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1
Strom, Steven. "Tree pits as urban gardens." Landscape Research 15, no. 2 (June 1990): 19–22. http://dx.doi.org/10.1080/01426399008706311.
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Webb, Sara L. "Windstorm damage and microsite colonization in two Minnesota forests." Canadian Journal of Forest Research 18, no. 9 (September 1, 1988): 1186–95. http://dx.doi.org/10.1139/x88-182.
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Scattered trees were uprooted, snapped, or bent during a 1983 windstorm in two northwestern Minnesota pine forests. I tested potential correlates (tree species, tree size, cause of damage) of damage type, and compared consequences of the uprooting, snapping, and bending of trees by assessing postdamage survival and by surveying formation and colonization of microsites (mounds, pits, stumps, and dead boles). Larger trees damaged directly by wind were usually snapped and killed in both study areas, regardless of tree species. Smaller trees damaged by falling neighbors were either (i) bent without sustaining mortality or forming microsites, a damage type prevalent among strong-wooded Acersaccharum and Ostryavirginiana in a Pinus–Acer study area, or (ii) uprooted, forming small mounds and pits, a damage type prevalent among weakwooded Abiesbalsamea and Picea spp. in a Pinus–Abies study area. Bent trees usually survived, at least for several years. However, uprooted and snapped trees were equally unlikely to survive their damage. Thus, uprooting and snapping were equally likely to result in dead bole formation. Windstorm-related microsites covered small proportions (6 and 18%) of the floor of the two forests, most as dead boles rather than as stumps, mounds, or pits. Microsites from uprooting, microsites from snapping, and background substrates did not differ in colonizing tree flora but did differ in density of colonists. The role of microsites varied with the autecology of tree species present. In the Pinus–Abies area, rotting wood of stumps and boles was the major establishment substrate for all regenerating tree species. In the Pinus–Acer area, Acersaccharum and A. rubrum were numerically dominant over other species on all substrates, with seedling densities highest away from microsites. Observed patterns of survival and tree regeneration indicate that uprooting and snapping of trees do not differ strongly in their consequences for either forest.
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Moya Roque, Róger, Mario Tomazelo Fo, and Edwin Canessa Amador. "Fiber morphology in fast growth Gmelina arborea plantations." Madera y Bosques 13, no. 2 (August 30, 2016): 3–13. http://dx.doi.org/10.21829/myb.2007.1321225.
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Gmelina arborea is planted in large areas of forest with the objective of producing solid wood using well known silvicultural techniques and taking advantage of the properties of the wood quality of fast-growing tree species managed in short rotation systems. The aim of this study was to analyze the morphology and dimension of fibers from the pith to the bark in trees from fast growth plantations in northern Costa Rica.The results indicate that fiber morphology is irregular in both diameter and shape; with 1 to 4 septa, abundant crystals deposited in fiber lumina and minutely bordered pits with oblique and nonvestured apertures. Fiber length, width and cell wall thickness increased with tree age in the early stages. Lumen diameter was not correlated with tree age.
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Hassanpoor Tichi, Ali, Habibollah Khademieslam, and Mojtaba Rezanezhad Divkolae. "Evaluation of physical, anatomical, and biometric characteristics of Citrus sinensis trees in longitudinal and transverse axes of stem." BioResources 15, no. 3 (June 3, 2020): 5696–709. http://dx.doi.org/10.15376/biores.15.3.5696-5709.
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Three healthy Citrus sinensis (orange) trees in Babol, Iran, were randomly selected and cut. Two discs of 5 cm thickness were prepared along the tree (breast height and crown). In the transverse direction, the test specimens were cut 2 × 2 cm to 3 cm from the pith to the bark sequentially and examined. The biometric and physical properties were measured, and microscopic sections of wood near the bark were studied using light microscopy according to the International Association of Wood Anatomists’ (IAWA) List. Anatomical examination of the C. sinensis wood showed that the species was a diffuse porous hardwood, with indistinct growth rings, simple perforation plates, alternate intervessel pits, and banded parenchyma. The basic density and oven-dry density increased from the pith towards the tree bark and from the bottom of the tree towards the crown. There was a significant difference in both the transverse and longitudinal directions of the C. sinensis tree in terms of fiber length, fiber lumen diameter, fiber diameter, and cell wall thickness. The mean fiber length, fiber diameter, fiber lumen diameter, and cell wall thickness were 0.76 mm, 23.64 µm, 9.23 µm, and 14.41 µm, respectively.
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Beatty, Susan W., and Earl L. Stone. "The variety of soil microsites created by tree falls." Canadian Journal of Forest Research 16, no. 3 (June 1, 1986): 539–48. http://dx.doi.org/10.1139/x86-094.
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The uprooting of forest trees leads to the formation of microsites on the forest floor, contributing to fine-scale heterogeneity in soil properties. We found the types of microsites formed depended on the way the tree fall occurred. Tree falls were classified as either hinge or rotational types. Hinge tree falls formed when the root mat of a tree and the surrounding soil were uplifted vertically, leaving an adjacent pit in the soil. Hinge tree falls varied as to thickness of the root mat and angle of uplift. Rotational tree falls were usually a result of a ball and socket motion of the root mat and soil, which positioned the tree bole over the newly created pit. The tree falls disrupted and redistributed surface soil organic matter and subsoil. In rotational tree falls, the surface material remained intact, covering some of the pit and the adjacent side of the mound. In hinge tree falls, the surface organic matter was deposited on the throw side of the mound, leaving subsoil on the other side and in the pit. With time, however, hinge-type pits accumulated litter and eventually had more organic matter than mounds. Old mounds from both hinge and rotational tree falls had lower concentrations of calcium and magnesium, lower pH, and less moisture than pits. The tree fall process creates long-term soil patterns and maintains microsite heterogeneity in forest communities.
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Hassanpoor Tichi, Ali, Hadi Gholamiyan, and Mojtaba Rezanezhad Divkolae. "Changes in biometric, density, and microscopic features of Parrotia persica trees in longitudinal and radial directions of the stem." BioResources 16, no. 2 (March 26, 2021): 3563–74. http://dx.doi.org/10.15376/biores.16.2.3563-3574.
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The biometric, density, and microscopic features of Parrotia persica species were investigated in this work. Three completely healthy P. persica trees were randomly felled. Three discs of 5 cm thickness were cut at three height levels (at breast height, 3 m, and 4.5 m) of each stem. The test specimens were sequentially taken from pith to bark. The biometric characteristics of the fiber and their density were analyzed. The microscopic features were studied according to the IAWA List of Hardwoods. It was found that all biometric factors of P. persica were decreased with increasing tree height from base to top. In contrast, these factors were also increased with the increase of distance from the pith toward the bark. Oven-dry density and basic density were decreased with an increase in the height along the tree stem. However, in the transverse direction, oven-dry density and basic density were increased from pith to bark. The anatomical study indicated that P. persica is a diffuse-porous hardwood that has distinct growth ring boundaries, heterogeneous rays, scalariform perforation, and alternative intervessel pits.
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Yoshida, Toshiya. "Regeneration Dynamics on Treefall Mounds and Pits for 10 Years after a Windfall in a Natural Mixed Forest." Forests 12, no. 8 (August 10, 2021): 1064. http://dx.doi.org/10.3390/f12081064.
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The treefall mounds and pits resulting from uprooting caused by strong winds is an indispensable microtopography for the regeneration of many tree species through improved light conditions and mineral soil exposure. These microtopographies are expected to become more important because global warming is predicted to increase windstorm frequency. This study aimed to clarify the characteristics of mounds and pits that contribute to the early establishment of major tree species in a natural mixed forest of northern Japan. The 39 tip-up mounds caused simultaneously by a strong typhoon in September 2004 were selected. In 2006, light intensity and soil moisture contents were measured in each mound and pit. Seedlings of all tree species were counted, and in 2014, the height of saplings was measured. The initial seedling density, regardless of tree species, was significantly higher in the pits than on the mound, but the density at the 10-th growing season decreased significantly in the pits and was comparable between the two locations. Intense light conditions favor regeneration of Betula sp. (Betula platyphylla and B. ermanii). In contrast, for Abies sachalinensis and Picea glehnii, the light intensity had a negative effect, so it was concluded that regeneration of conifers would be limited under the condition where strong winds form large gaps.
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Brlansky, R. H., D. S. Howd, P. Broadbent, and V. D. Damsteegt. "Histology of Sweet Orange Stem Pitting Caused by an Australian Isolate of Citrus tristeza virus." Plant Disease 86, no. 10 (October 2002): 1169–74. http://dx.doi.org/10.1094/pdis.2002.86.10.1169.
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Some strains of the Citrus tristeza virus (CTV) cause stem pitting in sweet orange (Citrus sinensis (L.) Osbeck). This abnormality causes tree decline and reduction in fruit size and yield of affected citrus trees. Stem-pitting symptoms can occur on trunks, on all sizes of limbs, and on the twigs where fruit are produced. Variously sized pits or grooves in the wood often contain a yellow gum. Irregular growth of the phloem occurs in the area of these xylem pits. The histology of stem pitting caused by an Australian CTV isolate was studied in sweet orange using light and electron microscopy. Using scanning electron microscopy, details of the wood pits containing the gumming material were revealed. In thin sections of bark tissue, outgrowths of the phloem tissue were found at various intervals that corresponded to the pits in the wood. Higher numbers of viral inclusions were detected in the phloem outgrowths than were present in the other sieve elements.
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Tu, Min-cheng, Joshua Caplan, Sasha Eisenman, and Bridget Wadzuk. "When Green Infrastructure Turns Grey: Plant Water Stress as a Consequence of Overdesign in a Tree Trench System." Water 12, no. 2 (February 19, 2020): 573. http://dx.doi.org/10.3390/w12020573.
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Green infrastructure (GI) systems are often overdesigned. This may be a byproduct of static sizing (e.g., accounting for a design storm’s runoff volume but not exfiltration rates) or may be deliberate (e.g., buffering against performance loss through time). In tree trenches and other GI systems that require stormwater to accumulate in an infiltration bed before it contacts the planting medium, overdesign could reduce plant water availability significantly. This study investigated the hydrological dynamics and water relations of an overdesigned tree trench system and identified factors contributing to, compounding, and mitigating the risk of plant stress. Water in the infiltration bed reached soil pits only once in three years, with that event occurring during a hydrant release. Moreover, minimal water was retained in soil pits during the event due to the hydraulic properties of the soil media. Through a growing season, one of the two tree types frequently experienced water stress, while the other did so only rarely. These contrasting responses can likely be attributed to roots being largely confined to the soil pits vs. reaching a deeper water source, respectively. Results of this study demonstrate that, in systems where soil pits are embedded in infiltration beds, overdesign can raise the storm size required for water to reach the soil media, reducing plant water availability between storms, and ultimately inducing physiological stress.
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Akkermans‐Rutgers, Marlot, Jeannette Doornenbal, Annelies Kassenberg, Roel Bosker, and Simone Doolaard. "Is the twig bent as the tree is inclined? Children and parents interacting with school‐distributed literacy assignments." Psychology in the Schools 58, no. 2 (November 20, 2020): 377–99. http://dx.doi.org/10.1002/pits.22452.
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Schott, M. R., and Rex D. Pieper. "Succession in Tree Pits Following Cabling in Pinyon-Juniper Communities." Southwestern Naturalist 32, no. 3 (September 28, 1987): 399. http://dx.doi.org/10.2307/3671464.
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Grey, Vaughn, Stephen J. Livesley, Tim D. Fletcher, and Christopher Szota. "Tree pits to help mitigate runoff in dense urban areas." Journal of Hydrology 565 (October 2018): 400–410. http://dx.doi.org/10.1016/j.jhydrol.2018.08.038.
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Lazzarin, Martina, Alan Crivellaro, Cameron B. Williams, Todd E. Dawson, Giacomo Mozzi, and Tommaso Anfodillo. "TRACHEID AND PIT ANATOMY VARY IN TANDEM IN A TALL SEQUOIADENDRON GIGANTEUM TREE." IAWA Journal 37, no. 2 (July 7, 2016): 172–85. http://dx.doi.org/10.1163/22941932-20160129.
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Across land plants there is a general pattern of xylem conduit diameters widening towards the stem base thus reducing the accumulation of hydraulic resistance as plants grow taller.In conifers, xylem conduits consist of cells with closed end-walls and water must flow through bordered pits imbedded in the side walls. As a consequence both cell size, which determines the numbers of walls that the conductive stream of water must cross, as well as the characteristics of the pits themselves, crucially affect total hydraulic resistance. Because both conduit size and pit features influence hydraulic resistance in tandem, we hypothesized that features of both should vary predictably with one another. To test this prediction we sampled a single tall (94.8 m) Sequoiadendron giganteum tree (giant sequoia), collecting wood samples from the most recent annual ring progressively downwards from the tree top to the base. We measured tracheid diameter and length, number of pits per tracheid, and the areas of pit apertures, tori, and margos. Tracheid diameter widened from treetop to base following a power law with an exponent (tracheid diameterstem length slope) of approximately 0.20. A similar scaling exponent was found between tracheid length and distance from tree top. Additionally, pit aperture, torus, and margo areas all increased (again with a power of ~0.20) with distance from tree top, paralleling the observed variation in tracheid diameter and length. Pit density scaled isometrically with tracheid length. Within individual tracheids, total permeable area of pits, measured as the sum of the margo areas, scaled isometrically with lumen area. Given that pores of the margo membrane are believed to increase in parallel with membrane area, from a strictly anatomical perspective, our results support the interpretation that pit resistance remains a relatively constant fraction of total resistance along the hydraulic pathway.
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Jinxing, Lin. "Distribution, Size and Effective Aperture Area of the Inter-Tracheid Pits in the Radial Wall of Pinus Radiata Tracheids." IAWA Journal 10, no. 1 (1989): 53–58. http://dx.doi.org/10.1163/22941932-90001111.
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The distribution, size and effective aperture area of inter-tracheid pits were studied in a 29-year-old plantation-grown tree of Pinus radiata by means of light and electron microscopy. It was found that the number of pits per tracheid in the first ten years is related more to tracheid length than to the age of the wood. Beyond the tenth year, the number of pits per tracheid is mainly related to the age of the wood, regardless of tracheid length. In addition, there is a positive linear relationship between tracheid diameter and pit diameter, indicating that the larger tracheids contain larger pits. The percentage of the effective aperture area per mrn length of radial tracheid wall is discussed, in relation to the 'percentage of aspirated pits and total area of pit aperture per tracheid.
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Pahno, Steve, Jidong J. Yang, and S. Sonny Kim. "Use of Machine Learning Algorithms to Predict Subgrade Resilient Modulus." Infrastructures 6, no. 6 (May 21, 2021): 78. http://dx.doi.org/10.3390/infrastructures6060078.
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Modern machine learning methods, such as tree ensembles, have recently become extremely popular due to their versatility and scalability in handling heterogeneous data and have been successfully applied across a wide range of domains. In this study, two widely applied tree ensemble methods, i.e., random forest (parallel ensemble) and gradient boosting (sequential ensemble), were investigated to predict resilient modulus, using routinely collected soil properties. Laboratory test data on sandy soils from nine borrow pits in Georgia were used for model training and testing. For comparison purposes, the two tree ensemble methods were evaluated against a regression tree model and a multiple linear regression model, demonstrating their superior performance. The results revealed that a single tree model generally suffers from high variance, while providing a similar performance to the traditional multiple linear regression model. By leveraging a collection of trees, both tree ensemble methods, Random Forest and eXtreme Gradient Boosting, significantly reduced variance and improved prediction accuracy, with the eXtreme Gradient Boosting being the best model, with an R2 of 0.95 on the test dataset.
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McClellan, Michael H., Bernard T. Bormann, and Kermit Cromack Jr. "Cellulose decomposition in southeast Alaskan forests: effects of pit and mound microrelief and burial depth." Canadian Journal of Forest Research 20, no. 8 (August 1, 1990): 1242–46. http://dx.doi.org/10.1139/x90-163.
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In southeast Alaska, where wildfires are rare, uprooting is the predominant disturbance influencing stand development in Tsugaheterophylla (Raf.) Sarg. – Piceasitchensis (Bong.) Carr. forests. We compared 1-year decomposition of confined cellulose filter paper placed in the organic horizon and at the organic–mineral interface on both tree-throw mounds and adjacent pits. Decomposition rates were not significantly different between pits and mounds, but filter papers within the organic layer lost 33.7% of their original dry mass, and packs within the mineral layer lost 14.5% of their mass. This effect was highly significant (p < 0.01). We concluded that the greater organic accumulations observed in pits are largely due to litter redistribution.
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Moser-Reischl, Astrid, Thomas Rötzer, Peter Biber, Matthias Ulbricht, Enno Uhl, Laiye Qu, Takayoshi Koike, and Hans Pretzsch. "Growth of Abies sachalinensis Along an Urban Gradient Affected by Environmental Pollution in Sapporo, Japan." Forests 10, no. 8 (August 20, 2019): 707. http://dx.doi.org/10.3390/f10080707.
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Urban tree growth is often affected by reduced water availability, higher temperatures, small and compacted planting pits, as well as high nutrient and pollution inputs. Despite these hindering growth conditions, recent studies found a surprisingly better growth of urban trees compared to trees at rural sites, and an enhanced growth of trees in recent times. We compared urban versus rural growing Sakhalin fir (Abies sachalinensis (F. Schmidt) Mast.) trees in Sapporo, northern Japan and analyzed the growth differences between growing sites and the effects of environmental pollution (NO2, NOX, SO2 and OX) on tree growth. Tree growth was assessed by a dendrochronological study across a gradient from urban to rural sites and related to high detailed environmental pollution data with mixed model approaches and regression analyses. A higher growth of urban trees compared to rural trees was found, along with an overall accelerated growth rate of A. sachalinensis trees over time. Moreover, environmental pollution seems to positively affect tree growth, though with the exception of oxides OX which had strong negative correlations with growth. In conclusion, higher temperatures, changed soil nutrient status, higher risks of water-logging, increased oxide concentrations, as well as higher age negatively affected the growth of rural trees. The future growth of urban A. sachalinensis will provide more insights as to whether the results were induced by environmental pollution and climate or biased on a higher age of rural trees. Nevertheless, the results clearly indicate that environmental pollution, especially in terms of NO2 and NOX poses no threat to urban tree growth in Sapporo.
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Scharenbroch, B. C., and J. G. Bockheim. "Pedodiversity in an old-growth northern hardwood forest in the Huron Mountains, Upper Peninsula, Michigan." Canadian Journal of Forest Research 37, no. 6 (June 2007): 1106–17. http://dx.doi.org/10.1139/x06-312.
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We investigated three primary causes of old-growth forest pedodiversity imposed by top-down trophic interactions, including pit and mound topography from past tree fall events, current canopy gaps from tree falls, and the influence of individual tree species on soil properties and processes. In this paper, we discuss the effects of pits, mounds, gaps, and individual tree species on pedodiversity in a single soil map unit in an old-growth northern hardwood forest. Pits and level areas had significantly greater soil organic matter, cation-exchange capacity, and exchangeable K and Ca contents than mounds. Gap subplots had significantly less cation-exchange capacity, K, Mg, and Ca compared with level areas within the contiguous forest. Base cations (K, Mg, and Ca) were significantly greater under sugar maple ( Acer saccharum Marsh.) compared with eastern hemlock ( Tsuga canadensis (L.) Carr.). Extractable P was significantly greater under yellow birch ( Betula alleghaniensis Britt.) compared with eastern hemlock. We quantified pedodiversity in an old-growth northern hardwood forest stand and single soil map unit using principal components analyses, ArcGIS, and biodiversity indices. Our results suggest that pedodiversity should be considered in soil survey and forest management.
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Rodriguez-Reyes, Oris, Peter Gasson, Carolyn Thornton, Howard J. Falcon-Lang, and Nathan A. Jud. "Panascleroticoxylon crystallosa gen. et sp. nov.: a new Miocene malpighialean tree from Panama." IAWA Journal 38, no. 4 (December 6, 2017): 437–55. http://dx.doi.org/10.1163/22941932-20170178.
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ABSTRACTWe report fossil wood specimens from two Miocene sites in Panama, Central America: Hodges Hill (Cucaracha Formation; Burdigalian, c. 19 Ma) and Lago Alajuela (Alajuela Formation; Tortonian, c. 10 Ma), where material is preserved as calcic and silicic permineralizations, respectively. The fossils show an unusual combination of features: diffuse porous vessel arrangement, simple perforation plates, alternate intervessel pitting, vessel–ray parenchyma pits either with much reduced borders or similar to the intervessel pits, abundant sclerotic tyloses, rays markedly heterocellular with long uniseriate tails, and rare to absent axial parenchyma. This combination of features allows assignment of the fossils to Malpighiales, and we note similarities with four predominantly tropical families: Salicaceae, Achariaceae, and especially, Phyllanthaceae, and Euphorbiaceae. These findings improve our knowledge of Miocene neotropical diversity and highlight the importance of Malpighiales in the forests of Panama prior to the collision of the Americas.
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Christof, Andreas, Anders Ræbild, and Lisbeth G. Thygesen. "Pit and pit aperture dimensions in plantation-grown Douglas fir as affected by local growth conditions and height in stem." IAWA Journal 41, no. 2 (May 12, 2020): 131–40. http://dx.doi.org/10.1163/22941932-bja10003.
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Abstract This study assessed whether allometric scaling applied to pit sizes in stems of Douglas fir. Pit and pit aperture diameters were measured in xylem from stems of four plantation-grown Douglas fir (Pseudotsuga menziesii) trees from each of two different sites in Denmark. One site had fertile soil, the other had poor soil fertility. Three different heights were accessed for each tree, and 40 pits were measured per height. Results showed that pit diameter varied between 17 and 24 μm and decreased significantly with increasing height above ground. Representing the position in the tree as a power function of distance from the top of the tree (L0.2) rather than the height above ground improved the model fit for pit diameter as expressed by the R2 value. However, the pit diameter relationship was found to be significantly affected by site, suggesting that anatomic dimensions relate not only to tree size but also to growth conditions. This would imply that even though pit size supposedly has a strong biophysical determination, some xylem plasticity may still be induced by environmental factors.
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Ruel, Jean-Claude, Denis Loustau, and Marius Pineau. "Relations entre la microtopographie, les caractéristiques de la couverture morte et la répartition des essences dans une érablière à Bouleau jaune." Canadian Journal of Forest Research 18, no. 9 (September 1, 1988): 1196–202. http://dx.doi.org/10.1139/x88-183.
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Some effects of microtopography on forest floor, organic matter dynamics, and tree species distribution were studied in a northern hardwood stand near Québec. Forest floor thickness was 12.4 cm in pits while it was only 7.6 cm on mounds. These variations in thickness were attributed to a smaller litter accumulation (186 vs. 318 g m−2 year−1 in pits) and a more rapid decomposition on mounds (weight losses of wooden probes, 17.3 vs. 13.7% in pits). Over 43% of yellow birch stems (Betulaalleghaniensis Britton) were found on mounds in comparison with 20% for beech (Fagusgrandifolia Ehrh.). Sugar maple (Acersaccharum Marsh.) distribution was intermediate between those species. Thus, mounds seem more suitable for yellow birch installation, either because of their characteristics after their formation or because of the thinner forest floor formed on these microsites.
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Qu, Bingpeng, Yuanxin Liu, Xiangyang Sun, Suyan Li, Xinyu Wang, Kaiyi Xiong, Binghui Yun, and Hua Zhang. "Effect of various mulches on soil physico—Chemical properties and tree growth (Sophora japonica) in urban tree pits." PLOS ONE 14, no. 2 (February 6, 2019): e0210777. http://dx.doi.org/10.1371/journal.pone.0210777.
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Chang, K. T., C. Lin, Y. C. Lin, and J. K. Liu. "ACCURACY ASSESSMENT OF CROWN DELINEATION METHODS FOR THE INDIVIDUAL TREES USING LIDAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 585–88. http://dx.doi.org/10.5194/isprsarchives-xli-b8-585-2016.
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Forest canopy density and height are used as variables in a number of environmental applications, including the estimation of biomass, forest extent and condition, and biodiversity. The airborne Light Detection and Ranging (LiDAR) is very useful to estimate forest canopy parameters according to the generated canopy height models (CHMs). The purpose of this work is to introduce an algorithm to delineate crown parameters, e.g. tree height and crown radii based on the generated rasterized CHMs. And accuracy assessment for the extraction of volumetric parameters of a single tree is also performed via manual measurement using corresponding aerial photo pairs. A LiDAR dataset of a golf course acquired by Leica ALS70-HP is used in this study. Two algorithms, i.e. a traditional one with the subtraction of a digital elevation model (DEM) from a digital surface model (DSM), and a pit-free approach are conducted to generate the CHMs firstly. Then two algorithms, a multilevel morphological active-contour (MMAC) and a variable window filter (VWF), are implemented and used in this study for individual tree delineation. Finally, experimental results of two automatic estimation methods for individual trees can be evaluated with manually measured stand-level parameters, i.e. tree height and crown diameter. The resulting CHM generated by a simple subtraction is full of empty pixels (called "pits") that will give vital impact on subsequent analysis for individual tree delineation. The experimental results indicated that if more individual trees can be extracted, tree crown shape will became more completely in the CHM data after the pit-free process.
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Chang, K. T., C. Lin, Y. C. Lin, and J. K. Liu. "ACCURACY ASSESSMENT OF CROWN DELINEATION METHODS FOR THE INDIVIDUAL TREES USING LIDAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 585–88. http://dx.doi.org/10.5194/isprs-archives-xli-b8-585-2016.
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Forest canopy density and height are used as variables in a number of environmental applications, including the estimation of biomass, forest extent and condition, and biodiversity. The airborne Light Detection and Ranging (LiDAR) is very useful to estimate forest canopy parameters according to the generated canopy height models (CHMs). The purpose of this work is to introduce an algorithm to delineate crown parameters, e.g. tree height and crown radii based on the generated rasterized CHMs. And accuracy assessment for the extraction of volumetric parameters of a single tree is also performed via manual measurement using corresponding aerial photo pairs. A LiDAR dataset of a golf course acquired by Leica ALS70-HP is used in this study. Two algorithms, i.e. a traditional one with the subtraction of a digital elevation model (DEM) from a digital surface model (DSM), and a pit-free approach are conducted to generate the CHMs firstly. Then two algorithms, a multilevel morphological active-contour (MMAC) and a variable window filter (VWF), are implemented and used in this study for individual tree delineation. Finally, experimental results of two automatic estimation methods for individual trees can be evaluated with manually measured stand-level parameters, i.e. tree height and crown diameter. The resulting CHM generated by a simple subtraction is full of empty pixels (called "pits") that will give vital impact on subsequent analysis for individual tree delineation. The experimental results indicated that if more individual trees can be extracted, tree crown shape will became more completely in the CHM data after the pit-free process.
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Hugron, Sandrine, Roxane Andersen, Monique Poulin, and Line Rochefort. "Natural plant colonization of borrow pits in boreal forest highlands of eastern Canada." Botany 89, no. 7 (July 2011): 451–65. http://dx.doi.org/10.1139/b11-036.
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Plant colonization after gravel extraction for road construction is slow and is often considered to be primary succession. The goal of this study was to identify the plant communities that spontaneously colonized borrow pits located in boreal climate zones and to assess how environmental variables influenced this colonization process. It also helped identifying potential combinations of plants to use as well as environmental factors to improve to restore borrow pits. A total of 505 plots were inventoried in 117 borrow pits located in the boreal forest highlands 120 km northeast of Quebec City, Quebec, Canada (Parc national des Grands Jardins). Species cover was visually estimated for different plant communities within each borrow pit where slope and soil characteristics were also evaluated. We used multivariate analyses, including clustering, redundancy, and regression tree analyses. The borrow pits studied were undergoing primary succession processes decades after abandonment. The main pioneer species were bryophytes and lichens. Soil water content and soil physicochemistry had the greatest influence on the natural colonization of borrow pits. We observed that, based on the prevailing conditions, the bryophytes Polytrichum piliferum Hedw. and Niphotrichum canescens (Hedw.) Bednarek-Ochyra & Ochyra, lichens of the genus Stereocaulon , and the lichen Trapeliopsis granulosa (Hoffm.) Lumbsch could potentially act as nurse species and could initiate the restoration of borrow pits located in boreal forests.
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Turgeon, Jean J., John Pedlar, Peter de Groot, Michael T. Smith, Chuck Jones, Mary Orr, and Ben Gasman. "Density and location of simulated signs of injury affect efficacy of ground surveys for Asian longhorned beetle." Canadian Entomologist 142, no. 1 (February 2010): 80–96. http://dx.doi.org/10.4039/n09-049.
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AbstractSurveys for signs of attack by Asian long-horned beetles, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), currently rely upon visual examination of trees to discover signs of attack. By embedding simulated A. glabripennis oviposition pits and exit holes on open-grown Norway maples, Acer platanoides L. (Aceraceae), we evaluated the effect of sign density, height (below or above 2.5m), and position (bole or branch) when foliage was present or absent on inspector ability to distinguish trees with or without signs. From this, we quantified detectability, or the proportion of trees correctly identified as infested, and determined the time taken to do so. Effectiveness in detecting trees with signs improved when sign density increased, when signs were below 2.5m, and when oviposition pits were located on boles and exit holes on branches. These main findings require some caveats, due to a number of significant interactions. Foliage presence/absence had no apparent influence on effectiveness; possible reasons are provided for this result. Time-to-find curves, which illustrated the proportion of inspectors who accurately identified an infested tree as a function of survey duration, revealed that for most treatment combinations, most infested trees were detected within the first 2 min of survey time. These findings provide baseline data to assist managers in designing effective protocols for ground surveys of A. glabripennis.
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Zheng, Chong, Cui Yan Guo, Jing Wei Xue, Shi Bing Liu, and Tao Chen. "Flow Field Analysis for Plant Vessel and Bionic Structural Microfluidic Chip." Key Engineering Materials 645-646 (May 2015): 1345–50. http://dx.doi.org/10.4028/www.scientific.net/kem.645-646.1345.
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Microfluidic chips have been widely used in various of areas, such as biology, chemistry, medical science and so on. As one of the key techniques of microfluidic chips, the technique of micro driven of the water has been studied by experts all around the world for years. Of all kinds of the driven methods, the power costed by bionic driven is lowest. Moreover, as xylem is the main channel to transport the water in a tree, the mechanism of water transportation has been always an important issue in the study of physiological plant ecology. In this paper, the models of a single vessel element with different pit numbers (5 pits, 10 pits and 20 pits) or diameters(4µm and 7µm) were established according to the xylem and the pits’ structure. The 3-dimensional flow distribution was analyzed by ANSYS 12.0 calculating by realizable κ-ε algorithm. The pressure distribution contours and the velocity distribution contours of a single vessel element could be obtained after calculated by the software. According to the results, the flow field in a single vessel element of the xylem was studied. In addition, the influence of pits on the pressure and velocity were analyzed. The results showed that the influence on pressure and velocity is less when the diameter is smaller. As the number of pits on the vessel increased, the influence on the distribution of pressure and velocity is greater. Based on the result of numerical simulation of vessel element, a bionic structural microfluidic chip was designed and then analyzed by ANSYS 12.0.
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Yue, Chengyan, R. Karina Gallardo, James J. Luby, Alicia L. Rihn, James R. McFerson, Vicki McCracken, Tom Gradziel, et al. "An Evaluation of U.S. Peach Producers’ Trait Prioritization: Evidence from Audience Surveys." HortScience 49, no. 10 (October 2014): 1309–14. http://dx.doi.org/10.21273/hortsci.49.10.1309.
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We conducted audience surveys at three major peach producer meetings across the United States. We found that the relative importance assigned to fruit quality and tree traits by producers varied across producers’ end markets. Fresh peach producers indicated fruit flavor and size were the most important fruit quality traits, whereas processed peach producers viewed fruit size, fruit firmness, and absence of split pits as being the most important traits for a successful peach cultivar. These results have potential to ensure that peach breeding programs are consonant with fresh and processed peach producers’ needs for fruit and tree traits.
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Angélico, Talita dos Santos, Carmen Regina Marcati, Sergio Rossi, Magali Ribeiro da Silva, and Júlia Sonsin-Oliveira. "Soil Effects on Stem Growth and Wood Anatomy of Tamboril Are Mediated by Tree Age." Forests 12, no. 8 (August 9, 2021): 1058. http://dx.doi.org/10.3390/f12081058.
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Soil influences the growth of trees and the characteristics of the wood; but could this influence change during the ontogeny of trees? To answer this question, we analyzed the wood anatomy of 9-year-old trees and 2-year-old saplings of Enterolobium contortisiliquum, known as “tamboril”, growing in eutrophic and oligotrophic soil in the Brazilian Cerrado, and assessed the effect of age on plant–soil relationship. Sapwood samples were collected from the main stem, anatomical sections were prepared in the lab, and 12 anatomical wood traits were measured. Individuals in eutrophic soil had greater stem diameter and height than those in oligotrophic soil. Trees in eutrophic soil had vessel-associated parenchyma cells with abundant storage compounds. Fibers walls were 47% thicker and intervessel pits diameter were 14% larger in trees of eutrophic soil. A greater proportion of solitary vessels (74%) was observed in trees rather than in saplings (50%). The secondary xylem of trees was mainly formed by fibers (63%) whereas in saplings it was mainly formed by storage tissue (64%). Our study provides evidence that the influence of soil conditions on tree growth reflects variations in wood anatomical features. No significant response to soil type was observed in saplings, thus demonstrating that the relationship between soil type and wood growth is mediated by tree age. These findings help to develop reliable reforestation strategies in tropical ecosystems characterized by different levels of soil fertility.
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Legge, NJ. "Anatomical Aspects of Water Movement Through Stems of Mountain Ash (Eucalyptus regnans F. Muell.)." Australian Journal of Botany 33, no. 3 (1985): 287. http://dx.doi.org/10.1071/bt9850287.
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Introduction of a stain through the severed roots of Eucalyptus regnans of two age classes showed that a spiral interlocked sap ascent pattern in young trees tended towards a vertical sectorial pattern by age 40 years. Microscopic examination of the stained wood suggests that intercellular water movement occurs principally via the pits. Serial transverse sections of wood from a young tree showed a limited degree of intervessel contact, with a network coefficient of 13.7 contacts m-1 and approx. 0.9% of vessel surface area in contact with other vessels. Analysis of the frequency of vessel endings indicates an average vessel length of approx. 1.8 m. Trunk segments of 40-year-old trees had relative conductivities of approx. 3.3 x 10-11 m2, while small lateral roots had values up to 10 times greater.
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Cieśliński, Satanisław, and Ewa Jaworska. "Changes in the lichen flora of pine-tree (Pinus sylvestris L.) under the effect of emissions of cement-lime industrial works and lime-pits." Acta Mycologica 22, no. 1 (August 20, 2014): 3–14. http://dx.doi.org/10.5586/am.1986.001.
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Singh, Ashok Kumar, and Aginaparru Sambasiva Rao. "Blade Lock Ring of 4th Stage Compressor Rotor: Failure Investigation." International Journal of Engineering Materials and Manufacture 4, no. 3 (September 18, 2019): 85–95. http://dx.doi.org/10.26776/ijemm.04.03.2019.01.
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Present work describes the failure investigation of blade lock ring of 4th stage compressor rotor. The lock ring is fabricated from martensitic stainless steel. The microstructure of failed lock ring is tempered martensite. It shows non-metallic inclusions with three distinct shapes namely, elongated (MnS), globular (Al2O3) and complex shaped (oxy-sulphide). The corrosion pits and corrosion debris are observed in un-etched microstructure and fracture surface, respectively. The tree like branching cracks has observed at several places near surface. These cracks have initiated from the corrosion pits and then propagated inside the material. The interface of inclusions and matrix has also acted as crack initiator. The lock ring has initially suffered pitting corrosion in service and then cracks have propagated inside the material by stress corrosion cracking.
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Freycon, Vincent, Christelle Wonkam, Adeline Fayolle, Jean-Paul Laclau, Eric Lucot, Christophe Jourdan, Guillaume Cornu, and Sylvie Gourlet-Fleury. "Tree roots can penetrate deeply in African semi-deciduous rain forests: evidence from two common soil types." Journal of Tropical Ecology 31, no. 1 (December 8, 2014): 13–23. http://dx.doi.org/10.1017/s0266467414000595.
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Abstract:Despite the important functional role of deep roots in withdrawing water during drought, direct measurements of root distribution are very rare in tropical rain forests. The aim of this study was to investigate the root distribution of Entandrophragma cylindricum, a common tree species in the Central African semi-deciduous rain forest, in Ferralsols and Arenosols. We dug two pits to a depth of 6 m in Ferralsols and two pits to a depth of 3 m in Arenosols, close to E. cylindricum trees. The vertical soil profiles were divided into 10 × 10-cm grid cells and the roots counted were distributed in three diameter classes. We fitted a root distribution model to our dataset. We found that vertical root distribution was shallower in Arenosols than in Ferralsols. Root penetration was not stopped even by a Ferralsol with high gravel content in its subsoil. Overall, our measurements showed that 95% of all roots were distributed to depths of between 258 and 564 cm from the soil surface, which is much deeper than the 95 cm depth previously reported in the literature for tropical rain forests. As sampling depth could explain this discrepancy, we recommend a sampling depth of at least 3–5 m to accurately estimate root distribution. The drier the dry season, the deeper the sampling depth should be. Our results are consistent with global models of root distribution in forest ecosystems, which are driven by climate variables. We thus suggest that deep rooting could be common in rain forests with a marked dry season.
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Yanai, Ruth D., Byung B. Park, and Steven P. Hamburg. "The vertical and horizontal distribution of roots in northern hardwood stands of varying age." Canadian Journal of Forest Research 36, no. 2 (February 1, 2006): 450–59. http://dx.doi.org/10.1139/x05-254.
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Coring methods cannot reveal the distribution of roots with depth in rocky soil, and fine roots are typically sampled without regard to the location of trees. We used quantitative soil pits to describe rooting patterns with soil depth and distance to trees in northern hardwood stands. We sited three 0.5 m2 quantitative soil pits in each of three young (1927 years) and three older (5669 years) stands developed after clear-cutting. Live roots were divided into diameter classes delimited at 0.5, 1, 2, 5, 10, 20, and 100 mm; dead roots were not distinguished by size. Mean total live-root biomass was 2900 ± 500 g·m2 in older stands and 1500 ± 400 g·m2 in young stands. The root mass in the 220 mm class was 2.7 times greater in the older stands (p = 0.03); fine-root (<2 mm) biomass was 1.5 times greater (p = 0.12), suggesting that fine-root biomass continues to increase past the age of canopy closure in this forest type. Root biomass density declined with soil depth, with the finest roots (<0.5 mm) declining most steeply; roots were found at low densities well into the C horizon. We analyzed root biomass density as a function of the influence of nearby trees (represented as the sum of basal area divided by the distance from the pit) and found that fine as well as coarse roots reflected this influence. In systems where this is the case, root measurements should be made with attention to patterns of tree distribution.
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Christman, Mairgareth A., John S. Sperry, and Duncan D. Smith. "Rare pits, large vessels and extreme vulnerability to cavitation in a ring-porous tree species." New Phytologist 193, no. 3 (December 7, 2011): 713–20. http://dx.doi.org/10.1111/j.1469-8137.2011.03984.x.
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Hýsek, Štěpán, Radim Löwe, and Marek Turčáni. "What Happens to Wood after a Tree Is Attacked by a Bark Beetle?" Forests 12, no. 9 (August 27, 2021): 1163. http://dx.doi.org/10.3390/f12091163.
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Advancing climate change is affecting the health and vitality of forests in many parts of the world. Europe is currently facing spruce bark beetle outbreaks, which are most often caused by wind disturbances, hot summers, or lack of rainfall and are having a massive economic impact on the forestry sector. The aim of this research article was to summarize current scientific knowledge about the structure and physical and mechanical properties of wood from bark beetle-attacked trees. Spruce stands are attacked by a number of beetles, of which Ips typographus is the most common and widespread in Central Europe. When attacking a tree, bark beetles introduce ophiostomatoid fungi into the tree, which then have a greater effect on the properties of the wood than the beetles themselves. Fungal hyphae grow through the lumina of wood cells and spread between individual cells through pits. Both white rot and brown rot fungi are associated with enzymatic degradation of lignin or holocellulose, which is subsequently reflected in the change of the physical and mechanical properties of wood. Wood-decay fungi that colonize wood after infestation of a tree with bark beetles can cause significant changes in the structure and properties of the wood, and these changes are predominantly negative, in the form of reducing modulus of rupture, modulus of elasticity, discolouration, or, over time, weight loss. In certain specific examples, a reduction in energy consumption for the production of wood particles from beetle-attacked trees, or an increase in surface free energy due to wood infestation by staining fungi in order to achieve better adhesion of paints or glues, can be evaluated positively.
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Silva, Jane Rodrigues da, Sergio Rossi, Siddhartha Khare, Eduardo Luiz Longui, and Carmen Regina Marcati. "Disentangling the Effects of Genotype and Environment on Growth and Wood Features of Balfourodendron riedelianum Trees by Common Garden Experiments in Brazil." Forests 11, no. 9 (August 19, 2020): 905. http://dx.doi.org/10.3390/f11090905.
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Intraspecific studies with populations replicated in different sites allow the effects of genotype and environment on wood features and plant growth to be distinguished. Based on climate change predictions, this distinction is important for establishing future patterns in the distribution of tree species. We quantified the effects of genotype and environment on wood features and growth of 30-year-old Balfourodendron riedelianum trees. We used three provenances planted in two common garden experiments with difference in precipitation and temperature. We applied linear models to estimate the variability in wood and growth features and transfer functions to evaluate the responses of these features to temperature, precipitation, and the standardized precipitation evapotranspiration index (SPEI). Our results showed that genotype had an effect on vessels and rays, where narrower vessels with thinner walls and larger intervessel pits, and shorter, narrower and more numerous rays were observed in provenances from drier sites. We also observed the effect of the environment on wood features and growth. Trees growing in the wetter site were taller and larger, and they had wider vessels with thicker walls and lower ray density. Transfer functions indicated that an increase in temperature results in larger vessels with thicker walls, taller and denser rays, shorter and narrower fibers with thinner walls, and lower wood density. From a functional perspective, these features make trees growing in warmer environments more prone to drought-induced embolisms and more vulnerable to mechanical damage and pathogen attacks. Tree growth varied with precipitation and SPEI, being negatively affected in the drier site. Overall, we demonstrated that both genotype and environment affect wood features, while tree growth is mainly influenced by the environment. Plastic responses in hydraulic characteristics could represent important functional traits to mitigate the consequences of ongoing climate change on the growth and survival of the species within its natural range.
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Galle, Nadina, William Brinton, Robin Vos, Fábio Duarte, Marcus Collier, Carlo Ratti, and Francesco Pilla. "Spatial variability of urban forest topsoil properties: towards representative and robust sampling design." Open Research Europe 1 (April 29, 2021): 45. http://dx.doi.org/10.12688/openreseurope.13502.1.
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Background: Soil spatial variability is a major concern when deciding how to collect a representative topsoil sample for laboratory analysis. Sampling design to capture site-specific variability is documented in the agricultural literature, but poorly understood for urban forest soils where soils may be characterized by strong horizontal and vertical variability and large temporal anthropogenic disturbances. Methods: This paper evaluates the spatial variability of selected topsoil properties under urban trees to define a statistically robust sampling design that optimizes the number of samples to reliably characterize basal soil respiration (BSR), a property associated with soil health. To provide a reference on variability, two additional soil properties were measured, unrelated to BSR: electrical conductivity (EC) and bulk density (BD). Thirteen sampling sites comprising both park and street trees (Acer rubrum) were selected in Cambridge, MA, USA. Results: Results indicate street tree topsoil had approximately twice as much variation, requiring more intensive sampling, as did park tree topsoil, even though street trees had smaller soil sampling zones, constricted by tree pits. The variability of BSR was nearly identical to that of EC, and BD results varied least. A large number of samples would be required for acceptable levels of statistical reliability (90% CI - 10% ER) of 44.4, 41.7, and 6.4 for BSR, EC, and BD, respectively, whereas by accepting a lower level of certainty (80% CI - 20% ER) the number of required soil samples was calculated as 6.8, 6.4, and 0.4 for BSR, EC, and BD, respectively. Conclusions: The use of EC testing as a baseline measure to determine spatial variation in the topsoil is proposed, to alleviate the financial implications of more expensive BSR testing. Factors of topsoil disturbance and soil access restrictions at sites with severe root-sidewalk conflicts and the overall generalizability of the results are also discussed.
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Krewer, Gerard, Tom Beckman, Jose Chaparro, and Wayne Sherman. "`GULFKING' AND `GULFCREST', NEW PEACHES FOR THE LOWER COASTAL PLAIN." HortScience 40, no. 3 (June 2005): 882d—882. http://dx.doi.org/10.21273/hortsci.40.3.882d.
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`Gulfking' and `Gulfcrest' peaches are jointly released for grower trials by the U.S. Department of Agriculture, Agricultural Research Service, the Georgia Agricultural Experiment Station, and the Florida Agricultural Experiment Station. Trees of `Gulfking' and `Gulfcrest' produce an attractive, sweet-tasting, yellow and non-melting flesh fruit intended for the fresh fruit market. They are expected to produce fruit with tree-ripened aroma and taste while retaining firmness for longer shelf life than fruit from conventional melting-flesh cultivars. Trees of `Gulfking' reach full bloom most seasons in mid-February in lower southern Georgia and are estimated to require 350 chill units. We expect this new peach to be adapted in areas where `Flordaking' has been successfully grown. Fruit ripen 73 to 80 days from full bloom, typically in early May, usually with `Flordaking' in southern Georgia. The fruit are large, ranging from 105 to 130 grams. Commercially ripe fruit exhibit 80% to 90% red (with moderately fine darker red stripes) over a deep yellow to orange ground color. Fruit shape is round with a recessed tip. Pits are medium small and have little tendency to split even when crop loads are low. Trees of `Gulfcrest' are estimated to require 525 chill units. This is based on full bloom consistently occurring with `Sunfre' nectarine at Attapulgus, Ga. where full bloom occurs most seasons in early-March. Fruit ripen 62 to 75 days from full bloom, typically in early to mid-May, usually a few days after `Flordacrest' in southern Georgia. The fruit are medium-large, averaging about 105 g. Commercially ripe fruit exhibit 90% to 95% red over a deep yellow to orange ground color. Fruit shape is round with a recessed tip. Pits are medium small and have little tendency to split even when crop loads are low.
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Sass, Emma M., Anthony W. D’Amato, David R. Foster, Audrey Barker Plotkin, Shawn Fraver, Peter K. Schoonmaker, and David A. Orwig. "Long-term influence of disturbance-generated microsites on forest structural and compositional development." Canadian Journal of Forest Research 48, no. 8 (August 2018): 958–65. http://dx.doi.org/10.1139/cjfr-2018-0097.
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Wind disturbance generates heterogeneous microsite structures, including downed logs, windthrow mounds, and pits. While these structures can provide opportunities for regeneration of certain tree species, the long-term influence of microsites and microsite heterogeneity on forest development has not been quantified. We used long-term measurements of a formerly old-growth Tsuga canadensis – Pinus strobus forest severely damaged by a category 3 hurricane in 1938 to quantify the impact of microsite conditions on overstory composition and structure. We asked (i) “What are the patterns in live-tree size, growth, and mortality five and seven decades after disturbance?” and (ii) “What roles do microsite heterogeneity and the presence of disturbance-generated microsites play in long-term forest development following disturbance?” We compared live-tree (>2 cm DBH) development and survival to microsite heterogeneity at the 100 m2 scale. Microsite diversity was positively related to overstory species diversity and stem density and negatively related to average tree size. We propose that plots with higher microsite diversity may have experienced more severe local disturbance, which allowed more species and individuals to establish and created varied niches that allowed these individuals to coexist and generate greater stand-level diversity. These persistent relationships highlight how microsite conditions affect forest development after severe disturbances.
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Skorton, David. "Branches from the same tree: The case for integration in higher education." Proceedings of the National Academy of Sciences 116, no. 6 (February 4, 2019): 1865–69. http://dx.doi.org/10.1073/pnas.1807201115.
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The nature of work is changing rapidly in the digital age, increasing the demand for skills in specific disciplines. Across the United States and beyond, this evolution has led to an increased emphasis on science, technology, engineering, and mathematics (STEM) education at every level. Meanwhile, at US institutions of higher education, the proportion of undergraduate students who earn a degree in the humanities is declining. However, while the public discussion often pits the disciplines against one another, the sciences, arts, and humanities are—as Albert Einstein once wrote—“branches of the same tree” [(2006)The Einstein Reader]. They are mutually reinforcing. Therefore, the best way to prepare the next generation for the future of work, life, and citizenship is to provide broad, holistic educational experiences that integrate the STEM disciplines with the arts and humanities. A new study from the Board on Higher Education and Workforce of the National Academies of Sciences, Engineering, and Medicine bolsters the case for such an approach, finding considerable evidence that the mutual integration of disciplines leads to improved educational and career outcomes for undergraduate and graduate students.
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Sun, Qiang, Kazutaka Kobayashi, and Mitsuo Suzuki. "INTERCELLULAR SPACE SYSTEM IN XYLEM RAYS OF PNEUMATOPHORES IN SONNERATIA ALBA (SONNERATIACEAE) AND ITS POSSIBLE FUNCTIONAL SIGNIFICANCE." IAWA Journal 25, no. 2 (2004): 141–54. http://dx.doi.org/10.1163/22941932-90000356.
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Sonneratia alba J. Smith is a fast-growing pioneer mangrove tree species, and woody pneumatophores are one of the main morphological characters distinguishing this species from other mangrove species. Xylem rays of the pneumatophores in S. alba were exclusively uni-seriate and homocellular with procumbent cells. Intercellular spaces developed mainly between rows of procumbent ray cells to form continuous canals along the pneumatophore radius. Short axial intercellular spaces were present at the end wall sites of spindle-like procumbent ray cells within the same row, and interconnected with the neighboring radial intercellular canals into an intercellular space network within the xylem rays. The radial intercellular canals of xylem rays were larger in the outer secondary xylem than in the inner secondary xylem of a pneumatophore, and in the underground part than in the aboveground part. Blind pits (unilateral pits) towards the radial intercellular canals developed in the radial walls of vessels and the transverse walls of ray cells. The blind pits of vessels were bordered and vestured, and arranged radially in two regular rows in larger radial intercellular canals, but in one row or diffusely in narrower canals. The structural characters of the xylem rays and the intercellular space system of the pneumatophore suggest their possible involvement in water transport in the secondary xylem. An intercellular space system did not occur in xylem rays of the cable roots and stems of this species.
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Schmitz, Nele, Gerald Koch, Hans Beeckman, Nico Koedam, Elisabeth M. R. Robert, and Uwe Schmitt. "A Structural and Compositional Analysis of Intervessel pit Membranes in the Sapwood of some Mangrove Woods." IAWA Journal 33, no. 3 (2012): 243–56. http://dx.doi.org/10.1163/22941932-90000091.
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Intervessel pits are prominent wall structures involved in the water transport mechanism of land plants. The role of their intra-tree variation in the regulation of water transport, however, remains enigmatic. The hypothesis was tested that pit membrane thickness and degree of impregnation with phenolic substances increase along the stem axis with increasing tension on the water column as an adaptation to the higher risk for cavitation. Wood samples were taken at different heights from the mangrove tree Rhizophora mucronata growing at Gazi Bay (Kenya). Additional samples were taken along the stem radius to distinguish height from age effect, and from six other mangrove species growing in the same forest. Intervessel pit membranes were studied via transmission and scanning electron microscopy and cellular UV-microspectrophotometry. The hypothesis of pit membrane thickness and composition as a static adaptation to the hydrostatic conditions during vessel differentiation could be refuted. Instead, our findings point to a more dynamic pit membrane appearance with seasonal changes in thickness and chemical composition.
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Hejnowicz, Alina. "Anatomical studies on the development of Metasequoia glyptostroboides Hu et Cheng wood." Acta Societatis Botanicorum Poloniae 42, no. 3 (2015): 473–91. http://dx.doi.org/10.5586/asbp.1973.037.
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Variability of anatomical characters within a 15 year old stem is presented by the method of contour lines, where against a schematic longitudinal section of a stem points corresponding to the same values for a character are joined by lines, similarly as altitudes in cartography. The method permits prediction of future trends in character changes. It was thus established that tracheid dimensions and diameter of bordered pits in early wood tracheids increase with age of tree and do not reach maximal values before the 15th year. The annual ring width and the height of the rays attain maximal values before the 15th year while the dimensions of ray cells and the percentage of late wood reach almost constant values during the first year or two.
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Elliott, Robert M., Elizabeth R. Adkins, Patricia J. Culligan, and Matthew I. Palmer. "Stormwater infiltration capacity of street tree pits: Quantifying the influence of different design and management strategies in New York City." Ecological Engineering 111 (February 2018): 157–66. http://dx.doi.org/10.1016/j.ecoleng.2017.12.003.
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Nandris, D., R. Moreau, F. Pellegrin, H. Chrestin, J. Abina, and P. Angui. "Rubber Tree (Hevea brasiliensis) Bark Necrosis Syndrome II: First Comprehensive Report on Causal Stresses." Plant Disease 88, no. 9 (September 2004): 1047. http://dx.doi.org/10.1094/pdis.2004.88.9.1047a.
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Bark necrosis (BN), described and first studied in Côte d'Ivoire in the 1980s (2), affects most modern rubber plantations (i.e., grafted trees with high-yielding clones, intensive exploitation due to tapping frequency, and use of Ethrel as a yield stimulant) worldwide with a wide range of severity across sites. While previous (3) and recent (4) etiological analyses remain inconclusive, environmental factors were shown associated with BN. Numerous epidemiological surveys conducted in various African and Asian plantations on recently tapped blocks (less than 10-year-old trees) revealed the nonrandom location of the earliest single diseased trees. These risky areas are mainly characterized by the proximity of a swamp, plantation road, windrow, old bulldozer track, residual forest stump, or slope break. In BN emergence areas, while no significant correlation was found with chemical soil parameters, physical soil analyses (e.g., penetrometer) revealed higher soil compaction often associated with poorer rhizogenesis in BN trees (comparative root counts made in pits close to healthy or BN trees). Furthermore, initial BN symptoms were preferentially observed near the grafted bud at the rootstock/scion junction (RS/S). Numerous comparative ecophysiological measurements of leaf water potential, stem water potential, and predawn base potential using a plant moisture stress (PMS) pressure chamber indicated water stress in BN trees. These results and preliminary dye transfer studies at the RS/S junction suggested a nonoptimal vascular relation between the root system and the trunk of BN trees. In conclusion, compaction-associated reduced water availability of the soil and poor root capacity to meet the water demand during drier dry seasons combined with disturbed sap flows and recurrent local water drainage (latex flows) are now suspected to jointly act as the main exogenous causal stresses that induce the BN process at the RS/S bud zone before spreading upward to the tapping cut. This multidisciplinary approach gives a new comprehensive scenario for the emergence of this multifactorial physiological disease, now suspected to involve cyanide release (1) into the inner phloem of the rubber tree. References: (1) H. Chrestin. Plant Dis. 88:1047, 2004. (2) D. Nandris et al. Eur. J. For. Pathol. 21:325, 1991. (3) D. Nandris et al. Eur. J. For Pathol. 21:340, 1991. (4) F. Pellegrin et al. Plant Dis. 88:1046, 2004.
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Ozerina, Irina. "Monitoring Tree-Shrub, and Meadow Vegetation in the Volga-Akhtuba Floodplain Using Remote Sensing Methods (Based on “Krasnyy Buksir” Range)." Natural Systems and Resources, no. 3 (April 2020): 53–60. http://dx.doi.org/10.15688/nsr.jvolsu.2019.3.7.
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The article deals with the assessment of the state of tree-shrub and meadow vegetation by remote sensing methods. The author reveals the reasons of degradation and change of floristic richness of vegetation. These include: trampling of grass cover and forest floor (1), mechanical damage of trees (2), increasing the area of fire pits (3), and littering and contamination of the territory (4). In addition, mowing and grazing have a great influence. The development of the path network leads to changes in water-physical properties of the soil. Changes in the species composition of meadow vegetation indicate an increase in the processes of xerophytization and pasture digression. The article considers various methods of decoding forest plantations. Among them, the method of aerospace research is the most effective. This method makes it possible to assess the state of tree-shrub and meadow vegetation in dynamics and to carry out continuous monitoring. For a greater accuracy of the assessment, Earth remote sensing data are confirmed by on-site studies. Projective coverage has been used as a sign of degradation for the assessment. The level of preservation of plantings has been determined by the area of the canopy of the stand, that is the ratio of the canopy area to the entire area of the plantings. Under the area of the canopy a set of pixels that match the tone assigned to the canopy is understood. Using the methodology given in the article, the author has carried out the vegetation analysis at “Krasnyy Buksir” range. The area of land belonging to different environmental levels has been calculated for this purpose. The author draws the conclusion that the studied site is subject to a significant anthropogenic load and environmental protection measures are strongly necessary in this area.
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Liu, Ru, Min Liu, Shenghui Hu, Anmin Huang, and Erni Ma. "Comparison of six WPCs made of organo-montmorillonite-modified fibers of four trees, moso bamboo and wheat straw and poly(lactic acid) (PLA)." Holzforschung 72, no. 9 (September 25, 2018): 735–44. http://dx.doi.org/10.1515/hf-2017-0206.
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AbstractFibers of four tree species, moso bamboo and wheat straw were modifiedin situwith organo-montmorillonite (OMMT). The characterization of the physical and mechanical properties of the resulting composites showed that OMMT can be synthesizedin situwithin the fibers’ matrix. Some individual OMMT layers were clearly observed, while some agglomeration was seen on the fiber surface. After blending with poly(lactic acid) (PLA), redistributions of OMMT in the PLA matrix occurred and most properties of the composites were improved. The modification effect of Chinese fir was the best while that of moso bamboo and straw wheat was rarely poor because of their different chemical components, anatomical structures and densities. In short, a higher lignin content, large diameter of pits and lower density contributed to the improved properties of the wood plastic composites (WPCs) with the participation of OMMT.
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Kargar, Maryam, Pierre Jutras, O. Grant Clark, William H. Hendershot, and Shiv O. Prasher. "Macro-nutrient availability in surface soil of urban tree pits influenced by land use, soil age, and soil organic matter content." Urban Ecosystems 18, no. 3 (March 13, 2015): 921–36. http://dx.doi.org/10.1007/s11252-015-0439-7.
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Dibog, L., P. Eggleton, L. Norgrove, D. E. Bignell, and S. Hauser. "Impacts of canopy cover on soil termite assemblages in an agrisilvicultural system in southern Cameroon." Bulletin of Entomological Research 89, no. 2 (February 1999): 125–32. http://dx.doi.org/10.1017/s0007485399000206.
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AbstractTermites were sampled using randomized soil pits in 64 cropping plots, each 25 x 25 m, forming an experimental agrisilvicultural system in both a 6- and an 18-year-old Terminalia ivorensis plantation, in which canopy cover, crop, cropping system and land preparation were the principal treatment variables. The treatments were established in April 1995 and sampling was carried out in November 1995, February 1996 and July 1996. A total of 82 termite species were found, of which 67 were soil-feeders. Overall termite abundance and the abundance of soil-feeders increased between November 1995 and July 1996, reaching a mean of nearly 6000 m-2. Pooling termite data from these sampling dates, in the old plantation, the high canopy cover treatment (192 stems ha-1) had a greater abundance of termites, compared with the low canopy cover treatment (64 stems ha-1) and this effect was independent of crop type (plantain or cocoyam), cropping system (single stands or mixed crops) and land preparation (mulch retained or burned, plantain only). The young tree plantation (same tree densities as in the old plantation) showed no significant difference in termite abundance between high and low canopy (levels of tree foliage) densities, though the high canopy sheltered a greater number of termites. Analysis of covariance showed that crop yield (both plantain and cocoyam) was not directly linked to the abundance of all termite populations, but that the cocoyam yield was positively correlated with the abundance of soil-feeding termites (the majority in the assemblage) in the young plantation. This may be due to the beneficial conditioning of soil resulting from the foraging and construction activities of soil-feeders.