Drivers of individual oak tree selection by acorn dispersing animals inferred from a genotyped seedling cohort

ABSTRACTSeed-dispersing animals can strongly influence plant reproductive success and resulting population structures. Few studies have disentangled different drivers of disperser foraging behavior in natural settings and their actual relevance for plant fitness. Here we adopt a novel approach to investigate the drivers of individual trees’ dispersal success in a mixed Pedunculate oak-Pyrenean oak (Quercus robur and Q. pyrenaica) forest stand. We genotyped a seedling cohort (n = 825) upon emergence and performed Bayesian parentage analyses to infer the acorn dispersal success of each oak tree in the stand. We then modeled this estimate as a function of six tree characteristics. The absolute number of animal-dispersed seedlings was exclusively predicted by crop size and the proportion of dispersed seedlings by the number of fruiting oaks in the neighborhood. Neither the oak species nor tree height, acorn size or shape played any role. Our findings contrast with results from experimental studies and suggest that effective acorn dispersers, despite being scatter-hoarders, behaved much like avian dispersers of fleshy-fruited species when selecting trees to forage on. Their behavior should favor the dominance of large, prolific trees for the dynamics and genetic composition of naturally regenerating oak stands.

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Improved tree height estimation of secondary forests in the Brazilian Amazon

Acta Amazonica ◽

10.1590/1809-4392201700844 ◽

2018 ◽

Vol 48 (3) ◽

pp. 179-190 ◽

Cited By ~ 4

Author(s):

Henrique Luis Godinho CASSOL ◽

Yosio Edemir SHIMABUKURO ◽

João Manuel de Brito CARREIRAS ◽

Elisabete Caria MORAES

Keyword(s):

Tree Height ◽

Brazilian Amazon ◽

Hyperbolic Model ◽

Secondary Forests ◽

Validation Data ◽

Novel Approach ◽

Brazilian Amazon Region ◽

Species Groups ◽

Ecological Species Groups ◽

Individual Trees

ABSTRACT This paper presents a novel approach for estimating the height of individual trees in secondary forests at two study sites: Manaus (central Amazon) and Santarém (eastern Amazon) in the Brazilian Amazon region. The approach consists of adjusting tree height-diameter at breast height (H:DBH) models in each study site by ecological species groups: pioneers, early secondary, and late secondary. Overall, the DBH and corresponding height (H) of 1,178 individual trees were measured during two field campaigns: August 2014 in Manaus and September 2015 in Santarém. We tested the five most commonly used log-linear and nonlinear H:DBH models, as determined by the available literature. The hyperbolic model: H = a.DBH/(b+DBH) was found to present the best fit when evaluated using validation data. Significant differences in the fitted parameters were found between pioneer and secondary species from Manaus and Santarém by F-test, meaning that site-specific and also ecological-group H:DBH models should be used to more accurately predict H as a function of DBH. This novel approach provides specific equations to estimate height of secondary forest trees for particular sites and ecological species groups. The presented set of equations will allow better biomass and carbon stock estimates in secondary forests of the Brazilian Amazon.

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Slenderness of pedunculate oak (Quercus robur L.) according to biosocial position

Agronomy Science ◽

10.24326/asx.2018.3.4 ◽

2018 ◽

Vol 73 (3) ◽

pp. 37-43

Author(s):

ZDZISŁAW KACZMARSKI ◽

KATARZYNA MASTERNAK ◽

MATEUSZ JARMUŁ

Keyword(s):

Basal Area ◽

Tree Height ◽

Projection Area ◽

Pedunculate Oak ◽

Single Tree ◽

Crown Length ◽

Crown Width ◽

Growth Space ◽

Oak Tree ◽

Crown Projection Area

The paper presents results of an analysis of pedunculate oak slenderness. The dependence between slenderness of the oak tree and dimensions of the trunk and the crown dimensions of a single tree were examined. The biosocial position of each tree was determined based on the Kraft’s classification criteria. Following dimensions were measured for each tree: height, height of base of live crown, crown radius, diameter at breast height. The following crown parameters related to the growth space of a single tree were determined: crown length, crown width, crown projection area, space of a single tree, Seebach’s growth space number, crown projection area to basal area ratio, crown spread. Based on the obtained results, the following was found: biosocial position of the oak tree in vertical structure of the stand has significant impact on the size of the tree slenderness; the slenderness increases with deterioration of the biosocial position of the tree, but it decreases with the increase in the value of the tree’s measurement characteristics and the measures of its crown.

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Konkurrenz zwischen Stieleiche und Buche auf Lothar-Sturmflächen | Competition between pedunculate oak and European beech on Lothar windthrow areas

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2009.0114 ◽

2009 ◽

Vol 160 (5) ◽

pp. 114-123 ◽

Cited By ~ 4

Author(s):

Daniel Otto ◽

Sven Wagner ◽

Peter Brang

Keyword(s):

Large Scale ◽

Early Stage ◽

Tree Height ◽

European Beech ◽

Threshold Value ◽

Test Methods ◽

Permanent Plots ◽

Pedunculate Oak ◽

Competitive Pressure ◽

Competition Index

The competitive pressure of naturally regenerated European beech (Fagus sylvatica) saplings on planted pedunculate oak (Quercus robur) was investigated on two 1.8 ha permanent plots near Habsburg and Murten (Switzerland). The plots were established with the aim to test methods of artificial oak regeneration after large-scale windthrow. On both plots, 80 oaks exposed to varying levels of competitive pressure from at most 10 neighbouring beech trees were selected. The height of each oak as well as stem and branch diameters were measured. The competitive pressure was assessed using Schütz's competition index, which is based on relative tree height, crown overlap and distance from competing neighbours. Oak trees growing without or with only slight competition from beech were equally tall, while oaks exposed to moderate to strong competition were smaller. A threshold value for the competition index was found above which oak height decreased strongly. The stem and branch diameters of the oaks started to decrease even if the competition from beech was slight, and decreased much further with more competition. The oak stems started to become more slender even with only slight competition from beech. On the moderately acid beech sites studied here, beech grow taller faster than oak. Thus where beech is competing with oak and the aim is to maintain the oak, competitive pressure on the oak must be reduced at an early stage. The degree of the intervention should, however, take the individual competitive interaction into account, with more intervention if the competition is strong.

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Pros and Cons of the Cannabinoid System in Cancer: Focus on Hematological Malignancies

Molecules ◽

10.3390/molecules26133866 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3866

Author(s):

Natasha Irrera ◽

Alessandra Bitto ◽

Emanuela Sant’Antonio ◽

Rita Lauro ◽

Caterina Musolino ◽

...

Keyword(s):

Cannabinoid Receptors ◽

Hematological Malignancies ◽

Antitumor Agents ◽

Control Cell ◽

Experimental Studies ◽

Endocannabinoid System ◽

Chemotherapeutic Agents ◽

Cancer Cell Growth ◽

Cell Functions ◽

Novel Approach

The endocannabinoid system (ECS) is a composite cell-signaling system that allows endogenous cannabinoid ligands to control cell functions through the interaction with cannabinoid receptors. Modifications of the ECS might contribute to the pathogenesis of different diseases, including cancers. However, the use of these compounds as antitumor agents remains debatable. Pre-clinical experimental studies have shown that cannabinoids (CBs) might be effective for the treatment of hematological malignancies, such as leukemia and lymphoma. Specifically, CBs may activate programmed cell death mechanisms, thus blocking cancer cell growth, and may modulate both autophagy and angiogenesis. Therefore, CBs may have significant anti-tumor effects in hematologic diseases and may synergistically act with chemotherapeutic agents, possibly also reducing chemoresistance. Moreover, targeting ECS might be considered as a novel approach for the management of graft versus host disease, thus reducing some symptoms such as anorexia, cachexia, fatigue, anxiety, depression, and neuropathic pain. The aim of the present review is to collect the state of the art of CBs effects on hematological tumors, thus focusing on the essential topics that might be useful before moving into the clinical practice.

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Adjudicating Perspectives on Forest Structure: How Do Airborne, Terrestrial, and Mobile Lidar-Derived Estimates Compare?

Remote Sensing ◽

10.3390/rs13122297 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2297

Author(s):

Jonathon J. Donager ◽

Andrew J. Sánchez Meador ◽

Ryan C. Blackburn

Keyword(s):

Ponderosa Pine ◽

Laser Scanning ◽

Canopy Cover ◽

Basal Area ◽

Tree Height ◽

Absolute Error ◽

Forest Monitoring ◽

Individual Tree ◽

Structural Configurations ◽

Individual Trees

Applications of lidar in ecosystem conservation and management continue to expand as technology has rapidly evolved. An accounting of relative accuracy and errors among lidar platforms within a range of forest types and structural configurations was needed. Within a ponderosa pine forest in northern Arizona, we compare vegetation attributes at the tree-, plot-, and stand-scales derived from three lidar platforms: fixed-wing airborne (ALS), fixed-location terrestrial (TLS), and hand-held mobile laser scanning (MLS). We present a methodology to segment individual trees from TLS and MLS datasets, incorporating eigen-value and density metrics to locate trees, then assigning point returns to trees using a graph-theory shortest-path approach. Overall, we found MLS consistently provided more accurate structural metrics at the tree- (e.g., mean absolute error for DBH in cm was 4.8, 5.0, and 9.1 for MLS, TLS and ALS, respectively) and plot-scale (e.g., R2 for field observed and lidar-derived basal area, m2 ha−1, was 0.986, 0.974, and 0.851 for MLS, TLS, and ALS, respectively) as compared to ALS and TLS. While TLS data produced estimates similar to MLS, attributes derived from TLS often underpredicted structural values due to occlusion. Additionally, ALS data provided accurate estimates of tree height for larger trees, yet consistently missed and underpredicted small trees (≤35 cm). MLS produced accurate estimates of canopy cover and landscape metrics up to 50 m from plot center. TLS tended to underpredict both canopy cover and patch metrics with constant bias due to occlusion. Taking full advantage of minimal occlusion effects, MLS data consistently provided the best individual tree and plot-based metrics, with ALS providing the best estimates for volume, biomass, and canopy cover. Overall, we found MLS data logistically simple, quickly acquirable, and accurate for small area inventories, assessments, and monitoring activities. We suggest further work exploring the active use of MLS for forest monitoring and inventory.

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Hypoxic mechanisms in primary headaches

Cephalalgia ◽

10.1177/0333102416647037 ◽

2016 ◽

Vol 37 (4) ◽

pp. 372-384 ◽

Cited By ~ 8

Author(s):

Josefine Britze ◽

Nanna Arngrim ◽

Henrik Winther Schytz ◽

Messoud Ashina

Keyword(s):

Cluster Headache ◽

High Altitude ◽

Acute Mountain Sickness ◽

Experimental Studies ◽

Epidemiological Studies ◽

Primary Headaches ◽

Secondary Headaches ◽

Novel Approach ◽

Calcitonin Gene ◽

Level Of Knowledge

Background Hypoxia causes secondary headaches such as high-altitude headache (HAH) and headache due to acute mountain sickness. These secondary headaches mimic primary headaches such as migraine, which suggests a common link. We review and discuss the possible role of hypoxia in migraine and cluster headache. Methods This narrative review investigates the current level of knowledge on the relation of hypoxia in migraine and cluster headache based on epidemiological and experimental studies. Findings Epidemiological studies suggest that living in high-altitude areas increases the risk of migraine and especially migraine with aura. Human provocation models show that hypoxia provokes migraine with and without aura, whereas cluster headache has not been reliably induced by hypoxia. Possible pathophysiological mechanisms include hypoxia-induced release of nitric oxide and calcitonin gene-related peptide, cortical spreading depression and leakage of the blood-brain barrier. Conclusion There is a possible link between hypoxia and migraine and maybe cluster headache, but the exact mechanism is currently unknown. Provocation models of hypoxia have yielded interesting results suggesting a novel approach to study in depth the mechanism underlying hypoxia and primary headaches.

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Tree-soil-water relations in a mature temperate forest under elevated CO2

10.5194/egusphere-egu21-4557 ◽

2021 ◽

Author(s):

Susan Quick ◽

Giulio Curioni ◽

Phillip J Blaen ◽

Stefan Krause ◽

Angus Robert MacKenzie

Keyword(s):

Carbon Dioxide ◽

Soil Water ◽

Temperate Forest ◽

Xylem Sap ◽

Pedunculate Oak ◽

Plant Water ◽

Sap Flux ◽

Water Usage ◽

Individual Trees ◽

Xylem Sap Flux

Extreme anthropogenic global change, such as increasing atmospheric carbon dioxide, can challenge long-lived organisms including trees. Carbon uptake by trees, during photosynthesis, is inevitably accompanied by leaf transpiration; elevated atmospheric CO2 is, therefore, expected to reduce daytime plant water usage. The Free-Air Carbon-dioxide Enhancement (FACE) experiment at the Birmingham Institute of Forest Research (BIFoR) UK manipulates atmospheric CO2 in a 150 year old mixed deciduous temperate forest. In the sub-project described here, we compare diurnal and seasonal plant-water dynamics from individual trees under treatment (elevated CO2) and control conditions. Response of Pedunculate oak (Quercus robur), as the dominant tree species, is reported for the initial three years of elevated CO2, enabling us to characterise whether the woodland is starting to adapt. Xylem sap flux measurement reflects tree water usage and has been used as a proxy for transpiration at stand scale in forest experiments. This project explores a modified sap flux analysis approach, enabling individual trees to be compared and responses to be scaled up to treatment patch level. It considers: inputs-outputs (e.g. precipitation, transpiration), water flow (e.g. xylem sap flux), temperature and radiation to see how tree-soil-water interfaces behave and change with increased CO2. Measurement methods include spot observations (phenology, porometry), and data-logged measures (e.g. of soil moisture and xylem flow). Initially sap flux and stomatal conductance are considered in comparison with previous reported studies of tree water use efficiency and estimations of water storage. By considering these key measurements driven by a tree-centred view the results provide valuable data to improve vegetation, soil and landscape models and increase understanding of trees in mature future- forest environments.

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Assessment of the Pulpwood Quality of Standing Trees Using near Infrared Spectroscopy

Journal of Near Infrared Spectroscopy ◽

10.1255/jnirs.178 ◽

1998 ◽

Vol 6 (A) ◽

pp. A117-A123 ◽

Cited By ~ 9

Author(s):

L. R. Schimleck ◽

A. J. Michell ◽

C. A. Raymond ◽

A. Muneri

Keyword(s):

Near Infrared ◽

Nir Spectroscopy ◽

Tree Height ◽

Tree Breeding ◽

Pulp Yield ◽

Calibration Model ◽

Standing Trees ◽

Sampling Height ◽

Individual Trees ◽

Whole Tree

In Australia, considerable effort has been directed at improving the pulp yield of plantation grown trees through tree breeding programs. However, an improvement in pulp yield relies on the assessment of large numbers of trees. Traditional methods of assessment are expensive, time consuming and destructive, inhibiting their use. Cores can be extracted non-destructively from standing trees using TRECOR, a handheld motor driven drill. The cores are milled, their near-infrared spectra obtained and pulp yield estimated using an appropriate calibration model. The height at which the core is taken is very important. It must represent the whole tree and sampling must be easy and practical. The longitudinal and radial (within-tree) variation of pulp yield for 15 Eucalyptus nitens trees was examined using near-infrared (NIR) spectroscopy. The trees were taken from three families (five trees per family) selected for giving high, medium and low pulp yields respectively. Three trees (one from each family) were examined in detail. Maps of within-tree variation of pulp yield were developed. Pulp yield was found to be highly variable within individual trees and between trees of the same family. The yield of samples from 10% of tree height (approximately 2.2 m) gave the best correlation with whole-tree yield. Samples from 5% of tree height (approximately 1.1 m) gave a slightly lower correlation but provided a more convenient sampling height. Ten Eucalyptus globulus and ten E. nitens trees growing on five sites in Australia were used to examine the longitudinal variation of pulp yield. Trees from sites in Tasmania, Western Australia and Victoria were sampled. The optimal sampling height for E. globulus was 1.1 m. No single sampling height could be recommended for E. nitens due to large site effects.

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Multi-Channel-Based Microgrid for Reliable Operation and Load Sharing

Energies ◽

10.3390/en12112070 ◽

2019 ◽

Vol 12 (11) ◽

pp. 2070 ◽

Cited By ~ 2

Author(s):

Ali Elrayyah ◽

Sertac Bayhan

Keyword(s):

Control System ◽

Critical Loads ◽

Experimental Studies ◽

Load Sharing ◽

Reliable Operation ◽

Performance Simulation ◽

Power Exchange ◽

Novel Approach ◽

Active Channels ◽

Level Of Importance

This paper presents a novel approach to distribute available power among critical and non-critical loads in microgrids. The approach is based on supplying power over a number of channels with distinguishable frequencies where loads could be served by these channels according to their level of importance. The multi-channel scheme not only offers flexibility to supply loads but also to share power among adjacent microgrids. The control system, which can deal with multi-channel scheme, is presented and different applications that can be offered whereby are discussed. The number of channels that can be supplied by any inverter is determined based on the parameters of the used filter. Moreover, the power exchange efficiencies over the active channels at various power levels are determined and approximated formulas for quick evaluation are presented. To verify the proposed solution performance, simulation and experimental studies were performed. The obtained results demonstrate the effectiveness of using multi-channel scheme for power exchange in microgrid and also confirm the accuracy of the provided formula related to power exchange efficiencies.

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Effectiveness of Partition and Graph Theoretic Clustering Algorithms for Multiple Source Partial Discharge Pattern Classification Using Probabilistic Neural Network and Its Adaptive Version: A Critique Based on Experimental Studies

Journal of Electrical and Computer Engineering ◽

10.1155/2012/479696 ◽

2012 ◽

Vol 2012 ◽

pp. 1-19

Author(s):

S. Venkatesh ◽

S. Gopal ◽

K. Kannan

Keyword(s):

Neural Network ◽

Probabilistic Neural Network ◽

Partial Discharge ◽

Clustering Algorithms ◽

Research Work ◽

Experimental Studies ◽

Multiple Sources ◽

Graph Theoretic ◽

Large Sets ◽

Novel Approach

Partial discharge (PD) is a major cause of failure of power apparatus and hence its measurement and analysis have emerged as a vital field in assessing the condition of the insulation system. Several efforts have been undertaken by researchers to classify PD pulses utilizing artificial intelligence techniques. Recently, the focus has shifted to the identification of multiple sources of PD since it is often encountered in real-time measurements. Studies have indicated that classification of multi-source PD becomes difficult with the degree of overlap and that several techniques such as mixed Weibull functions, neural networks, and wavelet transformation have been attempted with limited success. Since digital PD acquisition systems record data for a substantial period, the database becomes large, posing considerable difficulties during classification. This research work aims firstly at analyzing aspects concerning classification capability during the discrimination of multisource PD patterns. Secondly, it attempts at extending the previous work of the authors in utilizing the novel approach of probabilistic neural network versions for classifying moderate sets of PD sources to that of large sets. The third focus is on comparing the ability of partition-based algorithms, namely, the labelled (learning vector quantization) and unlabelled (K-means) versions, with that of a novel hypergraph-based clustering method in providing parsimonious sets of centers during classification.

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