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In this paper, empirical relationships between diameter at breast height (DBH), crown diameter (CD), and stem number per hectare (N) were improved in a Paulownia Shan Tong plantation. Various functions of these variables were defined, focusing on growing space (Gs) and stem number per hectare. The linear crown index between CD and DBH seems to be particularly important in predicting stem number per hectare. Based on an analysis of the relationships, a CD-DBH (R2 = 0.7254) and a DBH-N graphic model (R2 = 0.7302) can be applied widely in plantation forestry. Under suitable site conditions, the investigated Paulownia hybrid can provide a higher increment in DBH than most of poplar hybrids at a certain age. The aim of this study was to explore the relationships between the Gs based on CD and DBH. These types of investigations are of fundamental importance in terms of the growing technology of tree plantations.

In this paper, empirical relationships between diameter at breast height (DBH), crown diameter (CD), and stem number per hectare (N) were improved in a Paulownia Shan Tong plantation. Various functions of these variables were defined, focusing on growing space (Gs) and stem number per hectare. The linear crown index between CD and DBH seems to be particularly important in predicting stem number per hectare. Based on an analysis of the relationships, a CD-DBH (R² = 0.7254) and a DBH-N graphic model (R² = 0.7302) can be applied widely in plantation forestry. Under suitable site conditions, the investigated Paulownia hybrid can provide a higher increment in DBH than most of poplar hybrids at a certain age. The aim of this study was to explore the relationships between the Gs based on CD and DBH. These types of investigations are of fundamental importance in terms of the growing technology of tree plantations. [ABSTRACT FROM AUTHOR]

Rare domestic tree species are increasingly being viewed as promising alternatives and additions to current main tree species in forests facing climate change. For a feasible management of these rare species, it is, however, necessary to know their growth patterns and space requirements. This information has been lacking in management and science up to now. Our study investigated the basic crown allometries of four rare domestic tree species (European hornbeam, European white elm, field maple and wild service tree) and compared them to the more established and assessable European beech and oak (sessile oak and pedunculate oak). For our analysis, we used data from eight temporary research plots located on seven sites across south-eastern Germany, augmented by data from long-term plots. Using quantile regression, we investigated the fundamental relationships between crown projection area and diameter, and height and diameter. Subsequently, we used a mixed-effect model to detect the dependence of crown allometry on different stand variables. We derived maximum stem numbers per hectare for each species at different stand heights, thus providing much-needed practical guidelines for forest managers. In the early stages of stand development, we found that European white elm and field maple can be managed with higher stem numbers than European beech, similar to those of oak. European hornbeam and wild service tree require lower stem numbers, similar to European beech. However, during first or second thinnings, we hypothesise that the rare domestic tree species must be released from competitors, as shade tolerance and competitiveness decrease with age. Furthermore, we argue that thinnings must be performed at a higher frequency in stands with admixed European beech because of the species' high shade tolerance. When properly managed, rare species can reach target diameters similar to oak and beech. [ABSTRACT FROM AUTHOR]

Tree morphological traits are related to the structural stability and their ability to provide ecological benefits such as carbon sequestration and water conservation. The allometric relationship can be used to construct the corresponding prediction equations in forests. However, the urban environment differs from the natural environment for trees. This study aims to enhance the urban tree growth model by classifying urban habitats. We achieved this by collecting morphological traits (DBH, height, crown depth, and width) commonly used in growth model researches of six Ficus spp. in Guangzhou, China, including Ficus virens , Ficus religiosa , Ficus elastica , Ficus benjamina , Ficus altissima , Ficus celebensis. We specifically examine how these trees grow in different urban settings. Urban habitats are classified based on growth space limitations, considering above-ground and underground. Results showed that certain morphologies in urban habitats did not conform to allometry (R2 < 0.4), and the model fitted with height as independent variable is better than that fitted with DBH. The model parameter following allometric relationship with tree height as the independent variable showed no significant difference, but the fit was worse in different urban habitats. On the contrary, models with DBH as the independent variable showed differences, for example, the allometric exponent of maximum crown width relative to DBH were 0.915 and 0.557 in two different habitats. Crown depth and tree height showed significant and stable allometry in the three habitats. The response of tree morphology to different habitats varied, and the allometric relationships among morphological traits showed differences in habitats where the growth space was limited. This underscores the considerable effect of the urban environment on urban tree growth models. Consequently, we recommend developing a series urban tree growth models tailored to different urban habitats to accurately quantify urban ecosystem services for assessing their sustainability in urban development and planning. [ABSTRACT FROM AUTHOR]

Abstract Strip width management is a critical factor for producing higher crop yields in relay intercropping systems. A 2‐year field experiment was carried out during 2012 and 2013 to evaluate the effects of different strip width treatments on dry‐matter production, major‐nutrient (nitrogen, phosphorus, and potassium) uptake, and competition parameters of soybean and maize in relay intercropping system. The strip width (SW) treatments were 0.40, 0.40, and 0.40 m (SW1); 0.40, 0.40, and 0.50 m (SW2); 0.40, 0.40, and 0.60 m (SW3); and 0.40, 0.40, and 0.70 m (SW4) for soybean row spacing, maize row spacing, and spacing between soybean and maize rows, respectively. As compared to sole maize (SM) and sole soybean (SS), relay‐intercropped maize and soybean accumulated lower quantities of nitrogen, phosphorus, and potassium in all treatments. However, maize in SW1 accumulated higher nitrogen, phosphorus, and potassium than SW4 (9%, 9%, and 8% for nitrogen, phosphorus, and potassium, respectively). Soybean in SW3 accumulated 25% higher nitrogen, 33% higher phosphorus, and 24% higher potassium than in SW1. The improved nutrient accumulation in SW3 significantly increased the soybean dry matter by 19%, but slightly decreased the maize dry matter by 6% compared to SW1. Similarly, SW3 increased the competition ratio value of soybean (by 151%), but it reduced the competition ratio value of maize (by 171%) compared to SW1. On average, in SW3, relay‐cropped soybean produced 84% of SS seed yield and maize produced 98% of SM seed yield and achieved the land equivalent ratio of 1.8, demonstrating the highest level in the world. Overall, these results suggested that by selecting the appropriate strip width (SW3; 0.40 m for soybean row spacing, 0.40 m maize row spacing, and 0.60 m spacing between soybean and maize rows), we can increase the nutrient uptake (especially nitrogen, phosphorus, and potassium), dry‐matter accumulation, and seed yields of relay‐intercrop species under relay intercropping systems.

Strip width management is a critical factor for producing higher crop yields in relay intercropping systems. A 2‐year field experiment was carried out during 2012 and 2013 to evaluate the effects of different strip width treatments on dry‐matter production, major‐nutrient (nitrogen, phosphorus, and potassium) uptake, and competition parameters of soybean and maize in relay intercropping system. The strip width (SW) treatments were 0.40, 0.40, and 0.40 m (SW1); 0.40, 0.40, and 0.50 m (SW2); 0.40, 0.40, and 0.60 m (SW3); and 0.40, 0.40, and 0.70 m (SW4) for soybean row spacing, maize row spacing, and spacing between soybean and maize rows, respectively. As compared to sole maize (SM) and sole soybean (SS), relay‐intercropped maize and soybean accumulated lower quantities of nitrogen, phosphorus, and potassium in all treatments. However, maize in SW1 accumulated higher nitrogen, phosphorus, and potassium than SW4 (9%, 9%, and 8% for nitrogen, phosphorus, and potassium, respectively). Soybean in SW3 accumulated 25% higher nitrogen, 33% higher phosphorus, and 24% higher potassium than in SW1. The improved nutrient accumulation in SW3 significantly increased the soybean dry matter by 19%, but slightly decreased the maize dry matter by 6% compared to SW1. Similarly, SW3 increased the competition ratio value of soybean (by 151%), but it reduced the competition ratio value of maize (by 171%) compared to SW1. On average, in SW3, relay‐cropped soybean produced 84% of SS seed yield and maize produced 98% of SM seed yield and achieved the land equivalent ratio of 1.8, demonstrating the highest level in the world. Overall, these results suggested that by selecting the appropriate strip width (SW3; 0.40 m for soybean row spacing, 0.40 m maize row spacing, and 0.60 m spacing between soybean and maize rows), we can increase the nutrient uptake (especially nitrogen, phosphorus, and potassium), dry‐matter accumulation, and seed yields of relay‐intercrop species under relay intercropping systems. [ABSTRACT FROM AUTHOR]

Highlights • Data harmonized from several structurally complex, mixed-species experimental forests. • Distance-dependent competition metrics included sophisticated light interception indices. • No general superiority of distance-dependent competition metrics over distance-independent counterparts. • Modest improvements for ΔDBH in shade-tolerant trees of lower crown classes post-harvest. • Model complexity strong factor affecting distance-dependent competition metric performance. Abstract Most studies comparing the predictive performance of distance-independent and -dependent competition metrics have been conducted in even-aged, single species stands. In addition, past studies have generally not considered more sophisticated distance-dependent competition metrics such as open sky-view or light interception indices. Using data from fully stem mapped inventory plots (n = 260) established in structurally complex, mixed-species experimental forests (n = 5) in the Northeastern US, we evaluated prediction performance of one- and two-sided distance-dependent as well as more conventional distance-independent competition metrics in both annualized diameter increment (n = 1735) and probability of survival models (n = 1953) developed across 26 contrasting softwood and hardwood species. Prediction accuracy of non-spatial and spatial models was further assessed by classifying observations by species shade-tolerance, relative tree height, time since harvest, and tree clumping. Our analyses revealed no general superiority of distance-dependent competition metrics over their distance-independent counterparts for either diameter increment or survival, which was particularly true for the latter variable. Distance-dependent metrics tended to outperform distance-independent ones for observations from shade-tolerant species, trees of lower crown classes, and immediately after harvest. However, results on the comparative analysis of the predictive power of the different types of competition metrics under varying stand conditions and situations were often inconsistent and not always conclusive. In addition, model complexity, i.e. number of non-spatial explanatory variables in the base model, strongly affected the performance of distance-dependent competition metrics. Our findings thus appear to support the critical assumption that distance-independent competition metrics are sufficient for most operational growth and yield applications, even in managed, naturally-regenerated and species rich forests. [ABSTRACT FROM AUTHOR]

Background and Purpose: Black locust (Robinia pseudoacacia L.) is the most widespread tree species in Hungary, occupying approximately 24% of the forested land and providing 25% of the annual timber output of the country. Due to the demands of consumers new cultivars are to be produced by improvement techniques and introduced into practical forestry use. This review provides a practice-oriented survey on black locust cultivar’s management in Hungary. Material and Methods: There are several cultivars and cultivar-candidates for high volume, high quality saw logs; for pole and prop, fuelwood and fodder production, of which there are several multipurpose varieties. Tending guidelines of stands established with the selected black locust cultivars are in some ways different from stands established by seedlings or regenerated by coppicing. Results and Conclusion: It is important to know how stand density influences production and how it can be manipulated. This has already been worked out for most of the major European tree species that can be grown plantation-like. Many countries have some form of production or yield models based on various spacing and thinning regimes, which are usually entered via site index curves based on height and age. Black locust plantation silviculture can come to be synonymous with high-input intensive management of monocultures for the production of a relatively narrow range of industrial products. However, there is no doubt that plantation silviculture will become increasingly important in more and more countries with special regard to the marginal site conditions.

ABSTRACT This study focuses on the effects of different thinning regimes on clonal Eucalyptus plantations growth. Four different trials, planted in 1999 and located in Bahia and Espírito Santo States, were used. Aside from thinning, initial planting density, and post thinning fertilization application were also evaluated. Before canopy closure, and therefore before excessive competition between trees took place, it was found that stands planted under low densities (667 trees per hectare) presented a lower mortality proportion when compared to stand planted under higher densities (1111 trees per hectare). However, diameter growth prior to thinning operations was not statistically different between these two densities, presenting an overall mean of 4.9 cm/year. After canopy closure and the application of the thinning treatments, it was found that thinning regimes beginning early in the life of the stand and leaving a low number of residual trees presented the highest diameter and height growth. Unthinned treatments and thinning regimes late in the life of the stand (after 5.5 years), leaving a large number of residual trees presented the highest values of basal area production. The choice of the best thinning regime for Eucalyptus clonal material will vary according to the plantation objective.

Forest policies and management rules imposed on forests in Romania provide favourable habitat conditions for many species across forest landscapes. This is empirically proven by the high biodiversity of the Carpathians and their surroundings. However, they do not explicitly address the spatial arrangement of forest patches across landscapes. Therefore, assessment of the connectivity (inside tracts of continuous forest – i.e. intrapatch connectivity – and also among spatially separate patches – i.e. interpatch connectivity) is important. To analyze this, the CORINE Land Cover data set (2012) available for Romania was used. Forest patches were classified into three size categories considered to ensure survival of tree populations on short term, medium and long term: Interconnectivity Nodes (IN: 1,5 to 14,9 ha, minimum 30 m width), Habitat Islands (HI: 15,0 ha and 499,0 ha, minimum 100 m width) and Habitat Continuum (HC: over 500 ha with a minimum 200 m width) respectively. The connectivity of each patch to others around it was assessed for a maximum threshold distance of 1 km. Further connectivity was classified in terms of its strength (depending on the size category to which a patch is connected) and quality (size and structure of a resulting connected cluster). Next, the distributions of the main forest tree species on the various sizes, connectivity strength and quality patches of forest vegetation were assessed. The results showed good connectivity between forest patches, both in terms of intrapatch connectivity (85% of the area was included in the HC class) and interpatch connectivity (92,4% are included in 12 clusters over 10.000 ha; among these the one around Carpathians comprised 86,7% of the total forest area). The main tree species showed good connectivity in general, higher in mountainous areas than at lower elevations (area in Habitat Continuum patches: 97,5% for Norway spruce vs. 63,3% for pedunculate oak; strong connection – 97,8% for Norway spruce vs. 67,2% for pedunculate oak; high quality connectivity – 98,2% for Norway spruce vs. 68,6% for pedunculate oak). These results confirm that management policies and guidelines inherited from the past provide good conditions for connectivity of the main forest tree species and for forests in general. Further enforcement of these practices in the future should ensure the conservation of species across the forested landscapes at national scale and also provide routes for species migration in the context of climate change. However, as a large proportion of forestland is today not state-owned, financial incentives for private owners are a key condition for further acceptance of these policies and ensure these major goals are met. [ABSTRACT FROM AUTHOR]

Stand density management tools help forest managers and landowners to more effectively allocate growing space so that specific silvicultural objectives can be met. Due to the economic importance of Oriental beech (Fagus orientalis Lipsky) forests in Turkey, a stand density management tool was developed for this species to optimize regeneration success rate and tree growth. For the development of this tool, named stand density management diagram (SDMD), we utilized forest inventory data from the Kastamonu Regional Forest Directorate in Turkey. Previously published forest management approaches and models were employed during the development of the tool. The SDMD illustrates the relation among four forest indexes: the basal area per hectare, number of trees per hectare, forest stand volume per hectare, and quadratic mean diameter of the beech stands. The stand stocking percent (SSP) can be determined based upon any two of these four measurements. The results suggest that SSP is a better predictor of tree growth than BA in Oriental beech forests. The newly developed SDMD allows for a more effective use of the growing space to achieve specific silvicultural objectives including tree regeneration, timber production, thinning planning, and wildlife protection in Oriental beech forests. [ABSTRACT FROM AUTHOR]

Uneven-aged silviculture is increasingly favored where diverse management objectives require complex stand structures. Traditional uneven-aged silvicultural methods have been criticized as inflexible and lacking ecological basis. Stocking indices such as Reineke's stand density index (SDI) are flexible and easy to apply, but ore not necessarily ecologically meaninghL We used data from Black Hills ponderosa pine stands to test whether SDI is a suitable proxy for leaf area index (LAI) in uneven.aged stands. LAI has clear ecological meaning, and is interpretable in terms of resource use efficiency and site quality. We found SDI explained almost 90% of the variation in LAI in 21 uneven-aged stands, and was unbiased by tree size. Our results show SDI is a useful tool for regulation of complex stand structures. [ABSTRACT FROM AUTHOR]

The subject of the study was a dynamic population of Sorbus torminalis resulting from spontaneous regeneration from seeds in northern Poland. The population, occupying a fenced plot of 1.72 ha in Forest District Jamy, amounted to 579 individuals. The spatial structure of population and some basic individual traits of trees were recorded, then the growing space of individual trees was examined. The following measures of tree growing space were investigated: crown diameter and projection area, and tree volume. The spatial structure of population was non-random, and there was evidence for effects of population density on tree performance. The observations have to be continued in order to describe optimal growing space of wild service tree; the results could be used to improve in situ conservation of this rare and valuable species. [ABSTRACT FROM AUTHOR]

The amount of growing space occupied by trees of given sizes and species is traditionally assessed on a plot basis, using observations from groups of trees growing within an area of fixed size. Our study combines individual-tree with plot-based observations of upper-canopy trees representing a range of shade tolerance (Fagus grandifolia ≥ Acer saccharum > Betula alleghaniensis ≥ Fraxinus americana) in three young, fully stocked, even-aged northern hardwood stands. The amount of canopy growing space used by a stem of given size was described by the ratios of crown projection area and crown surface area to stem basal area. These variables were related to species, stand, and relative basal area using analysis of covariance. Both ratios were generally highest in the youngest (19 years) stand, intermediate in the mid-aged stand (24 years), and lowest in the oldest stand (29 years). A few differences were detected among species, with shade-tolerants having larger ratios. Allometric models were used in conjunction with plot density data to estimate canopy cover at the stand level. Considerable crown overlap was indicated among upper-canopy trees in all three stands. Estimates from tree-centered plots suggested that crowns occupied 1.81 ± 0.02 times the ground area in the youngest stand and 1.45 ± 0.03 times in the mid-aged and oldest stands; when corrected for sampling bias, these ratios were at least 1.30 and 0.96, respectively. Combining individual-tree with plot-level measurements afforded a comprehensive assessment of trends in growing-space occupancy not possible using either technique alone. [ABSTRACT FROM AUTHOR]

Abstract: We tested hypotheses on the effect of growing space and biomechanics on tree growth, using data from two field experiments where Scots pine seedlings had been planted in a fixed but systematically irregular pattern. After 16 or 18 years, respectively, stem diameter was measured at 1.3m (d 1.3) and 0.3m above ground (d 0.3). Total tree height, length and diameter of the crown, and height to crown gravity point were also measured. Analyses were split in two parts: influence of growing space on tree and crown dimensions, and biomechanical influence of the crown on stem diameter. The results showed that crown size was closely related to tree height, and that there was a small but statistically significant effect of growing space on both crown size and shape. The biomechanical model explained about 85% of the variation in stem diameter, but growing space had no influence on this relationship, indicating that the wind load absorbed by a given crown size was not affected by growing space. The results were discussed in relation to future growth modelling and new ways of estimating site productivity. [ABSTRACT FROM AUTHOR]

Abstract: Explicit linkages between various levels of regeneration stocking and yield have been assumed for most of the last century but have rarely been quantified. There are many variations in methodology for measuring stocking, but the implications for yield prediction of employing different methods are poorly understood. For the purpose of yield prediction, contrasts are drawn here between several variations on two basic regeneration survey methodologies: stocked quadrats and the British Columbia Ministry of Forests’ well-spaced survey system. Curve shape and dispersion for the relationships between survey summary statistics and yield varied dramatically by varying survey parameters such as quadrat size and the maximum number of tallied well-spaced trees. Also of importance is the stand height at which yield is assessed. Finally, it is critical to standardize survey parameters so that summary statistics are consistently comparable. [ABSTRACT FROM AUTHOR]

This paper summarises the results from 35 years-observed thinning experiments on 256 permanent sample plots in 10–60 year-old stands of ash, aspen, birch, oak, pine and spruce in Lithuania. Thinning enhanced crown projection area increment of residual trees. The largest effect was observed in stands of aspen and birch (growth increase by 200%), followed by ash and oak (over 100%), and spruce and pine (about 80%). Thinning also promoted dbh increment, especially in younger stands, and the increase of dbh increment was positively correlated with the thinning intensity. The strongest reaction was exhibited by oak and aspen, while ash, birch and conifers reacted to a lower extent. Low and moderate intensities of thinning stimulated volume production in younger stands while the opposite was observed in older stands with increasing removals. Spruce stands exhibited relatively strongest increase of volume increment and pine, –the weakest, while the effect on deciduous species was intermediate. The results demonstrate that significant increase in volume increment is achievable with thinning of only young forest stands, e.g. 10–20 year-old pine, birch and ash, or 10–30 year-old oak, aspen and spruce. [ABSTRACT FROM AUTHOR]

• Manifold benefits and advantages of mixed tree stands have been known for many decades. • Appropriate tools are needed to effectively control development of mixed forests. • A solution of this problem is offered by demographic equilibrium approach. • A utility of the approach is confirmed in an exemplary forest sustainability unit. Manifold benefits and advantages of mixed tree stands have been known for many decades. However, while developing and maintaining multiaged and mixed-species forests with complex stand structures has often been advocated and has recently become a worldwide priority, it is not a simple task. One important reason for this is a lack of appropriate methods for controlling long-term development of such stands. Here, we present a possible solution for this problem by applying the demographic equilibrium approach to guide stocking and structure regulation in mixed stands. We tested the practical usefulness of this approach using permanent-plot inventories from 2002, 2011 and 2018, in mixed tree stands in the Experimental Sustainability Unit (ESU) Browsk 28C, in the managed part of Białowieża Forest (NE Poland). For our analysis, ESU Browsk 28C (about 30 ha) was treated as a silvicultural planning unit. First, on the basis of target stand types defined in Polish Silvicultural Guidelines (2012) and forest sites occurring at the study site, desirable tree species composition was determined. Eleven tree species of varying life histories and ecological attributes were included: aspen, birch, alder, pine, oak, maple, ash, elm, spruce, lime, and hornbeam. In the second step equilibrium diameter distributions were constructed for each species, taking into account species-specific growth and mortality rates, as well as targeted proportional representation. Next, theoretical species-specific equilibrium diameter distributions were visually and quantitatively compared with empirical distributions from permanent sample plots. Finally, departures of empirical from theoretical distributions served as a basis for silvicultural recommendations and prescriptions. We prioritized silvicultural measures (such as patch cuts opening larger gaps in forest canopy, proper site treatment, planting, protection against browsing by large herbivores), promoting compositionally diverse forest reproduction and recruitment as essential to long-term maintenance of demographic sustainability in mixed forest stands. We conclude that the demographic equilibrium approach is particularly valuable for creating and maintaining complex forest structures in multi-species stands. [ABSTRACT FROM AUTHOR]

Tree growth depends on many factors such as microsite conditions, vitality, and variations in climate and genetics. It is generally accepted that higher growth indicates both an economic benefit and better vitality of any tree. Here we use a modified approach of evaluating tree social area to study mutual tree competition based on the orientation and shape of trees social area. The investigation was performed in nine Norway spruce stands in the Czech Republic. The objective of this study performed from 2008 to 2012 was to quantify relative tree radial increments with respect to the lowest and highest competition found in specific sectors of tree social area (AS). Specific groups of trees (tree classes) were evaluated according to their classes (dominant, co-dominant and sub-dominant) and their composition status in ninety-degree sectors of AS using established classifying rules. The results showed that a spatially-available area (AA) is an inappropriate parameter for predicting tree growth, whereas AS provided robust explanatory power to predict relative radial growth. Tree size was observed as an important indicator of relative radial increments. A significantly positive correlation was found for a radial increment of sub-dominant trees with the lowest competition from western directions; whereas a negative correlation was observed when the lowest competition was observed from eastern directions. For dominant trees, there was an evident growth reaction only when more than 50% of the AS was oriented towards one of the cardinal points. Individual differences in the orientation of tree AS may be important parameters with regard to competition and its spatial variability within an area surrounding a particular tree and deserve more detailed attention in tree growth models and practice. [ABSTRACT FROM AUTHOR]

• Competition indices were evaluated to explain tree growth. • Distance-independent indices were more sensitive. • Including crown variables did not improve prediction ability. The objective of this study was to select and discuss indices to explain competition among trees in an unmanaged stand in order to support decision-making in forest management. The work was carried out in a plantation of Araucaria angustifolia (Bertol.) Kuntze located in a national forest in southern Brazil. The plantation was established in 1946 in 2 × 2 m spacing, with only one thinning that happened sometime between 1970 and 1980. Forty-six sample plots were established using an adaptation of the Prodan method. We tested distance-independent and distance-dependent competition indices that included or excluded crown area variables. An equation was generated to describe the relation between diameter at breast height and crown diameter, since these were highly correlated (r = 0.87); this permitted calculation of the growth space required for the trees in the stand. It is important to carefully choose the variables and competition indices to be tested in each study case. Including crown variables did not improve prediction ability to overcome the performance of the Stage distance-independent index. In general, the distance-independent indices performed better than the distance-dependent ones, even the stand arrangement in our study area was modified through thinning, mortality, and natural regeneration. When the goal is to better understand the ecological significance of a competition index and not only its statistical ability to predict short-term growth, simpler indices are recommended. [ABSTRACT FROM AUTHOR]