Computer search for large trees with minimal ABC index

Abstract:Bayesian inferencing as a machine learning technique was evaluated for identifying pre-crash activity and crash type from accident narratives describing 3,686 motor vehicle crashes. It was hypothesized that a Bayesian model could learn from a computer search for 63 keywords related to accident categories. Learning was described in terms of the ability to accurately classify previously unclassifiable narratives not containing the original keywords. When narratives contained keywords, the results obtained using both the Bayesian model and keyword search corresponded closely to expert ratings (P(detection)≥0.9, and P(false positive)≤0.05). For narratives not containing keywords, when the threshold used by the Bayesian model was varied between p>0.5 and p>0.9, the overall probability of detecting a category assigned by the expert varied between 67% and 12%. False positives correspondingly varied between 32% and 3%. These latter results demonstrated that the Bayesian system learned from the results of the keyword searches.

Download Full-text

LBA-ECO CD-08 RADIOCARBON DATES FOR LARGE TREES FROM A FOREST NEAR MANAUS, BRAZIL

ORNL Distributed Active Archive Center Datasets ◽

10.3334/ornldaac/996 ◽

2011 ◽

Author(s):

J.Q. CHAMBERS, ◽

N. HIGUCHI, ◽

J.P. SCHIMEL,

Keyword(s):

Radiocarbon Dates ◽

Large Trees

Download Full-text

ASSESSMENT OF PINE CROPS GROWTH IN BAIMAK FORESTRY

RUSSIAN ELECTRONIC SCIENTIFIC JOURNAL ◽

10.31563/2308-9644-2020-37-3-83-90 ◽

2020 ◽

Vol 37 (3) ◽

pp. 83-90

Author(s):

T.Z. Mutallapov ◽

Keyword(s):

Scots Pine ◽

Forest Ecosystem ◽

Distribution Curve ◽

Comparative Assessment ◽

Tree Distribution ◽

Entire Structure ◽

Structure Changes ◽

Large Trees ◽

Different Types ◽

The Stability

The article presents the results of evaluating the growth of Scots pine in the Baymak forest area. The analysis of forestry and taxation indicators of Scots pine crops on the studied sample areas is carried out, and a comparative assessment of the growth of forest crops growing in different types of forest is given. Increased competition in plantings leads to the natural decline of stunted trees, which is the result of differentiation in the stand. As a result, its structure changes, the number of large trees increases, and, accordingly, the stability of the forest ecosystem increases. In this regard, the appearance of the tree distribution curve by thickness levels also changes. It becomes more "flat", and its competitive load is more evenly distributed over the entire structure of the stand, and competition is weakened.

Download Full-text

Effects of habitat edges on vegetation structure and the vulnerable golden-brown mouse lemur (Microcebus ravelobensis) in northwestern Madagascar

BMC Ecology ◽

10.1186/s12898-020-00337-z ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Bertrand Andriatsitohaina ◽

Daniel Romero-Mujalli ◽

Malcolm S. Ramsay ◽

Frederik Kiene ◽

Solofonirina Rasoloharijaona ◽

...

Keyword(s):

Body Mass ◽

Edge Effects ◽

Vegetation Structure ◽

Species Abundance ◽

Tree Height ◽

Logistic Function ◽

Study Region ◽

Large Trees ◽

Significant Difference ◽

Vegetation Parameters

Abstract Background Edge effects can influence species composition and community structure as a result of changes in microenvironment and edaphic variables. We investigated effects of habitat edges on vegetation structure, abundance and body mass of one vulnerable Microcebus species in northwestern Madagascar. We trapped mouse lemurs along four 1000-m transects (total of 2424 trap nights) that ran perpendicular to the forest edge. We installed 16 pairs of 20 m2 vegetation plots along each transect and measured nine vegetation parameters. To determine the responses of the vegetation and animals to an increasing distance to the edge, we tested the fit of four alternative mathematical functions (linear, power, logistic and unimodal) to the data and derived the depth of edge influence (DEI) for all parameters. Results Logistic and unimodal functions best explained edge responses of vegetation parameters, and the logistic function performed best for abundance and body mass of M. ravelobensis. The DEI varied between 50 m (no. of seedlings, no. of liana, dbh of large trees [dbh ≥ 10 cm]) and 460 m (tree height of large trees) for the vegetation parameters, whereas it was 340 m for M. ravelobensis abundance and 390 m for body mass, corresponding best to the DEI of small tree [dbh < 10 cm] density (360 m). Small trees were significantly taller and the density of seedlings was higher in the interior than in the edge habitat. However, there was no significant difference in M. ravelobensis abundance and body mass between interior and edge habitats, suggesting that M. ravelobensis did not show a strong edge response in the study region. Finally, regression analyses revealed three negative (species abundance and three vegetation parameters) and two positive relationships (body mass and two vegetation parameters), suggesting an impact of vegetation structure on M. ravelobensis which may be partly independent of edge effects. Conclusions A comparison of our results with previous findings reveals that edge effects are variable in space in a small nocturnal primate from Madagascar. Such an ecological plasticity could be extremely relevant for mitigating species responses to habitat loss and anthropogenic disturbances.

Download Full-text

Big trees drive forest structure patterns across a lowland Amazon regrowth gradient

Scientific Reports ◽

10.1038/s41598-021-83030-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tassiana Maylla Fontoura Caron ◽

Victor Juan Ulises Rodriguez Chuma ◽

Alexander Arévalo Sandi ◽

Darren Norris

Keyword(s):

Forest Structure ◽

Natural Regeneration ◽

Basal Area ◽

Significant Decline ◽

Forest Regrowth ◽

Large Trees ◽

Amazonian Forests ◽

Mammal Diversity ◽

Structure Patterns ◽

Plot Type

AbstractDegraded Amazonian forests can take decades to recover and the ecological results of natural regeneration are still uncertain. Here we use field data collected across 15 lowland Amazon smallholder properties to examine the relationships between forest structure, mammal diversity, regrowth type, regrowth age, topography and hydrology. Forest structure was quantified together with mammal diversity in 30 paired regrowth-control plots. Forest regrowth stage was classified into three groups: late second-regrowth, early second-regrowth and abandoned pasture. Basal area in regrowth plots remained less than half that recorded in control plots even after 20–25 years. Although basal area did increase in sequence from pasture, early to late-regrowth plots, there was a significant decline in basal area of late-regrowth control plots associated with a decline in the proportion of large trees. Variation in different forest structure responses was explained by contrasting variables, with the proportion of small trees (DBH < 20 cm) most strongly explained by topography (altitude and slope) whereas the proportion of large trees (DBH > 60 cm) was explained by plot type (control vs. regrowth) and regrowth class. These findings support calls for increased efforts to actively conserve large trees to avoid retrogressive succession around edges of degraded Amazon forests.

Download Full-text

Vegetation dynamics under residual large trees following a volcanic eruption in a Valdivian temperate rainforest

Plant Ecology ◽

10.1007/s11258-021-01151-3 ◽

2021 ◽

Author(s):

Lisa Hintz ◽

Dylan Fischer ◽

Nina Ferrari ◽

Charles M. Crisafulli

Keyword(s):

Vegetation Dynamics ◽

Volcanic Eruption ◽

Temperate Rainforest ◽

Large Trees

Download Full-text

Territory and Nest-Site Selection of Cerulean Warblers in Eastern Ontario

The Auk ◽

10.1093/auk/118.3.727 ◽

2001 ◽

Vol 118 (3) ◽

pp. 727-735 ◽

Cited By ~ 10

Author(s):

Jason Jones ◽

Raleigh J. Robertson

Keyword(s):

Site Selection ◽

Nest Site ◽

Deciduous Forest ◽

Spatial Scales ◽

Nest Site Selection ◽

Population Characteristics ◽

Dendroica Cerulea ◽

Large Trees ◽

Eastern Ontario ◽

Cerulean Warblers

Abstract We examined habitat selection by breeding Cerulean Warblers (Dendroica cerulea) at three spatial scales in eastern Ontario over three years (1997–1999). Territories were characterized by well-spaced large trees, with high canopies and dense foliage cover at heights between 12–18 m. Nesting habitat additionally was characterized by dense foliage cover above 18 m. The results of our nest-patch (0.04 ha circle around nest) and nest-site (0.01 ha circle) analyses indicate that male Cerulean Warblers may take active roles in nest-site selection when selecting territories. We conclude from our nest-patch and nest-site selection analyses that territories likely contain multiple nest patches and sites and that male Cerulean Warblers may defend areas with multiple nest patches or sites, which may attract females to settle with them. Whether or not Cerulean Warbler females use nest-site availability as a mate- or territory-choice cue remains unknown. We also tested the validity of a commonly made assumption that a random sampling of habitat by researchers is representative of the habitat actually available to birds and found that, in our study area, the assumption was invalid. Taken together, our results point toward the need to maintain sizeable stands of mature, deciduous forest to ensure the persistence of Cerulean Warblers in eastern Ontario. Population characteristics such as lower minimum area requirements and a resilience to habitat disturbance may make that an easier job in eastern Ontario than elsewhere in this species' breeding range.

Download Full-text

A New Category of Three-Dimensional Chaotic Flows with Identical Eigenvalues

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127420500261 ◽

2020 ◽

Vol 30 (02) ◽

pp. 2050026 ◽

Cited By ~ 1

Author(s):

Zahra Faghani ◽

Fahimeh Nazarimehr ◽

Sajad Jafari ◽

Julien C. Sprott

Keyword(s):

Chaotic Systems ◽

Autonomous Systems ◽

Three Dimensional ◽

Special Property ◽

Computer Search ◽

Chaotic Flows ◽

Stable Equilibria ◽

Dynamical Properties ◽

Simple Systems ◽

First Time

In this paper, some new three-dimensional chaotic systems are proposed. The special property of these autonomous systems is their identical eigenvalues. The systems are designed based on the general form of quadratic jerk systems with 10 terms, and some systems with stable equilibria. Using a systematic computer search, 12 simple chaotic systems with identical eigenvalues were found. We believe that systems with identical eigenvalues are described here for the first time. These simple systems are listed in this paper, and their dynamical properties are investigated.

Download Full-text