Methodology for classification of images based on the characteristics of a new interpretation of Shannon’s entropy

A new visual inspection method for the classification of wooden plates used in pencil manufacturing is presented. Darker regions in wooden plates indicate the presence of growth rings which are regions of hard wood. Pencils manufactured with these plates are more difficult to sharpen and have a tendency to bend and crack; therefore, these plates are classified as not being adequate for pencil manufacturing. The proposed method is based on the extraction and analysis of the features of the wooden plates using gray level images. The method classifies the plates using the results obtained by an automatic threshold determination based on Shannons entropy. The method was idealized aiming at low computational complexity, i.e., algorithm calculations involving only simple operations such as addition, subtraction, multiplication and division which could be implemented in hardware using VLSI technology or programmable logic devices. The wooden plate is mapped in an optimal number of regions; each region is pre-classified considering some relevant features based on the entropy gray level distribution of the pixels. Information from all regions is combined based on heuristic decision rules, arriving in a pre-classification stage where the regions are labeled in four classes (A, B, C and X). Two decision algorithms have been investigated for the final classification: one based in a co-occurrence matrix considering only a uni-directional horizontal neighborhood of the regions and the second is based on a heuristic method of information reduction considering combinations of the pre-classified regions. The final results obtained by the two algorithms were compared with the classification made by a human expert, demonstrating that the proposed method had very good performance.     

Changes in root growth and relationships between plant organs and root hydraulic traits in American elm （Ulmus americana L.） and red oak （Quercus rubra L.） seedlings due to elevated CO2 level

The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-replicated experiment was conducted with two times 24 American elm(Ulmus americana L.) and 23 and 24 red oak(Quercus rubra L.) seedlings growing in ambient CO2(around 360 μmol·L-1) and 540 ± 7.95 μmol·L-1 CO2 in a greenhouse. After 71 days of treatment for American elm and 77 days for red oak,14...     

Correction to: Restrictions on natural regeneration of storm‑felled spruce sites by silver birch (Betula pendula Roth) through limitations in fructification and seed dispersal

European Journal of Forest Research - The article “Restrictions on natural regeneration of storm-felled spruce sites by silver birch (Betula pendula Roth) through limitations in...     

Intraspecific leaf morphological variation in Quercus dentata Thunb.: a comparison of traditional and geometric morphometric methods,a pilot studyOA

To compare the application of traditional morphometric methods(TMMs) and geometric morphometric methods(GMMs) in the study of intraspecific leaf morphological characters of Quercus dentata, fifteen linear measurement indices and thirteen landmarks of leaves were used to study leaf morphology of three provenances(H1, H2, and H3). In TMMs, principal component analysis(PCA) showed that leaf size–related indices played an important role in population classification. Partial least square(PLS) analysi...     

Effects of nitrogen content on growth and hydraulic characteristics of peach （Prunus persica L.） seedlings under different soil moisture condi- tions

A pot experiment was conducted to investigate the effects of nitrogen content [N1(no fertilizer), N2(0.15 g?kg–1), and N3(0.3 g?kg–1)] on the growth and the hydraulic characteristics of peach seedlings under different soil moisture conditions(W1, W2 and W3, in which the soil water content was 45% to 55%, 60% to 70%, and 75% to 80% of the field water capacity, respectively) by using a specialized high pressure flow meter with a root chamber and a coupling, which was connected to plant organs. Leaf area and leaf hydraulic conductivity(KL) increased significantly in the seedlings because of increased soil moisture and N content. KL increased with leaf area. A linear correlation was documented between KL and leaf area. KL was higher in the morning and began to decline sharply after 16:00, at which KL declined after an initial increase. Soil moisture and N content enhanced shoot(Ks) and root(Kr) hydraulic conductivities, thereby improving the low soil moisture condition to a large extent. Ks and Kr of the seedlings were reduced by 32% and 27% respectively in N1, and by 14.7% and 9.4%, respectively in N2, and both in W1, compared with the control treatment. N3 had no significant effect on Ks and Kr under similar conditions. Linear negative correlations were observed between Kr and the excised root diameter as well as between Ks and the shoot stem diameter. The shoot-to-root ratio increased with increase in N content. The shoot-to-root ratio in N3 was increased by 14.37%, compared with N1 in W1 as well as by 12% and 4.39% in W2 and W3, respectively. Knowledge of the effects of soil moisture and N fertilizer on hydraulic characteristics and growth is important. Our results provide basic guidelines for the implementation of water-saving irrigation and fertilization management of nursery stock.     

Dating branch growth units in a tropical tree using morphological and anatomical markers: the case of Parkia velutina Benoist (Mimoso?deae)

Context

In tropical areas, studies based on the retrospective analysis of tree development have focused principally on growth ring research. The interpretation of primary growth markers is overlooked although it opens perspectives to provide long time-series on tree-crown development.

Aims

This study focused on Parkia velutina, an emergent tree of neotropical rain forests. Our objectives were (1) to characterize the phenological cycle of this species, and (2) to identify temporally interpretable morphological and anatomical markers.

Methods

We collected dominant branches in 14 adult trees and identified growth markers that limit longitudinal and radial increments. We coupled this approach with a 2-year phenological survey of 20 trees.

Results

Leaf shedding, growth unit elongation and growth ring formation define the phenological cycle. At tree scale, this cycle is synchronous and affects all axes. At population scale, trees can be desynchronized. This cycle is annual despite some slight variability. Successive growth units and growth rings are easily identifiable.

Conclusion

Dating a branch by counting the number of growth units or growth rings is possible in many years with a reasonable error. Nevertheless, estimating their precise month of formation in order to study climatic influences remains difficult.     

Influence of foliar phenology and shoot inclination on annual photosynthetic gain in individual beech saplings: A functional–structural modeling approach

We developed a functional–structural plant model for Fagus crenata saplings and calculated annual photosynthetic gains to determine the influences of foliar phenology and shoot inclination on the carbon economy of saplings. The model regenerated the three-dimensional shoot structure and spatial and temporal display of leaves; we calculated the hourly light interception of each leaf with a detailed light model that allowed us to estimate hourly leaf photosynthetic gain taking leaf age into account. To evaluate the importance of simultaneous foliar phenology and slanting shoots in beech saplings, we calculated the photosynthetic budgets for saplings with contrasting foliar phenologies and shoot inclinations. In our simulations, we distinguished between simultaneous and successive foliar phenologies, upright and slanting shoot inclinations, and environments with and without a vertical gradient in light intensity. Other model parameters (including photosynthesis vs. light curve, leaf size, and leaf shape) were obtained directly from live beech saplings. With no vertical gradient in light intensity, modeled saplings with simultaneous foliar phenology and slanting shoots (as in live beech) had larger annual photosynthetic gains than saplings with other combinations of traits. Hence, simultaneous foliar phenology and slanting shoots are efficient ways to display leaves in the shaded forest understory light regime where beech saplings thrive. In the presence of vertical light gradients, which can occur in canopy gaps, saplings with upright shoots had larger annual photosynthetic gains than counterparts with slanting shoots. Although mean daily photosynthetic gains of saplings with successive foliar phenology were elevated by exposing leaves to strong light when young and productive, the annual photosynthetic budget of these saplings was reduced (compared to saplings with simultaneous foliar phenology) by their relatively short leaf lifespan. Overall, our results suggest that slanting shoots with simultaneous foliar phenology are particularly successful in shaded environments, where beech often dominates, because they appear to maximize the annual carbon budget by avoiding self-shading and extending leaf lifespans.     

Sprouting characteristics of <Emphasis Type="Italic">Quercus pubescens</Emphasis> Willd. and <Emphasis Type="Italic">Quercus frainetto</Emphasis> Ten. trees after a wildfire: To cut or not to cut the burned trees?

The aims of this study were to analyze the sprouting characteristics of Quercus pubescens and Q. frainetto trees after a wildfire and to recommend the appropriate silvicultural treatments in order to achieve dense sprout origin regeneration. This study was carried out in the area that was burned in a wildfire in northeastern Greece. Three years later, 140 Q. pubescens trees and 140 Q. frainetto trees were selected. Seventy trees for each species were individuals that were cut after the fire and were in the form of stumps, while 70 trees were intact top-killed trees, as a result of fire. In each stump and intact tree that was selected, various parameters were measured or counted: the diameter at the level of ground, the number of the developed sprouts (if any) and the height as well as the basal diameter of the tallest sprout, etc. Both species have similar sprouting behavior after a wildfire. Mother tree dimensions positively influenced the number of sprouts and the growth of the tallest sprout per individual. The mean height of the tallest sprout per stump, after three growing seasons from the forest fire, is high in both species (2.08 m for Q. pupescens and 2.29 m for Q. frainetto). Cut stumps had more sprouts than intact trees in both species. Forest practice, in order to maximize the sprouting of Q. pubescens and Q. frainetto trees after a forest fire, should cut the burned trees before the next growing season.     

Unraveling the tripartite interactions among the woolly poplar aphid,its host tree,and their environment: a lead to improve the management of a major tree plantation pest?

Key message

For an optimal deployment of poplar resistance to the gall-inducing aphid Phloeomyzus passerinii , a laboratory susceptibility assay has been developed. The nature of aphid–tree interactions during compatible and incompatible situations has been studied in detail. This should help at identifying specific resistance markers and at testing effects of site conditions on tree–pest interactions.

Context

P. passerinii is a major pest of poplar plantations in Europe, and the plantation of resistant poplar genotypes is regarded as the best long-term management strategy for this pest. This requires a sound knowledge of the interactions among the pest, its host and their environment.

Aims

Here, we review the recent advances aiming at developing an optimal deployment of host resistance versus P. passerinii.

Results

Investigations on aphid-host interactions demonstrated that P. passerinii induces pseudogalls within the bark of susceptible hosts. This results in a reduction of starch bark content during aphid outbreaks, which could be involved in tree death. The constitutive level of starch in the bark could be related to the tolerance level of trees. A susceptibility test has been designed for poplar genotypes, discriminating three categories of susceptibility depending on tree’s ability to totally or partially inhibit pseudogall induction. The test still has several limitations however. It neither takes into account the large level of individual genetic diversity of the aphid in France, nor the environmental modulation of tree resistance and tolerance, while water deficit and fertilization could potentially affect these parameters.

Conclusion

The hypotheses drawn regarding the processes leading to tree death or resistance should help at identifying resistance markers, and at testing effects of site conditions on tree–pest interactions.

     

Division of ecological species groups and functional groups based on interspecific association — a case study of the tree layer in the tropical lowland rainforest of Jianfenling in Hainan Island, China

Twenty-three sample plots dominated by Vatica mangachapoi at various elevations in the tropical lowland rainforest in the Jianfengling National Nature Reserve of Hainan Island were established. The interspecific association among the 32 dominant species was analyzed and the division of ecological species groups and functional groups are discussed. The results showed that these dominant populations had an overall positive interspecific association. The species pairs with significant, positive association accounted for only about 10% of the total 496 species pairs. Most of the other species pairs showed weak association or non-association, i.e., the dominant populations investigated had relatively independent distributions. The 32 dominant species were divided into four ecological species groups and ten functional groups according to their interspecific association coefficients, based on a cluster analysis of the species. Recognition characteristics of the ten functional groups are proposed. __________ Translated from Scientia Silvae Sinicae, 2007, 43(4): 9–16 [译自: 林业科学]     

Problems with models assessing influences of tree size and inter-tree competitive processes on individual tree growth:a cautionary taleOA

In forest growing at any one site,the growth rate of an individual tree is determined principally by its size,which reflects its metabolic capacity,and by competition from neighboring trees.Competitive effects of a tree may be proportional to its size;such competition is termed ’symmetric’ and generally involves competition below ground for nutrients and water from the soil.Competition may also be’asymmetric’,where its effects are disproportionate to the size of the tree;this generally involves ...     

Introduction of Mandshurian ash (Fraxinus mandshurica Rupr.) to Estonia: Is it related to the current epidemic on European ash (F. excelsior L.)?

Recent investigations in Japan have suggested that the causal organism of the ongoing epidemic affecting European ash (Fraxinus excelsior) in Europe, Hymenoscyphus pseudoalbidus, may originate in East Asia. The fungus may have been unintentionally carried to Europe during the introduction of Mandshurian ash (F. mandshurica), the host tree of the fungus in East Asia. Still unicentric emergence hypothesis is in force: An area in the eastern Poland or Baltic has been shown to be the presumed epicentre of the epidemic. Really, during the Soviet occupation, several consignments of F. mandshurica seeds and plants, originating directly from the natural range of F. mandshurica in East Asia (Russian Far East), reached Baltic areas. In this paper, an overview about the Mandshurian ash is presented, the history of introduction of F. mandshurica to Estonia is reviewed and colonization of F. excelsior in this country by H. pseudoalbidus is briefly discussed. At present, we could not find any evidence, spatial or temporal, for a direct connection of the disease emergence on native F. excelsior with the introduction of F. mandshurica. The pathogen first colonized northwest Estonia and moved southeast and not from south to north as would be expected according to the hitherto existing unicentric hypothesis. However, more information is needed from different regions before to pose a multicentric emergence hypothesis and to deepen more into the investigations of the environmental factors that affected the host and supported to the epidemic in different areas.     

Experimental approaches to select tree species for forest restoration: effects of light,water availability and interspecific competition in degraded areasOA

Knowing what native trees can recr uit on degraded areas allows selecting the best species to restore these sites. However, as this information is not often available, experimentation is required before large-scale planting. This study used ex situ experiments to make these decisions on recruitment. Competition with r-strategist plants, excessive solar radiation and water shortage commonly impair tree recruitment in open habitats. The experiments focused on the interactions among these factors a...