Rapid Height Research Articles

Etiological profile of precocious puberty in children at a Tertiary Care Hospital.

Objective: To determine the etiological profile of precocious puberty in children. Study Design: Cross-sectional study. Setting: Department of Endocrinology, National Institute of Child Health, Karachi, Pakistan. Period: October 2023 to September 2024. Methods: Children of either gender, girls aged below 8 years, boys below < 9 years, and newly diagnosed cases of precocious puberty were analyzed. At the time of enrollment, demographic and clinical features were documented. Radiological and hormonal profiling were performed for the confirmation of etiology and type of precocious puberty. Results: In a total of 48 children, 23 (47.9%) were boys, and 25 (52.1%) girls. The mean age was 5.72±1.78 years. The most frequent clinical features were rapid height growth, adult body odor, and breast enlargement, noted in 48 (100%), 42 (87.5%), and 25 (52.1%) cases, respectively. Precocious puberty type was central, and peripheral among 25 (52.1%), and 23 (47.9%) children, respectively. Among central precocious puberty cases (n=25), the evaluation of etiology revealed that idiopathic in 17 (68.0%) children, hypothalamic hemartoma 3 (12.0%), mitochondrial encephalopathy 2 (8.0%), craniopharyngioma 2 (8.0%), and arachnoid cyst 1 (4.0%). Among 23 peripheral puberty cases, congenital adrenal hyperplasia was identified in 18 (78.3%) children, adrenocorticol carcinoma 2 (8.7%), ovarian teratoma 2 (8.7%), and Mccune-Albright syndrome in 1 (4.3%). Conclusion: Idiopathic central precocious puberty and congenital adrenal hyperplasia emerged as the most common causes of central and peripheral precocious puberty, respectively.

Evaluation of Average Post-menarche Height Growth and Associated Factors: A Cross-Sectional Study

Background: Adolescents experience rapid height growth during puberty, which eventually slows down and ceases due to epiphyseal senescence. Menarche marks the final stage of puberty and often raises concerns about the cessation of height growth. Objectives: This study aims to examine post-menarche height growth and identify the factors associated with it. Methods: This retrospective cross-sectional study included adolescent females who visited pediatric endocrinology clinics in Hamadan between 2001 and 2018 and had a minimum follow-up period of three years. Data extracted from patients' medical records included demographic details, birth weight, birth order, height, weight, Body Mass Index (BMI), and stages of thelarche and pubarche. Data analysis was conducted using SPSS version 26. Results: The medical records of 91 girls were evaluated. The mean age of menarche was 11.93 ± 1.27 years. On average, the participants grew 7.98 ± 3.47 cm in height within three years after menarche. The study revealed a significant inverse correlation between post-menarche height growth and both the age at menarche and height at the onset of menarche. No correlation between height growth and other variables was observed. Conclusions: Post-menarche height growth was negatively correlated with height and age at menarche. However, there is limited research on post-menarche height growth in Iranian girls, highlighting the need for further studies.

One-shot structured light illumination based on shearlet transform.

Balancing speed and accuracy has always been a challenge in 3D reconstruction. One-shot structured light illuminations are of perfect performance on real-time scanning, while the related 3D point clouds are typically of relatively poor quality, especially in regions with rapid height changes. To solve this problem, we propose a one-shot reconstruction scheme based on shearlet transform, which combines spatial and frequency domain information to enhance reconstruction accuracy. First, we apply the shearlet transform to the deformed fringe pattern to obtain the transform coefficients. Second, pixel-wise select the indices associated with the N largest coefficients in magnitude to obtain a new filter. Finally, we refocus globally to extract phase using these filters and generate a reliable quality map based on coefficient magnitudes to guide phase unwrapping. Simultaneously, we utilize the maximum coefficient value to generate a quality map for guiding the phase unwrapping process. Experimental results show that the proposed method is robust in discontinuous regions, resulting in more accurate 3D point clouds.

Perkembangan Fisik dan Kognitif pada Masa Kanak-Kanak Pertengahan

Physical and cognitive development in middle childhood undergoes many significant changes. Children at this age develop problem-solving skills, abstract thinking, and language development in cognitive aspects. They have the ability to understand the concepts of time and space, as well as improve their reading and writing skills. At this stage, physical development includes rapid body growth, muscle strengthening, and improved motor coordination. Children usually experience rapid height growth and organ development. Physical activities and activities involving movement are becoming increasingly important for achieving an optimal level of physical fitness. These two components are interrelated, and good physical health can support cognitive development. Positive simulations, environmental factors, and education also played an important role in shaping the holistic development of the time.

Prevalence of and Factors Associated With High Blood Pressure at 15 Years of Age: A Birth Cohort Study.

Arterial hypertension is the greatest cause of morbidity and mortality worldwide. Our aim was to investigate the prevalence of and factors associated with high blood pressure (HBP) among adolescents. The Pelotas 2004 Birth Cohort included 4231 newborns from hospital births in Pelotas, Brazil. A digital automatic OMRON sphygmomanometer (model HEM 742) was used to measure blood pressure on 3 occasions (at 6, 11, and 15 years of age). Those with blood pressure ≥95th percentile for age, height, and sex on each of the 3 occasions were considered as presenting HBP. Independent variables included family (income and history of arterial hypertension), maternal (schooling, age, pregestational body mass index, and smoking during pregnancy), and adolescent characteristics at birth (sex, skin color, gestational age, intrauterine growth, and systolic and diastolic genetic factors), and at 15 years (sleep, physical activity, sodium intake, screen time, work, body mass index, fat mass index, fat-free mass index, growth pattern, and puberty status). The prevalence of HBP (95% CI) was calculated. Crude and adjusted odds ratios (ORs) stratified by sex were obtained by logistic regression. A total of 1417 adolescents with complete information on blood pressure on the 3 occasions were analyzed. The prevalence of HBP was 3.2% (95% CI, 1.9%-4.5%) in female adolescents and 4.3% (95% CI, 2.8%-5.8%) in male adolescents. Female adolescents with a family history of arterial hypertension had a 3 times higher chance of HBP than their counterparts (OR, 3.1 [95% CI, 1.26-7.54]). In male adolescents, excessive maternal pregestational weight was associated with a 2.3-fold increase in the chance of HBP. In both sexes, excessive adolescent weight was associated with HBP (ORs, 3.5 and 5.0, for female and male adolescents, respectively). A higher fat mass index and fat-free mass index in female (ORs, 1.4 and 1.2, respectively) and male adolescents (ORs, 2.5 and 3.0, respectively) increased the chance of HBP. Among male adolescents, the chance of HBP was higher among those with rapid weight gain between 48 months and 6 years and between 6 and 11 years and rapid height gain between 6 and 11 years. Higher fat mass in both sexes and rapid weight gain in male adolescents are risk factors for HBP in adolescents aged 15 years, potentially amenable to prevention.

Morphological Crown Attributes Contributing to Differential Height and Diameter Growth among Families in a Coastal Douglas-Fir Progeny Test: Crown Structural Evidence for Crop Ideotypes

Theoretical tree crop ideotypes have long and narrow live crowns with a high total leaf area. This crown form allows more efficient exploitation of site resources, in part by physically occupying less growing space per unit leaf area and by packing a greater number of trees into a given area. Genetic selection for crop ideotypes has been proposed as a strategy for maximizing productivity per unit area in stands managed under intensive silviculture. The primary objective of this study was to test the relationship between the relative growth performance of different families in a Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) progeny test and morphological crown attributes that conform to a theoretical crop ideotype. The overarching goal was to identify attributes conferring superior height and diameter growth on families and to facilitate the incorporation of these attributes and associated growth mechanisms into hybrid growth models for intensively managed plantations. Crown structural attributes were measured on destructively sampled trees and averaged for the entire crown and each third of live crown length among families. Multivariate analysis revealed that crown attributes averaged over the entire crown performed best for identifying families with different height and diameter growth, followed successively by the bottom, middle, and top crown third. Trees with relatively short branch lengths and steep branch angles tended to have higher total leaf area per unit crown length (TLACL), and this structural attribute showed a strong positive correlation with cumulative diameter growth. The ratio of crown width to crown length (CWL) was moderately and negatively correlated with cumulative height growth. The families displaying the most rapid diameter growth in this progeny test conformed to a theoretical crop ideotype, while those with the most rapid height growth displayed crown attributes with a less obvious relationship to the crop ideotype concept. TLACL implied one possible mechanism driving genetic gain in Douglas-fir families, given its high heritability and strongly positive correlation with growth performance. Incorporating TLACL as an explanatory variable in diameter growth models could at least partly represent different genetic levels. TLACL is less strongly correlated with height growth rate, so incorporating CWL may better represent genetic effects on height growth models.

Solutions to fire and shade: resprouting, growing tall and the origin of Eurasian temperate broadleaved forest.

Tree species of Eurasian broadleaved forest possess two divergent trait syndromes with contrasting patterns of resource allocation adapted to different selection environments: short-stature basal resprouters that divert resources to a bud bank adapted to frequent and severe disturbances such as fire and herbivory, and tall trees that delay reproduction by investing in rapid height growth to escape shading. Drawing on theory developed in savanna ecosystems, we propose a conceptual framework showing that the possession of contrasting trait syndromes is essential for the persistence of broadleaved trees in an open ecosystem that burns. Consistent with this hypothesis, trees of modern Eurasian broadleaved forest bear a suite of traits that are adaptive to surface and crown-fire regimes. We contend that limited opportunities in grassland restricts recruitment to disturbance-free refugia, and en masse establishment creates a wooded environment where shade limits the growth of light-demanding savanna plants. Rapid height growth, which involves investment in structural support and the switch from a multi-stemmed to a monopodial growth form, is adaptive in this shaded environment. Although clustering reduces surface fuel loads, these establishment nuclei are vulnerable to high-intensity crown fires. The lethal effects of canopy fire are avoided by seasonal leaf shedding, and aerial resprouting enhances rapid post-fire recovery of photosynthetic capacity. While these woody formations satisfy the structural definition of forest, their constituents are clearly derived from savanna. Contrasting trait syndromes thus represent the shift from consumer to resource regulation in savanna ecosystems. Consistent with global trends, the diversification of most contemporary broadleaved taxa coincided with the spread of grasslands, a surge in fire activity and a decline in wooded ecosystems in the late Miocene-Pliocene. Recognition that Eurasian broadleaved forest has savanna origins and persists as an alternative state with adjacent grassy ecosystems has far-reaching management implications in accordance with functional rather than structural criteria. Shade is a severe constraint to the regeneration and growth of both woody and herbaceous growth forms in consumer-regulated ecosystems. However, these ecosystems are highly resilient to disturbance, an essential process that maintains diversity especially among the species-rich herbaceous component that is vulnerable to shading when consumer behaviour is altered.

Tracking the Rates and Mechanisms of Canopy Damage and Recovery Following Hurricane Maria Using Multitemporal Lidar Data

Hurricane Maria, a Category 4 storm, snapped and uprooted canopy trees, removed large branches, and defoliated vegetation across Puerto Rico. The magnitude of forest damages and the rates and mechanisms of forest recovery following Maria provide important benchmarks for understanding the ecology of extreme events. We used airborne Lidar data acquired before (2017) and after Maria (2018, 2020) to quantify landscape-scale changes in forest structure along a 439-ha elevational gradient (100–800 m) in the Luquillo Experimental Forest. Damages from Maria were widespread, with 73% of the study area losing ≥ 1 m in canopy height (mean = −7.1 m). Taller forests at lower elevations suffered more damage than shorter forests above 600 m. Yet only 13.5% of the study area had canopy heights ≤ 2 m in 2018, a typical threshold for forest gaps, highlighting the importance of damaged trees and advanced regeneration on post-storm forest structure. Heterogeneous patterns of regrowth and recruitment yielded shorter and more open forests by 2020. Nearly 45% of forests experienced initial height loss > 1 m (2017–2018) followed by rapid height gain > 1 m (2018–2020), whereas 21.6% of forests with initial height losses showed little or no height gain, and 17.8% of forests exhibited no height changes larger than ± 1 m in either period. Canopy layers < 10 m tall accounted for most increases in canopy height and fractional cover between 2018 and 2020, with gains split evenly between height growth and lateral crown expansion by surviving individuals. These findings benchmark rates of gap formation, crown expansion, and canopy closure following hurricane damage and highlight the diversity of ecosystem impacts from heterogeneous spatial patterns and vertical stratification of forest regrowth following a major disturbance event.

Variation in Bark Allocation and Rugosity Across Seven Co-occurring Southeastern US Tree Species

Bark is a complex multifunctional structure of woody plants that varies widely among species. Thick bark is a primary trait that can protect trees from heat generated in surface fires. Outer bark on species that allocate resources to thick bark also tends to be rugose, with bark being thickest at the ridges and thinnest in the furrows. Tree diameter or wood diameter is often used as a predictor for bark thickness but little attention has been made on other factors that might affect bark development and allocation. Here we test multiple mixed effect models to evaluate additional factors (height growth rate, measure height) that correlate with bark allocation and present a method to quantify bark rugosity. We focused on seven co-occurring native tree species in the Tallahatchie Experimental Forest in north Mississippi. Approximately ten saplings of Carya tomentosa, Nyssa sylvatica, Prunus serotina, Pinus echinata, Pinus taeda, Quercus marilandica, and Quercus falcata were destructively sampled for stem analyses. Outer bark thickness (OBT) ranged from 0.01 to 0.77 cm with the thickest maximum outer bark occurring on P. taeda (0.77 cm) and the thinnest maximum outer bark occurring on P. serotina (0.17 cm). Our outer bark allocation models suggest that some individuals with rapid height growth allocate less to outer bark in C. tomentosa, N. sylvatica, P. taeda, and P. serotina, but not for P. echinata or either oak species. All species except for C. tomentosa and N. sylvatica showed evidence for outer bark taper, allocating more outer bark at the base of the bole. Inner bark also was tapered in Carya and the oaks. Bark rugosity varied among species from 0.00 (very smooth) to 0.17 (very rugose) with P. Serotina and C. tomentosa having the smoothest bark. OBT was the best fixed effect for all species. Aside from providing data for several important yet understudied species, our rugosity measures offer promise for incorporating into fluid dynamics fire behavior models.

Evolutionary loss of thermal acclimation accompanied by periodic monocarpic mass flowering in Strobilanthes flexicaulis

While life history, physiology and molecular phylogeny in plants have been widely studied, understanding how physiology changes with the evolution of life history change remains largely unknown. In two closely related understory Strobilanthes plants, the molecular phylogeny has previously shown that the monocarpic 6-year masting S. flexicaulis have evolved from a polycarpic perennial, represented by the basal clade S. tashiroi. The polycarpic S. tashiroi exhibited seasonal thermal acclimation with increased leaf respiratory and photosynthetic metabolism in winter, whereas the monocarpic S. flexicaulis showed no thermal acclimation. The monocarpic S. flexicaulis required rapid height growth after germination under high intraspecific competition, and the respiration and N allocation were biased toward nonphotosynthetic tissues. By contrast, in the long-lived polycarpic S. tashiroi, these allocations were biased toward photosynthetic tissues. The life-history differences between the monocarpic S. flexicaulis and the polycarpic S. tashiroi are represented by the “height growth” and “assimilation” paradigms, respectively, which are controlled by different patterns of respiration and nitrogen regulation in leaves. The obtained data indicate that the monocarpic S. flexicaulis with the evolutionary loss of thermal acclimation may exhibit increased vulnerability to global warming.

Climatic, vegetative, and disturbance predictors of lichen species’ height in Arctic Alaska, USA

Lichens cover approximately 8% of land surface, primarily in alpine and polar habitats. Lichen biomass is often correlated with cover and thallus height, but quick and effective methods of lichen biomass estimation have not been tested across large areas. We utilize a dataset of over 7800 height measurements made throughout the Arctic Network of National Parks in the US to model mat-forming macrolichen height by species as a function of morphological, climatic, and habitat factors. Our goal was to understand how lichen height, as proxy for biomass, varied by species in different areas, and determine which factors best predict lichen height. We found that the single best predictor of lichen height was surface downwelling shortwave radiation. Climatic, vegetative, and other physiographic variables were moderate predictors of lichen height. We determined that differences in height observed between species were not explained by the degree of branching nor thallus width. Our findings highlight that the key factors predicting lichen height may not be easy to mitigate through management (e.g., radiation, vapor pressure deficit, length of growing season), yet may be altered in future climate change scenarios. Further, rapid height field measurements, like those used in our study, could improve our understanding of the drivers of lichen biomass, underscore its variability across species, and could be used for other applications. Accurate biomass measurements are necessary for landscape-scale monitoring and predictions of future lichen biomass in the face of climate perturbations.

Options for estimating horizontal visibility in hemiboreal forests using sparse airborne laser scanning data and forest inventory data

Abstract Horizontal visibility v in hemiboreal forest transects was measured in the field and then predicted, both from forest inventory (FI) data and from airborne laser scanning (ALS) data. Stand density N and mean diameter at breast height D were used as arguments in an FI predictive model assuming Poisson distribution of trees on a horizontal plane. It was found that a lack of FI data on forest regrowth and understorey trees caused v to be overestimated. Point cloud metrics of sparse ALS data from summer 2017 and spring 2019 were used as predictive variables for v in regression models. The best models were based on three variables: the 10th percentile of the point cloud height distribution, relative density of returns in a horizontal layer ranging 0.7–2.2 m above the ground, and canopy cover. The models had a coefficient of determination of up to 67% and a residual standard error of less than 25 m. In forests in which fertile soil produces rapid height growth of understorey woody vegetation after recent thinning, visibility was found to be substantially overestimated because the understorey was not detected by the lidar measurements.

Deer browsing and shrub competition set sapling recruitment height and interact with light to shape recruitment niches for temperate forest tree species

For temperate forests, Michigan, USA, we asked: (1) does evidence exist for a height-dependent sapling recruitment bottleneck caused by shrub layer competition and white-tailed deer (Odocoileus virginianus) browsing and, if so, (2) how do these factors interact with light availability in shaping species-specific sapling recruitment niches? The combination of deer browsing effects on tree population height structure and the effects of deer and shrubs on tree seedling height and mortality indicate a shrub-deer bottleneck for sapling recruitment. The maximum height of deer browsing and shrub canopies as well as height dependent seedling mortality rates revealed a critical height threshold of approximately 2 m, above which trees escape from shrub and deer effects (i.e. sapling recruitment). Species’ sapling recruitment niches differed across a harvest gap size (i.e. light availability) gradient, over which tree seedling height growth potential and shrub competition increased with gap size, but deer browsing probability decreased. Specific to forests with high deer populations, niche differences were related to species growth and survival properties, with species generally falling into three groups: High Light, Broad, and Nowhere. High Light species incur high mortality from shade, shrub competition, and deer browsing. However, recruitment can occur in recently formed large gaps, where seedlings growing within developing shrub canopies avoid competition via rapid height growth and are partially protected from browsing deer. Broadspecies have lower mortality in shade and grow slower thanHigh Lightspecies and, compared to other groups, exhibit height growth and mortality rates that are less-sensitive to deer browsing pressure.These properties allowssapling recruitment ofBroadspecies over a wide range of gap sizes, including larger gaps, where, via advance regeneration, they can avoid competition with developing shrub layers following canopy disturbance.Nowherespecies are similar toBroadspecies, except their height growth and mortality are sensitive to deer browsing pressure. Heavy browsing pressure in smaller gaps and an inability to maintain taller advance regeneration to contend with shrub competition when large gaps form leaveNowherespecies without a sapling recruitment niche. In conclusion, we provide evidence that shrub competition, ungulate browsing, harvest gap size and their interactions constrain height-specific sapling recruitment among tree species in the temperate forests of Michigan. Similar mechanisms may operate in other forests with high ungulate populations. Given these drivers and current management regimes, increasing tree species diversity and resilience to future disturbances may hinge on changing and integrating forest and ungulate management paradigms.

Assessing tall stature

Abstract Children and adults are considered ‘tall’ when their height is above 98th centile for age i.e. 2 standard deviations (SD) above the mean. Tall stature is familial in most cases. In assessing children with tall stature the mid-parental height centile should always be calculated and this article gives advice on how to proceed with investigation and management for children who are unexpectedly tall. Other common causes of tall stature are obesity or early normal puberty. Precocious puberty, hyperthyroidism and GH excess are less common but these will also cause rapid height velocity at any age and precocious puberty should be excluded in every child presenting with tall stature. Where height centile exceeds mid-parental centile prediction it is helpful to look for genetic syndromes, metabolic conditions and sex chromosome abnormalities. Constitutional tall stature i.e. physiologically normal advanced growth and development is a diagnosis of exclusion and treatment is rarely required. Treatment options include early and accelerated induction of pubertal development with a physiological sex hormone regimen, or epiphysiodesis, but need to be considered before puberty onset. High dose sex steroids are no longer indicated.

Weight and height growth of malnourished school-age children during re-feeding. Three historic studies published shortly after World War I.

In view of the ongoing debate on "chronic malnutrition" and the concept of "stunting" as "a better measure than underweight of the cumulative effects of undernutrition and infection (WHO)", we translate, briefly comment and re-publish three seminal historic papers on catch-up growth following re-feeding after severe food restriction of German children during and after World War I. The observations were published in 1920 and 1922, and appear to be of particular interest to the modern nutritionist. The papers of Abderhalden (1920) and Bloch (1920) describe German children of all social strata who were born shortly before World War I, and raised in apparently "normal" families. After severe long-standing undernutrition, they participated in an international charity program. They experienced exceptional catch-up growth in height of 3-5 cm within 6-8 weeks. Goldstein (1922) observed 512 orphans and children from underprivileged families. Goldstein described very different growth patterns. These children were much shorter (mean height between -2.0 and -2.8 SDS, modern WHO reference). They mostly failed to catch-up in height, but tended to excessively increase in weight particularly during adolescence. Whereas Abderhalden and Bloch illustrate rapid height catch-up in children from intact social background, Goldstein's observations in orphans and children from poor social background parallel the growth patterns observed in children of modern middle and low-income countries. The historic observations question the current concept of stunting as prima facie evidence of malnutrition and chronic infection, and support the view that "the child's longitudinal growth is largely independent of the extent and nature of the diet".

Light emitting diodes (LEDs) affect morphological, physiological and phytochemical characteristics of pomegranate seedlings

Abstract The impact of light-emitting diodes (LED) on developmental, physiological, and phytochemical characteristics of pomegranate (Punica granatum L.) seedlings was investigated. Five LED lights [L20AP67 (moderate blue and red, high green), AP673L (moderate blue, high red and red:far-red), G2 (low blue, high red and far-red), AP67 (moderate blue, high red), and NS1 (high blue and green, low red, high red:far-red, 1% UV) with wide and continuous radiation spectra were used. Fluorescent [FL (high blue and green, low red)] tubes constituted the control treatment. Among treatments, seedlings grown under L20AP67 exhibited the best morphological and growth characteristics (rapid height increase, longer roots, greater fresh and dry weight, greater leaf area). Root activity was comparable among the various treatments, with FL exhibiting the lowest arithmetic value. A variant effect on pigments and secondary metabolites was recorded with the highest chlorophyll and carotenoid content detected under FL, flavonoid under G2 and AP67, and anthocyanin under G2, AP67 and NS1. In addition, NS1 produced the highest total phenolic compound content. Root growth capacity (RGC) was monitored in specialized chambers, then assessed to evaluate the transplanting capacity. Transplanted seedlings of AP67 had the longest, of L20AP67 the heaviest newly formed roots, thus securing a successful transplantation. The herein undertaken study demonstrates that certain LEDs promoted developmental characteristics in pomegranate more efficiently than conventional FL. In particular, the use of L20AP67 was proven a promising tool for producing robust pomegranate seedlings, while some of the other LEDs tested apparently imposed a stressful situation on plants.

Divergent effect of electric fields on the mechanical property of water-filled carbon nanotubes with an application as a nanoscale trigger

Polar water molecules exhibit extraordinary phenomena under nanoscale confinement. Through the application of an electric field, a water-filled carbon nanotube (CNT) that has been successfully fabricated in the laboratory is expected to have distinct responses to the external electricity. Here, we examine the effect of electric field direction on the mechanical property of water-filled CNTs. It is observed that a longitudinal electric field enhances, but the transverse electric field reduces the elastic modulus and critical buckling stress of water-filled CNTs. The divergent effect of the electric field is attributed to the competition between the axial and circumferential pressures induced by polar water molecules. Furthermore, it is notable that the transverse electric field could result in an internal pressure with elliptical distribution, which is an effective and convenient approach to apply nonuniform pressure on nanochannels. Based on pre-strained water-filled CNTs, we designed a nanoscale trigger with an evident and rapid height change initiated by switching the direction of the electric field. The reported finding provides a foundation for an electricity-controlled property of nanochannels filled with polar molecules and provides an insight into the design of nanoscale functional devices.

Internode morphometrics and allometry of Tonkin Cane Pseudosasa amabilis.

Pseudosasa amabilis (McClure) (Poales: Gramineae) is a typical bamboo species naturally distributed in large area of south China and famous for its culm strength. Although bamboos were found to share the same development rule, the detailed internode morphology of bamboo culm was actually not fully expressed. We explored internode morphology of P. amabilis using 11 different physical parameters in different dimensions (1–4). As Taylor's power law (TPL) is generally applicable to describe relationship between mean and variance of population density, here we used TPL to evaluate the differences between internodes, and further, the relationship between dimension and TPL. Results showed that length (L), hollow radius (HR), hollow area (HA), hollow cylinder volume (HCV), total cylinder volume (TCV), density (De), and weight (W) all presented positive skewed distribution in varying degrees. For the basic one‐dimensional parameters, the 9th internode was the longest, the 7th the heaviest, while thickness (T) decreased with internodes. Diameter (D) decreased in general but with an inconspicuous local mode at the 5–6th internodes, potentially due to the rapid height growth. The longest (9th) internode was the “turning point” for T‐D and HR‐D relationships. Scatter plot changing trends of W to the one‐dimensional parameters after the heaviest (7th) internode were reversed, indicating a deceleration of growth speed. TPL was not holding well in one‐dimensional parameters (R 2: 0.5413–0.8125), but keep increasing as the parameter's dimension increasing (R 2 > 0.92 for two‐dimensional, R 2 > 0.97 for three‐dimensional, and R 2 > 0.99 for four‐dimensional parameters.), suggesting an emergence mechanism of TPL related to both the physical dimensions of morphological measures and the allometric growth of bamboo. From the physical fundamental level, all existences are the expression of energy distribution in different dimensions, implying a more general rule that energy distribution holds better TPL in higher dimension level.

Remnant Trees in Enrichment Planted Gaps in Quintana Roo, Mexico: Reasons for Retention and Effects on Seedlings

Natural forest management in the tropics is often impeded by scarcity of advanced regeneration of commercial species. To supplement natural regeneration in a forest managed by a community in the Selva Maya of Mexico, nursery-grown Swietenia macrophylla seedlings were planted in multiple-tree felling gaps, known as bosquetes. Remnant trees are often left standing in gaps for cultural and economic reasons or due to their official protected status. We focus on these purposefully retained trees and their impacts on planted seedlings. Sampled bosquetes were 400–1800 m2, of which remnant trees covered a mean of 29%. Seedling height growth rates over the first 18 months after out-planting more than doubled with increased canopy openness from 0.09 m year−1 under medium cover to 0.22 m year−1 in full sun. Liana infestations and shoot tip damage were most frequent on seedlings in the open, but, contrary to our expectations, height growth rates were 0.14 m year−1 faster for liana-infested seedlings than non-infested and did not differ between damaged and undamaged seedlings. Apparently the more rapid height growth of well-illuminated seedlings more than compensated for the effects of lianas or shoot tip damage. Despite the abundance of remnant trees and their negative effects on seedling growth, enrichment planting in bosquetes has potential for community-based natural forest management in the tropics in supplementing natural regeneration of commercial species. One obvious recommendation is to leave fewer remnant trees, especially those of commercial species that are non-merchantable due to stem defects and trees retained for no apparent reason, which together constituted half of the remnant crown cover in the sampled bosquetes. Finally, given the rapid growth of lianas and understory palms in large canopy gaps, at least the most vigorous of the planted seedlings should be tended for at least two years.

An assessment of potential of hybrid poplar for planting in the Virginia Piedmont

Poplar species grow well across the temperate zone, but hybrid varieties have not previously been evaluated for planting in the Virginia Piedmont region. The top 12 clones in height growth and rust resistance from a screening trial involving 98 hybrid poplar varieties of three taxa (Populus deltoides × P. maximowiczii, DxM; P. deltoides × P. nigra, DxN; P. deltoides × P. trichocarpa, DxT) were selected for planting in replicated yield trials at two locations in the Virginia Piedmont. Results through the first four growing seasons showed that the DxM taxon had the most rapid height development. It was, however, the taxon most affected by a late spring frost at the Appomattox-Buckingham State Forest site and by Septoria stem canker at the Reynolds Homestead site. Analysis of variance of clonal and location effects showed highly significant differences among replicates within location and among clones within taxon. Among seven clones within the DxM taxon, pairwise comparison tests of height growth identified two groups: a group of four better clones that were significantly different (p = 0.05) from a second group of three. These early results suggest that multi-selection criteria, including growth, disease and frost resistance, are important when developing hybrid poplar clones for planting in the Piedmont region.