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Atlas of wood, bark and pith anatomy of Eastern Mediterranean trees and shrubs : with a special focus on Cyprus
This atlas presents anatomical descriptions of the xylem, bark and pith of 264 species belonging to 69 families. It highlights the anatomical diversity of trees, shrubs, dwarf shrubs, woody lianas and several of the prominent perennial herbs from the Eastern Mediterranean region, with a focus on the island of Cyprus. The island's topography and biogeographic history combine to provide a wide range of habitats and diverse flora including widespread, endemic, and ornamental species. The monograph for each species includes a description of the anatomical structures of the stem and twig xylem and the twig's bark and pith, as well as color micrographs of double-stained sections of each of these plant parts. These entries are accompanied by a photograph and a brief description of the plant including stem wood density, height, habit, flower, leaf and fruit characteristics, and a map showing its geographic and altitudinal distribution in the region. Xylem descriptions follow the IAWA lists of microscopic features for hardwood and softwood identification. For bark and pith descriptions, a new coding system developed by the authors is applied. Lastly, the atlas offers a key for wood identification that was developed to differentiate between groups of species by using a small number of features that are unambiguous and clearly visible. The atlas will be a valuable guide for botanists, ecologists, foresters, archeologists, horticulturists and paleobotanists.
Book
Tree defence and bark beetles in a drying world : carbon partitioning, functioning and modelling
Drought has promoted large-scale, insect-induced tree mortality in recent years, with severe consequences for ecosystem function, atmospheric processes, sustainable resources and global biogeochemical cycles. However, the physiological linkages among drought, tree defences, and insect outbreaks are still uncertain, hindering our ability to accurately predict tree mortality under ongoing climate change. Herewepropose an interdisciplinary research agenda for addressing these crucial knowledge gaps. Our framework includes field manipulations, laboratory experiments, and modelling of insect and vegetation dynamics, and focuses on how drought affects interactions between conifer trees and bark beetles. We build upon existing theory and examine several key assumptions: (1) there is a trade-off in tree carbon investment between primary and secondary metabolites (e.g. growth vs defence); (2) secondary metabolites are one of the main component of tree defence against bark beetles and associated microbes; and (3) implementing conifer-bark beetle interactions in current models improves predictions of forest disturbance in a changing climate. Our framework provides guidance for addressing a major shortcoming in current implementations of large-scale vegetation models, the under-representation of insect-induced tree mortality.
Journal Article
Bark thickness across the angiosperms: more than just fire
Global variation in total bark thickness (TBT) is traditionally attributed to fire. However, bark is multifunctional, as reflected by its inner living and outer dead regions, meaning that, in addition to fire protection, other factors probably contribute to TBT variation.
To address how fire, climate, and plant size contribute to variation in TBT, inner bark thickness (IBT) and outer bark thickness (OBT), I sampled 640 species spanning all major angiosperm clades and 18 sites with contrasting precipitation, temperature, and fire regime.
Stem size was by far the main driver of variation in thickness, with environment being less important. IBT was closely correlated with stem diameter, probably for metabolic reasons, and, controlling for size, was thicker in drier and hotter environments, even fire-free ones, probably reflecting its water and photosynthate storage role. OBT was less closely correlated with size, and was thicker in drier, seasonal sites experiencing frequent fires. IBT and OBT covaried loosely and both contributed to overall TBT variation. Thickness variation was higher within than across sites and was evolutionarily labile.
Given high within-site diversity and the multiple selective factors acting on TBT, continued study of the different drivers of variation in bark thickness is crucial to understand bark ecology.
Journal Article
Conifer-killing bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes
Outbreaks of the Eurasian spruce bark beetle ( Ips typographus ) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I . typographus can distinguish fungal symbionts of the genera Grosmannia , Endoconidiophora , and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle’s host tree, Norway spruce ( Picea abies ), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans -4-thujanol and other oxygenated products. Electrophysiological measurements showed that I . typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans -4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus ( Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I . typographus . Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.
Journal Article
Charles Benson : mariner of color in the Age of Sail
\"Raised in a small town in Massachusetts, Charles Augustus Benson was the great-great-grandson of slaves, the great-grandson of a rare eighteenth-century intermarriage between a white woman and a black man, and the grandson of a veteran of the American Revolution. His own life had its share of difficulties, marked by economic struggle, marital conflict, and the social ambiguities of mixed race heritage.\" \"In his personal writings, Benson reflected on both the man he was and the man he wanted to be. Living in a culture that prized \"self-made\" individuals, he sought to forge his own identity even as he labored under structures that severely limited opportunities for blacks. From his youth in rural Middlesex County, Massachusetts, to his subsequent adult life in the bustling port city of Salem, Benson measured himself against the mores of white, middle-class America. Undeterred by early failures in both marriage and finance, he held fast to his personal vision and eventually became a respectable husband, provider, worker, and member of the black community\"-- Provided by publisher.
Book
The Andean Wonder Drug
In the eighteenth century, malaria was a prevalent and deadly disease, and the only effective treatment was found in the Andean forests of Spanish America: a medicinal bark harvested from cinchona trees that would later give rise to the antimalarial drug quinine. In 1751, the Spanish Crown asserted control over the production and distribution of this medicament by establishing a royal reserve of \"fever trees\" in Quito. Through this pilot project, the Crown pursued a new vision of imperialism informed by science and invigorated through commerce. But ultimately this project failed, much like the broader imperial reforms that it represented. Drawing on extensive archival research, Matthew Crawford explains why, showing how indigenous healers, laborers, merchants, colonial officials, and creole elites contested European science and thwarted imperial reform by asserting their authority to speak for the natural world.The Andean Wonder Druguses the story of cinchona bark to demonstrate how the imperial politics of knowledge in the Spanish Atlantic ultimately undermined efforts to transform European science into a tool of empire.
eBook
Bark ecology of twigs vs. main stems: functional traits across eighty-five species of angiosperms
Although produced by meristems that are continuous along the stem length, marked differences in bark morphology and in microenvironment would suggest that main stem and twig bark might differ ecologically. Here, we examined: (1) how closely associated main stem and twig bark traits were, (2) how these associations varied across sites, and (3) used these associations to infer functional and ecological differences between twig and main stem bark. We measured density, water content, photosynthesis presence/absence, total, outer, inner, and relative thicknesses of main stem and twig bark from 85 species of angiosperms from six sites of contrasting precipitation, temperature, and fire regimes. Density and water content did not differ between main stems and twigs across species and sites. Species with thicker twig bark had disproportionately thicker main stem bark in most sites, but the slope and degree of association varied. Disproportionately thicker main stem bark for a given twig bark thickness in most fire-prone sites suggested stem protection near the ground. The savanna had the opposite trend, suggesting that selection also favors twig protection in these fire-prone habitats. A weak main stem-twig bark thickness association was observed in non fire-prone sites. The near-ubiquity of photosynthesis in twigs highlighted its likely ecological importance; variation in this activity was predicted by outer bark thickness in main stems. It seems that the ecology of twig bark can be generalized to main stem bark, but not for functions depending on the amount of bark, such as protection, storage, or photosynthesis.
Journal Article
Exploring the bark thickness–stem diameter relationship
Bark thickness is ecologically crucial, affecting functions from fire protection to photosynthesis. Bark thickness scales predictably with stem diameter, but there is little consensus on whether this scaling is a passive consequence of growth or an important adaptive phenomenon requiring explanation.
With a comparative study across 913 species, we test the expectation that, if bark thickness–stem diameter scaling is adaptive, it should be possible to find ecological situations in which scaling is predictably altered, in this case between species with different types and deployments of phloem.
‘Dicots’ with successive cambia and monocots, which have phloem-free bark, had predictably thinner inner (mostly living) bark than plants with single cambia. Lianas, which supply large leaf areas with limited stem area, had much thicker inner bark than self-supporting plants. Gymnosperms had thicker outer bark than angiosperms.
Inner bark probably scales with plant metabolic demands, for example with leaf area. Outer bark scales with stem diameter less predictably, probably reflecting diverse adaptive factors; for example, it tends to be thicker in fire-prone species and very thin when bark photosynthesis is favored. Predictable bark thickness–stem diameter scaling across plants with different photosynthate translocation demands and modes strongly supports the idea that this relationship is functionally important and adaptively significant.
Journal Article