Effects of competitor spacing in individual-tree indices of competition

2001 ◽  
Vol 31 (12) ◽  
pp. 2143-2150 ◽  
Author(s):  
Thomas Ledermann ◽  
Albert R Stage
Keyword(s):  
Prediction Model ◽  
Tree Size ◽  
Distance Functions ◽  
Individual Tree ◽  
Growth Prediction ◽  
Graphical Displays ◽  
Functional Forms ◽  
The Many

All indices of competition represent effects of distance between competing trees. However, the functional forms of these distance relations differ, because distance interacts with tree size in the many of the indices. In particular, some of the newer indices use vertical angles and crown geometry to define the effect of separation implicitly. Graphical displays showing effects of distance between subject tree and a competitor in published distance-dependent indices of competition are presented to permit visual comparisons of the indices. Nine pairs of subject and competitor crown classes are included for each index. Relation of these distance functions to the function implicit in distance-independent (stand-level) variables included in the growth prediction model is discussed.

A comparison of competition measures for predicting growth of loblolly pine trees

1986 ◽  
Vol 16 (6) ◽  
pp. 1230-1237 ◽  
Author(s):  
Richard F. Daniels ◽  
Harold E. Burkhart ◽  
Terry R. Clason
Keyword(s):  
Loblolly Pine ◽  
Relative Size ◽  
Stand Density ◽  
Tree Size ◽  
Size Ratio ◽  
Multiple Correlation ◽  
Individual Tree ◽  
Growth Prediction ◽  
Point Density ◽  
Stand Attributes

Five families of competition indices were evaluated and compared on the basis of simple correlation with loblolly pine individual tree growth and multiple correlation with growth in the presence of other tree and stand attributes. The family of distance-independent indices included various relative size measures in the form of tree size to mean size ratios. Crown ratio was also included as a distance-independent measure. The four families of distance-dependent indices included various influence area overlap indices, distance-weighted size ratio indices, Spurr's point density, and Brown's point density or area potentially available (APA). All indices were significantly correlated with dbh and basal area growth. The relative size ratio indices, crown ratio, Spurr's point density, and several APA variations were judged best in simple correlations after accounting for tree size and stand density. The best distance-dependent indices had little if any advantage, either in simple or multiple correlation, over the best distance-independent indices. However, the point density index of Spurr and especially APA contributed significantly to growth prediction even in the presence of tree size, stand density, and the distance-independent size ratio and crown ratio indices. Further, APA had the highest partial correlation when all variables were included in this multiple correlation. It was concluded the APA would be a good index for growth prediction models when other tree and stand attributes are already known.

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.

Intertree competition in uneven-aged ponderosa pine stands

2003 ◽  
Vol 33 (9) ◽  
pp. 1719-1726 ◽  
Author(s):  
C W Woodall ◽  
C E Fiedler ◽  
K S Milner
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Basal Area ◽  
Growth Efficiency ◽  
Tree Size ◽  
Basal Area Increment ◽  
Diameter Class ◽  
Individual Tree ◽  
Sapwood Area ◽  
Competition Indices

Intertree competition indices and effects were examined in 14 uneven-aged ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) stands in eastern Montana. Location, height, diameter at breast height (DBH), basal area increment, crown ratio, and sapwood area were determined for each tree (DBH >3.8 cm) on one stem-mapped plot (0.2-0.4 ha) in each sample stand. Based on tree locations, various competition indices were derived for each sample tree and correlated with its growth efficiency by diameter class. In addition, trends in individual tree attributes by diameter class and level of surrounding competition were determined. For trees with a DBH <10 cm, growth efficiency was most strongly correlated with the sum of surrounding tree heights within 10.6 m. The index most highly correlated for larger trees was the sum of surrounding basal area within 6.1 m. Regardless of tree size, individual tree growth efficiency, basal area increment, and crown ratio all decreased under increasing levels of competition, with the effect more pronounced in smaller trees. These results suggest that individual trees in uneven-aged stands experience competition from differing sources at varying scales based on their size, with response to competition diminishing as tree size increases.

scholarly journals Development of a three-dimensional growth prediction model for the Japanese scallop in Funka Bay, Japan, using OGCM and MODIS

2015 ◽  
Vol 72 (9) ◽  
pp. 2684-2699 ◽  
Author(s):  
Yang Liu ◽  
Sei-Ichi Saitoh ◽  
Yu Ihara ◽  
Satoshi Nakada ◽  
Makoto Kanamori ◽  
...  
Keyword(s):  
Prediction Model ◽  
Three Dimensional ◽  
Temperature Data ◽  
Japanese Scallop ◽  
Growth Prediction ◽  
Chl A ◽  
Funka Bay ◽  
Dimensional Growth ◽  
In Situ Observations

Abstract The Japanese scallop (Patinopecten (Mizuhopecten) yessoensis) is an important commercial species in Funka Bay, Japan, where it is farmed using the hanging culture method. Our study was based on 6 years (from 2006 to 2011) of monthly in situ observations of scallop growth at Yakumo station. To produce a basic spatial distribution dataset, we developed an interpolation solution for the shortage of Chl-a concentration data available from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite. Additionally, we integrated four-dimensional variational (4D-VAR) assimilation water temperature data from ocean general circulation models (OGCMs), with four vertical levels (6, 10, 14, and 18 m) from the sea surface. Statistical models, including generalized additive models (GAMs) and generalized linear models, were applied to in situ observation data, satellite data, and 4D-VAR data to identify the influence of environment factors (interpolated Chl-a, temperature, and depth) on the growth of scallops, and to develop a three-dimensional growth prediction model for the Japanese scallops in Funka Bay. We considered three methods to simulate the growth process of scallops (accumulation, summation, and product), and used them to select the most suitable model. All the interpolated Chl-a concentrations and 4D-VAR temperature data were verified by shipboard data. The results revealed that GAM, using an accumulation method that was based on a combination of integrated temperature, integrated log Chl-a, depth, and number of days, was best able to predict the vertical and spatial growth of the Japanese scallop. The predictions were verified by in situ observations from different depths (R2 = 0.83–0.94). From the distribution of three-dimensional predicted scallop growth maps at each depth, it was suggested that the growth of the Japanese scallop was most favourable at 6 m and least favourable at 18 m, although variations occurred in each aquaculture region in different years. These variations were probably due to the ocean environment and climate variation.

Trend surface analysis of spatial patterns of tree size, microsite effects, and competitive stress

1986 ◽  
Vol 16 (2) ◽  
pp. 279-282 ◽  
Author(s):  
A. J. Thomson
Keyword(s):  
Surface Analysis ◽  
Spatial Patterns ◽  
Three Dimensional ◽  
Tree Size ◽  
Dimensional Representation ◽  
Trend Surface Analysis ◽  
Individual Tree ◽  
Spatial Trend ◽  
Trend Surface ◽  
Three Dimensional Representation

Trend surface analysis was used to determine the spatial patterns of tree size, competitive stress, and effects of microsite on growth. A three-dimensional representation of the trend surface facilitated interpretation. Gradients of competitive stress depended on the competition index used. Microsite effects have a spatial trend and individual tree genetic effects are represented by the residuals from this trend.

Development and evaluation of an automated tree detection–delineation algorithm for monitoring regenerating coniferous forests

2005 ◽  
Vol 35 (10) ◽  
pp. 2332-2345 ◽  
Author(s):  
D A Pouliot ◽  
D J King ◽  
D G Pitt
Keyword(s):  
Absolute Error ◽  
Tree Regeneration ◽  
Tree Size ◽  
Detection Accuracy ◽  
Individual Tree ◽  
Commission Errors ◽  
Tree Detection ◽  
Crown Diameter ◽  
Accuracy Index ◽  
The Individual

An algorithm is presented for automated detection–delineation of coniferous tree regeneration that combines strategies of several existing algorithms, including image processing to isolate conifer crowns, optimal image scale determination, initial crown detection, and crown boundary segmentation and refinement. The algorithm is evaluated using 6-cm pixel airborne imagery in operational regeneration conditions typically encountered in the boreal forest 5–10 years after harvest. Detection omission and commission errors as well as an accuracy index combining both error types were assessed on a tree by tree basis, on an aggregated basis for each study area, in relation to tree size and the amount of woody competition present. Delineation error was assessed in a similar manner using field-measured crown diameters as a reference. The individual tree detection accuracy index improved with increasing tree size and was >70% for trees larger than 30 cm crown diameter. Crown diameter absolute error measured from automated delineations was <23%. Large crown diameters tended to be slightly underestimated. The presence of overtopping woody competition had a negligible effect on detection accuracy and only reduced estimates of crown diameter slightly.

Lidar detection of individual tree size in tropical forests

2016 ◽  
Vol 183 ◽  
pp. 318-333 ◽  
Author(s):  
António Ferraz ◽  
Sassan Saatchi ◽  
Clément Mallet ◽  
Victoria Meyer
Keyword(s):  
Tropical Forests ◽  
Tree Size ◽  
Individual Tree
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