scholarly journals Estructura y composición de la vegetación ribereña de la barranca del río Tembembe, Morelos, México

2017 ◽  
pp. 17
Author(s):  
Fernando Camacho-Rico ◽  
Irma Trejo ◽  
Consuelo Bonfil
Keyword(s):  
Riparian Vegetation ◽  
Basal Area ◽  
Ecological Information ◽  
The Third ◽  
Breast Height ◽  
Crown Cover ◽  
Tree Layer ◽  
Alnus Acuminata ◽  
Trema Micrantha ◽  
Del Rio

Structure and composition of the riparian vegetation of the middle-upper basin of the Tembembe river, in the state of Morelos, was analyzed. Height, diameter at breast height, crown area and taxonomic identity of each individual having a DBH 1 cm were recorded in 23 quadrats of 100 m2 each. A total of 74 species and 516 individuals were found. Mean density was 2,148 ind. ha-1, mean basal area was 88.39 m2 ha-1, and mean height (of individuals with DBH 20 cm) w as 10.5 m. Classification analysis allowed the discrimination of three communities whose distribution was associated to the altitudinal gradient: the first (G1) in the upper part (1,700 - 1,650 m a.s.l.) was dominated by species (like Alnus acuminata) having a holartic affinity; the second (G2) at an  intermediate altitude (1,640 - 1,340 m a.s.l.) was dominated by Trema micrantha; and the third (G3) in the lower portion (1,210 - 1,110 m a.s.l.) dominated by species (like Daphnopsis salicifolia) having a tropical affinity. Diversity, density and crown cover did not differ among them, but mean basal area was largest in the highest and lowest communities than in the intermediate one. Mean height of the tree layer decreased with altitude. This study contributes to the knowledge of the riparian vegetation in Morelos state and provides basic ecological information for future restoration programs of the riparian vegetation of the Tembembe river

Phenotypic selection in Betulapapyrifera

1983 ◽  
Vol 13 (6) ◽  
pp. 1159-1173 ◽  
Author(s):  
Brian J. Stanton ◽  
David S. Canavera
Keyword(s):  
Basal Area ◽  
Phenotypic Selection ◽  
Height Growth ◽  
Basal Area Increment ◽  
Selection Methods ◽  
The Third ◽  
Greenhouse Trial ◽  
Breast Height ◽  
Independent Variable ◽  
And Control

Phenotypically superior trees of Betulapapyrifera Marsh, were identified on the basis of their breast height stem diameters in two even-aged stands in western Maine. The growth superiority of each of the candidate trees was evaluated further using one of three different selection methods. Two methods were based on mean annual volume increment and differed in regard to their use of comparison trees. Selected trees were those which grew the most volume throughout the life of the stand. In the third procedure, periodic basal area increment was compared with the estimated basal area increment using an equation incorporating crown surface area as an independent variable. Trees rated as most superior were those which produced the largest increment in relation to crown size. Open-pollinated progenies of selected and control trees were evaluated for height growth and stem diameter in a greenhouse trial. Although significant differences in height existed among the selection methods, no one method was successful in identifying trees whose progenies, as a group, were significantly taller than the average of the control progenies.

scholarly journals Un paisaje sacralizado por grabados rupestres protohistóricos e históricos en las hoces del río Mesa (Calmarza, Zaragoza) = A Sacralized Landscape by Protohistoric and Historical Rock Engravings in the Gorges of the River Mesa (Calmarza, Zaragoza)

2020 ◽  
pp. 105
Author(s):  
José Ignacio Royo Guillén ◽  
Francisco José Navarro Cabeza ◽  
Serafín Benedí Monge
Keyword(s):  
19Th Century ◽  
Iron Age ◽  
Rock Art ◽  
Archaeological Remains ◽  
The Third ◽  
Christian Iconography ◽  
Siglo Xix ◽  
Del Rio ◽  
The 19Th Century

Los estudios sobre grabados rupestres al aire libre de cronología postpaleolítica, adolecen de importantes carencias que, en el valle medio del Ebro, se han visto superadas con la llegada del tercer milenio. Con la presentación de este trabajo se pretende dar a conocer un nuevo núcleo de grabados rupestres, localizado en el extremo suroeste de la provincia de Zaragoza, en las gargantas calcáreas del río Mesa. Entre los nuevos enclaves rupestres, destacan los abrigos con grabados protohistóricos, pero muy especialmente los de cronología medieval andalusí y los de iconografía cristiana entre los siglos XIV y XVIII, con perduraciones hasta mediados del siglo XIX y algunas escenas relacionadas con la primera Guerra Carlista en Aragón. La distribución de los hallazgos, su tipología e iconografía y los restos arqueológicos asociados, permiten documentar una importante ocupación del territorio desde la Iª Edad del Hierro y la sacralización del paisaje a través del arte rupestre, con pervivencias que se perpetúan a lo largo de la Edad Media y Moderna, destacando como novedad la presencia de un importante conjunto de inscripciones epigráficas islámicas que deben situarse entre los siglos XI y XII. AbstractThe studies on open-air rock engravings in post-Paleolithic chronology suffer from important deficiencies, which in the middle valley of the Ebro, have been overcome with the arrival of the third millennium.With the presentation of this work, the aim is to make known a new nucleus of rock engravings, located in the extreme southwest of the province of Zaragoza, in the limestone gorges of the River Mesa. Among the new rock engravings, the shelters with protohistoric engravings stand out, but especially those with a medieval Andalusian chronology and those with Christian iconography between the 14th and 18th centuries, which lasted until the middle of the 19th century and some scenes related to the first Carlist War in Aragon. The distribution of the findings, their typology and iconography and the associated archaeological remains, allow us to document an important occupation of the territory since the First Iron Age and the sacralization of the landscape through rock art, with survivals that are perpetuated throughout the Middle and Modern Ages, highlighting as a novelty the presence of an important set of Islamic epigraphic inscriptions that must be located between the 11th and 12th centuries.

scholarly journals Regeneration Status and Importance of Hyphaene thebaica L. (Doum Palm) and Associated Species in Tekeze Riverine Vegetation of the North Western Zone of Tigray, Northern Ethiopia

2020 ◽  
pp. 1-8
Author(s):  
Kiros Abay ◽  
Kahsu Gebretsion
Keyword(s):  
Riparian Vegetation ◽  
Ricinus Communis ◽  
Basal Area ◽  
Northern Ethiopia ◽  
The North ◽  
Regeneration Status ◽  
Western Zone ◽  
Riverine Vegetation ◽  
Associated Species ◽  
North Western

Aims: The aim of the study was to investigate the regeneration status and importance of Hypahene thebaica L. and associated species in Tekeze riparian vegetation of the North western zone of Tigray, Northern Ethiopia.  Study Design: Systematic sampling technique. Place and Duration of Study: The study was carried out along Tekeze riverine vegetation, northern Ethiopia between January 2015 and March 2015. Methodology: Three transects (one and two transects on the right and left side of the Tekeze River, respectively) were laid. The distance between the two transects on the left side of the river was 200 m. Along the transects, 30 plots were established systematically at intervals of 100 m to collect vegetation data. Results:  Eighteen plant species belonging to 12 families were recorded. Fabaceae was found to be the dominant family in the study area and were represented by five species, which contributed to 27.7% of the total species documented, whereas nine families were represented by one species each. The overall density of the study area was 70.97 individuals/ha. Hyphaene thebaica was the second abundant species with 16.13 individuals/ha, and contributed 22.7% to the total density of the riparian vegetation. The total basal area of plants was 1.03 m2 ha-1. Hyphaene thebaica was ranked third and accounts for 12.6% of the total basal area with 0.13 m2 ha-1. The species was the most frequent with 17.02%, followed by Ricinus communis and Balanites aegyptiaca. Balanites aegyptiaca (53.52%), H. thebaica (52.37%) and Ricinus communis (51.76%) were the three most important species. Conclusion: More mature trees were documented than saplings and seedlings, indicating “poor’’ regeneration status for the riparian vegetation. Hyphaene thebaica has shown “fair’’, while most species were found to have “poorly’’ or “no’’ regenerating. Hence a sound management plan is urgently required to sustainably utilize and conserve the riverine vegetation. 

scholarly journals Morphological plasticity of Ilex theezans Mart. ex Reissek (Aquifoliaceae) in two restinga vegetation of Santa Catarina coastal plain

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Izabel da Silva Liberato ◽  
João Carlos Ferreira Melo Junior
Keyword(s):  
Coastal Plain ◽  
Morphological Plasticity ◽  
The Third ◽  
Breast Height ◽  
Soil Variables ◽  
Functional Attributes ◽  
Plastic Potential ◽  
Heterogeneous Formations ◽  
The City ◽  
Diverse Plant

The restinga, an environment of the rain Forest, is an ecosystem by the seacoast composed of diverse plant communities commonly found in sandy and undeveloped soils. This study aims to investigate possible intraspecific differences in Ilex theezans species, whose distributionin restinga includes two heterogeneous formations, shrub-tree restinga and transition forest. The study focused on a restinga remnant area located in Acaraí State Park, in the city of São Francisco do Sul (SC, Brazil). In each environment, five adult individuals were selected andhad wood samples collected from their stems at breast height and 25 leaves of the third and fourth nodes of the outer canopy branches sampled. Chemical and physical soil variables were analyzed for each formation. The results show that there are significant differencesbetween the leaf and the stem functional attributes and soil data analyzed, but as the PPI (Phenotypic Plasticity Index), the species Ilex theezans in the studied formations present low plastic potential.

scholarly journals EFICIÊNCIA DE DUAS VARIAÇÕES ESTRUTURAIS DO MÉTODO DE AMOSTRAGEM DE ÁREA FIXA EM PLANTAÇÕES DE Pinus taeda

FLORESTA ◽  
2013 ◽  
Vol 43 (4) ◽  
pp. 621
Author(s):  
João Paulo Druszcz ◽  
Nelson Yoshihiro Nakajima ◽  
Sylvio Pellico Netto ◽  
Sebastião do Amaral Machado ◽  
Nelson Carlos Rosot ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Relative Efficiency ◽  
Block Design ◽  
Basal Area ◽  
Average Diameter ◽  
Breast Height ◽  
Variable Diameter ◽  
Randomized Block Design ◽  
Fixed Area ◽  
Pinus Taeda L

Este estudo foi conduzido em três diferentes condições de plantações de Pinus taeda L., sem desbastes, com 10, 9 e 7 anos de idade, 2.000 árvores por hectare e diferentes inclinações no terreno, localizados no Estado do Paraná. O objetivo foi avaliar a eficiência do inventário florestal, utilizando-se a amostragem de área fixa com a estrutura de parcela circular (PC) e conglomerado em cruz (CC), através da análise do comportamento quanto às precisões e eficiências relativas nas estimativas das seguintes variáveis: diâmetro médio (cm), número de árvores por ha, área basal (m2/ha) e volume total (m3/ha). Para isso, utilizou-se o delineamento em blocos casualizados com 40 unidades amostrais para a PC e 10 unidades para o CC, sendo este composto por 4 subunidades circulares. Concluiu-se que, para as variáveis diâmetro médio (cm), número de árvores (N/ha), área basal (m2/ha) e volume total (m3/ha), indica-se a utilização do método de área fixa com PC, tendo em vista a maior eficiência no levantamento dessas variáveis.Palavras-chave: Eficiência relativa; precisão; reflorestamento. AbstractStructural efficiency of two variations of method of sampling of fixed area in plantations of Pinus taeda. This study was carried out in three different stands of Pinus taeda L., unthinned and aged 10, 9 and 7 years. The stands have 2.000 trees per hectare and are located in Parana State. The aim was to evaluate the efficiency of inventories using circular plot (PC) and cross cluster (CC) by analyses of behavior towards accuracies and relative efficiencies for estimation of the following variables: average diameter at breast height, number of trees, basal area and total volume per hectare. For this study, it was taken a sample of 40 units to the PC structure and 10 units for the CC structure, which is composed of four circular subunits, and it was used the randomized block design. It was concluded that for the variable diameter (cm), number of trees (ha), basal area (m2/ha) and total volume (m3/ha) it is indicated the use of PC, since its greater efficiency in the survey of these variables.Keywords: Relative efficiency; accuracy; reforestation.

Clonal variation in basal area growth patterns during stand development in hybrid poplar

2001 ◽  
Vol 31 (12) ◽  
pp. 2059-2066 ◽  
Author(s):  
Brian J Stanton
Keyword(s):  
Hybrid Poplar ◽  
Basal Area ◽  
Growth Patterns ◽  
Repeated Measurements ◽  
Clonal Variation ◽  
Stand Development ◽  
The Third ◽  
Short Rotation ◽  
Periodic Growth ◽  
Response Variation

Two-year periodic basal area increments (PBAI) of short-rotation Populus stands were followed through a 6-year rotation in monoclonal plots at three sites to assess variation in response patterns among 20 Populus trichocarpa Torr. & Gray × Populus deltoides Bartr. clones. Data were analyzed using a split-plot model for repeated measurements with the main effect of time and the time × clone interaction partitioned into their linear and quadratic orthogonal components. The form of the mean clone growth response was mainly quadratic with PBAI culminating during the second period at 145–160% of the rotation mean. Increments fell to 95–116% of the rotation mean during the following period. Response variation occurred mainly in the degree of linearity at two sites with clones varying in the rate of growth deceleration during the third period, while quadratic response variation was of prime importance at the third site. Changes in basal area levels among the topmost clones over the last stage of stand development were associated with the divergence in the linear and quadratic responses. Selection on the basis of interaction contrasts of periodic growth from monoclonal plot trials is discussed in terms of sustaining yield improvements and maintaining adaptation to short rotation strategies.

Response of Nine-Year-Old Plantation Sweetgum to Nitrogen Fertilization in Mississippi

1992 ◽  
Vol 16 (3) ◽  
pp. 146-150
Author(s):  
L. E. Nelson ◽  
G. L. Switzer
Keyword(s):  
Nitrogen Fertilization ◽  
Basal Area ◽  
Woody Biomass ◽  
Growing Season ◽  
Maximum Growth ◽  
Liquidambar Styraciflua ◽  
Stem Volume ◽  
Breast Height ◽  
Seed Sources ◽  
N Rates

Abstract Nine-year-old planted sweetgum (Liquidambar styraciflua L.) consisting of four half-sib seed sources were refertilized with nitrogen in 1981 at the beginning of the tenth field-growing season. Increases in periodic annual height, diameter at breast height, basal area, stem volume (ob),and woody biomass increments of all four half-sib seed sources from applied nitrogen were observed during the 9 years following application. Periodic annual stem volume (ob) increments averaged over all half-sib seed sources were 120, 152, 192, and 266 ft³/ac/yr for the 0, 89, 178, and356 lb/ac N rates, respectively. The half-sib seed sources from alluvial sites were superior to those from upland sites in terms of productivity and response to N. The response of all half-sibs to N was immediate, occurring during the year of application; however, the increased growth ratesdue to N persisted for only 3 years. This suggests that on responsive sites, applications of N may be necessary every fourth year to maintain maximum growth rates. South. J. Appl. For. 16(3):146-150.

Growth Response to Fertilization in Young Douglas-Fir Stands

1989 ◽  
Vol 4 (4) ◽  
pp. 116-119 ◽  
Author(s):  
Linda S. Heath ◽  
H. N. Chappell
Keyword(s):  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Volume Growth ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Intermediate Region ◽  
Fertilizer Response ◽  
Breast Height ◽  
Inverse Effect

Abstract Response surface methodology was used to estimate six-year volume growth response to 1 application of 200 lb nitrogen per acre in unthinned and thinned Douglas-fir (Pseudotsuga menziesii) stands of breast height age (bha) 25 years or less. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as basal area increased in both unthinned and thinned stands. Response varied little over site index in regions of low basal area, decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high basal area region. West. J. Appl. For. 4(4):116-119, October 1989.

Effect of midrotation fertilization on growth and specific gravity of loblolly pine

2009 ◽  
Vol 39 (5) ◽  
pp. 928-935 ◽  
Author(s):  
Finto Antony ◽  
Lewis Jordan ◽  
Richard F. Daniels ◽  
Laurence R. Schimleck ◽  
Alexander Clark ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Loblolly Pine ◽  
Block Design ◽  
Wood Property ◽  
Basal Area ◽  
Wood Properties ◽  
Fertilization Rate ◽  
Breast Height ◽  
Four Levels ◽  
Property Changes

Wood properties and growth were measured on breast-height cores and on disks collected at different heights from a thinned and fertilized midrotation loblolly pine ( Pinus taeda L.) plantation in the lower Coastal Plain of North Carolina. The study was laid out in a randomized complete-block design receiving four levels of nitrogen (N) fertilizer: unfertilized control and 112, 224, and 336 kg/ha plus 28 kg/ha of phosphorus with each treatment. The effect of fertilization was analyzed for the whole-disk and for a 4 year average following fertilization on data collected from breast-height cores and from disks. The fertilization treatments did not significantly affect whole-disk wood properties but significantly increased radial growth. Fertilization rate of 336 kg/ha N significantly reduced 4 year average ring specific gravity and latewood specific gravity. Wood properties of trees that received 112 and 224 kg/ha N were not affected following treatment. There was no height related trend in wood property changes due to fertilization. Fertilization significantly increased ring basal area and earlywood basal area. In summary, there was a decline in wood properties and an increase in basal area growth immediately after fertilization; both depended on the rate of fertilizer applied irrespective of height.

scholarly journals Twentieth-century shifts in forest structure in California: Denser forests, smaller trees, and increased dominance of oaks

2015 ◽  
Vol 112 (5) ◽  
pp. 1458-1463 ◽  
Author(s):  
Patrick J. McIntyre ◽  
James H. Thorne ◽  
Christopher R. Dolanc ◽  
Alan L. Flint ◽  
Lorraine E. Flint ◽  
...  
Keyword(s):  
Forest Structure ◽  
Forest Biomass ◽  
Basal Area ◽  
Hydrologic Model ◽  
Forest Composition ◽  
Demographic Shift ◽  
Small Tree ◽  
Breast Height ◽  
Large Tree ◽  
Climatic Water Deficit

We document changes in forest structure between historical (1930s) and contemporary (2000s) surveys of California vegetation through comparisons of tree abundance and size across the state and within several ecoregions. Across California, tree density in forested regions increased by 30% between the two time periods, whereas forest biomass in the same regions declined, as indicated by a 19% reduction in basal area. These changes reflect a demographic shift in forest structure: larger trees (>61 cm diameter at breast height) have declined, whereas smaller trees (<30 cm) have increased. Large tree declines were found in all surveyed regions of California, whereas small tree increases were found in every region except the south and central coast. Large tree declines were more severe in areas experiencing greater increases in climatic water deficit since the 1930s, based on a hydrologic model of water balance for historical climates through the 20th century. Forest composition in California in the last century has also shifted toward increased dominance by oaks relative to pines, a pattern consistent with warming and increased water stress, and also with paleohistoric shifts in vegetation in California over the last 150,000 y.

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