Marginal Parenchyma Bands Research Articles

Tree-ring dating of the common trees in Wadi Allaqi Biosphere Reserve, South-East Egypt

Twenty-five increment cores and tree discs were sampled for four common trees in Wadi Allaqi, an extremely arid region in South-East Egypt (19 for Acacia tortilis subsp. raddiana (Savi) Brenan and 2 for each of Balanites aegyptiaca (L.) Delile, Acacia ehrenbergiana Hayne, and Tamarix nilotica (Ehrenb.) Bunge). The main aim of the current study is to achieve a longer temporal perspective on growth, longevity, and marginal parenchyma of the wood samples. The growth ring boundaries of the acacias are differentiated by thin parenchyma bands, which run around the entire stem discs. Samples of Acacia tortilis subsp. raddiana were located along this Wadi from its upstream to downstream parts; based on the mean distance between the bands of marginal parenchyma, longevity, based on the marginal parenchyma bands, indicated that Acacia tortilis subsp. raddiana grew slowly and some of its studied individuals reflected 2 age scenarios in the downstream part, while the measurement interval reflected an established date of around 1884 or 1886. Both scenarios grew fast over a long period of time, and so the chiefly recent growth was dated back to 1885. Approximate dates for the midstream part dated back to 1648, while the overall growth for the upstream part dated back to 1482. Samples of Balanites aegyptiaca may be established between 1608 and 1715, while those of Acacia ehrenbergiana may be established between 1945 and 1975. Tamarix nilotica swiftly established itself, and a new ecosystem replaced the severe arid habitat after the dropping of the water level in 1980s.Two scenarios of age are probably true for the downstream part, implying a date of establishment between 1884 and 1886. It was also discovered that the outdated scenario for B. aegyptiaca and A. ehrenbergiana is more in line with asymptotic value and current growth, indicating larger possibility for future expansion.

Wood anatomy, fire wounds and dendrochronological potential of Prosopis pugionata Burkart (Fabaceae) in arid Argentine Chaco

Abstract Prosopis pugionata (Fabaceae) is a halophyte tree species that grows exclusively in Argentina’s arid environments, whose woodlands are mainly affected by fires and overgrazing. Here, we describe the wood anatomy and fire wounds of P. pugionata and their relationship with plant size and bark thickness. Besides, we attempt to determine the potential of P. pugionata for dendrochronological studies in order to date fire events throughout time. We tested the hypothesis that P. pugionataforms datable fire wounds, allowing its use for dendrochronological studies. The study area is located in the arid Argentine Chaco region. Seventeen individuals, varying from 15 to 65 years of age, were randomly sampled and bole disks were taken at 0.3, 1.3 and 2.3 m high. P. pugionatais a diffuse and semi-ring-porous hardwood species with growth rings delimited by marginal parenchyma bands. The bark is longitudinally fissured, with an average thickness of 0.19 cm, and a scarce increase with age. Seventy-seven percent of the samples showed fire wounds (). We identified fire scars (70%) and marks (30%), and differentiated them by wood growth interruption in the former. Sixty-one percent of fire wounds affected less than 20% of the cambial perimeter and there were no significant effects of age, bole diameter, bole height and bark thickness on the cambial damage percentage. After cross-dating, P. pugionata showed a mean correlation value between series of 0.5, which represents an accurate potential for dendrochronological studies. Twenty wildfires were dated from 1943 to 2007 in the study area with a fire frequency of 0.40 fires/year and a mean fire interval of 2.5 years. Wildfires frequency increased from 1980 to 0.48 fires/year and a mean fire interval of 2 years. Our results indicate that P. pugionata has the potential to date fires, considering its potential for dendrochronological studies, its ability to survive recurrent fires and forms identifiable wound scars in the wood.

Growth ring formation of Dichrostachys cinerea and Senegalia mellifera in arid environments in Namibia

Dichrostachys cinerea and Senegalia mellifera trees are the most widespread invasive encroacher species in Namibia. Understanding their growth performance under arid conditions is key to understanding and managing the arid ecosystems of Namibia. To determine their utility in dendrochronology, we analyzed the formation of growth rings for two species from three sites in Namibia. We applied cross-dating techniques to 69 tree discs, the analysis of which confirmed the formation of annual growth rings. The rings are characterised by alternating layers of low and high vessel density and are separated by bands of marginal parenchyma. D. cinerea shows a well-defined pattern of growth rings, whereas the ring patterns of S. mellifera are more complex. Because aging trees tend to display narrower rings toward the outside of the stem, we applied both ring-width index and basal area increment methods in developing ring-width chronologies for the two species. Descriptive statistics for the chronologies indicate that the average ring chronologies are of good quality and that the trees are responding to common environmental signals. The basal area increment methodology produced better statistics than the ring-width index for these two species. Furthermore, statistical characteristics of the chronologies indicate that D. cinerea has a higher mean sensitivity (MS), expressed population signal (EPS), and signal-to-noise ratio (SNR) than S. mellifera. Thus, we find that both species are suitable for dendrochronological study, with D. cinerea being better than S. mellifera.

Wood anatomy of the rare species Dinizia jueirana-facao (Fabaceae), “Tabuleiros” Atlantic Forest, Brazil

We present the first wood anatomy description for the rare species Dinizia jueirana-facao G. P. Lewis & G. S. Siqueira, which grows in a megadiverse tropical forest subjected to rainfall seasonality, in SE Brazil. Growth rings are visible to the naked eye and demarcated by thin marginal parenchyma bands and, sometimes, by thick-walled fibers in the latewood. Axial paratracheal parenchyma is vasicentric to lozenge aliform with short confluences. Rays are 2–6-seriate, homocellular (procumbent cells) and non-storied. Vessels are visible to the naked eye, some irregular clusters, with diffuse distribution, sometimes filled with gums. Crystals are absent. Intercellular canals of traumatic origin are present. In general, wood anatomical characteristics of D. jueirana-facao agree with those previously reported for other Mimosoid species. As other cooccurring Fabaceae, the studied species has visible growth rings, but more conspicuous than reported for its sister species. Growth rings in D. jueirana-facao are likely triggered by the marked rainfall seasonality.

Dendrochronology and dendroclimatology of Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae) exposed to urban pollution in Rio de Janeiro city, Brazil

Nowadays, the biological monitoring through the growth rings has received increasing attention from ecologists and toxicologists. Structural analysis of these rings allows the incorporation of a time component in the study of plant responses to environmental variation. This allows also to evaluate long time series from the woody plants. In this paper, we assessed the dendrochronological characteristics of Ceiba speciosa growing in forest environment and under urbanization impact. Stem samples were obtained with Pressler probe into trees growing the campus of the Oswaldo Cruz Foundation, adjacent to one of the main urban thoroughfares of the city of Rio de Janeiro (Avenida Brasil), and at Tinguá Biological Reserve, an important remnant of Atlantic Forest. The samples were processed and analyzed following usual dendrochronological methods, with COFECHA and ARSTAN softwares. A negative exponential curve was used for standardization of the series. The residual chronologies were correlated with precipitation and temperature indexes obtained from NOAA weather database. Growth rings are distinct and annual, marked by bands of marginal parenchyma, thick-walled and radially flattened fibres in latewood and distended rays in earlywood. In both sites, the intercorrelation between the trees was above 0.40. Ages ranged from 11 to 41 years in the urban site and from 27 to 64 years in the forest site. In urban area, mean annual increment and cumulative average growth rates were 6 mm/year and 142.62 mm, respectively. At the forest site, these rates were 4 mm/year and 173.07 mm, respectively. The comparison between cumulative radial increment of the two sites revealed that trees of the urban site had higher increment rates beginning at the start of their development and consequently, they showed similar diameters despite lower ages. Correlation analysis between the chronologies and climatic factors revealed a positive association between growth and hot and rainy periods for both study sites. However, there is an immediate response of urban trees in relation to the rains and, a late response of forest trees to the same factor. The dry and hot climate, typical of urban environments, and the absence of natural water reserves in urban soil, may explain this more immediate response of urban tree growth to rainfall and temperature indexes. Our results revealed that Ceiba speciosa is a plastic and stress-tolerant species that is able to survive and adapt to polluted urban conditions. These features, along with its wide natural distribution and frequent planting for city landscaping, make this species an important biomarker for environmental monitoring studies.

Dendroecology of Macrolobium acaciifolium (Fabaceae) in Central Amazonian floodplain forests

ABSTRACT The forest dynamics in the Amazonian floodplains is strongly triggered by the flood pulse. Trees respond to unfavorable growth conditions during the flood period by cambial dormancy, which results in the formation of annual growth rings. We determined tree age and compared the mean annual rates of increase in the diameter of Macrolobium acaciifolium with hydrological and climatic factors in three regions of central Amazonian floodplain forest. A wood sample was obtained from each tree using an increment borer. Ring growth was assessed by marginal parenchyma bands to determine tree age and the mean diameter increment. Ring widths were indexed to construct cross-dating chronologies and correlated with climatic and hydrological variables. The analyses demonstrate that the mean annual diameter increment did not differ between the three study sites. The chronologies correlated significantly with the terrestrial phase. There was no significant difference in the ring-width index between El Niño years and other years, and between La Niña and other years. These results show that the hydrological variables can be considered crucial to the rates of tree growth and diameter increment in floodplains, and El Niño signals were not detected in the tree-ring chronologies.

Wood anatomy and growth ring boundaries of Copaifera lucens (Fabaceae)

ABSTRACT The wood anatomy of Copaifera lucens Dwyer was studied with an emphasis on its growth ring boundaries. Growth rings are visible to the naked eye and demarcated by marginal parenchyma bands and, sometimes, by thick-walled fibers in the latewood. Secretory canals are associated with marginal parenchyma bands, but not all marginal parenchyma bands are associated with canals. Paratracheal parenchyma is vasicentric to lozenge-aliform. Rays are 1–4-seriate, heterocellular and non-storied. Vessels are visible to the naked eye, diffuse, predominantly solitary, some in multiples, sometimes filled with gums. Crystals present. Wood anatomical characteristics of C. lucens are in agreement with those previously reported for other species of Copaifera. In addition to what had already been described for C. lucens, we observed gelatinous fibers, and some bifurcate fibers, and extremely rare clustered vessels. The growth ring boundaries are well-defined in mature wood but less distinctive near the pith. There are also partial and confluent (wedging) rings, which are difficult to classify by anatomy only, but which represent false rings and complicate tree-ring analysis in this species.

Tree Growth Rings in Tropical Peat Swamp Forests of Kalimantan, Indonesia

Tree growth rings are signs of the seasonality of tree growth and indicate how tree productivity relates to environmental factors. We studied the periodicity of tree growth ring formation in seasonally inundated peatlands of Central Kalimantan (southern Borneo), Indonesia. We collected samples from 47 individuals encompassing 27 tree species. About 40% of these species form distinct growth zones, 30% form indistinct ones, and the others were classified as in between. Radiocarbon age datings of single distinct growth zones (or “rings”) of two species showing very distinct rings, Horsfieldia crassifolia and Diospyros evena, confirm annual growth periodicity for the former; the latter forms rings in intervals of more than one year. The differences can be explained with species-specific sensitivity to the variable intensity of dry periods. The anatomical feature behind annual rings in Horsfieldia is the formation of marginal parenchyma bands. Tree ring curves of other investigated species with the same anatomical feature from the site show a good congruence with the curves from H. crassifolia. They can therefore be used as indicator species for growth rate estimations in environments with weak seasonality. The investigated peatland species show low annual growth increments compared to other tropical forests.

DENDROCRONOLOGIA DE ÁRVORES DE Schizolobium parahyba(Vell.) S. F. Blake DE OCORRÊNCIA NA REBIO DE TINGUÁ-RJ

O Schizolobium parahyba (Vell.) Blake, popularmente conhecido por “guapuruvu”, apresenta anéis de crescimento distintos, evidenciados por maior espessamento de suas paredes no lenho tardio e pela presença de parênquima em faixa marginal. Neste contexto, o objetivo deste estudo foi construir a cronologia dos anéis de crescimento de árvores de S. parahyba de ocorrência na ReBio de Tinguá, RJ, visando gerar conhecimento sobre a dinâmica de crescimento da espécie, bem como sobre a sensibilidade da formação dos anéis de crescimento por fatores climáticos. Das 30 árvores selecionadas foram coletadas quatro amostras radiais do tronco, utilizando-se uma sonda Pressler. As amostras passaram por polimento mecânico para melhor visualização dos anéis de crescimento e posterior delimitação e mensuração da largura deles. Para verificar a sincronização da largura dos anéis de crescimento e gerar uma série mestra da cronologia para a espécie, foi utilizado o programa estatístico COFECHA. A espécie apresenta ótimo potencial dendrocronológico, confirmado por elevada correlação da largura dos anéis de crescimento dentre e entre árvores. Além disso, exibe elevado coeficiente de sensibilidade média, que demonstra resposta às variações ambientais. O crescimento da espécie é correlacionado com a precipitação na estação seca.

Developmental and structural features of secretory canals in root and shoot wood of Copaifera langsdorffii Desf. (Leguminosae–Caesalpinioideae)

Copaifera langsdorffii Desf., popularly known as copaiba, is an oleoresin-producing tree has been overexploited in Brazil by the pharmaceutical, cosmetic and varnish industries. Despite the long history of the use of this species, the structural knowledge on the resin-producing sites remains inadequate and is limited to the trunk. The aim of this study was to describe the origin, structure and developmental features of secretory spaces present in shoot and root wood of C. langsdorffii, based on the usual techniques of wood anatomy studies. Both root and shoot wood present secretory canals distributed along the marginal parenchyma bands which delimit growth layers. Secretory canals are constituted by a locally biseriate epithelium and lume that contains terpenes. They are arisen in the cambial zone from fusiform cambial initial cells and, eventually, ray initials. The origin of lumen is schizogenous. The epithelial cells have meristematic potential and are responsible for the locally biseriate epithelium. Mature secretory canals are wider and are separated between themselves only by a row of radial cells. The fusion of these adjacent secretory canals is frequent and results from the radial cell collapse. The finding of an interconnected system of resin canals in C. langsdorffii might be of value in terms of sustainable extraction of the resin and realistically assess its sustainable harvest potential.

Age determination of Acacia erioloba trees in the Kalahari

High quality wood core samples were collected from individual Acacia erioloba trees of unknown age in the Kgalagadi Transfrontier Park. In the majority of samples examined, seasonal changes were reflected in the wood anatomy as bands of marginal parenchyma on the polished surfaces of discs or cores. Estimated radiocarbon age was determined by means of 14C analysis for all samples. There was a strong correlation between the annual growth ring count and estimated radiocarbon age. A correlation was also found between age and stem circumference. Age structure of several A. erioloba populations in the Kgalagadi Transfrontier Park was subsequently determined. It could be demonstrated that the populations growing in the bed of the Nossob River showed poor recruitment; however, no clear relationship was found between flooding and regeneration of A. erioloba in the riverbed. The population growing in the dune field had a healthy age structure.

Annual tree rings revealed by radiocarbon dating in seasonally flooded forest of the Mapire River, a tributary of the lower Orinoco River, Venezuela

The occurrence of seasonal growth rings in the wood of Campsiandra laurifolia, Acosmiun nitens, Pouteria orinocoensis and Psidium ovatifolium, common species growing in the flooding forest of the Mapire river, was analyzed using wood anatomy and ring- width analysis. The test of the annual ring formation was performed using radiocarbon analysis based on the nuclear weapon effect. All species showed growth rings visible to the naked eye. The ring boundaries in all cases were marked by bands of marginal parenchyma. The index ring-width curves of the four studied species showed a strong relationship with the fluctuation of the water river level during the non flooded months, suggesting that an increase in the water level during these months positively influenced the growth indicating that the rings were formed on an annual basis. The content of radiocarbon in the wood of anatomically predated rings of Campsiandra laurifolia and Pouteria orinocoensis confirm these results. All studied trees are slow growing with less than 2.5 mm annual increment.

ANATOMICAL FEATURES OF GROWTH RINGS IN FLOOD-PRONE TREES OF THE ATLANTIC RAIN FOREST IN RIO DE JANEIRO, BRAZIL

The anatomical features of growth rings of 13 representative species of the swamp forests within the Atlantic rain forest of the State of Rio de Janeiro, southeastern Brazil, were studied. Most species showed distinct rings. The growth ring boundaries were marked by fibrous zones frequently associated with marginal parenchyma bands, and growth ring boundary features were characteristic of the particular families and genera analysed. Leaf fall can be related to the occurrence of growth rings in seven species, whereas in evergreen species growth rings can be related to flooding. In Euphorbiaceae species, flooding regime differences (periodical or permanent) are related to the shape and distribution of new cells produced by the cambium and, thus, growth ring structure.

Wood production in a natural stand of Acacia karroo in Zimbabwe

Trees are important components of agricultural systems in the dry tropics of Africa. The assumption that exotic species are more productive than the indigenous woodland in these situations is seldom supported by quantitative data. In this study a new technique of recognising annual growth rings from the bands of marginal parenchyma has been used to model growth in a natural population of Acacia karroo Hayne, one of the most widespread and useful trees in the savanna woodlands of southern Africa. The study showed both basal area and sectional area at ankle height to be excellent predictors of total tree volume. Stands may yield from about 1 to 4 m 3 ha −1 year −1 dependent upon spacing and site; individual trees produced up to 1 m 3 of wood in 26 years. Maximum current annual increment was reached about 12 years after the trees approached breast height, thereafter declining until they became moribund about 8 years later. The economic rotation for wood production was close to the lifespan of the tree.

Growth ring characteristics of some AfricanAcaciaspecies

ABSTRACTThe age of most temperate tree species can be estimated accurately by counting the annual rings revealed by concentric changes in their wood anatomy. In the tropics and sub-tropics, this growth periodicity is seldom clearly and unambiguously defined. This research investigates whether a wood anatomical feature is present that delimits annual periods in one of the most widely distributed genera in the semi-arid and arid areas of Africa,Acacia.Most research on this topic has been based on sample trees from natural stands, often the largest and putatively oldest trees. In contrast, the trees sampled for this study were actively sought from material of known age, particularly those for which the history of management was known. Several AfricanAcaciaspecies were examined for growth rings. These were apparent in most species as narrow bands of marginal parenchyma filled with long crystal chains. The crystals were sub-sequendy identified as calcium oxalate through the use of a scanning proton microprobe. The number of bands formed annually corresponded to the number of peaks in the annual rainfall distribution. Ring widths were highly correlated with total annual rainfall.

Calcium Oxalate Crystals in African Acacia Species and Them Analysis by Scanning Proton Microprobe (Spm)

The radial and cross sections of wood samples from individual trees of known age of African Acacia species were examined for growth rings. These were apparent in most species as narrow bands of marginal parenchyma filled with long crystal chains. The crystals were subsequently identified as calcium oxalate through the use of a scanning proton microprobe. Several other chemical elements were concentrated around this zone. The number of parenchyma bands formed annually corresponded to the number of peaks in the annual rainfall distribution. These results suggest that the presence of marginal parenchyma bands and crystalliferous chains define growth phases in African Acacia species, and can be used for age determination.

Marginal Parenchyma Bands and Crystalliferous Chains as Indicators of Age in African Acacia Species

The radial cross sections of wood samples from individuals of known age in six African Acacia species were examined for growth rings, which were apparent in most species as narrow bands of marginal parenchyma filled with long crystal chains. The number of bands formed annually corresponded to the number of peaks in rainfall distribution. Samples from specimens of African Acacia species from the Oxford Forestry Institute's xylarium (FHOw) were also examined for similar crystalliferous chains, which were generally present. These results suggest that marginal parenchyma bands and crystalliferous chains define growth phases in African Acacia species, and may therefore be useful for age determination.