Sampling Unit, Spatial Distribution of Trees, and Precision

1992 ◽  
Vol 9 (1) ◽  
pp. 3-6 ◽  
Author(s):  
Robin M. Reich ◽  
Loukas G. Arvanitis
Keyword(s):  
Spatial Distribution ◽  
Sample Size ◽  
Spatial Patterns ◽  
Basal Area ◽  
Sampling Unit ◽  
Sample Variance ◽  
Plot Size ◽  
Plot Area ◽  
The Relationship

Abstract The relationship between plot size and sample variance as affected by the spatial patterns of trees, volume, and basal area is reported. This information is useful for practicing foresters in determining the best combination of sample size, plot area, or basal area factor in forest surveys. North. J. Appl. For. 9(1):3-6.

The effect of spatially variable overstory on the understory light environment of an open-canopied longleaf pine forest

2002 ◽  
Vol 32 (11) ◽  
pp. 1984-1991 ◽  
Author(s):  
Michael A Battaglia ◽  
Pu Mou ◽  
Brian Palik ◽  
Robert J Mitchell
Keyword(s):  
Spatial Variation ◽  
Spatial Patterns ◽  
Longleaf Pine ◽  
Light Availability ◽  
Canopy Structure ◽  
Basal Area ◽  
Pinus Palustris ◽  
Pine Forest ◽  
Large Group ◽  
The Relationship

Spatial aggregation of forest structure strongly regulates understory light and its spatial variation in longleaf pine (Pinus palustris Mill.) forest ecosystems. Previous studies have demonstrated that light availability strongly influences longleaf pine seedling growth. In this study, the relationship between spatial structure of a longleaf pine forest and spatial pattern of understory light availability were investigated by comparing three retention harvest treatments: single-tree, small-group, large-group, and an uncut control. The harvests retained similar residual basal area but the spatial patterns of the residual trees differed. Hemispherical photographs were taken at 300 stations to calculate gap light index (GLI), an estimate of understory light availability. Stand-level mean, variation, and spatial distribution of GLI were determined for each treatment. By aggregating residual trees, stand mean GLI increased by 20%, as well as its spatial variation. Spatial autocorrelation of GLI increased as the size of the canopy gaps increased and the gaps were better defined; thus, the predictability of GLI was enhanced. The ranges of detrended semivariograms were increased from the control to the large-group harvest indicating the spatial patterns of understory GLI became coarser textured. Our results demonstrated that aggregated canopy structure of longleaf pine forest will facilitate longleaf pine seedling regeneration.

scholarly journals INFLUÊNCIA DO TAMANHO DE PARCELA NO CÁLCULO DA DISTRIBUIÇÃO ESPACIAL DE Anadenanthera peregrina (L.) Speng. E Apuleia leiocarpa J. F. Macbr EM UMA FLORESTA ESTACIONAL SEMIDECIDUAL

Nativa ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 183
Author(s):  
Aguida Beatriz Travaglia Viana ◽  
Carlos Moreira Miquelino Eleto Torres ◽  
Liniker Fernandes da Silva ◽  
Samuel José Silva Soares da Rocha
Keyword(s):  
Spatial Distribution ◽  
Spatial Analysis ◽  
Distribution Pattern ◽  
Unit Size ◽  
Plot Size ◽  
Distribution Calculation ◽  
Plot Area ◽  
Real Value ◽  
Semideciduous Seasonal Forest ◽  
Morisita Index

Objetivou-se com este estudo avaliar o comportamento dos índices de distribuição espacial das espécies Anadenanthera peregrina e Apuleia leiocarpa, em diferentes tamanhos de parcelas. Realizou-se um censo na Mata da Silvicultura, localizada em Viçosa, M.G. por meio do qual todos indivíduos das duas espécies, com DAP ≥ 20 cm, foram medidos e georreferenciados. Os dados foram agrupados em unidades amostrais de (10x10) m², (10x30) m², (10x50) m², (20x10) m², (20x30) m² e (20x50) m². O padrão de distribuição espacial das espécies foi identificado por meio dos índices de Payandeh (Pi), MacGuinnes (IGAi), Fracker e Brischle (Ki) e Morisita (IMi). Posteriormente, para cada tamanho de unidade amostral, selecionou-se aleatoriamente 10% do número total de parcelas e os índices foram calculados. Foram realizadas 10 repetições desse procedimento e a análise da distribuição espacial foi feita com base na média dos valores encontrados. O IGAi, Pi, e Ki foram diretamente proporcionais a área das parcelas e o IMi, inversamente proporcional. O IGAi apresentou as menores diferenças entre as médias das amostragens e os valores reais aferidos pelo censo. Diante disso, o IGAi foi o índice mais adequado para se estudar a distribuição espacial das espécies.Palavra-chave: análise espacial de árvores, índice de Morisita, agregação. PLOT SIZE INFLUENCE IN THE SPATIAL DISTRIBUTION CALCULATION OF Anadenanthera peregrina (L.) Speng. AND Apuleia leiocarpa J. F. Macbr IN SEMIDECIDUOUS  SEASONAL FOREST ABSTRACT:The objective of this study was to evaluate the behavior of spatial distribution indexes of the species Anadenanthera peregrina and Apuleia leiocarpa, in different plot sizes. A forest census was carried out in the Mata da Silvicultura, located in Viçosa, M.G. through which all individuals of both species, with DBH ≥ 20 cm, were measured and georeferenced. The data were grouped into sampling units of (10x10) m², (10x30) m², (20x10) m², (20x10) m² and (20x50) m². The spatial distribution pattern of the species was identified through the Payandeh (Pi), MacGuinnes (IGAi), Fracker and Brischle (Ki) and Morisita (IMi) indexes. Subsequently, for each sampling unit size, 10% of the total number of plots were randomly selected and the indexes were calculated. Ten replicates of this procedure were perfomed and the spatial analysis was done based on the average of the values found. The IGAi, Pi, and Ki were directly proportional to the plot area and the IMi, inversely proportional. The IGAi presented the smallest differences between the sampling means and the real value measured by the census. Noted that, it was clear that the IGAi was the most adequate index to study a spatial distribution of the species.Keywords: tree spatial analysis, Morisita Index, aggregation. DOI:

Observations on Spatial Distribution and the Relative Precision of Systematic Sampling

1971 ◽  
Vol 1 (4) ◽  
pp. 216-222 ◽  
Author(s):  
Bijan Payandeh ◽  
Alan R. Ek
Keyword(s):  
Spatial Distribution ◽  
Frequency Estimation ◽  
Empirical Studies ◽  
Basal Area ◽  
Simple Random Sampling ◽  
Forest Stand ◽  
Systematic Sampling ◽  
Relative Precision ◽  
Plot Size ◽  
Better Than

In this paper, several observations are presented to point out the behavior of systematic sampling in forest inventory. A brief literature review and the results of empirical studies indicate that the relative precision of two-dimensional systematic sampling for a given forest stand varies with the variable of interest, spatial distribution of trees, plot size, and sampling intensity. More specifically, results of this study indicate that systematic sampling performs better than or as well as simple random procedures for clustered or near-randomly distributed forest populations for tree frequency estimation. For uniformly spaced populations such as plantations, however, simple random sampling should be most precise for tree frequency estimation. With basal area, results were less clear but considering this study plus others reported in the literature, systematic sampling should usually perform as well as or better than simple random procedures for most tree populations.

scholarly journals ESTRUTURA E PADRÃO ESPACIAL DA VEGETAÇÃO EM UMA ÁREA DE CAATINGA

FLORESTA ◽  
2013 ◽  
Vol 43 (1) ◽  
pp. 83 ◽  
Author(s):  
Gabriel Paes Marangon ◽  
Rinaldo Luiz Caraciollo Ferreira ◽  
José Antônio Aleixo Da Silva ◽  
David Fagner de Souza e Lira ◽  
Emanuel Araújo Silva ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Forest Management ◽  
Spatial Pattern ◽  
Spatial Patterns ◽  
Tree Species ◽  
Vegetation Structure ◽  
Diversity Index ◽  
Basal Area ◽  
History Of ◽  
Aggregated Distribution

A vegetação do Nordeste revela carência relacionada ao manejo florestal da Caatinga. Objetivou-se estudar o padrão espacial de espécies e estrutura da vegetação em área de Caatinga, localizada no município de Floresta, PE. Em uma área de aproximadamente 10 ha, com histórico de perturbação, foram instaladas 20 parcelas de 20 x 20 m, de forma sistemática. Todas as árvores com CAP a 1,30 m do solo ≥ 6 cm foram identificadas e tiveram suas circunferências e alturas mensuradas. Foram encontradas 18 espécies arbóreas, distribuídas em 15 gêneros, dentro de 6 famílias botânicas, com índice de diversidade de Shannon (H') de 2,11 nats.ind-1, e área basal total estimada de 4,53 m2.ha-1. Destacaram-se as famílias Fabaceae, com 48,93% dos indivíduos, e Euphorbiaceae, com 41,28%. As espécies Poincianella bracteosa (Tul.) L. P. Queiroz, Croton rhamnifolius Kunth, Manihot cartaginenses subsp. glaziovii (Muell. Arg.) Allem. e Mimosa ophtalmocentra Mart. ex Benth somaram 55% do total do valor de importância. A maioria das espécies apresentou distribuição agregada, exceto algumas, como Myracrodruon urundeuva Fr. Allem. para o índice de McGuinnes (IGA), Commiphora leptophloeos (Mart.) J. B. Gillett para McGuinnes (IGA) e Payandeh (Pi) e Manihot cartaginenses subsp. glaziovii (Muell. Arg.) Allem. para Fracker e Brischle (Ki), que obtiveram tendência ao agrupamento.Palavras-chave: Semiárido; Pernambuco; distribuição espacial.AbstractStructure and spatial pattern of vegetation in a caatinga area. Forest management deficiency in relation to Northeast vegetation, specifically caatinga, are remarkable. This research aims to analyze spatial patterns of species and vegetation structure in Caatinga area, located in the municipality of Floresta-PE. In an area of approximately 10 ha, and a history of disturbance, 20 plots (20 x 20 m) were installed in systematic way. All trees with CAP (at 1.30 m above the ground) ≥ 6 cm had been identified, and their circumferences and heights measured. 18 tree species were sampled, distributed in 15 genus, within 6 botanical families, with diversity index of Shannon (H ') of 2.11 nats / ind, and estimated total basal area of 4, 53 m2.ha-1. The highlighted families were Fabaceae, 48.93% of individuals, and Euphorbiaceae 41.28%. The species Poincianella bracteosa (Tul.) L.P.Queiroz, Croton rhamnifolius Kunth, Manihot cartaginenses Subsp. glaziovii (Muell. Arg.) Allem., and Mimosa ophtalmocentra Mart. ex Benth totalized 55% of the total value of importance. Most species revealed aggregated distribution, except some like Myracrodruon urundeuva Fr. Allem. for the McGuinness index (IGA), Commiphora leptophloeos (Mart.) J.B.Gillett for McGuinness (IGA) and Payandeh (Pi), and Manihot cartaginenses Subsp. glaziovii (Muell. Arg.) Allem. for Fracker and Brischle (Ki), which obtained grouping tendency.Keywords: Semiarid; Pernambuco; spatial distribution. 

scholarly journals Relationship between the spatial distribution of SMS messages reporting needs and building damage in 2010 Haiti disaster

2012 ◽  
Vol 12 (2) ◽  
pp. 255-265 ◽  
Author(s):  
C. Corbane ◽  
G. Lemoine ◽  
M. Kauffmann
Keyword(s):  
Spatial Distribution ◽  
Spatial Structure ◽  
Spatial Patterns ◽  
Damage Assessment ◽  
Spatial Relationship ◽  
Remote Sensing Data ◽  
Building Damage ◽  
Direct Support ◽  
On Line ◽  
The Relationship

Abstract. Just 4 days after the M = 7.1 earthquake on 12 January 2010, Haitians could send SMS messages about their location and urgent needs through the on-line mapping platform Ushahidi. This real-time crowdsourcing of crisis information provided direct support to key humanitarian resources on the ground, including Search and Rescue teams. In addition to its use as a knowledge base for rescue operations and aid provision, the spatial distribution of geolocated SMS messages may represent an early indicator on the spatial distribution and on the intensity of building damage. This work explores the relationship between the spatial patterns of SMS messages and building damage. The latter is derived from the detailed damage assessment of individual buildings interpreted in post-earthquake airborne photos. The interaction between SMS messages and building damage is studied by analyzing the spatial structure of the corresponding bivariate patterns. The analysis is performed through the implementation of cross Ripley's K-function which is suitable for characterizing the spatial structure of a bivariate pattern, and more precisely the spatial relationship between two types of point sets located in the same study area. The results show a strong attraction between the patterns exhibited by SMS messages and building damages. The interactions identified between the two patterns suggest that the geolocated SMS can be used as early indicators of the spatial distribution of building damage pattern. Accordingly, a statistical model has been developed to map the distribution of building damage from the geolocated SMS pattern. The study presented in this paper is the first attempt to derive quantitative estimates on the spatial patterns of novel crowdsourced information and correlate these to established methods in damage assessment using remote sensing data. The consequences of the study findings for rapid damage detection in post-emergency contexts are discussed.

scholarly journals Field Note–Selecting Plot Sizes When Quantifying Growing Conditions in Understories

2002 ◽  
Vol 19 (3) ◽  
pp. 137-140 ◽  
Author(s):  
Klaus J. Puettmann ◽  
Anthony W. D'Amato
Keyword(s):  
Basal Area ◽  
Diameter Ratio ◽  
Seedling Height ◽  
Plot Size ◽  
Field Note ◽  
Growing Conditions ◽  
The Relationship ◽  
Overstory Trees ◽  
Linear Correlations ◽  
Stand Characteristics

Abstract While the importance of selecting a neighborhood size for competition studies has been documented, the choice of plot sizes has received little attention when measuring the influence of overstory trees on growing conditions of understory seedlings. Based on data from four sites, we show how plot sizes for measures of overstory cover (using a “cone” approach) and basal area (using an angle gauge) were related. The relationship was a function of the height/diameter ratio of the overstory trees, with taller trees increasing the plot sizes for “cone” plots and trees with larger diameters increasing the plot sizes for basal area plots. Further, we point out that data derived from measurements of diffuse noninterceptance (DIFN) using the “cone” approach varied with the choice of cone opening. Smaller cone openings led to a greater range in DIFN values. Linear correlations between these data and 2 yr seedling height pointed out that the optimal plot size, i.e., cone opening, differs among the sites. The lack of any obvious stand characteristics that would explain these differences indicated the need for further investigations.

scholarly journals Identify Urban Spatial Patterns Based on the Plot Shapes and Building Setting in Downtown of Nanjing.

2017 ◽  
Author(s):  
Wowo Ding ◽  
Yusheng Gu ◽  
Lian Tang
Keyword(s):  
Spatial Patterns ◽  
Urban Form ◽  
Spatial Configuration ◽  
Urban Morphology ◽  
Boundary Line ◽  
General Survey ◽  
Plot Size ◽  
Modern Cities ◽  
Master's Thesis ◽  
The Relationship

Yusheng Gu, Lian Tang, Wowo DingSchool of Architecture & Urban Planning, Nanjing University, No.22 Hankou Rd, Jiangsu 210093, P.R.ChinaE-mail: [email protected], [email protected], [email protected]: +86 13951786797; +86 25 8359 7205Key words: Spatial Configuration, Building Pattern, Plot Pattern, Plot Boundary Line The geometric characteristics of modern cities have been difficult to describe that is important for urban design, which deserve to be further interpreted. Taking advantage of Conzen’s methodology, the building is tightly related with its plot, which means the certain building pattern can be described by examining the generation of the building arrangement within the plot. Simultaneously, the building pattern is highly affected by the plot pattern it is located. In view of these, plot patterns together with land property and site coding could be taken as the clue for understanding both building patterns and urban spatial configuration. 35 commercial blocks in Nanjing downtown areas are chosen as research samples. Firstly, the internal structure of the blocks will be studied by analyzing the patterns, functions and land utilities of its plots. Focusing on the site coding and regulation, the building arrangement could be clarified and mapped. The results will identify the urban spatial patterns in downtown of Nanjing by mapping the characteristics of plot size, shape, properties and boundary lines. Therefore, the method on describing urban spatial configuration in modern cities could be developed. References(70 words) Conzen, M.R.G.(1960) “Alnwick, Northumberland: A Study in Town Plan Analysis" , Institute of British Geographers. Conzen, Michael P. (2004) Thinking about urban form : papers on urban morphology, Peter Lang Publishing. Dongxue Wang(2016) The relationship between the space of block and the plot boundary-based on a general survey in Nanjing, Master's thesis of Nanjing University. Jingjing Jiang(2015)Commercial plots and building patterns analysis-based on a general survey in Nanjing, Master's thesis of Nanjing University.  

scholarly journals Insights Into the Correspondence Between Land Use Pattern and Spatial Distribution of Rail Transit Services

2021 ◽  
Author(s):  
Zhongqi Wang ◽  
Qi Han ◽  
Bauke de Vries ◽  
Li Dai
Keyword(s):  
Land Use ◽  
Spatial Distribution ◽  
Operations Management ◽  
Latent Variable ◽  
Structural Equation ◽  
Equation Modeling ◽  
Rail Transit ◽  
Land Use Patterns ◽  
Transit Services ◽  
The Relationship

AbstractThe identification of the relationship between land use and transport lays the foundation for integrated land use and transport planning and management. This work aims to investigate how rail transit is linked to land use. The research on the relationship between land use and rail-based transport is dominated by the impacts of rail projects on land use, without an in-depth understanding of the reverse. However, it is important to note that issues of operation management rather than new constructions deserve greater attention for regions with established rail networks. Given that there is a correspondence between land use patterns and spatial distribution of heavy railway transit (HRT) services at such regions, the study area (i.e., the Netherlands) is partitioned by the Voronoi diagram of HRT stations and the causal relationship between land use and HRT services is examined by structural equation modeling (SEM). The case study of Helmond (a Dutch city) shows the potential of the SEM model for discussing the rail station selection problem in a multiple transit station region (MTSR). Furthermore, in this study, the node place model is adapted with the derivatives of the SEM model (i.e., the latent variable scores for rail service levels and land use characteristics), which are assigned as node and place indexes respectively, to analyze and differentiate the integration of land use and HRT services at the regional level. The answer to whether and how land use affects rail transit services from this study strengthens the scientific basis for rail transit operations management. The SEM model and the modified node place model are complementary to be used as analytical and decision-making tools for rail transit-oriented regional development.

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