Open Crown Research Articles

Nesting Ecology of the Grey-Headed Fish-Eagle At Prek Toal, Tonle Sap Lake, Cambodia

Little is known about the ecology of the Grey-headed Fish-Eagle (GHFE; Ichthyophaga ichthyaetus) despite it being a globally near-threatened species in apparent decline. We here present the first quantitative information on nesting ecology of this species, in a regionally significant population at Prek Toal, part of the seasonally flooded swamp forest surrounding the Tonle Sap Lake, Cambodia. We found that GHFE selected trees as nest sites that had an open crown structure and were relatively tall. Grey-headed Fish-Eagles preferred nesting closer to permanent water than expected, but the timing of breeding did not differ according to distance to permanent water: we suggest that their preference for nests near water may reflect an advantage based on prey availability. Water snakes, known prey of GHFE, were significantly more abundant at a site in permanent water than at a temporarily flooded site, in December. We also found that human habitation was negatively correlated to GHFE nest-site occupancy rates. This may reflect indirect effects of human exploitation of GHFE food supplies, which may be exacerbated in the future by changes to the Tonle Sap ecosystem resulting from upstream dam construction.

Water’s Role in Reshaping a Macrocycle’s Binding Pocket: Infrared and Ultraviolet Spectroscopy of Benzo-15-crown-5−(H2O)n and 4′-aminobenzo-15-crown-5−(H2O)n, n = 1, 2

Laser-induced fluorescence (LIF), resonant two-photon ionization (R2PI), ultraviolet hole-burning (UVHB), resonant ion-dip infrared (RIDIR), and infrared-infrared ultraviolet hole-burning (IR-IR-UV) spectroscopies were carried out on benzo-15-crown-5 ether-(H(2)O)(n) (B15C-(H(2)O)(n)) and 4'-amino-benzo-15-crown-5 ether-(H(2)O)(n) (ABC-(H(2)O)(n)) clusters with n = 1,2 formed in a supersonic expansion. Two isomers of B15C-(H(2)O)(1) with S(0)-S(1) origins at 35,628 and 35,685 cm(-1) (B15C-(H(2)O)(1)(A) and B15C-(H(2)O)(1)(B), respectively) were identified and, on the basis of the combined evidence from the single-isomer UV and IR spectra, assigned to structures in which the H(2)O molecule donates both its OH groups to H-bonds to the crown oxygens. Both isomers share the same open, chairlike C(s) symmetry structure for the crown ether that exposes the crown oxygen lone pairs to binding to H(2)O on the interior of the crown. This crown conformation is not among those represented in the observed conformers in the absence of the H(2)O molecule, indicating that even a single water molecule is capable of reshaping the crown binding pocket in binding to it. In B15C-(H(2)O)(1)(A), the water molecule takes up a position parallel to the crown plane of symmetry, using one OH group to bind to the two benzo oxygens, while the other OH binds to a single crown oxygen on the opposite side of the crown. The H(2)O molecule in B15C-(H(2)O)(1)(B) binds to the other two crown oxygens, in an orientation perpendicular to the crown's symmetry plane. B15C-(H(2)O)(2) also has two isomers. The first, B15C-(H(2)O)(2)(A) with S(0)-S(1) origin at 35,813 cm(-1), is assigned to a structure in which the two water molecules take up the two positions occupied by individual water molecules in B15C-(H(2)O)(1) A and B. The second isomer, with S(0)-S(1) origin at 35,665 cm(-1), has an OH stretch RIDIR spectrum that reflects a water-water H-bond, with the second water molecule binding to the crown-bound water in the parallel binding site. The combined data from B15C-(H(2)O)(1), ABC-(H(2)O)(1), and ABC-(HOD) complexes is used to deduce the uncoupled OH stretch wavenumber shifts associated with each of the unique binding sites for H(2)O to the crown. Arguments are presented that the binding pocket present in benzo-15-crown-5 ether is of a near ideal size to accommodate strong bidentate binding of individual water molecules to its most open crown conformation.

Habitat Use by a Dense Population of Southern Fox Squirrels

Abstract We determined seasonal macro- and microhabitat preferences of radio-collared Sciurus niger niger (Southern Fox Squirrel) in a high-density population. Fox squirrels preferred hardwood, live oak, and mixed hardwood-pine macrohabitats to pine, early successional, and turf macrohabitats. During winter, early summer, and late summer, they preferred mixed hardwood-pine, live oak, and hardwood microhabitats to pine microhabitats. Fox squirrels preferred an open or moderate crown spacing to a dense crown spacing during all seasons, and during the summer, they preferred microhabitats with at least 1 cone-bearing pine tree. Preferred microhabitats had a short-open or leaf-litter understory structure. Although the hardwood and hardwood-pine habitats on our barrier island study site differed from typical pine-dominated southeastern fox squirrel habitat, our results demonstrating preference for these types indicated that they are capable of supporting an abundant fox squirrel population when managed by mowin...

THE SOCIAL LIFE OF THE BYZANTINE GIFT: THE ROYAL CROWN OF HUNGARY RE‐INVENTED

Inspired by what anthropologists have called the social life of things, this article traces the shifting significations of the Royal Crown of Hungary. As an object central to notions of legitimacy in a land that served as a battleground for Eastern and Western powers during the medieval and modern eras, the crown over its contested history has come to be seen as a composite symbol of political independence and Western cultural affiliation. A thorough archaeology of the crown, however, reveals its origins as an eleventh‐century diadem designed for a Byzantine princess. Subsequently this open crown was transformed into the closed crown worn by the king of a powerful and emerging Western monarchy. In the process of this re‐gendering, the object was reconceived as papal gift. Bridging both instantiations is the crown's status as a gift, replete with associations of power and subjugation that anthropologists of gift‐giving practices have long recognized.

Reduced carbon sequestration in terrestrial ecosystems under overcast skies compared to clear skies

There is still no consensus on the impact of cloud on terrestrial carbon sequestration. Nevertheless, the fraction of sky irradiance which is diffuse (fDIF) is close to half as a global annual average, owing mainly to the presence of clouds. Furthermore, as a consequence of human-induced perturbations, the occurrence and opacity of cloud is changing both regionally (due to deforestation and drainage) and globally (shortwave “solar” dimming). In this study, we quantify the impact of cloud on carbon assimilation at an unprecedented number of FLUXNET sites (38) and for six plant functional types (PFTs). We compare results from previously established empirical and statistical methods with novel land-surface and three-dimensional (3D) radiative-transfer (RT) simulations that take explicit account of diffuse sunlight. We record a much lower enhancement in canopy light-use efficiency (LUE) under diffuse sunlight relative to direct sunlight (factor 1.12–1.80) compared to previous authors (factors 2–3). Increased radiation-sharing, due to varied leaf orientation within the canopy, is the primary cause of LUE-enhancement rather than beam penetration within an open crown structure. Under cloud, we consistently record a decrease in primary productivity (≥10–40%) and an unequivocal decline in daily carbon sequestration (60–80%), owing to the dramatic reduction in total (direct plus diffuse) irradiance that occurs when clouds obscure the solar disk (≥60% attenuation). A cooling-induced reduction in ecosystem respiration offsets the decline in primary productivity by about one third.

Crown openness as influenced by tree and site characteristics for yellow birch, sugar maple, and eastern hemlock

Crown openness (CO) of mature trees influences light transmission within the forest canopy. However, in modeling, this variable is often considered constant within species, and its potential regional variability is ignored. The objective of this study was to evaluate if CO values of yellow birch ( Betula alleghaniensis Britt.), sugar maple ( Acer saccharum Marsh.), and eastern hemlock ( Tsuga canadensis (L.) Carrière) vary according to the following factors: (i) species, (ii) regional actual evapotranspiration (AET), (iii) tree size (i.e., diameter at breast height, DBH), and (iv) angle of transmission from zenith. To achieve this, CO was evaluated for 136 yellow birches, 109 sugar maples, and 68 hemlocks from different regions of western Quebec, southern Ontario, and northern Michigan. Results showed that all of the studied factors affected CO. While dominant trees can intercept light laterally as well as vertically, smaller trees are more efficient at intercepting light vertically. Increasing AET is associated with more open crowns. Given its importance in light transmission in the understory, a better understanding of how CO varies between individuals, species, and regions is needed.

Pruning of plum trees and maintenance of balanced yielding

In this review, we give an overview of the pruning techniques that should be applied in commercial plum orchards. First, a detailed description of pruning for shaping the different crown types for the first, second, third, fourth and fifth years and the phytotechnical works is given for crowns with a circular projection area. Then, pruning for open crowns forms, such as the vase form is discussed. Following the shaping of the crown, it should be maintained by pruning. Detailed information is given on pruning for maintenance with special emphasis on the comparison of winter and summer pruning. In the following part of the manuscript, pruning experience is described separately for the major commercial plum cultivars in Hungary such as Cacanska lepotica, President, Bluefre, Stanley. Recommendations for cultivation systems under non-irrigated conditions are also included. Finally, light requirements, growth characteristics and suggested crown forms of the different cultivars are described for cvs. Ageni, Althan Tingle), Besztercei szilva Nm. 122, Bluefre, Cacanska lepotica, Cacanska rodna, Debreceni muskotály, Montfort, President, Ruth Gerstetter, Sermina, Stanley, Tuleu gras and Zöld ringló).

Hurricanes and the Urban Forest: I. Effects on Southeastern United States Coastal Plain Tree Species

Several hurricanes struck Florida, U.S. in 2004 and 2005 causing widespread damage to urban and rural areas. We measured the impacts of five of these hurricanes on the urban forest and combined these results with four other hurricanes to present an assessment of wind resistance for southeastern United States coastal plain tree species. Urban forest loss was positively correlated with wind speed. Tree species demonstrating the highest survival in winds were sand live oak (Quercus geminata), American holly (Ilex opaca), southern magnolia (Magnolia grandiflora), live oak (Quercus virginiana), wax myrtle (Myrica cerifera), sweetgum (Liquidambar styraciflua), crapemyrtle (Lagerstroemia indica), dogwood (Cornus florida), and sabal palm (Sabal palmetto). In a statistical comparison of sand live oak, live oak, and laurel oak (Quercus laurifolia) survival after four panhandle hurricanes, laurel oak had significantly poorer survival than both live oak and sand live oak. Among all species, larger trees lost more branches than medium and smaller trees. Leaf loss had a positive relationship with survival; losing leaves during the hurricane meant higher survival. Trees growing in groups or clusters had greater survival than those growing as individual trees. Tree species with higher wood density had greater survival. Tree species categorized as having dense crowns lost more branches than those with moderate and open crowns; however, contrary to the literature, dense-crowned species survived best. A survey of arborists, scientists, and urban foresters ranked species for their wind resistance. Using our results from hurricane measurements and incorporating results from the survey and the scientific literature, we have developed lists of relative wind resistance for tree species in the southeastern coastal plain. These lists should be used with caution with the knowledge that no species and no tree is completely windproof. In addition, local considerations such as soil, cultural practices, tree age and health, and other urban forest conditions need to be taken into account.

Insect Infestations Linked to Shifts in Microclimate: Important Climate Change Implications

Changes in vegetation due to drought-influenced herbivory may influence microclimate in ecosystems. In combination with studies of insect resistant and susceptible trees, we used long-term herbivore removal experiments with two herbivores of pinon (Pinus edulis Endelm.) to test the general hypothesis that herbivore alteration of plant architecture affects soil microclimate, a major driver of ecosystem-level processes. The pinon needle scale (Matsucoccus acalyptus, Herbert) attacks needles of juvenile trees causing them to develop an open crown. In contrast, the stem-boring moth (Dioryctria albovittella Hulst.) kills the terminal shoots of mature trees, causing the crown to develop a dense form. Our studies focused on how the microclimate effects of these architectural changes are likely to accumulate over time. Three patterns emerged: (1) scale herbivory reduced leaf area index (LAI) of susceptible trees by 39%, whereas moths had no effect on LAI; (2) scale herbivory increased soil moisture and temperature beneath susceptible trees by 35 and 26%, respectively, whereas moths had no effect; and (3) scale and moth herbivory decreased crown interception of precipitation by 51 and 29%, respectively. From these results, we conclude: (1) the magnitude of scale effects on soil moisture and temperature is large, similar to global change scenarios, andmore » sufficient to drive changes in ecosystem processes. (2) The larger sizes of moth-susceptible trees apparently buffered them from most microclimate effects of herbivory, despite marked changes in crown architecture. (3) The phenotypic expression of susceptibility or resistance to scale insects extends beyond plant-herbivore interactions to the physical environment.« less

Insect Infestations Linked to Shifts in Microclimate

Changes in vegetation due to drought‐influenced herbivory may influence microclimate in ecosystems. In combination with studies of insect resistant and susceptible trees, we used long‐term herbivore removal experiments with two herbivores of piñon (Pinus edulis Endelm.) to test the general hypothesis that herbivore alteration of plant architecture affects soil microclimate, a major driver of ecosystem‐level processes. The piñon needle scale (Matsucoccus acalyptus, Herbert) attacks needles of juvenile trees causing them to develop an open crown. In contrast, the stem‐boring moth (Dioryctria albovittella Hulst.) kills the terminal shoots of mature trees, causing the crown to develop a dense form. Our studies focused on how the microclimate effects of these architectural changes are likely to accumulate over time. Three patterns emerged: (i) scale herbivory reduced leaf area index (LAI) of susceptible trees by 39%, whereas moths had no effect on LAI; (ii) scale herbivory increased soil moisture and temperature beneath susceptible trees by 35 and 26%, respectively, whereas moths had no effect; and (iii) scale and moth herbivory decreased crown interception of precipitation by 51 and 29%, respectively. From these results, we conclude: (1) the magnitude of scale effects on soil moisture and temperature is large, similar to global change scenarios, and sufficient to drive changes in ecosystem processes. (2) The larger sizes of moth‐susceptible trees apparently buffered them from most microclimate effects of herbivory, despite marked changes in crown architecture. (3) The phenotypic expression of susceptibility or resistance to scale insects extends beyond plant‐herbivore interactions to the physical environment.

Analisis Pertumbuhan dan Fenologi Trubus pada Berbagai Struktur Tajuk Durian (Durio zybethinus)

Two parallel experiments were conducted to study the effect of training and pruning on the growth and development of durian. Two-years old durian clones Matahari and Monthong had been pruned and or trained for 19 months as open center, central leader, palmette leader and left untreated (control treatment) in five (for Matahari) and six (for Monthong) replications. Training and pruning treatments resulted in more open crown as indicated by lower (35 - 40%) leaf area index, better growth analysis as indicated by better dry matter partition and growth rate. Relative growth rate (RGR) and net assimilation rate (NAR) of trained and pruned trees were high during 12 - 15 months after treatment, although their absolute growth rate cumulative crown dry matter low compared to untreated trees. Compared to pruning \, training treatment gave higher contribution to NAR. Due to wet climate of local Bogor and ontogeny of the durian used in this experiment (at late juvenile stage, 3.5 year old durian), the effect of training and pruning on the development of the durian as observed by flushing phenology had not been revealed. Flushing rhythmic pattern of treated and untreated durian were almost same. Key words: durian, tree architecture, training, pruning, phenology.

Photosynthetically active radiation transmittance of forest plantation canopies in the Ethiopian highlands

Hemispherical photographs and a quantum sensor were used to study the canopy photosynthetic photon flux density (PPFD) transmittance of five forest plantation species in Ethiopia. Red/far-red (R/FR) ratios and temperatures beneath the forest plantations were also measured. The species studied were: Eucalyptus globulus, Pinus patula, Cupressus lusitanica, Grevillea robusta, and Juniperus procera. The canopies of E. globulus, P. patula and G. robusta transmitted about three times as much PPFD as J. procera or C. lusitanica plantations. Furthermore, plantations of G. robusta and E. globulus had the highest, while J. procera had the lowest R/FR ratio. In contrast to J. procera and C. lusitanica, E. globulus and G. robusta had relatively open crowns, higher crown-bases and lower leaf area indices, and as a result, their canopies had higher PPFD transmittance percentages as well as higher below-canopy R/FR ratios and temperatures. From the perspective of understory light regime, plantations of E. globulus and G. robusta are best suited for promoting the natural regeneration of native species. In general, opening of gaps in plantations of heavy-shading tree species may increase the herbaceous layer ground cover, enhance the colonisation and growth of native woody species and consequently may also increase the floristic diversity of mono-specific plantations.

High extraction efficiency solid-phase microextraction fibers coated with open crown ether stationary phase using sol–gel technique

In this paper, the open crown ether α, ω-diallyltriethylene glycol/hydroxyl-terminated silicone oil was used as stationary phases with the aid of vinyltriethoxylsilane as bridge in solid-phase microextraction using sol–gel-coating method and cross-linking technology. It has high extraction efficiency for both polar and non-polar analytes in comparison with poly(dimethylsiloxane) and carbowax–divinylbenzene-coated fiber. Limits of detection of the polar compound phenols are from 0.32 to 2.6 ng ml −1 and the precisions are from 2.5 to 3.5% ( n=5), while the limits of detection of the non-polar benzene, toluene and xylenes are 0.03–0.3 ng ml −1 and the relative standard deviation ( n=5) is found to be 2.1–5.2%. The novel coating proved to be very stable at high temperature by investigating it with the extraction of high-boiling compound phthalate esters.

‘Grasslands Lakota’ prairie grass (Bromus catharticus Vahl.)

‘Grasslands Lakota’ prairie grass (Bromus catharticus Vahl.) was selected from 72 Bromus breeding lines and accessions evaluated in Oregon and Pennsylvania, United States, between 1995 and 1998. The aim was to produce a cultivar of B. catharticus that was better adapted to the northern regions of the United States than the currently available cultivar ‘Grasslands Matua’. From 1996, all 72 lines were screened in New Zealand for seed production, and for uniformity and distinctness. In March 1998, the data at all three sites were collated and Cb 1307 was selected as the preferred line. It was discovered in a sandframe at Palmerston North, but the ancestry is unknown. Since 1998, this selection has been certified and commercialised, and has been named ‘Grasslands Lakota’. (In the United States it will be registered simply as ‘Lakota’.) It was given Plant Variety Rights in New Zealand in 1999 and Plant Variety Protection in the United States in 2001. Compared with the standard New Zealand cultivar ‘Grasslands Matua’, ‘Grasslands Lakota’ is less erect, and later to head. It also has a wider and more open crown, a feature that may help to explain the much lower susceptibility to powdery mildew (Blumeria graminis (DC) Speer) in the United Sates.

Control of transpiration in three coffee cultivars: the role of hydraulic and crown architecture

Water use and hydraulic architecture were studied in the coffee (Coffea arabica) cultivars San Ramon, Yellow Caturra and Typica growing in the field under similar environmental conditions. The cultivars differed in growth habit, crown architecture, basal sapwood area and total leaf surface area. Transpiration per unit leaf area (E), stomatal conductance (g s), crown conductance (g c), total hydraulic conductance of the soil/leaf pathway (G t) and the stomatal decoupling coefficient, omega (Ω) (Jarvis and McNaughton 1986) were assessed over a range of soil moisture and during partial defoliation treatments. The relationship between sap flow and sapwood area was linear and appeared to be similar for the three cultivars. Variation in g c, E, and G t of intact plants and leaf area-specific hydraulic conductivity (k l) of excised lateral branches was negatively correlated with variation in the ratio of leaf area to sapwood area. Transpiration, g c, and g s were positively correlated with G t. Transpiration and G t varied with total leaf area and were greatest at intermediate values (10 m2) of leaf area. Omega was greatest in Yellow Caturra, the cultivar with the greatest leaf area and a dense crown, and was smallest in Typica, the cultivar with an open crown. Differences in omega were attributable primarily to differences in leaf boundary layer conductance among the cultivars. Plants of each cultivar that were 40% defoliated maintained sap flows comparable to pretreatment plants, but expected compensatory increases in g s were not consistently observed. Despite their contrasting crown morphologies and hydraulic architecture, the three cultivars shared common relationships between water use and hydraulic architectural traits.

Decomposition of small diameter woody debris of red fir determined by nuclear magnetic resonance

Red fir (Abies magnifica A. Murr.) woody debris decomposing for 17 years in untreated (Control) and nitrogen‐fertilized plus widely thinned (NT2) plots was examined by 13C nuclear magnetic resonance (NMR). Total carbon (C) and total N concentrations were also determined. Combined data of wood and bark showed correlations between carboxylic, aromatic, O‐alkyl and aliphatic C fractions, and C fractions with C/N, but phenolic and methoxyl correlations were non‐significant. Wood mass losses averaged 38% for both Controls and NT2. Bark mass losses were 61% for Controls and 66% for NT2, but these were not significantly different at p<0.05; bark sloughing added considerable variance. Wood in Controls decreased O‐alkyl (66 to 50%) and aromatic (16 to 13%), increased carboxyl (1.5 to 6.5%) and aliphatic (2.0 to 15.5%), and decreased Cm/Lm, i.e., carbohydrate/lignin monomers (2.78 to 1.82). In NT2 plots, open crowns allowed greater drying of the forest floor during warm, dry summers. The C/N averages were slightly lower in NT2 than in Controls for wood (167 versus 188), and the same for bark (45 and 43), but differences were not significant at p<0.05. Decompositional pathways in different environments, by brown‐rot and whiterot fungi, are discussed.

Heavy Alkaline-Earth Polyether Carboxylates. The Crystal Structure of {Ca[OOC(CH2)O(CH2)2]2O(H2O)2}21

Calcium, strontium, and barium derivatives of 2-(2-methoxyethoxy)acetic acid, 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, and 3,6,9-trioxaundecanedioic acid (Htodd) can be prepared from the metal hydroxides and the free acids in water. The calcium salt of Htodd has been studied with X-ray diffraction; it forms a discrete dinuclear unit in which bridging carboxylates are twisted into fan-like shapes in an “open crown” arrangement.

Relation of Crown and Foliage Traits to Height Growth of Sitka Spruce

Abstract Four crown and foliage traits of a young Sitka spruce (Picea sitchensis) stand were tested with rooted cuttings in greenhouse and field plots for possible thinning selection guidelines. Repeatability estimates of the amount of genetic control over the four traits and the relation of those traits to height growth were evaluated 5 years after rooting. Only the blue-green trait was significantly associated (P &lt; 0.05) with height growth. Average height of cuttings selected for green foliage was 17% greater than cuttings selected for blue foliage. Under greenhouse conditions, repeatability estimates of green or blue foliage were 98% versus 66%, respectively; 72% versus 89% for trees with dense or open crowns, respectively; 65% for the comparison of upright and horizontal branches; and 75% for the comparison of long or short branches. West. J. Appl. For. 11(3):77-80.

Open crown ether polysiloxane stationary phases for capillary gas chromatography

AbstractIn this paper, two new open crown ether polysiloxane stationary phases were prepared for capillary gas chromatography. Chromatographic characteristics, including column efficiency, operational temperature range, thermal stability, and polarity were studied. The open crown ether polysiloxane was found to have unique selectivity for alcohols, aromatic hydrocarbons, and nitrogen‐containing compounds. The separation mechanism and various thermodynamic parameters are discussed.

Radiative transfer modelling of discontinuous tree canopies at microwave frequencies

Development of a first-order radiative transfer model for predicting backscatter from tree canopies has been underway at the University of Michigan Radiation Laboratory for some time. This model is known as the Michigan Microwave Canopy Scattering (MIMICS) model. This article presents the second-generation MIMICS model (MIMICS II) which accounts for canopies with discontinuous (open) crown layer geometries. MIMICS II models open crown layers by treating the location, size, and shape of the individual tree crowns as random variables. The backscattering coefficients for the canopy are then determined by introducing statistics derived from these parameters into the radiative transfer solution. Application of the radiative transfer equations to the discontinuous canopy geometry is presented. The resulting model is a robust fully polarimetric solution that is applicable over a wide variety of canopy architectures. Model simulations are compared to results generated with the continuous canopy model. The effect of the open crown geometry is found to be most significant at shallow incidence angles and at high frequencies for trees with well-developed crowns. Under these conditions, the gaps in the crown layer give rise to a notable increase in crown layer transmissivity which allows the radar to see through to the lower layers of the canopy more easily, thereby directly affecting the backscatter contribution of the trunks and ground.