Search

We examined crown architecture and within crown leaf area distribution effects on Pinus taeda L. growth in North Carolina (NC), Virginia (VA), and Brazil (BR) to better understand why P. taeda can grow much better in Brazil than in the southeastern United States. The NC, VA, and BR sites were planted in 2009, 2009, and 2011, respectively. At all sites, we planted the same two genetic entries at 618, 1236, and 1854 trees ha(-1). In 2013, when trees were still open grown, the VA and NC sites had greater branch diameter (24%), branch number (14%), live crown length (44%), foliage mass (82%), and branch mass (91%), than the BR site. However, in 2017, after crown closure and when there was no significant difference in tree size, site did not significantly affect these crown variables. In 2013, site significantly affected absolute leaf area distribution, likely due to differences in live crown length and leaf area, such that there was more foliage at a given level in the crown at the VA and NC sites than at the BR site. In 2017, site was still a significant factor explaining leaf area distribution, although at this point, with crown closure and similar sized trees, there was more foliage at the BR site at a given level in the crown compared to the VA and NC sites. In 2013 and 2017, when including site, genetic entry, stand density, and leaf area distribution parameters as independent variables, site significantly affected individual tree growth efficiency, indicating that something other than leaf area distribution was influencing the site effect. Better BR P. taeda growth is likely due to a combination of factors, including leaf area distribution, crown architecture, and other factors that have been identified as influencing the site effect (heat sum), indicating that future work should include a modeling analysis to examine all known contributing factors. Public domain – authored by a U.S. government employee

The research has been conducted in Zhytomyr Polissya at stationary experiment № 1. Some parameters of tree crowns such as diameter, projection area and length of the crown and canopy closure of Scots pine (Pinus sylvestris L.) plantations with density 4000, 2000 and 1000 trees·ha-1 were analysed. Tree crown parameters were measured in the experiment according to common forestry and forest taxation methods. We have defined that with the density plantation 4000 trees·ha-1 average crown diameter ranges from 2.4 to 2.7 m, with stand density 2000 trees·ha-1 – 2.9‑3.1 m, and with stand density 1000 trees·ha-1 – 3.6‑4.0 m, the difference between these values ranges from 9 % to 40 %. We have also proved the true difference between the average tree crown diameters by single factor ANOVA at 95 % confidence interval, where Fф = 7.82…126.03 > Fт(0.95) = 3.89. We have demonstrated that with plantation density 4000-2000 trees·ha-1 the form of crowns is oval (compressed in the line and elongated interstitial), where the plantation density 1000 trees·ha-1 – is almost round. There are some exceptions, i.e. plantations with the density 2000 and 1000 trees·ha-1, where crowns are formed one-sided toward the southwest. We have also revealed, that the average crown projection area with plantation density 4000 trees·ha-1 is 5.5‑6.1 m2, but with plantation density 1000 trees·ha-1 – 10.6‑13.1 m2, the difference between given parameters ranges from 42 to 58 %. We confirmed the difference between the values of tree crown projection area ANOVA, where Fф = 8.0…108.7 > Fт(0.95) = 3.89. We have diagnosed that crown length with plantation density 4000 trees·ha-1 is 4.1‑5.1 m, with plantation density 2000 trees·ha-11 it is 5.0‑6.6 m, and with plantation density 1000 trees·ha-1 it is 5.1‑8.1 m, the difference between the given values ranges from 9 to 43 %, in some cases it is small or absent. Therefore, the canopy closure of plantations with various densities is from 0.80 to 0.93, the difference between the given values in the variants ranges from 1 to10 %. We have made the conclusion that the density influences average diameter, projection area and length of tree crowns, whereas the influence of density on the canopy closure of the plantation is not found.

Assessment of aboveground biomass stocks in the coniferous forests of the inland northwest USA is important for timber, bioenergy, and carbon inventories, as well as for wildfire risk determination. In this study, individual tree biomass equation systems are developed for 7 regionally important conifer species using data from 470 felled trees sampled across 84 stands and spanning a range of diameters at breast height (1.37 m; dbh) running from 5 cm to 105 cm. The equation systems permit estimation of crown biomass components (i.e., foliage, dead branches, and live branches by size class) and stem components (abovestump stemwood and stembark), as well as compatible estimates of (sub)totals. The systems draw on commonly collected inventory variables including dbh, tree height, and live crown length. All biomass components scaled approximately linearly with dbh on the logarithmic scale, but equation systems drawing on both dbh and height provided more accurate estimates for all species; systems drawing additionally on live crown length provided more accurate estimates still for all species but one. In line with previous work, incorporation of live crown length improved live crown component equations most, but also improved stem component equations for two species. Across species and systems, stem components and subtotals were most accurately estimated (mean absolute errors ∼ 10%) while dead branch biomass estimation proved least tractable (mean absolute errors > 50%). Overall, the reported biomass equation systems draw on the largest felled tree samples collected from the region, and provide the most comprehensive basis developed to date for regional forest biomass assessments over the inland northwest.

Crown architecture has long been evaluated for its impact on taper modeling. However, most of the research has focused on a limited number of crown dimensions. This study examined the effect of adding several crown dimensions in improving the diameter and volume estimates of Dahurian larch, Korean spruce, and Manchurian fir in northeast China. The crown dimensions included crown length, crown ratio, crown width, height to live crown base, diameter at the crown base, and crown shape. A well-known taper model of Clark et al. (1991) was fitted to the data of 276 trees from natural stands. To adjust the inherent autocorrelation in the data, we added a third-order continuous-time error structure in the model fit. Model fitting was carried out with the NLMIXED procedure (Non-linear Mixed Procedure), followed by the MODEL procedure of SAS using the generalized nonlinear least-squares method. Fit statistics and graphical assessments were used to evaluate the original and modified models. Above 98% of the total variance of d was explained by the models for all species. The addition of crown variables showed slight improvements for root mean square error (RMSE) values in the analyzed species. The RMSE plots indicated that the models with crown variables slightly improved the diameter and volume predictions for the species but only for the upper stem (&gt, 50%–90%). The study demonstrated that crown dimensions influence the stem taper, but the original model of Clark et al. (1991) reasonably realized that effect.

This paper investigates the slenderness of black locust (Robinia pseudoacacia) trees in relation to the biosocial status of the trees, stand age class, crown parameters and habitat type. The research material was collected on 35 research plots in the Sława Śląska, Sulechów and Głogów forest districts in western Poland and comprises 1058 trees. For each tree, we measured height (h) as well as diameter at breast height (d) and determined its biosocial status (Kraft class), crown length (CL) and relative crown length (rCL). The age class and habitat type were assessed at the plot level. Because the obtained values for slenderness (s=h/d) diverged significantly from the normal distribution, we used Kruskal-Wallis and Mann-Whitney tests to investigate the influence of the above-mentioned parameters on the h/d ratio. Black locust slenderness ranged from 0.31 to 1.95 with an average of 0.91 (standard deviation 0.24). It furthermore differed significantly between Kraft classes (the higher the biosocial status, the lower the slenderness) and age classes (the older the trees, the lower their slenderness). We also found a significant effect of the habitat type (in oligotrophic sites trees formed more slender trunks than in mesotrophic sites) and crown parameters on the h/d ratio (decreasing with increasing crown length and relative crown length). The obtained results suggest that the slenderness of black locust does not differ substantially from native broadleaved trees in Poland.

The present study was conducted to understand the growth performance and productivity potential of Tectona grandis grown in plantation as well as in the farmlands at coastal zone of Karnataka. The growth of teak tree grown in farmland was significantly higher than tree grown in pure plantation. For instance, the overall height(11.95 m), diameter (23.69 cm), clear bole height (6.20 m), tree volume (0.61 m3) and timber volume (0.33 m3) was higher in farmland than trees grown in pure plantation (11.60 m, 20.33 cm, 4.90 m, 0.42 m3 and 0.18 m3, respectively). However, crown parameters did not show significant difference among trees grown in pure plantations and farmlands. There was a strong influence of age on growth of teak trees grown in both farmland and pure plantation. For instance, tree height (14.72 m) and diameter (30.52 cm) of higher age class (A4: 21-25 years) was maximum as compared lower age class (A1: 5-10 years) with values of 8.29 m and 17.14 cm, respectively. Similar trend was also recorded for volume, clear bole height, crown height, crown length and crown diameter in teak. It was concluded that teak grown in farmland may produce higher growth and volume as compared to pure plantation.

Se analizó, mediante regresión logística, la proporción de galerías de Ips con respecto a otros insectos descortezadores (Pityophthorus, Hylastes, Hylurgops) y barrenadores de madera, en su interacción con el diámetro del árbol y tres variables de daño por incendio (altura del quemado del fuste, nivel de daño en la copa y longitud de copa viva). La proporción de galerías de Ips disminuye al aumentar el diámetro del árbol y la altura de quemado del fuste, mientras que dicha proporción aumenta con el incremento en la longitud de copa viva. En árboles con la copa chamuscada en su totalidad, pero con yemas terminales vivas, se incrementa la proporción de galerías de los barrenadores de madera, lo mismo sucede al aumentarse la altura de quemado del fuste y en árboles con diámetros superiores a los 30 cm.

Most models of modulus of elasticity (MOE) and modulus of rupture (MOR) use classical dendrometric variables and do not use crown characteristics that are known to influence wood formation and properties. The objective of this study was to evaluate the benefit of including crown variables in black spruce MOE and MOR models. Values of MOE and MOR were measured on 99 boards from 21 black spruce trees located in nine stands in the Lac-Saint-Jean region of Quebec (Canada). Site, tree and crown variables (crown surface area, crown length, branch basal area) were measured. Stand age and basal area were found to be positively related to MOE and MOR. Stem DBH and crown length were negatively related to MOE and MOR. When including crown variables, Akaike's Information Criterion was stable while the R2 increased slightly (+ 2.7% for MOE and + 1% for MOR). The small benefit in model performance associated with the inclusion of crown variables in MOE and MOR models suggests that models without crown variables could b...

Taiwan red cypress (Chamaecyparis formosensis Matsum) is an indigenousand important cypress conifer with a broad area of natural forests and plantations in Taiwan. Because of the high economic value and multiple uses of the species, numerous researchers have studied its growth and yield within plantation forests. However, few studies have examined how the crown characteristics of the tree respond to different thinning regimes, particularly in the long run. The crown is a dominant outline of aboveground component of a tree that can sensitively reflect competitions from trees located nearby. This study evaluated the crown form of Taiwan red cypress at three different growth stages with different thinning intensities over 20 years. The study began in 1982, when the three plantations examined were aged 7, 15, and 21 years, and when thinning treatments began. In 2002, crown form parameters (CFPs) and crown profile equations (CPEs) were used to analyze the thinning effects at the tree level. Two-way analysis of variance (ANOVA) revealed that age class influenced most CFPs and that thinning treatments influenced all CFPs, indicating that both factors could simultaneously affect the CFPs. Moreover, the CPEs fit the observed data well for all age classes, demonstrating that the equation had a high capacity for predicting crown form. The CPEs were used to determine the mean crown shape profile for each thinning treatment and age class. According to the mean crown profile predicted by CPEs, we found that crown length and width increased with thinning intensity for all aged trees, especially after a heavy thinning treatment.

plots which represent mixed oak stands of the Eastern Polissya of Ukraine, we have conducted an assessment and analysis of periodic and current increment of crown branches of oak trees by individual components as a basis for development of normative and information support for assessment of biotic productivity of this category of forests. A special technique was developed in order to study periodic and current increment of crown branches of oak trees by the main mensurational indices within three layers of crown - bottom, middle and top. To perform a study of increment of crown branches of oak trees by individual components, 20 model trees were cut down, 56 model branches were selected and measured. Model branches were grouped according to certain intervals of beginning and ending boundaries of the lower, middle and apical part of crown. After grouping, it was found that there were 23 branches from lower parts of crowns, 19 – from middle, and 10 branches – from apical parts of crowns. There was a separate study of increments of vertexes of model branches (20 pcs.). All model trees have different age and different mensurational parameters. Age of model trees ranges from 6 to 105 years; diameter at breast height – from 2,4 to 50,5 cm; height – from 3,4 to 31,5 m, average diameter of crown – from 1,1 to 10,0 m, length of crown – from 2,6 to 18,7 m, weight of tree greenery – from 0,2 to 160,4 kg, weight of branches – from 0,2 to 619,6 kg. It is found that the periodic increment of crown branches by diameter at zero section and length in various parts of crown depending on tree age and age of model branches have different pattern of change. In lower and middle part of crown with increasing crown length, and with increasing branch linkage height, periodical increment by diameter has an increasing trend, while in apical part of crown it has a decreasing tendency. It was also found that the highest values of current increment of crown branches of oak trees are observed in middle part of crown at tree age up to 20 years. The collected experimental data, their statistical and graph-analytical evaluation yielded information basis for modeling the periodic and current increment parameters of tree crown branches and stands of oak, which builds up a basis for forecasting volumes and rates of carbon accumulation in this category of stands.

The aim of the present study was to model the crown volume in black wattle stands (Acacia mearnsii De Wild.) in Rio Grande do Sul, Brazil. The study was carried out in plots installed in black wattle stands in area where the plantations of the species are common. Two trees in each plot of average diameter were felled to determination total height, crown length (crown height) and crown width taken twice, each measurement oriented perpendicular to the other across the bole axis and parallel to the base of the crown. To calculate crown volume (cv) widths were taken every meter starting at the base of the tree bole. Stepwise, backward, and forward variable selection methods were used to formulate the volume equations. The combined variable squared diameter and crown height (d²ch) was the most highly correlated with crown volume (r=0.84). This in turn was the variable that was integrated into the selected model, both in the stepwise and forward selection methods. The equation cv = b1 d²ch + ei was the model that provided the best fit for predicting crown volume in black wattle stands, both in age rotation and in young stands. Key words: Acacia mearnsii; morphometry; stepwise; models.

To analyze the main variables affecting crown biomass, we measured crown biomass and a number of variables describing tree size, such as stem diameter at breast height (D), tree height (H), crown width (Cw) and crown length (Cl), from 754 sample trees of four pine species in China, specifically, Pinus massoniana, P. yunnanensis, P. tabulaeformis and P. elliottii. In addition, we developed individual tree crown biomass equations and compatible branch and needle biomass equations based on one-, two- and multi-variable models using nonlinear mixed-effects modeling and error-in-variable simultaneous equations. The results showed that: (i) crown biomass was strongly correlated to D and H, and the new combined variables (D4/H) and (D2/H) were suitable for modeling two- and multi-variable crown biomass equations, respectively, (ii) the four species were ranked as P. yunnanensis, P. massoniana, P. elliottii and P. tabulaeformis from small to large based on estimates from crown biomass equations, and the crown biomass estimate of P. tabulaeformis was about 60% greater than that of P. yunnanensis, (iii) the ratio of branch to crown biomass increased with increasing D, and the four species were ranked as P. elliottii, P. tabulaeformis, P. massoniana and P. yunnanensis from small to large by the proportion of the branch to crown biomass, (iv) the mean prediction errors (MPE’s) of the crown biomass equations for the four species were less than 10%, which could meet precision needs for biomass estimation.

This paper presents the results of an analysis on characteristics of birch crowns (Betula pendula Roth) in relation to measures of the growth space occupied by a single tree at a young age. It also presents the relationships between the seedling height and certain crown characteristics. The study focused on four-year-old common birches growing in four different areas in the Elk Forest District in either fresh mixed coniferous or broadleaved forest. The measurements conducted on the chosen trees were used to calculate their crown characteristics such as crown diameter, length, height to the crown base, relative length and spread. They were also used to determine the growth characteristics of a single tree’s growth space, such as the crown area projected onto the ground, single tree space and the percentage use of unit area. Furthermore, fresh and dry leaf mass was determined. The birches growing in the fresh mixed coniferous forest reached an average height of 1.30 m, whereas in the fresh mixed broadleaved forest, the height of the trees was lower and amounted to 0.67 m. 95% of the trees had crown diameters of 0.57 m to 0.74 m in the fresh mixed coniferous forest, but only 0.19 m to 0.25 m in the fresh mixed broadleaved forest. The average lengths of the crowns in the fresh mixed coniferous and broadleaved forests amounted to 0.97 m and 0.37 m respectively. The author shows that there is a statistically significant correlation between the seedling height and the other examined characteristics. The best correlation was found between the height and the length of the crown (r = 0.9858) for birches growing in the fresh mixed coniferous forest and between the height and single tree space (r = 0.8468) for birches growing in the fresh mixed broadleaved forest.

Indole acetic acid (IAA) was believed to be an important regulator in xylem formation in conifers. However, few studies have been done on the endogenous amount of IAA in cambial region tissues in sugi (Cryptomeria japonica) trees. In this study, we report the IAA amounts in the lower and upper trunk of mature sugi cultivars (Kumotoshi, Yaichi and Obiaka) in September, and the effects of growth traits on the IAA amounts. The effect of height position (lower or upper trunk) on IAA amounts was found to be larger than that of genetic variation (Kumotoshi, Yaichi or Obiaka) by two-way ANOVA. There was no significant interaction effect (genetic variation × height position). The IAA amounts of all trees varied from 3 to 42 ng/cm2 at the lower trunk and 9 to 47 ng/cm2 at the upper trunk. Crown length and distance from crown base had significant positive and negative effects on IAA amounts in the trunk of sugi cultivars, respectively. Distance from crown base had a larger effect on IAA amounts than crown length. In Yaichi, taller trees had larger IAA amounts at both the lower and upper trunk.

Crown efficiency is a relation of growth with the area tree occupies (available area efficiency). Efficiency is associated with the vertical and lateral expansion capacity of the tree and crown, increase, density and light absorption. Thus, our study aimed to evaluate crown efficiency with pine cones∙tree-1 production and dendro/morphometric variables of individual araucaria trees in three forest sites in south Brazil. In each site of each tree, dendrometric and morphometric variables were measured and increment rolls were taken at the breast height diameter level. Together with these data, the morphometric indexes, annual periodic increment in diameter of the last ten years (APId) and efficiency of the crown as a function of APId by the horizontal projection area of the crown (hpac) and number of pine cones∙tree-1 (np) by hpac were calculated. Crown efficiency was modeled as a function of the independent variables hpac, APId, crown length (cl), crown ratio (cr) and np. The accuracy of the adjustment was evaluated by the statistics of the deviance, Akaike’s information criterion and graph of the residuals. The results show that the number of pine cones∙tree-1 increases with annual periodic increment in diameter and diameter. Crown efficiency decreases with increasing hpac, cl and cr, indicating silvicultural treatments should be performed with the removal of trees of larger diameter and crown size. A higher pine cones production and efficiency correlates with forest growth, shape, competition, sociological position (stratum tree occupies) and density.

The purpose of this study was to develop an understanding of the pattern of variation in longitudinal, radial, and tangential shrinkage in two commercially important Canadian wood species using multivariate nonlinear mixed-effects models. Shrinkage data were measured in each growth ring at different heights on trees harvested from a mixed-species Nelder tree-spacing plot located in New Brunswick, Canada. Live crown base was reconstructed based on stem analysis. Cambial age, sampling height, crown characteristics (crown length, crown ratio, and distance to live crown base), and ring width at time of wood formation were used as prediction variables. The results indicated that shrinkage magnitude and pattern were closely related to crown dimensions and stem position at time of wood formation. Trees from wider tree spacings with larger crown lengths and ratios tended to have smaller tangential and radial shrinkage. Longitudinal shrinkage decreased nonlinearly from pith outwards with slower rate changes near the bottom of the trees. The model fixed effects accounted for more variation in jack pine (Pinus banksiana Lamb.) than in white spruce (Picea glauca (Moench) Voss) for shrinkage in the same anatomical direction. After further validation, the model developed can be used to provide shrinkage predictions for lumber distortion models within the framework of an individual tree growth model.

Conceptual models of wood formation suggest that trees with large crowns produce wood with reduced mechanical properties due to enhanced auxin production, but few studies have explicitly examined the relationship between crown dimensions and wood properties. Using white spruce (Picea glauca (Moench) Voss) trees harvested from spacing and thinning trials in central Ontario, Canada, this study examines how live crown ratio influences the strength and stiffness of wood. Modulus of rupture (MOR) and modulus of elasticity (MOE) were measured by conducting three-point bending tests on small (150 ×10×10 mm) defect-free samples selected from different radial positions at three heights within the stems. MOR and MOE were strongly and positively related to cambial age, and also increased slightly with sampling height. In addition, MOR showed a significant decrease with increasing live crown ratio ‐ calculated as the ratio of crown length to tree height ‐ in both the spacing and the thinning trials. However, MOE decreased significantly with live crown ratio only in the spacing trial, where the younger trees had a larger range of crown ratios. These results provide tentative support for models of wood formation that link wood quality with crown development, suggesting that crown metrics could be used to predict wood properties before harvest, but doing so may be problematic in mature stands that exhibit less variability in crown dimensions.

Analuddin K, Septiana A, Sharma S, Hagihara A. 2016. Crown shape dynamics of dense mangrove Kandelia obovata standsin Manko Wetland, Okinawa Island, Japan. Biodiversitas 17: 865-872. The objectives of this study were to elucidate the crown structure dynamics for dense mangrove stands, and to know the crown shape maintenances and its important role for ensuring the stability and vitality the crowded mangrove forest. The growth parameters of K. obovata Shue, Liu & Yong stands, such as tree height H (m), height at the lowest living leaves HL (m), crown length CL (m) and crown width CW (m), were measured in the summer from 2004 to 2008. The crown shape dynamics were analyzed. The results showed that the HL was significantly increased with increasing H, which suggests thatthe crown changed to be dumpy as the stands grew. However, the CL of young stands increased and then decreased continuously as the stands grew, while the CL of mature stands decreased from 2004 to 2007 and then increased in 2008. Meanwhile, the CL/CW ratio of young stands decreased as the stands grew, while the CL/CW ratio of mature stands decreased and then increased, which imply that dense Kandelia obovata trees might transform their crown shape for reducing of competition for light among trees. Therefore, these resultssuggested that the crown shape of dense mangrove treesare dynamics as developing stands.

The paper presents an attempt to apply measurable traits of a tree – crown projection area, crown length, diameter at breast height and tree height for classification of 135-year-old oak (Quercus L.) trees into Kraft classes. Statistical multivariate analysis was applied to reach the aim. Empirical material was collected on sample plot area of 0.75 ha, located in 135-year-old oak stand. Analysis of dimensional traits of oaks from 135-year-old stand allows quite certain classification of trees into three groups: pre-dominant, dominant and co-dominant and dominated ones. This seems to be quite promising, providing a tool for the approximation of the biosocial position of tree with no need for assessment in forest. Applied analyses do not allow distinguishing trees belonging to II and III Kraft classes. Unless the eye-estimation-based classification is completed, principal component analysis (PCA) method provided simple, provisional solution for grouping trees from 135-year-old stand into three over-mentioned groups. Discriminant analysis gives more precise results compared with PCA. In the analysed stand, the most important traits for the evaluation of biosocial position were diameter at breast height, crown projection area and height.

Models were developed for tree height and crown characteristics of eastern cottonwood (Populus deltoides Bartr. Ex. Marsh). Equations related cottonwood height to dbh and crown condition category (less than 50% live, at least 50% but less than 100% live, and 100% live). Crown width equations related crown width to dbh, crown condition category, and basal area per hectare. Additional equations related crown length to total height, basal area per hectare, and crown condition category. Data were obtained during a sample of trees located in a riparian area surrounding the Cimarron River on the Cimarron National Grassland. The band of trees on either side of the Cimarron River channel was surrounded by treeless, semiarid grassland typical of southwestern Kansas. Many trees were growing in scattered clumps or nearly open grown. In addition, there was variability in proportions of live crown present, as classified by crown condition category. These factors influence crown dimensions and are typical of cottonwood trees found in Great Plains riparian areas. Since height measurement trees were sampled on plots, mixed-effects models with random effects representing plot effects were developed for the height-diameter relationships (a model developed using ordinary least squares is also presented). Models of crown width and crown length were developed using ordinary least squares.

Black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) and white spruce (Picea glauca (Moench) Voss) are phylogenetically proximal species that differ in productivity. Crown characteristics of these two species have not been extensively studied, in spite of the importance of these two species to the Canadian boreal forest and the importance of tree crowns for understanding and modelling tree growth. In this paper, we characterize and compare the crown lengths, crown profiles (i.e., radii), shapes, and surface areas of these two species using 65 white spruce and 57 black spruce trees destructively sampled in the provinces of Alberta, Ontario, and Quebec, Canada. Crown length was measured on every sam- ple tree, while crown profile was obtained by reconstructing crowns from branch measurements. Our results showed that crown lengths did not differ between these two species given the same tree size and growth conditions. However, these two species establish under different growth conditions resulting in crown length differences. Further, differences in crown radii and profiles were found even under the same growth conditions. White spruce trees had wider crown radii and profiles changed from a parabola to a cone shape under increased density. As a result, differences in crown surface areas were found. Abstract: Les epinettes noires (Picea mariana (Mill.) Britton, Sterns & Poggenb.) et blanches (Picea glauca (Moench) Voss) sont des especes phylogenetiquement proximales dont la productivite differe. Les caracteristiques de la cime de ces

Before correct forest management decision is made, it’s a core issue that gripping the forest stand structure and dynamic variation regularity, estimating the production capacity of stands and effects after adopting particular silvicultural technical measures in different site conditions. A variety of stand growth and yield prediction models are precisely to solve these problems to provide effective guidance. In this dissertation, through sampling and researching Meihekou forest stumpage data, the individual growth models of Pinus koraiensis were established, including the crown width growth prediction model and the crown length growth prediction model. These models can reflect the growth of individual growth state, but also the performance of the various factors affecting the growth, and provide a scientific basis for reasonable forest management.

The study was carried out in Serbian spruce (Picea omorika Panc/Purkyn?) plantations in the western Serbia. The paper presents results of the analysis of crown development. The following elements were analyzed: total tree height, height of the crown base, absolute and relative crown length, maximal crown diameter, coefficient of crown spreading and degree of crown girth. We discuss approaches to the modeling of tree crown growth and development, growing under favorable environmental and stand conditions, without anomalies in development. In order to establish the relationship between analyzed factors, regression analyses were applied. Data fitting was by the analytic method, by the implementation of Prodan?s functions of growth, linear and parabolic function. Received models can be used for the simulation of various growth and developing processes in forest.

Crown length is a key aspect of vertical structure in multi-aged, multistrata, mixed-species forests. Crown length, defined as the distance from the tree top to the lowest live branch whorl, was determined for 3169 mapped trees ≥4.0 cm in diameter, in four 0.25 ha plots in each of two old-growth Abies lasiocarpa (Hook.) Nutt. – Picea engelmannii Parry ex Engelm. stands. We randomly selected half the trees to build models and half for validation. Crown length was modelled as a function of tree height, incorporating modifiers to account for neighbouring trees. The inclusion radius and height threshold for competition were 3 m and 70%, respectively. The addition of two modifiers significantly improved the model for A. lasiocarpa; crown length decreased as the number of neighbours increased and as the height of surrounding trees increased. In contrast, none of the modifiers significantly improved the model for P. engelmannii. Except at high levels of competition, Abies crowns were longer than those of Picea. However, both species in these forests have long crowns, typically three-quarters of the tree height and rarely less than half. The tightly programmed conical crown architecture of these species likely contributes to long crowns and to the limited effects of neighbours on crown length.

Aiming at describing and modeling the morphometric relationships among the crown diameter, the crown percentage, the length of the crown exposed to light and the height of the dominant trees in stand of Pinus taeda L., one hundred and eighty seven sample units were studied considering the type proposed by Prodan, modified for twelve trees, distributed on good and bad stands. In each sample unit, two dominant trees were identified and the dimensions of the diameter at breast height, the total height, the crown lengths and the length of crown exposed to light and the crown diameter under eight rays were measured. Results allowed concluding that the crown diameter and the length of the crown exposed to light grow with the increase of the dominant height, and the two relationships can be described with good statistical precision by a curvilinear mathematical model. The relationship of the crown percentage with the dominant height presented high statistical significance described by a decreasing curvilinear model, having been identified by analysis of covariance three different groups of curves according to the place of origin of the data. The crown percentage decreases with the increase of the dominant height.

Segmentation of stands by tracks is often the first phase of forest tending. However, a suitable track width is still discussed in forest practice in the Czech Republic. This article deals with the effect of track width on the growth characteristics of young spruce stands. Research involves several variants of European thinning experiment IUFRO CZ 14 Machov situated in Eastern Bohemia. Totally 3 variants were analyzed: 1 - non-segmented control plot without thinning and plots with forest tending (at top height 10 and 20 m) and with different present width of tracks (plot 3 - originally 3.5 m, plot 4 - originally 5.0 m). The significantly positive effect of stand segmentation and tracks on dbh and crown length was found only for individuals growing in the first row next to a track. As regards the stand volume and volume of mean stem, differences between variants with skidding track (3 and 4) were found minimal and insignificant. Therefore, the observation did not reveal any evident losses of production caused by different widths of skidding tracks.

Crown depth, tree spacing, and stand density have major effects on wood quality and fibre characteristics of trees. Lodgepole pine ( Pinus contorta Doug. ex Loud.) trees from a mixture of plantation and fire origin stands were employed to determine how crown ratio, a surrogate for stand density, affected mature wood production. In total, 104 trees were sampled, ranging from 24 to 110 years of age, from stands in western Alberta and interior British Columbia, Canada. Samples taken along the bole were measured for wood density, which was subject to segmented regression analysis to identify the transition point from juvenile to mature wood production. On average, the lodgepole pine trees were 31 (±17 SD) years old before mature wood production began. A mixed-effects model, in which combination of fixed effects (tree age, height of the sample disc relative to crown base, and crown length) and random effects (site, trees nested in sites, and discs nested in both trees and sites) proved to be the best predictor of years of mature wood production along the bole. The transition from juvenile to mature wood was shown to be below the crown base in trees

Cultural practices can affect the quality of pineapple fruits and its variation. The objectives of this study were to investigate (a) effects of weight class and type of planting material on fruit quality, heterogeneity in quality and proportion and yield of fruits meeting European export standards, and (b) the improvement in quality, proportion and yield of fruits meeting export standards when flowering was induced at optimum time. Experiments were conducted in Benin with cvs Sugarloaf (a Perola type) and Smooth Cayenne. In cv. Sugarloaf, experimental factors were weight class of planting material (light, mixed, heavy) and time of flowering induction (farmers', optimum) (Experiment 1). In cv. Smooth Cayenne an additional experimental factor was the type of planting material (hapas, ground suckers, a mixture of the two) (Experiment 2). Fruits from heavy planting material had higher infructescence and fruit weights, longer infructescences, shorter crowns, and smaller crown: infructescence length than fruits from light planting material. The type of planting material in Experiment 2 did not significantly affect fruit quality except crown length: fruits from hapas had shorter crowns than those from ground suckers. Crops from heavy planting material had a higher proportion and yield of fruits meeting export standards than those from other weight classes in Experiment 1 only; also the type of planting material in Experiment 2 did not affect these variates. Heterogeneity in fruit quality was usually not reduced by selecting only light or heavy planting material instead of mixing weights; incidentally the coefficient of variation was significantly reduced in fruits from heavy slips only. Heterogeneity was also not reduced by not mixing hapas and ground suckers. Flowering induction at optimum time increased the proportion and yield of fruits meeting export standards in fruits from light and mixed slip weights and in those from the mixture of heavy hapas plus ground suckers.

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests managed for timber in western Oregon frequently lack structure and diversity associated with old-growth forests. We examined thinning effects on overstory and understory development for 8 years after treatment. Three 30- to 33-year-old Oregon Coast Range plantations were partitioned into four overstory treatments: unthinned (~550 trees/ha) and lightly (~250 trees/ha), moderately (~150 trees/ha), and heavily (~75 trees/ha) thinned. Within each overstory treatment, two understory treatments were established: underplanted with Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.) or not underplanted. Thinning increased overstory stem growth, crown expansion, and retained crown length. Thinned overstory canopies began to close rapidly the third year after thinning, decreasing % skylight by approximately 2%/year, whereas % skylight in unthinned stands increased slightly. All seedlings planted in unthinned stands died, whereas eighth year survival in thinned stands averaged 88%. Natural regeneration densities and distributions were highly variable. Understory shrub cover was reduced by harvesting disturbance but recovered by the fifth year. Thinning increased understory plant species diversity, and no shrub species were lost. Thinning to low densities and underplanting has the potential to accelerate development of multilayered stands characteristic of old-growth Douglas-fir forests.

The relations between age, crown architecture, height and height increment of silver fir (Abies alba Mill.) saplings were analysed using a multivariate method. Individuals from the saplings bank in mixed, unevenly aged, seminatural stands in Western Poland were investigated. Examined features were analysed with respect to light availability, which varied between 5.9 and 25.8% of full sunlight. The age of firs in the saplings bank varied from 11 up to 101 years. Under shade, growth is suspended and saplings tend to form a flat crown. Reduction of growth of a sapling did not influence its mortality, and did not diminish its ability to vigorously grow for up to 90-year-old saplings. Results of the PCA showed that age was not connected with sapling size, growth or crown morphology. Height increment is related to the relative crown length (RCL) and to the size of the sapling. In looking for an objective and quantitative indicator of growth potential, results suggest the RCL as a feature not influenced by sapling size. It should be pointed out that the vitality defined in this way reflects only the current growth, but not the potential to survive or the ability for rapid growth along with a changing light environment. The apical dominance ratio (ADR) value seems to be an indicator of light conditions in the understorey, but this trait is influenced by the height of the sapling.

This work shows morphometric characteristics of Ilex paraguariensis St. Hil. pruned under reforestation. The study was carried out in Catanduvas, Santa Catarina State. All trees (about 14 years old) were cultivated in soil with similar characteristics. The experiment followed a randomized block design arranged in a factorial 3 x 3 corresponding to three distances between the rows of trees (3, 4, and 5 m) and three distances between trees within the rows (2, 3, and 4 m). The trees were divided into two groups. Each group was pruned in September or in January, when the crown was 24 or 28 months old, respectively. All trees were bifurcated near the ground, and, therefore, the perimeter at this level did not show a significant correlation with the crown biomass. The comparison of basal area and number of trunks per plant at the highs of 0.3, 0.6, and 0.9 m, showed that the ideal position to evaluate the trunk attributes was 0.60 m above the ground. The basal area of the trees at this position (g6) reduced with the reduction of the distance between the rows and between the trees within the rows (P < 0.05). The number of trunks per plant measured at 0.6 m above the ground (Nt6) was significantly affected by the distance between plants within the row, with the lowest value been observed when the distance between plants was 2 m. The crown diameter of the trees (Dc8) was higher on trees cultivated under higher spacing between the rows. Crown length and the total high of the trees (ht) were significantly affected by the distance between the rows and by the distance between the trees within the rows. Crown ratio (Cc/ht) was only affected by the distance between plants within the rows. The degree of coverage (Dc8/ht) was affected by the distance between rows. The crown shape (Dc8/Cc) values were close to unity, since the trees showed crown diameter proportional to the crown length.

The aim of this study was to determine relationships between selected properties of juvenile wood and characteristics of the stem and crown of Scots pine. Analyses were conducted in northern Poland on eight mature pine monocultures. Nine trees were selected in each experimental site and their stems were divided into five sections. The centers of the sections were established at a height of 1.3 m from the tree base and at points corresponding to 20, 40, 60 and 80% tree height. Samples were taken from these locations, and these samples were prepared for analyses of basic density, compressive strength along the grain and static bending, as well as the modulus of elasticity during bending. The mean height of the investigated group of trees was 26.0 m with an average diameter breast high of 33.6 cm. The mean crown depth was 7.8 m and crown diameter was 3.6 m, and the mean basic density (Qu) of juvenile pine wood was 416 kg/m3. The average compressive strength along the grain (CS) was determined to be 22.3 MPa, while static bending strength (BS) was 45.8 MPa. The recorded modulus of elasticity (MOE) was 4726 MPa. Both in general terms and when dividing stems into sections, the wood properties correlated with tree characteristics to various degrees. All indexes were negative indicating that trees of greater dimensions produce juvenile wood of inferior quality. Properties of juvenile wood formed during various periods of tree life were mostly related to diameter breast high and crown depth. They were also correlated with tree height, but only to a limited extent. In contrast, properties of wood from the middle stem sections were significantly correlated with crown diameter.

Allometric equations were developed to describe crown attributes of three species of open-grown Larix in Minnesota and compared with similar data from Maine and published works from Austria. No differences were detected in allometric relationships to predict crown length, projected crown radius, and crown radius at different depths within the crown among tamarack, European larch, and hybrid European×Japanese larch grown in Minnesota. Small (

The phenotypic characteristics of the plus trees ofLarix principis-rupprechtii such as stem form, branch angle, branch/stem ratio, branch density, the crown width, crown length, number of short branch over 5-cm branch segment in length, and the leaf number of each short branch were investigated in seed orchard in the Changcheng Mountain, Shaanxi Province. According to the morphological characters, the plus tree clones ofLarix principis-rupprechtii were classified into 4 natural types: the narrow-dense-crown type, wide-dense-crown type, wide-sparse-crown type, and the narrow-sparse-crown type. The result of the cluster analysis showed there was a very significant difference in tree growth among the four natural types. While comparing the tree growth of four natural types for the last ten years, it was found that the performance order of various types from good to bad is as follows: the narrow-dense crown type > the wide-dense crown type > the wide-sparse crown type > the narrow-sparse crown type. The plus trees of narrow-dense-crown, as a fine type, should be paid great attention to production and prepared to popularize.

Prosopis cineraria (L.) Druce is extensively lopped for fodder by farmers in the arid and semi arid areas of Rajasthan. Generally, complete lopping is practised. The effect of different lopping intensities on the growth and fodder yield of this species has been studied and the results are reported in the present paper. It was found that lopping does not significantly affect the height and dbh growth or the fodder production. It was determined that complete lopping was detrimental in nature for better diameter growth. It would be advisable to lop the trees moderately (approximately 2/3 of the crown length) preferably with a gap between successive lopping for better fodder yield on a sustained basis.

The effects of release cutting on cone, seed production, and seed quality were investigated in 1995-1996 among Scots pine (Pinus sylvestris L.) seed trees in central Sweden. The effects of diameter, height, crown length, and age of trees on cone production were also examined. Cone and seed production were about five times higher in seed trees that had been released for 4 or 5 years, compared with control trees in the unreleased forest. Seed trees released for less than 3 years had about the same level of cone production as the controls. After release, the number of cones increased more in the lower part of the tree crowns than in the uppermost 2 m. The mean 1000-seed weight, seed viability, and number of viable seeds per cone were not significantly different between released and unreleased trees. In 1996, there were about eight times more cones than in 1995, probably because summer temperatures were higher in 1994 than in 1993, the years when the respective flower buds were initiated. Within the investiga...

Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i)estimate the amount of foliage held by individual trees from sapwood cross-sectional area and (ii)define the relationship between stem volume growth and three variables: total foliage area, relative position in the stand, and the degree of past suppression. A model that included variables representing tree size (or relative social position) and degree of past suppression (live branch whorls per unit crown length) indicated that stem volume growth first increased but later decreased over leaf area when other variables were held constant. Growth efficiency declined with increasing tree leaf area, although greater height and diameter enhanced growth efficiency and greater past suppression diminished growth efficiency. The decline in growth efficiency with greater leaf area likely is attributable to one or several of the factors previously identified as contributing to growth declines in mature, even-aged stands.

The effect of the number of Pinus sylvestris trees in seed spots on the growth and external quality of the dominant trees was studied. The trees were monitored during the period between release cutting and the first commercial thinning. The treatments were one, two and four of the tallest seedlings retained per seed spot, and a control. The mean height of the dominant trees was highest in the one‐tree and two‐tree treatments. Diameter at breast height (DBH) increased with increasing spacing. On average, the stump diameter was 1.5–4.7 cm greater in the one‐tree treatment than in the control. Slenderness (height/DBH) was highest in the control treatments. The average living crown limit of the dominant trees was 4.6 m, and was at its highest in the two‐tree treatment. The results indicate that the competition in seed spots decreases the height growth of the dominant trees.

Stand-level models were derived to predict crown height or the distance from ground to the first live branch of unthinned planted loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm.) pine trees in East Texas. Average height of the tallest trees was the principal predictor in the models. In addition, the influence of number of planted trees per acre, nonplanted basal area and fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme ) was considered. The models quantify the plantation ages when the butt log and successive lower stem logs are clear of live branches. This information may assist with merchandising the planted pines. South. J. Appl. For. 21(3):130-133. One aspect of pine plantation ma agement is merchandising the planted trees into appropriate products. Many tree factors can influence the merchandising process, such as diameter, height, crown condition, stem quality, incidence of disease, and the length of lower stem from ground to the first live branch. This length of the lower stem is equivalent to crown height, while the length of the upper stem from the first live branch to the top of the tree is the crown length. Crown ratio is defined as crown length divided by tree height. In addition to merchandising the trees, reliable information on expected values of crown length, crown ratio and crown height may assist in planning: s Number of trees per acre to plant. s Pruning specifications. s Timing and intensity of intermediate harvests. s Specifying optimum rotation ages. Models for estimating crown ratio and crown height for individual trees have been developed in several studies (Ward 1964, Wykoff et al. 1982, Dell et al. 1979, Feduccia et al. 1979, Ek and Monserud 1975, Daniels and Burkhart 1975, Van Deusen and Biging 1985, Dyer and Burkhart 1987). Average stand crown ratio and average stand crown height have been estimated by Holdaway et al. (1979) and Cole and Jensen (1982). A "crown rise" model that estimated crown height on a stand-level basis was developed by Valentine et al. (1994). Several papers presented crown height increment prediction models for individual trees (Short and Burkhart NOTE: Manuscript received December 14, 1995, accepted August 13, 1996. 1992, Maguire and Hann 1990a,b and Liu et al. 1995). In this paper, models are presented to estimate average stand crown height for unthinned loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) plantations in East Texas. Plantation Measurements Information from permanent plots located in unthinned industrial loblolly and slash pine plantations throughout East Texas was analyzed inthis study. 1 In 1982-1984, 256 plots were established in separate plantations to start the East Texas Pine Plantation Research Project (ETPPRP). By 1995, about 25 % of the original ETPPRP plots have been destroyed by inadvertent acts of nature and man. The plots are measured on a 3 yr cycle, and each plot consists of two subplots. A subplot is 100 ft x 100 ft, and all planted pines within a subplot were tagged and numbered At each measurement, values such as dbh, total height, crown height, and occurrence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme) are measured and recorded for each surviving planted pine tree in a subplot In addition, two sampling points are situated within each subplot for measuring and recording dbh values of nonplanted trees. For this study, each subplot was a sampling unit. For an observation to be included in the data sets, crown height had to be 1 ft or more. As a result, the total number of observations 1 Support from participating companies--Champion International Corporation, International Paper Company, Louisiana-Pacific Corp., Resource Management Services, Inc. and Temple-Inland Forest Products Corp --lS appreciated.

The aim of the study was to establish single‐tree functions to predict crown height, defined as the height from the ground to the attachment of the lowest living branch to the trunk. Data from the Swedish National Forest Inventory 1983–1992 were used to construct country‐wide functions for Scots pine (Pinus sylvestris L.) and for Norway spruce (Picea abies (L.) Karst.). The model derived was based on the assumption that crown recession in closed forests is caused primarily by lack of light. A crown height function and a relative crown height (crown height/total tree height) function were calculated for each species and were found to predict crown height fairly accurately. Crown height was generally predicted more accurately for Scots pine than for Norway spruce. The crown height functions developed here can be used as an input for predicting the quality of timber. The functions are meant to form part of a system for the long‐term forecasting of timber yields, but they can also be used in calculations of t...

In this paper, we attempted to address the following issues: 1, The estimation of the total mass of leaves on a given tree. 2, The relationship between tree leaf mass and tree height as well as crown breadth area. Determining factors of tree growing mainly include tree height, crown length and diameter at breast height(DBH). We analyzed the relationship between all these factors and tree leaf area. Finally, we sought to clarify how tree height and leaf area correlates with leaf mass by establishing tree height inhibiting model, a regression model on tree height and leaf area. After acquiring the leaf mass per unit area, we based on the linear relationship between tree height and leaf area to estimate the total tree leaf mass on a given tree.

Objetivou-se gerar um modelo de incremento periódico em área basal (IPAG) para Pinus taeda válido para povoamentos localizados no Rio Grande do Sul e Paraná. Foram instaladas parcelas temporárias em povoamentos de Cambará do Sul (RS) e Ponta Grossa (PR), em que a árvore de maior diâmetro foi considerada dominante na parcela. De todas as árvores, foi medido o diâmetro à altura do peito e altura total, e das dominantes foi medido também o diâmetro de copa, altura de inserção da copa e comprimento de copa, para o cálculo do grau de esbeltez, proporção de copa, formal de copa, índice de abrangência e saliência. Foi retirado um rolo de incremento de todas as árvores dominantes, para o cálculo do IPAG dos últimos cinco anos. O modelo foi construído pelo método stepwise, no pacote estatístico SAS® e validado pelas condicionantes da regressão. Foram selecionadas as variáveis diâmetro inicial, diâmetro de copa, grau de esbeltez e índice de competição baseado na área basal total e relativa. O modelo apresentou alto coeficiente de determinação e baixo erro padrão da estimativa, e a análise estatística não demonstrou diferença entre as curvas reais e estimada, evidenciando o uso do modelo em ambos os locais analisados e em locais semelhantes a eles.

La habilidad de describir la forma y tamaño de la corona de los árboles es un importante pre-requisito para la estimación de la estabilidad de los árboles de un bosque. Este artículo describe modelos de corona para el Laurel (Cordia alliodora), adaptadas a las condiciones de crecimiento de sistemas agroforestales. La base de datos empíricos incluye un total de 207 observaciones. Un análisis de corona basado en el largo, ancho, base de corona, largo, radio y proyección de corona. Los árboles muestreados han crecido en sistemas agroforestales de 10 años de edad, los cuales fueron raleados a diferentes intensidades. Para determinar el ancho de corona existió una relación lineal entre DAP y ancho de corona. La modificación de los modelos en dirección hacia una relación no lineal no muestra mayores mejoramientos en la estimación de este parámetro. La base de la Corona, el modelo desarrollado por Dursky (2000) es el que mayor r2 (0,84) presentó, los valores de distorsión del mencionado modelo se acercan a los valores ideales de 0 (0,0083) y el cuadrado medio del error fue de 1.49 metros. Este modelo se ajustó a las características del Laurel. Se desarrolló un modelo para establecer el largo de la corona, el cual presentó un r2 de 0,71. Esto significa que únicamente el 71% de la variación observada en el Laurel para este parámetro puede ser explicada. Los modelos desarrollados dentro de esta investigación pueden ser utilizados para comprobar y calcular otro tipo de atributos forestales del Laurel.

A three-dimensional geometric model of crown competition was developed which can be used for empirical distance-dependent individual-tree models or biologically based process models. The crown model calculates the shape of a subject tree's crown based on the positions of its competitors' crowns and the rules of competition. It is necessary to use a crown profile equation to use the crown model. The crown profile equation was estimated from the crown width of open-grown trees at the base of the live crown. Ten replicates of a loblolly pine ( Pinus taeda L.) progeny study planted in a variable density Nelder's wheel layout re-measured annually from Ages 6 to 10 and at Age 12 were used for the analysis. The use of two different rules of competition and two different methods of calculating crown volume, surface area, and exposed surface area resulted in eight different estimates related to the geometry of each crown. The relationships of the natural logarithm of periodic annual wood volume growth of different time lengths were fit to geometric estimates generated from the crown model. These relationships were compared with crown length and wood volume relationships to evaluate the utility of the three-dimensional crown model. Exposed surface area of the crown was the best predictor of volume growth produced by the crown model. Wood volume was the single best predictor of growth until Age 9, when exposed surface area became superior. The best model of all possible models was wood volume, exposed surface area, and surface area. Wood volume, exposed surface area, and total surface area length accounted for 1–11% more of the variability than crown length and wood volume. This indicated that the crown model offered benefits over the use of the raw data. The relative performance of the crown model compared with wood volume and crown length improved as competition increased. The crown model appears to offer potential for growth and yield modeling; it must be further evaluated, however, for use in mature stands.

Changes in tree form and taper over time, as affected by changes in tree, stand, and site factors for interior lodgepole pine (Pinuscontorta var. latifolia Engelm.) were investigated using detailed stem analysis data from interior British Columbia. It was found that tree shape and taper change along the stem at one time and over time with changes in tree and stand factors, particularly the diameter at breast height to total tree height ratio, crown length, and crown ratio, and with predicted quadratic mean diameter at age 50 years, a stand density measure. At young ages, the trees were parabolic in shape from ground to top. However, as they increased in size over time, different portions of the stem took different shapes because of unequal growth in diameter along the stem. Changes in tree shape and taper over time were closely related to the crown size, which is related to stand density.

The crown development of red pine (Pinusresinosa Ait.) plantations originating from different initial spacings was studied between 13 and 33 years of age. First, the effect of spacing on models used to predict crown width and crown ratio from diameter at breast height (DBH) and height was examined. Models for trees of different ages that included all the spacings were found to predict crown growth measures as well as separate models derived for each spacing. Second, the following crown relative growth measures were studied: crown width/crown length (crown shape ratio), crown surface/crown volume, and foliage biomass/crown volume. The way such measures changed over time under different initial spacings was studied; these findings were compared with changes in relative growth rate (RGR), which can be used to evaluate the effect of competitive stress. Crown shape ratio decreased with an increase in DBH in the absence of severe competition, and increased with DBH under severe competitive stress. The other two crown relative growth measures were always negatively correlated with DBH; this shows that large trees use their aerial growing space less efficiently than small trees at all stages of stand development. Only crown shape ratio changed in the same way as RGR.

A spacing trial was established near Thunder Bay, Ontario in 1950. This trial consisted of black spruce (Picea mariana (Mill.) B.S.P.), white spruce (Picea glauca (Moench) Voss.), and red pine (Pinus resinosa Ait.) each established at three different spacings: 1.8 m, 2.7 m, and 3.6 m. This study examines the differences in growth and crown development as attributed to initial spacing, after 37 years. In addition, a benefit/cost analysis was performed to evaluate the economic efficiency of the various species/spacing combinations. Diameter at breast height, live crown length, and crown width, all exhibited significant (P < 0.001) increases as initial spacing increased, irrespective of species, but, height demonstrated a decreasing trend (P

To test whether and how morphological traits are linked with growth responses of plants to temperature and CO is important for understanding the mechanism underlying how plant growth will respond to global warming. In this study, using closed-top chambers to mimic future elevated CO and temperature, the growth response, morphological traits of Minjiang fir (Abies faxoniana Rehd.et Wils.) and the relationship of the two were investigated after two years of exposure to the single and combined elevation of CO and temperature. The results showed that biomass of Minjiang fir was 21%, 31%, and 35% greater than the control in elevated CO, elevated temperature and the combination of elevated CO and temperature treatments, respectively. Elevated CO and temperature significantly affected the morphology of Minjiang fir, and a few morphological traits were highly correlated with growth responses. Larger branch angles at the upper layer, crown volume, and relative crown length contributed to positive growth responses to elevated CO, while decreased specific leaf area (SLA) constricted any further growth response. Leaf morphological traits were more closely correlated with the response ratio than crown did in the elevated temperature, while in the combination of elevated CO and temperature, crown was more correlated with the response ratio than the leaf morphological traits. Thus, our results indicate that morphological traits may contribute differently to growth responses under different experimental conditions.22222222

The effects of green crown reduction (needle loss) on the nutrient status of needles were studied in Scots pine (Pinussylvestris L.) in Finland. Trees were either diseased with scleroderris canker (Gremmeniellaabietina (Lagerb.) Morelet) or had been green pruned. The concentrations of 15 different elements were determined in needles collected in March 1987 from 120 trees in six young Scots pine stands. Four of the stands had suffered from scleroderris canker over the last 10 years, whereas the other two stands were healthy and had been pruned about 2 years before sampling. To eliminate the effects of soil and environmental factors, sample trees were chosen in pairs. Each pair contained one tree with a severely reduced crown (about a 50% reduction in crown length as a result of disease or pruning) and an adjacent tree (control) with an unaffected crown. Compared with the control trees, concentrations of foliar B, Ca, N, and S were significantly higher in both diseased and pruned trees, while Mn was higher only in diseased trees and Na and Cu, only in pruned trees. Foliar Fe and Mg concentrations were lower in diseased trees than in control trees. In many stands there was a significant correlation between needle element concentrations and severity of crown reduction, suggesting that differences in foliar elemental concentration in Scots pine needles depend on the extent of crown reduction. This phenomenon should be considered when interpreting foliar analyses of recently defoliated conifers, particularly before conclusions are made about the need for fertilization, nutritional disturbances, or the effects of air pollution.