Search Results

Amalava Bhattacharyya and Santosh K. Shah

A large number of tree species, especially of conifers growing in the Himalaya and a few broad-leaved taxa in the peninsular region, have been dendrochronologically analyzed in India. This paper is a review providing information as regards the present status and future prospects of tree-ring research in India. Many trees are recorded to have datable tree rings but only some of them have been used for climate reconstruction and other aspects, e.g., glacial fluctuation or palaeo-seismic dating. In future not only ring width which is widely used so far, but also other tree-ring parameters need to be analyzed for a better understanding of the regional climate and its linkage with other climatic phenomena in a global perspective.

Anumeha Shukla and R.C. Mehrotra

. 2 ) Description – Wood diffuse porous. Growth rings present, marked by zones of dark coloured denser fibres. Vessels small to large, tangential diameter range 66–267 μm, mean 133 μm, solitary (about 70%) and in radial multiples of 2–5 (about 30%), occasionally in tangential pairs or clusters

Robin Adey-Johnson, J. Paul Mclean, Jan Van den Bulcke, Joris Van Acker and Peter J. McDonald

preparation. A continuous radial position was assigned to each measurement based on its relative y -coordinate within the CT volume as the image y -axis is parallel to the radial direction of the specimen. Radial positions presented here are defined relative to the latewood boundary with the next annual

Bei Luo, Tomoya Imai, Junji Sugiyama, Sri Nugroho Marsoem, Tri Mulyaningsih and Takao Itoh

induced radial sieve elements (Sharma et al. 1980; Aloni & Barnett 1996). Recently, we found radial sieve tubes in the rays of the secondary xylem in Aquilaria malaccensis , A. sinensis , A. crasna and Gyrinops versteeghii (Thymelaeaceae, Malvales). The present study describes the occurrence and

Achim Bräuning, Maaike De Ridder, Nikolay Zafirov, Ignacio García-González, Dimitar Petrov Dimitrov and Holger Gärtner

Wood anatomical features may be visible on the microscopic as well as on the macroscopic scale. While the former can often be quantified by detailed wood anatomical analyses, the latter are often treated as qualitative features or as binary variables (present/absent). Macroscopic tree-ring features can be quantified in terms of frequency, intensity, or classified according to their position within a tree ring, like intra-annual density variations (IADFs) in conifers or frost rings in earlywood or latewood. Although some of these tree-ring features, like e.g. missing rings or IADFs are often seen as anomalies, hampering dendrochronologists to perform proper crossdating of tree-ring series, many of these properties are formed under extreme environmental stress or heavy impact, and could mark these extreme events by the manifestation in the wood anatomical structures throughout the lifespan of trees. The described tree-ring features form discrete time-series of extreme events. For example, flood rings may be marked by lunar-shaped earlywood vessels or enlarged latewood vessels in ring-porous oaks. White earlywood rings and light rings indicate reduced cell wall thickness and lignification occurring in very cold years. Frost rings result from cambial cell death during abrupt cooling events in the growing season. Missing rings and IADFs are mainly caused by drought events. Characteristic variations in earlywood vessel size, shape, or number in ring-porous oak species are markers for flood events, defoliation, heat stress, or drought. Traumatic resin ducts may be triggered by a range of biotic or environmental stressors, including wounding, fires or mechanical factors. Reaction wood is indicative of mechanical stress, often related to geomorphic events. In many cases anatomical responses are unspecific and may be caused by different stressors or extreme events. Additionally, the sensitivity of trees to form such features may vary between species, or between life stages within one species. We critically evaluate the indicative value of different wood anatomical tree-ring features for environmental reconstructions.

Oris Rodriguez-Reyes, Peter Gasson, Carolyn Thornton, Howard J. Falcon-Lang and Nathan A. Jud

et al. 2010 ), Malvaceae ( Rodriguez-Reyes et al. 2014 ), Chrysobalanaceae ( Jud et al. 2016 ), Calophyllaceae ( Nelson & Jud , in press), and Fabaceae (Rodriguez-Reyes et al., under review). In the present paper we describe a new fossil wood type from the Miocene of Panama, which further

Elisabeth A. Wheeler, Rashmi Srivastava, Steven R. Manchester and Pieter Baas

Associate-editor Michael Wiemann

was thought that the Deccan Traps were younger (Eocene) and so, not surprisingly, the woods were identified by their general similarity with present-day Indian woods. Almost all Deccan woods were assigned either extant generic names or fossil wood generic names formed by adding - oxylon to an extant

Volker Haag, Gerald Koch, Hans-Georg Richter, Robert Evans, José Antonio Silva Guzmán and Uwe Schmitt

Edited by Lloyd A. Donaldson

durability was determined according to both DIN EN 350 and ASTM D 2107-05 standards. For the present investigation juvenile and adult heartwood of 14 trees (2 trees per species, Table 1 ) were investigated using the methods described below. Table 1. Species investigated.* Light microscopy Transverse, radial

Ünal Akkemik, Nevriye Neslihan Acarca and Murat Hatipoglu

. 2009 ) and Juniperus ( Dernbach et al. 1996 ). More recently, Akkemik et al. (2016) described Cedrus, Juniperus, Pinus, Picea, Acer, Liquidambar , palmae, Quercus - Ilex type, Salix/Populus, and Ulmus from the Seben Fossil Forest. The purpose of this study is to present the

Diana K. Pérez-Lara, Carlos Castañeda-Posadas and Emilio Estrada-Ruiz

rays (Fig. 2H, J); mean tangential diameter of 56 (range = 44–80) μm, delimited by a layer of 1–2 epithelial cells (Fig. 2H), occasionally two or three canals per ray (Fig. 2 J). Prismatic crystals present in the erect or square ray cells (Fig. 2K, arrow). Figure 2. Bosquesoxylon chiapasense Pérez