scholarly journals Competition Indexes to Evaluate Tree Growth in a Semi-Deciduous Seasonal Forest

2019 ◽  
Vol 26 (4) ◽  
Author(s):  
Ilvan Medeiros Lustosa Junior ◽  
Renato Vinícius Oliveira Castro ◽  
Ricardo de Oliveira Gaspar ◽  
Juliana Baldan Costa Neves Araújo ◽  
Fabiana de Gois Aquino
Keyword(s):  
Tree Growth ◽  
Basal Area ◽  
Natural Forests ◽  
Competition Index ◽  
Radius Of Influence ◽  
Fixed Radius ◽  
The Subject

ABSTRACT Most of the studies that analyze the behavior of tree competition approach even-aged plantations. Therefore, it is possible to notice a lack of this kind of information regarding natural forests with high biodiversity. The objective of this study was to evaluate the competition in a fragment of Semi-Deciduous Seasonal Forest, according to the ecologic group, light depending and non-depending groups for all species sampled in the fragment. The Distance Independent Competition Index and Semi-Distance Independent Competition Index were applied in this study. The basal area in larger trees index, without the radius of influence, was the most efficient to analyze how the competition affects the growth of the specimens in the studied fragment. It was stated that evaluating the competition per ecologic group is more efficient. The results confirm that the forest competition cannot be determined by considering only a fixed radius of influence that embraces the neighbors and the subject tree.

scholarly journals How Does Radial Growth of Water-Stressed Populations of European Beech (Fagus sylvatica L.) Trees Vary under Multiple Drought Events?

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Tamalika Chakraborty ◽  
Albert Reif ◽  
Andreas Matzarakis ◽  
Somidh Saha
Keyword(s):  
Soil Water ◽  
Fagus Sylvatica ◽  
Tree Growth ◽  
Radial Growth ◽  
Basal Area ◽  
European Beech ◽  
Canopy Openness ◽  
Fagus Sylvatica L ◽  
The Impact ◽  
Neighborhood Competition

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe.

A New Index Representing Individual Tree Competitive Status

1973 ◽  
Vol 3 (4) ◽  
pp. 495-500 ◽  
Author(s):  
James A. Moore ◽  
Carl A. Budelsky ◽  
Richard C. Schlesinger
Keyword(s):  
Spatial Distribution ◽  
Strong Correlation ◽  
Basal Area ◽  
Tree Size ◽  
Competition Index ◽  
Individual Tree ◽  
Silvicultural Practices ◽  
Basal Area Growth ◽  
Hardwood Species ◽  
Area Growth

A new competition index, modified Area Potentially Available (APA), was tested in a complex unevenaged stand composed of 19 different hardwood species. APA considers tree size, spatial distribution, and distance relationships in quantifying intertree competition and exhibits a strong correlation with individual tree basal area growth. The most important characteristic of APA is its potential for evaluating silvicultural practices.

Neural Processing of Gravito-Inertial Cues in Humans. II. Influence of the Semicircular Canals During Eccentric Rotation

2001 ◽  
Vol 85 (4) ◽  
pp. 1648-1660 ◽  
Author(s):  
D. M. Merfeld ◽  
L. H. Zupan ◽  
C. A. Gifford
Keyword(s):  
Nervous System ◽  
Time Course ◽  
Rotation Speed ◽  
Linear Acceleration ◽  
Otolith Organs ◽  
Centripetal Acceleration ◽  
Variable Radius ◽  
Fixed Radius ◽  
The Subject ◽  
Roll Tilt

All linear accelerometers, including the otolith organs, respond equivalently to gravity and linear acceleration. To investigate how the nervous system resolves this ambiguity, we measured perceived roll tilt and reflexive eye movements in humans in the dark using two different centrifugation motion paradigms (fixed radius and variable radius) combined with two different subject orientations (facing-motion and back-to-motion). In the fixed radius trials, the radius at which the subject was seated was held constant while the rotation speed was changed to yield changes in the centrifugal force. In variable radius trials, the rotation speed was held constant while the radius was varied to yield a centrifugal force that nearly duplicated that measured during the fixed radius condition. The total gravito-inertial force (GIF) measured by the otolith organs was nearly identical in the two paradigms; the primary difference was the presence (fixed radius) or absence (variable radius) of yaw rotational cues. We found that the yaw rotational cues had a large statistically significant effect on the time course of perceived tilt, demonstrating that yaw rotational cues contribute substantially to the neural processing of roll tilt. We also found that the orientation of the subject relative to the centripetal acceleration had a dramatic influence on the eye movements measured during fixed radius centrifugation. Specifically, the horizontal vestibuloocular reflex (VOR) measured in our human subjects was always greater when the subject faced the direction of motion than when the subjects had their backs toward the motion during fixed radius rotation. This difference was consistent with the presence of a horizontal translational VOR response induced by the centripetal acceleration. Most importantly, by comparing the perceptual tilt responses to the eye movement responses, we found that the translational VOR component decayed as the subjective tilt indication aligned with the tilt of the GIF. This was true for both the fixed radius and variable radius conditions even though the time course of the responses was significantly different for these two conditions. These findings are consistent with the hypothesis that the nervous system resolves the ambiguous measurements of GIF into neural estimates of gravity and linear acceleration. More generally, these findings are consistent with the hypothesis that the nervous system uses internal models to process and interpret sensory motor cues.

Soil disturbance and juvenile Douglas-fir growth following stump removal on moderately coarse textured soils in southwestern British Columbia: 10-year results

2019 ◽  
Vol 49 (7) ◽  
pp. 767-774
Author(s):  
Stefan Zeglen ◽  
Paul J. Courtin
Keyword(s):  
British Columbia ◽  
Tree Growth ◽  
Basal Area ◽  
Soil Disturbance ◽  
Douglas Fir ◽  
Stand Development ◽  
Site Productivity ◽  
Nutrient Analysis ◽  
Armillaria Ostoyae ◽  
Root Diseases

Mechanized treatment for root diseases such as Coniferiporia sulphurascens (Pilát) L. W. Zhou & Y. C. Dai (syn. Phellinus sulphurascens Pilát) and Armillaria ostoyae (Romagn.) Herink (syn. Armillaria solidipes Peck) is often avoided due to cost or the perception that removal of stumps creates detrimental soil disturbance or degradation that hinders site productivity. Our study tested five diseased stands that were treated by extracting stumps following harvesting and replanted with susceptible Douglas-fir. Soil disturbance surveys were conducted in treated and untreated plots, and individual planted spots were assessed and categorized for soil disturbance using existing and proposed new categories specific to disturbance caused by the stump removal. Tree measurements were taken at intervals over the first 10 years of stand development, and foliage was sampled for nutrient analysis. The percentage of total and counted disturbance was 20%–46% and 8%–11% greater, respectively, in treated versus untreated plots; however, mean tree growth in height and diameter was not statistically different between treatments and was more positive for treated plots at all sites but one. Tree nutrition and survival to age 10 was not negatively affected by stump removal. Total site productivity represented by basal area and tree volume differed widely between sites but was not significantly different between treatments.

Individual-tree basal area growth models for jack pine and black spruce in northern Ontario

2004 ◽  
Vol 80 (3) ◽  
pp. 366-374 ◽  
Author(s):  
Lianjun Zhang ◽  
Changhui Peng ◽  
Qinglai Dang
Keyword(s):  
Tree Growth ◽  
Black Spruce ◽  
Basal Area ◽  
Jack Pine ◽  
Mixed Stands ◽  
Northern Ontario ◽  
Individual Tree ◽  
Basal Area Growth ◽  
Wide Range ◽  
Area Growth

Individual-tree models of five-year basal area growth were developed for jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP) in northern Ontario. Tree growth data were collected from long-term permanent plots of pure and mixed stands of the two species. The models were fitted using mixed model methods due to correlated remeasurements of tree growth over time. Since the data covered a wide range of stand ages, stand conditions and tree sizes, serious heterogeneous variances existed in the data. Therefore, the coefficients of the final models were obtained using weighted regression techniques. The models for the two species were evaluated across 4-cm diameter classes using independent data. The results indicated (1) the models of jack pine and black spruce produced similar prediction errors and biases for intermediate-sized trees (12–28 cm in tree diameter), (2) both models yielded relatively large errors and biases for larger trees (> 28 cm) than those for smaller trees, and (3) the jack pine model produced much larger errors and biases for small-sized trees (< 12 cm) than did the black spruce model. Key words: mixed models, repeated measures, model validation

scholarly journals Effects of Basal Area Factor and Plot Size on Precision and Accuracy of Forest Inventory Estimates

2011 ◽  
Vol 28 (3) ◽  
pp. 152-156 ◽  
Author(s):  
Peter Becker ◽  
Tom Nichols
Keyword(s):  
Forest Inventory ◽  
Basal Area ◽  
Cost Effective ◽  
Sampling Errors ◽  
Plot Size ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Fixed Radius ◽  
Tree Number ◽  
Biased Estimates

Abstract We tested the effects of plot size (0.05-0.30 ac) and basal area factor (BAF) (5-30) on the accuracy and precision of per-acre estimates of tree number, basal area, biomass (all for trees ≥4.5 in. dbh), and sawtimber volume (for trees ≥11.6 in. dbh). Field sampling errors, such as missing in-trees, did not affect our tests. Virtual variable- and fixed-radius plots were randomly located within an artificial matrix of 130 real plots in well-stocked upland hardwood forests of sawtimber-sized trees in the Missouri Ozarks. Inventory parameters were essentially independent of plot size and BAF, whereas their coefficients of variation decreased with plot size and increased with BAF. Thus, our results for random plots agreed with sampling theory, unlike a previous study using concentric virtual plots in West Virginia forests. A very concentrated zone of high tree density around some plot centers apparently caused the biased estimates by concentric plots. Compared with the entire composite forest, inventory means were accurately estimated (to within 5%) and size class distributions were well represented for plots ≥0.1 ac or ≤15 BAF. Our procedures provide a basis for selecting an efficient and cost-effective sampling design suited to forest characteristics and the inventory's purpose.

Forest ecology on Java: human impact and vegetation of montane forest

1992 ◽  
Vol 8 (2) ◽  
pp. 129-152 ◽  
Author(s):  
Alfred C Smiet
Keyword(s):  
Forest Ecology ◽  
Basal Area ◽  
Forest Products ◽  
Forest Degradation ◽  
Montane Forest ◽  
Canopy Closure ◽  
Natural Forests ◽  
Mountain Areas ◽  
Tree Cutting ◽  
Landscape Units

ABSTRACTNatural forests on Java have been generally cleared and remnants are now confined to mountain areas Although legally protected, these forests are used by local people for products like firewood, timber and fodder Locally, such exploitation is carried out daily by hundreds of people, whose livelihood depends on forest products Using a landscape-guided approach, a 15,500 ha area of montane forest in East Java has been sampled and analysed at the sylvatic mosaic level Vegetation types, sociologic species groups and vegetation structure are described for landscape units The most accessible landscape units have the most degraded forest with basal area values < 15 m2 ha−1 and a canopy closure of < 20% The least accessible units have relatively undisturbed forest with basal area values of > 45 m2 ha−1 and a canopy closure of > 60% Human activities such as tree cutting have altered species composition and modified forest structure to such an extent that large stretches of forest have been replaced by woodland or shrubland Forest degradation is described as a human induced process in which basal area and canopy closure are ultimately reduced, in spite of regrowth Comparison with other forest areas on Java shows that degradation as a result of tree cutting is a widespread phenomenon

Predicting basal area increment in a spatially explicit, individual tree model: a test of competition measures with black spruce

2003 ◽  
Vol 33 (3) ◽  
pp. 435-443 ◽  
Author(s):  
Daniel Mailly ◽  
Sylvain Turbis ◽  
David Pothier
Keyword(s):  
Black Spruce ◽  
Basal Area ◽  
Basal Area Increment ◽  
Spatially Explicit ◽  
Competition Index ◽  
Individual Tree ◽  
Spatial Indices ◽  
Crown Shape ◽  
Spruce Stands ◽  
Competition Indices

A current trend in the development of forest stand models is to use spatially explicit, individual-tree information to simulate forest dynamics with increased accuracy. By adding spatial information, such as tree coordinates, crown shape, and size, it is hypothesized that the computation of the model's driving function is improved over traditional competition indices, especially when simulating multistoried stands. In this paper, we want to test whether computationally demanding competition indices outperform traditional indices in predicting mean basal area increment. The study was undertaken in old, uneven-aged black spruce (Picea mariana (Mill.) BSP) stands in northeastern Quebec, Canada. The predictability of individual tree growth rates was related to crown dimensions and other stand and tree variables measured in the field. Data were collected from 90 trees coming from stands of varying site quality (range 9.6–16.5 m height at 50 years, age taken at 1 m) and age (range 66–257 years). Hegyis's distance-dependent competition index was found to be the most strongly correlated competition measure (r = 0.57) with mean basal area growth of the last 20 years. This value, 12% higher than the value obtained from the best distance-independent competition index (r = 0.45), clearly shows that precision gains can be achieved when estimating basal area increment with spatial indices in black spruce stands. Using indices computed from virtual hemispherical images did not prove superior to simpler distance-dependent indices based on their individual correlations with basal area increment. When included in a basal area increment model for the last 20 years of growth, however, the gains in precision were comparable to Hegyi's competition index. This indicates that indices derived from a hemispherical approach have some value in spatially explicit forest simulations models but that further tests using younger stands are needed to confirm this result in black spruce stands.

Modeling the numerical relationships between chronic ambient sulphur dioxide exposures and tree growth

1996 ◽  
Vol 26 (4) ◽  
pp. 689-695 ◽  
Author(s):  
A.H. Legge ◽  
M. Nosal ◽  
S.V. Krupa
Keyword(s):  
Regression Model ◽  
Tree Growth ◽  
Basal Area ◽  
Basal Area Increment ◽  
Sampling Location ◽  
Model Parameters ◽  
Processing Plant ◽  
Pine Tree ◽  
Sampling Locations ◽  
Increment Growth

An exponential growth curve model was developed for Pinuscontorta Dougl. ex Loud. var. latifolia Engelm. × Pinusbanksiana Lamb, (lodgepole × jack pine) trees from basal area increment data collected from five ecologically analogous sampling locations (AI to AV) in the vicinity of a sulphur recovery sour gas processing plant emitting sulphur (S) gases (mainly SO2) in the West Whitecourt study area near the town of Whitecourt in west-central Alberta, Canada. The mean basal area increment growth declined by 1.2%, 1.4%, 0.8%, and 0.6% between 1959 and 1981 at sampling locations AI AII, AIII and AIV, respectively, in comparison to the reference sampling location, AV. Since 1974 there has been an increase in wood production at the impacted sites, AI to AIV. This was most likely the result of the significant and progressive reductions in total sulphur gas emissions from 1963 to 1981, of 58 403 to 6782 t S/year, respectively. A multivariate nonlinear, polynomial Fourier regression model was applied to explain the relationships between the ambient SO2 exposures at the five sampling locations and changes in pine tree basal area increment growth. The regression model included the ambient SO2 exposure parameters: (1) number of episodes (an episode is equivalent to single or successive occurrences of 0.5-h mean concentrations of ≥10 ppb); (2) cumulative integral of exposures (concentration with respect to time); and (3) peak episodal concentrations. The model parameters were estimated using the least squares approach. The MPF regression model captured the actual effects of the episodicity of SO2 exposures on radial tree growth of pine species and provided a high degree of forecasting power because of the use of the integral of the SO2 exposures. Peak episodal SO2 concentrations or the number of episodes appeared not to play as important a role in the model as the integral.

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