the present paper the bridging properties of several common wood fuels are studied and the in uence of particle size and proportion of long particles, bed depth, raw material, species and moisture content is described. The fuels tendency to bridge was deÿned as the maximum slot opening over which a fuel will create a bridge. Measurements were done for wood fuels made from whole trees, logging residues and roundwood from coniferous species (Norway spruce, Sitka spruce and Contorta pine) and various deciduous trees and cut by two chippers to four di erent nominal particle sizes (30 and 35 mm chip and 50 and 100 mm chunk). The most important variable was the proportion of particles longer than 100 mm, which was a result of chipper type, knife setting and raw material. For most fuels, a higher moisture content increased the tendency to bridge. Wood fuels made from roundwood showed no signiÿcant correlation between tendency to bridge and moisture content. The study shows that the bridging problems can be reduced by adaptation of the fuel preparation to the given opening. ?

Point-to-tree distance techniques (also known as k-tree or fixed count sampling) are a practical field sampling method for forest inventories and ecological surveys, but statistical estimation remains a problem. Various approximation techniques have been proposed, partly on an empirical basis, partly under model assumptions about the underlying point processes. In this paper we present a brief history of k-tree sampling in forestry and introduce a new and simple empirical approximation method. This method builds on calculating the variable sample plot area from the distance not only to the k tree but averaging the distance to the k and to the (k + 1) tree. Simulation studies were done on a tree map from the Miombo woodlands in northern Zambia and five artificially generated tree maps with different point patterns. In terms of bias, our techniques are superior to Prodan's approach; however, Eberhardt's estimator produces consistently the smallest bias for the studied clustered patterns, and is unbiased for random patterns. For the two uniform patterns studied, bias was smallest on average for our new estimators.

Changes in colour and stability of anthocyanins have been evaluated over pH range 2.0-8.7. The study was made on crude extract (XAD-7 Amberlite-retained fraction) as well as on the following pure pigments isolated from tamarillo fruit (Solanum betaceum Cav.):

Detection of edible oil adulteration is of utmost important to ensure product quality and customer protection. Campesterol, a sterol found in seed oils, represents less than 0.4% of argan oil total sterol content. Quantitative analysis of campesterol by gas chromatography of argan oil and of a mixture of argan oil and readily commercially available vegetable oils, consecutively with sterol separation, was carried out. Our study clearly demonstrated that determination of the campesterol level in argan oil (or oil presented as argan oil) can be proposed as the major analysis method to assess unambiguously argan oil purity up to 98%.

Đoàn Thị Cẩm Hồng và Nguyễn Trịnh Nhất Hằng Viện Cây ăn quả miền Nam TÓM TẮT Xoài là một trong những loại cây ăn quả quan trọng được trồng phổ biến vùng Đồng bằng sông Cửu Long. Bao quả xoài là một trong những biện pháp hạn chế sử dụng thuốc bảo vệ thực vật hiệu quả trong việc sản xuất xoài theo hướng an toàn. Nghiên cứu ảnh hưởng của vật liệu bao quả đến năng suất và phẩm chất xoài Cát Chu được thực hiện tại Cao Lãnh, Đồng Tháp từ năm 2013 đến 2014. Vào giai đoạn 35 ngày sau khi đậu quả, tiến hành bao quả với các vật liệu bao khác nhau như bao giấy 2 mặt của Thái Lan, bao không thấm nước của Đài Loan, bao Bikoo của Nhật và bao nylon trắng. Kết quả thí nghiệm ghi nhận các loại bao giấy hai mặt, bao giấy không thấm nước, bao Bikoo làm hạn chế sự rụng quả do côn trùng gây hại, tăng độ sáng bóng của vỏ quả khi thu hoạch và khi chín, gia tăng năng suất quả. Từ khóa: Mangifera indica L., Đồng Tháp, xoài Cát Chu, vật liệu bao quả xoài.

Data aggregation is an effective technique in saving energy in WSNs. With the help of data aggregation we reduce the energy consumption by eliminating redundancy. The main goal of data aggregation is to gather and aggregate redundant data in an energy efficient manner, so that network lifetime is enhanced. Since it is the most challenging task. Location based aggregation ensures the minimum distance between two nodes while aggregation. In this paper we discuss data aggregation approaches based on routing protocols. Data aggregation framework on wireless sensor network is presented.

During the Middle Ages northern Belgium and The Netherlands were gradually deforested. A steadily rising demand for quality timber obliged merchants to look for new timber sources. From the 13th century onwards, large volumes of timber were imported from surrounding regions and, despite the remote supply area, merchants of the Hanseatic League managed to organize a huge timber trade from towns around the Baltic Sea.

Riser weight increases with water depth. Supporting the risers, tensioning them to control their response, or optimising the platform motions in order to be "riser-friendly" is often one of the most challenging aspects of converting an old floater for use as a deepwater production or drilling platform. A new build platform will address these issues as part of its design for a particular application, but it will soon have payload and water depth limitations when used generically for multiple applications.

The feeding preferences and consumption rates of the exotic woodlouse Armadillidium vulgare were measured on litters from the autochthonous Rio Grande cottonwood and the exotic Russian olive. When offered a choice between five litter types (green and shed leaves of Russian olive and cottonwood, and fruits of Russian olive), the isopods consumed more of the exotic plant litter (green leaves and the fruits of Russian olive) than of the autochthonous cottonwood. When offered only one diet, consumption rates of green leaves and fruits of Russian olive were again the highest. Feeding was related with N and C:N ratios of the litter, with highest consumption of diets with low and high C:N ratios and lowest consumption of diets with intermediate C:N ratios. The N content was highest (and C:N ratios lowest) on isopods feeding shed leaves of Russian olive. Growth was not related to the amount or the C:N ratio of the food consumed, being highest for animals feeding on shed leaves of cottonwood. Our results show that the consumption patterns and the C and N body composition of the exotic woodlouse A. vulgare are altered when fed with Russian olive litter, suggesting that the replacement of the autochthonous cottonwood by the exotic Russian olive may negatively affect the maintenance of the population of these exotic detritivores in the area.

Volume equations were developed for common timber species in Nigeria's tropical rain forests. Data consisted of merchantable volume, stump diameter, diameter at breast height and merchantable height for 77 timber species. Number of observations per species ranged from 5 to 142, and diameter at breast height ranged from 20.0 to 230.0 cm. Schumacher-Hall's volume function was fitted to the data of each of the 33 well-sampled species (n ! 30), using weighted least squares. The coefficients from these species-specific equations were used as input variables for species grouping. Species grouping was obtained using a two-stage approach of cluster analysis followed by discriminant analyses. First, cluster analysis was used to group the 33 well-sampled species into five clusters, and then discriminant analysis was used to assign each of the remaining 44 species (with n < 30) into one of the five clusters. The species groups obtained did not follow any particular taxonomic pattern, as there were species of the same genus that fell into different clusters. The Schumacher-Hall's volume function was fitted to the data for each species group. The resulting equations possessed desirable statistical properties and model behaviours, and can be used to estimate merchantable volume for common timber species in the tropical rain forest areas of Nigeria.

Modelling Resilience Ecosystem Forest management Vulnerability Niche theory a b s t r a c t Understanding how vulnerable forest ecosystems are to climate change is a key requirement if sustainable forest management is to be achieved. Modelling the response of species in their regeneration niche to phenological and biophysical processes that are directly influenced by climate is one method for achieving this understanding. A model was developed to investigate species resilience and vulnerability to climate change within its fundamentalregeneration niche. The utility of the developed model, tree and climate assessment (TACA), was tested within the interior Douglas-fir ecosystem in south-central British Columbia.

We observed diurnal and seasonal patterns of leaf-scale gas exchange within the crown of a Dipterocarpus sublamellatus Foxw. tree growing in a lowland dipterocarp forest at Pasoh, Peninsular Malaysia. Observations were carried out nine times over 6 years, from September 2002 to December 2007. Observation periods included both wet and mild-dry periods, and natural and saturated photosynthetic photon flux density (PPFD) light conditions. In situ measurements of the diurnal change in net photosynthetic rate and in stomatal conductance were carried out on canopy leaves of a 40-m-tall D. sublamellatus tree, which was accessed from a canopy corridor. A diurnal change in electron transport rate was observed under saturated PPFD conditions. The maximum net assimilation rate was $ 10 lmol m À2 s À1 . There was a clear inhibition of the net assimilation rate coupled with stomatal closure after late morning and this inhibition occurred year-round. Although the electron transport rate decreased alongside this inhibition, it sometimes followed on. Numerical analysis showed that the main factor in the inhibition of the net assimilation rate was patchy bimodal stomatal closure, which occurred in both mild-dry and wet periods. The midday depression occurred year-round, though there are fluctuations in soil moisture during the mild-dry and wet periods. The magnitude of the inhibition was not related to soil water content but was related to vapor pressure deficit (VPD): that is, whether the days were sunny and hot or cloudy and cool. On cloudy, cool days in the wet period, the net photosynthesis was only moderately inhibited, but it still decreased in the afternoon and was coupled with patchy stomatal closure, even in quite moderate VPD, leaf temperature and PPFD conditions. Our results suggest that patchy stomatal closure signaled by the increase in VPD, in transpiration and by circadian rhythms, was the key factor in constraining midday leaf gas exchange of the D. sublamellatus canopy leaves.

We studied the seasonal patterns of water use in three woody species co-occurring in a holm oak forest in northeastern Spain. The three species studied, Quercus ilex L., Phillyrea latifolia L. and Arbutus unedo L., constitute more than 99% of the total basal area of the forest. The study period included the dry seasons of 1999 and 2000. Water use was estimated with Granier-type sap flux sensors. Standard meteorological variables, soil water content and leaf water potentials were also monitored. All monitored individuals reduced leafrelated sap flow (Q l ) during the summer, concurrent with an increase in soil moisture deficit (SMD). Despite similar maximum Q l between species, the decline in Q l with increasing SMD was species-dependent. The average reduction in Q l between early summer and the peak of the drought was 74% for A. unedo (n = 3), 58% for P. latifolia (n = 3) and 87% for Q. ilex (n = 1). The relationship between canopy stomatal conductance (G s ) and vapor pressure deficit (D) changed during the course of the drought, with progressively lower G s for any given D. Summertime reductions of Q l and G s were associated with between-species differences in vulnerability to xylem embolism, and with the corresponding degree of native embolism (lowest in P. latifolia and highest in Q. ilex). Our results, combined with previous studies in the same area, outlined differences among the species studied in manner of responding to water shortage, with P. latifolia able to maintain water transport at much lower water potentials than the other two species. In an accompanying experiment, A. unedo responded to an experimental reduction in water availability by reducing Q l during the summer. This species also modified its water use between years according to the different seasonal patterns of precipitation. These results are discussed in relation to the possible impacts that climate change will have on Q. ilex-dominated forests.

Lack of information on ecological characteristics of species across different continents hinders development of general world-scale quantitative vegetation dynamic models. We constructed common scales of shade, drought, and waterlogging tolerance for 806 North American, European/West Asian, and East Asian temperate shrubs and trees representing about 40% of the extant natural Northern Hemisphere species pool. These scales were used to test the hypotheses that shade tolerance is negatively related to drought and waterlogging tolerances, and that these correlations vary among continents and plant functional types. We observed significant negative correlations among shade and drought tolerance rankings for all data pooled, and separately for every continent and plant functional type, except for evergreen angiosperms. Another significant trade-off was found for drought and waterlogging tolerance for all continents, and for evergreen and deciduous angiosperms, but not for gymnosperms. For all data pooled, for Europe and East Asia, and for evergreen and deciduous angiosperms, shade tolerance was also negatively associated with waterlogging tolerance. Quantile regressions revealed that the negative relationship between shade and drought tolerance was significant for species growing in deep to moderate shade and that the negative relationship between shade and waterlogging tolerance was significant for species growing in moderate shade to high light, explaining why all relationships between different tolerances were negative according to general regression analyses. Phylogenetic signal in the tolerance to any one of the three environmental factors studied was significant but low, with only 21-24% of cladogram nodes exhibiting significant conservatism. The inverse relationships between different tolerances were significant in phylogenetically independent analyses both for the overall pool of species and for two multispecies genera (Pinus and Quercus) for which reliable molecular phylogenies were available. Only 2.6-10.3% of the species were relatively tolerant to two environmental stresses simultaneously (tolerance value !3), and only three species were tolerant to all three stresses, supporting the existence of functional trade-offs in adjusting to multiple environmental limitations. These trade-offs represent a constraint for niche differentiation, reducing the diversity of plant responses to the many combinations of irradiance and water supply that are found in natural ecosystems.

To assess the effects of forest management on soil erosion in Southeast Asia, clear distinctions must be made between surface erosion and landslide processes. Although surface erosion is a natural process, it is exacerbated by surface disturbance and compaction that reduce the soil hydraulic conductivity and break down soil aggregates. Management practices and attributes such as roads and trails, agricultural cultivation, fire, land clearing, and recreation all accelerate surface erosion processes due to their disturbance, compaction, and connectivity along hillslopes. Agroforestry practices in Southeast Asia that incorporate cover crops with trees reduce surface erosion by more than an order of magnitude compared to monoculture plantations with no ground cover. Cleared fields tilled up and down steep slopes are highly erodible; passive conservation practices (e.g., contour tillage, strip cropping, reduced tillage; maintaining adequate ground cover) are effective in reducing surface erosion if properly implemented. Poorly designed and managed terraces are not effective in controlling surface erosion and may actually increase mass wasting if they concentrate water.

Anatomical and physiological acclimation to water stress of the tree hydraulic system involves trade-offs between maintenance of stomatal conductance and loss of hydraulic conductivity, with short-term impacts on photosynthesis and long-term consequences to survival and growth. Here, we study the role of variations in root and branch maximum hydraulic specific conductivity (k s-max ) under high and low soil moisture in determining whole-tree hydraulic conductance (K tree ) and in mediating stomatal control of gas exchange in four contrasting tree species growing under ambient and elevated CO 2 (CO 2 a and CO 2 e ). We hypothesized that K tree would adjust to CO 2 e through an increase in root and branch k s-max in response to anatomical adjustments. However, physiological changes observed under CO 2 e were not clearly related to structural change in the xylem of any of the species. The only large effect of CO 2 e occurred in branches of Liquidambar styraciflua L. and Cornus florida L. where an increase in k s-max and a decrease in xylem resistance to embolism (−P 50 ) were measured. Across species, embolism in roots explained the loss of K tree and therefore indirectly constituted a hydraulic signal involved in stomatal regulation and in the reduction of G s-ref , the sap-flux-scaled mean canopy stomatal conductance at a reference vapour pressure deficit of 1 kPa. Across roots and branches, the increase in k s-max was associated with a decrease in −P 50 , a consequence of structural acclimation such as larger conduits, lower pit resistance and lower wood density. Across species, treatment-induced changes in K tree translated to similar variation in G s-ref . However, the relationship between G s-ref and K tree under CO 2 a was steeper than under CO 2 e , indicating that CO 2 e trees have lower G s-ref at a given K tree than CO 2 a trees. Under high soil moisture, CO 2 e greatly reduced G s-ref . Under low soil moisture, CO 2 e reduced G s-ref of only L. styraciflua and Ulmus alata. In some species, higher xylem dysfunction under CO 2 e might impact tree performance in a future climate when increased evaporative demand could cause a greater loss of hydraulic function. The results contributed to our knowledge of the physiological and anatomical mechanisms underpinning the responses of tree species to drought and more generally to global change.

2. Manuskripte können in deutscher, englischer oder französischer Sprache eingereicht werden. 3. Zusätzlich zu einem datierten Ausdruck müssen Aufsätze und Rezensionen auf üblichen EDV-Medien (CD) eingereicht werden. Die Texte sollten entweder im Format der gängigsten Textverarbeitungssysteme (vorzüglich MS WORD) oder im Rich Text Format (RTF) gespeichert werden ("Speichern unter" bzw. "save as") und müssen dem Papierausdruck entsprechen. 4. Abkürzungen sollten nach in den einschlägigen Fachbereichen eingeführten Listen gebraucht werden: Für das Ägyptische und Koptische Lexikon der Agyptologie sowie im Bedarfsfall Koptisches Handwörterbuch; für die Altorientalische Philologie Akkadisches Handwörterbuch, Chicago Assyrian Dictionary, Hethitisches Wörterbuch, Chicago Hittite Dictionary, The Sumerian Dictionary of the University Museum of the University of Pennsylvania; für die alttestamentliche Wissenschaft das Internationale Abkürzungsverzeichnis für Theologie und Grenzgebiete (IATG2, biblische Bücher sind nach der Theologischen Realenzyklopädie zu zitieren). Es genügt dann ein Hinweis in einer ersten Anmerkung auf das verwendete System und evtl. Abweichungen.

Fire, grazing, browsing and tree cutting are major anthropogenic determinants of vegetation patterns in African savannas. In Burkina Faso forest management policies prohibit grazing while recommending annual early fire and selective tree cutting of 50% of the merchantable standing volume on a 20-year rotation period. These management prescriptions are not based on long-term experimental evidence, particularly the responses of saplings to these management regimes are not well known. A factorial experiment with two levels was designed to examine the effects of moderate level of grazing, early fire and selective tree cutting on the dynamics of sapling populations on two sites, Laba and Tiogo, in the savanna woodland of Burkina Faso and assessed for 10 years from 1992 to 2002. Species richness, sapling population density, structure and growth were analysed. The results provide evidence that fire, grazing and selective cutting acted independently to influence the population dynamics of saplings. Annual early fire significantly reduced species richness ( p = 0.037 in Laba and p = 0.016 in Tiogo), population density ( p < 0.001 in Laba and p = 0.003 in Tiogo) and current annual increment (CAI) in basal area ( p < 0.001 in Laba and p = 0.016 in Tiogo). Grazing and fire affected sapling morphology but the response was site specific. Selective removal of trees did not affect any of the parameters studied, except the CAI in dominant height at the Tiogo site which was significantly ( p = 0.028) reduced by the cutting treatment. Early fire also significantly reduced the CAI in dominant height at Laba. The height class distribution revealed that more than 93% of the saplings recorded were less than 400 cm tall, and fire significantly reduced the rate of change in density of saplings in the 200-400 cm height class. It can be concluded that annual early fire was the factor that most affected sapling recruitment. The sapling response to these management regimes was species specific. #

We overview the recent development of oak dendrochronology in Europe related to archaeology and arthistory. Tree-ring series of European oaks (Quercus robur and Q. petraea) have provided a reliable framework for chronometric dating and reconstruction of past climate and environment. To date, long oak chronologies cover almost the entire Holocene, up to 8480 BC and the network over the entire area in which the two oaks grow is being improved. We present the main characteristics of oak ring series and discuss the latest methodological advances in defining the calendar year in which the tree-rings were formed and in interpreting such dating in terms of the age of a wooden object. Dendrochronology has established itself as a standard dating tool and has been applied in a wide variety of (pre-)historical studies. Archaeological wood, historical buildings, works of art (such as panel paintings and sculptures) have been successfully investigated. Recent advances in dendro-provenancing have helped to obtain more information on the timber trade in the past. Information on past forest structures, silviculture and timber use have become available through scrutinizing historical and contemporary ring-width patterns.

Développement d’un modèle forestier générique simulant les flux et les stocks de carbone et d’eau dans le cadre des changements climatiques

L’augmentation de la concentration en gaz carbonique dans l’atmosphère pourrait être à l’origine de changements climatiques importantes. La végétation semble constituer un puits conséquent au carbone: ~2Gt/an sur les 7Gt émises par an par les activités anthropiques, sont stockés dans les écosystèmes terrestres. Il est donc indispensable de mieux quantifier le cycle du carbone dans les biomes terrestres. Cette thèse s’inscrit dans ce cadre avec pour but d’améliorer la quantification des flux et des stocks de carbone et d’eau dans les écosystèmes forestiers. Le travail de thèse a été subdivisé en trois taches principales: l’amélioration et la validation d’un modèle de type SVAT et le renforcement de son caractère générique, l’étude des effets de la variabilité spatiale des paramètres d’entrées sur les flux de carbone et d’eau simulés et le développement de méthodes (utilisation de la télédétection) pour estimer certains des paramètres d’entrées à l’échelle de la région.

Tout d’abord, nous avons poursuivi le développement et l’amélioration d’un modèle forestier (CASTANEA). CASTANEA simule les flux suivants : la Production Primaire Brute (PPB), la respiration autotrophe aérienne et souterraine, la respiration hétérotrophe du sol, l’évapotranspiration du couvert et le drainage de l’eau. A partir de ses flux, l’évolution des stocks de carbone du sol, la croissance aérienne et souterraine du bois et la dynamique d’eau dans le sol sont calculées. Les flux sont calculés à un pas de temps semi-horaire alors que l’évolution des stocks (eau et carbone) est implémentée journellement. Le peuplement est représenté comme un arbre moyen avec 5 compartiments physiquement localisés : tiges, branches, feuilles, grosses racines et fines racines et un compartiment physiquement non localisé : les réserves glucidiques. Le couvert est schématisé par une série de strates horizontales d’indice foliaire identique. Seule la variabilité verticale des propriétés photosynthétiques et de la respiration des feuilles est prise en compte. Le modèle ne tient compte d’aucun type de variabilité horizontale. Les variables météorologiques, requises chaque demi-heure pour le fonctionnement de CASTANEA, sont le rayonnement global, la température de l’air, l’humidité relative, la vitesse du vent et les précipitations.


Le modèle a été précisément paramétré sur le site Euroflux de Hesse en 1997, nous avons étudié l’effet sur les variables de sortie de l’incertitude concernant la mesure des paramètres d’entrées. Nous avons montré que les incertitudes concernant les paramètres conditionnant le couplage eau carbone et de la réponse de la photosynthèse au PAR, pesaient fortement sur la simulation du Flux Net de Carbone (FNC). Ensuite nous avons évalué chaque processus implémenté dans le modèle. Pour cela, nous avons utilisé de nombreuses mesures auxiliaires disponibles sur le site de Hesse en 1997: croissance du bois, photosynthèse à l’échelle des branches, respiration du bois et du sol, transpiration, contenue en eau du sol et interception du rayonnement et de la pluie. Nous avons montré que le modèle reproduisait bien les bilans carboné et hydrique calculés par la somme des flux locaux mesurés (correspondant chacun à un processus). Cependant, il existe un biais quand on compare les simulations annuelles et les flux mesurés par la méthode des corrélations (mesure intégrative). Ce résultat questionne notamment le processus de changement d’échelle lorsque l’on construit un modèle. Ensuite nous avons évalué le modèle à Hesse sur le plus long terme de 1997 à 2003, par comparaison des simulations et des mesures de FNC, d’eau et d’accroissement du bois aérien. Le modèle reproduit bien les variations journalières et interannuelles mais ne capte pas une forte tendance à la hausse du FNC observée sur les mesures. Ce résultat questionne une fois de plus le changement d’échelle et notamment les variations de la surface d’intégrée par les mesures.

Nous avons aussi paramétré et validé le modèle pour 3 autres sites Euroflux en comparant à chaque fois nos simulations à plusieurs années de flux mesurés par la méthode des corrélations (1 site dominé par un chêne sempervirent et deux sites de conifères). Ensuite sur 6 peuplements représentatifs de la forêt française nous avons simulé les effets de la dérive climatique simulée par le modèle climatique ARPEGE de 1960 à 2099 sur les flux de carbone et d’eau. Nous avons montré que la Production Primaire Brute (PPB) et la respiration de l’écosystème (Reco) augmentaient dans tous les cas, mais dans des proportions différentes selon l’espèce et le site. La conséquence est l’augmentation du FNC (PPB-Reco) pour 4 peuplements, la stabilisation pour 1 et la décroissance pour le dernier. De plus, la sécheresse tend à augmenter aussi ce qui limite la hausse de PPB à partir de 2030.

Suite aux validations de la version de base du modèle deux améliorations du modèle ont été développées et testées : Tout d’abord, nous avons implémenté la résistance mésophyllienne dans le module de photosynthèse foliaire. La plupart des modèles de photosynthèse ne prennent en compte, que les résistances au trajet du CO2 comprises entre la surface des feuilles et les chambres sous stomatiques, alors que, quand le CO2 diffuse jusqu’au chloroplastes, il existe aussi des résistances internes (ou mésophylliennes) en phase liquide et en phase gazeuse. Nous avons observé, que la prise en compte de ces résistances modifiait la réponse de la photosynthèse foliaire au rayonnement mais changeait peu le couplage eau carbone contrairement à ce que l’on présupposait. La seconde modification concerne l’allocation du carbone : simulation de coefficients d’allocation variables en fonction des conditions du milieu, simulation de l’indice foliaire, simulation de la masse surfacique des feuilles. Le carbone disponible pour la mise en place de nouvelles structures est égal à la différence entre la Production Primaire Brute (PPB) et de la Respiration Autotrophe (RA) du couvert. Ensuite, ce carbone disponible est réparti entre les différents « compartiments », feuilles, bois aérien, grosses racines, fines racines selon des coefficients d’allocation. L’utilisation de coefficients d’allocation constants (comme dans la version de base de CASTANEA) ne permet pas de prendre en compte des effets âges ou des effets de fertilité. Il est alors nécessaire d’implémenter des règles mécanistes d’allocation, ou de contraindre les coefficients d’allocation selon différents critères. Nous avons développé un modèle d’allocation pour les espèces décidues en utilisant deux sortes de contraintes fonctionnelles : l’homéostasie de la quantité de réserves carbonées et les contraintes hydrauliques, l’arbre devant constamment maintenir un continuum d’eau entre le sol et les feuilles, ce qui conditionne sa surface de tissus conducteurs, sa conductance stomatique, et le rapport entre surface foliaire et surface racinaire. En utilisant un important jeu de donnée sur deux sites (Fontainebleau et Hesse), nous avons montré que la simulation des variations spatiales et temporelles de croissance aériennes est améliorée lorsque les variations d’allocation sont prises en compte. Nous avons aussi testé la validité de la simulation du LAI à partir de la quantité de réserves. Un module de simulation de la masse surfacique en fonction du rayonnement incident a aussi développé. A l’aide d’un large jeu de données (5 sites de mesures et trois espèces), nous avons démontré la fiabilité de ce modèle.

Un massif forestier comme celui de Fontainebleau, peut être considéré comme une mosaïque de parcelles, dont les caractéristiques du couvert dépendent des espèces présentes, de la fertilité du sol, des pratiques forestières ou de la pente. Si l’on est capable de déterminer sur chaque parcelle les caractéristiques conditionnant les FNC, il est possible de réaliser des cartes du FNC sur l’ensemble du massif avec un modèle comme CASTANEA. La parcelle constitue alors le niveau de résolution de l’étude. Mais pour déterminer le FNC directement à l’échelle du massif forestier, au lieu de réaliser près de 3000 simulations, chacune d’entre elles correspondant à une parcelle, une seule simulation peut être réalisée à partir des paramètres moyens sur le massif. Une parcelle « moyenne » est ainsi sensée représentée le massif forestier. C’est ce type de simplification qui est fait dans les modèles fonctionnant aux échelles continentales ou globales. Cependant, les flux de carbone et d’eau constituent la résultante de processus qui parfois présentent des réponses non linéaires aux caractéristiques du milieu. Si l’on procède à une agrégation spatiale de paramètres (par l’utilisation d’un peuplement moyen) présentant une variabilité pour laquelle la réponse du FNC sature, les estimations du FNC sont alors en théorie positivement biaisées. Nous avons donc étudié l’effet de l’hétérogénéité spatiale sur la simulation des flux de carbone de façon totalement théorique par une étude de sensibilité et de manière plus contrainte par l’hétérogénéité effective observée à trois échelles différentes. Dans un premier temps, une analyse de sensibilité a été menée en faisant varier simultanément, dans des gammes réalistes, six principaux paramètres d’entrées : la biomasse de bois, la réserve utile en eau du sol, l’agrégation du couvert, l’indice foliaire, et la masse surfacique des feuilles de lumière. Dans un deuxième temps, l’effet de l’agrégation spatiale des paramètres d’entrées sur la simulation des flux de carbone et d’eau est considérée à trois échelles différentes, de 0.8 à 1000 ha, en utilisant des résolutions spatiales allant de 10-2 ha à 20 ha. L’analyse de sensibilité indique que la photosynthèse et la respiration de l’écosystème montrent une réponse modérément non linéaire seulement pour le l’ind...

Variations in seed and germination characteristics among nine Juniperus procera populations in Ethiopia were evaluated. Bulk seed samples were collected and examined for variations in number of seeds per cone, seed length, width, 1000-seed weight and germination in the laboratory and nursery. In the laboratory, the effect of light conditions on seed germination was tested by incubating the seeds under continuous light or darkness. Significant variations ( p < 0.05 for all traits) among J. procera populations were detected for all seed characters: number of seeds per cone, seed length, width and 1000-seed weight. Germination in the laboratory also varied significantly among populations ( p = 0.012) as well as light conditions ( p = 0.037). The overall germination performance of seeds incubated under continuous light was significantly higher than seeds incubated in darkness. However, seeds from some populations germinated equally well in light and darkness, suggesting that photo-dormancy in juniper seeds varies between populations. Germination of seeds sown on nursery beds was relatively lower than seeds germinated under continuous exposure to light in the laboratory. Among geo-climatic variables, the mean annual rainfall of seed collection sites displayed a significant correlation with number of seeds per cone (r = 0.71; p < 0.05) and seed length (r = 0.73, p < 0.05), and between longitude and rate of germination (r = 0.73, p < 0.05). A significant intercharacter correlation was also found between seed length and seed width (r = 0.78, p < 0.05), and between seed weight and number of seeds per cone (r = 0.91, p < 0.01). It can be concluded that the observed patterns of variation will have an important implication for gene conservation and tree improvement program of the species in the future. #

Let G be a graph and (G) denote the domination number of G. A dominating set D of a graph G with |D| = (G) is called a -set of G. A vertex x of a graph G is called: (i) -fixed if x belongs to every -set, (ii) -free if x belongs to some -set but not to all -sets, (iii) -bad if x belongs to no -set, (iv)

Linguists studying grammar often describe their models using a syntax tree. Drawing a syntax tree involves the depiction of a rooted tree with additional syntactic features using specific domain conventions. TreeForm assists users in developing syntax trees, complete with movement lines, coreference, and feature association, in order to explore their syntactic theories and explain them to their colleagues. It is a drag-and-drop alternative to LaTeX and labelled bracket notation tools already available, which many linguists find difficult to use. We compare the output of TreeForm to those existing tools and show that it is able to better respect the conventions of the domain. We assess how easily linguists learn to use TreeForm through a series of cognitive walkthroughs. Our reviews find that TreeForm is a viable alternative to existing tools.

... For Suhrawardi and Illuminationism, see Hossein Ziai, Knowledge and Illumination: A Study of Suhrawardi&amp;amp;amp;#x27;s &amp;amp;amp;quot;Hikmat al-Ishraq&amp;amp;amp;quot;, (Brown Uni-versity Judaic Studies Series ... In other Middle Eastern scriptures, such as the Bible and the Qur&amp;amp;amp;#x27;an, of course, the story of Adam and Eve in ...