•Repeated ALS allows detecting the height increment variation influenced by stand density.•Higher stand density stimulate height growth, particularly on most productive sites.•Repeated ALS data ...allows developing density-dependent top height growth models.
The spread of remote sensing technologies allows for continuous and precise mapping of forest ecosystem attributes over large areas. One of the most important attributes of a forest ecosystem is site productivity, an essential determinant of resource availability. Knowledge of site productivity is crucial for sustainable forest management because it is the basis for predictions of future forest growth and is fundamental to long-term planning in forestry. Models of forest dynamics allow us to better understand the functioning of forest ecosystems and to assess the provision of ecosystem services. However, discussions on the factors affecting forest growth are ongoing. Previous research has not clarified the influence of stand density on the height increment of trees. Consequently, this uncertainty leads to inconsistent predictions for stand growth and nonoptimal forest-management decisions. We aimed to analyse the effect of stand density on top height (TH) growth and the development of the TH growth model for Scots pine based on bitemporal ALS measurements. We applied repeated ALS observations from two acquisitions (2011, 2019) to fit a density-sensitive TH growth model. We found that stand density affected the TH growth of Scots pine. A higher stand density stimulated TH growth, particularly in productive sites showing a TH increment of about 10%. We demonstrated the usefulness of bitemporal ALS measurements for developing a TH growth model for Scots pine considering stand density. We found that the predictive accuracy of the TH increment increased when stand density was considered.
•Repeated ALS allows detecting short-term variation of the height increment.•Mean annual precipitation sum affects the height increment of Norway spruce.•Repeated ALS allows developing ...weather-sensitive height growth models.
Fluctuations in weather conditions, particularly precipitation and water availability, may strongly affect growth rate patterns and lead to interannual height growth variation. Consequently, height growth models developed using airborne laser scanning (ALS) data collected at short time intervals may over- or underestimate long-term height growth trends and finally result in different growth forecasts. The objective of this study was to develop height growth models for Norway spruce, including the effect of weather conditions. We used ALS-derived top height (TH) estimates and meteorological data from the research area collected for 2007-2012 and 2013-2018 to develop a weather-sensitive height growth model. The top height (TH) growth of Norway spruce was affected by the mean annual precipitation sum (APS) in the studied periods, and a higher APS resulted in faster TH growth. This study demonstrates the high potential of repeated ALS for detecting short-term variation in the tree height increment and the development of weather-sensitive height growth models.
•Positive effect of stump removal on the height growth of the trees was revealed.•Stump removal had no effect on the nutritional status of the needles of young trees.•Positive trend of stump removal ...on twig and needle parameter revealed.•Stump removal had no effect on the spread of Heterobasidion sp., Armillaria sp.•The main causal agent of root rot on all the sampling sites was H. parviporum.
Stumpwood as a resource of renewable bioenergy has considerable potential in the Nordic and Baltic countries. So far, however, it has largely been left unutilised in Estonia. This study reports the results of the height growth, needle and twig traits, and Heterobasidion sp. and Armillaria sp. infection in emerging Norway spruce (Picea abies) stands after stump harvesting. After six and eight growing seasons, a significant positive effect of stump harvesting on the height growth of the trees was revealed, compared to control plots with no ground preparation. In one study site stump harvesting was revealed to have a positive effect on the morphologic parameters of twigs and needles, while no differences were noted in the other two sites. The nutrient content of the needles was similar between the treatments across all study sites. Stump harvesting had no effect on the spread of Heterobasidion sp. and Armillaria sp. in the new forest generation. Root infections in young trees with Heterobasidion sp. were detected as early as within two growing seasons from planting. The infection was most severe in the Hepatica site type stand, where 90% of the trees in the previous forest generation had been infected by Heterobasidion sp. In the two other stands studied, where the share of infected trees in the previous generation had been 26% and 16%, Heterobasidion sp. was significantly less widespread. The main causal agent of root rot on all the sampling sites was H. parviporum, but the presence of Armillaria sp. was also remarkable.
When combining multi-temporal airborne laser scanning (ALS) data sets, forest height growth assessments can be compromised due to variations in ALS acquisitions. Herein, we demonstrate the importance ...of assessing and harmonizing the vertical alignment of multi-temporal ALS data sets used for height growth calculations. Using four ALS acquisitions (2005-2018) in a temperate mixed wood forest, we developed an ALS data harmonization approach and quantified the impact of the harmonization on derived height periodic annual increment (PAI), comparing the ALS-derived PAI to PAI derived from non-harmonized ALS data sets and field measurements. We found significant differences in PAI derived from harmonized and non-harmonized data, and these differences were greater for shorter growth intervals. Data harmonization resulted in a consistent PAI series that reduced uncertainties associated with the different ALS acquisitions. Although overall there was a strong relationship between field and ALS height measures (R.sup.2 greater than or equal to 0.88), we found a weak relationship between the field- and ALS-derived PAI (R.sup.2 = 0.12). We identified systematic errors in field-based tree height measures in plots with complex crowns, tall trees, and restricted visibility. We demonstrate the need for harmonizing multi-temporal ALS data sets for the generation of PAI and, likewise, highlight the need of carefully scrutinize field-measured heights and associated increments.
•We present the latest version of the MOSES tree growth simulator.•A recalibration and validation of all tree growth functions for major central European tree species.•The underlying data set ...comprises 278,979 tree observations.•The recalibrated models provide reliable estimates for tree growth in central Europe
Moses (MOdelling Stand rESponse) is a distance and potential-dependent single-tree growth simulator. It consists of a diameter and height increment model, a dynamic crown model and models that calculate mortality and regeneration. It was originally calibrated for spruce, beech and pine forests in Austria and has been recalibrated several times throughout the years. In this study, we recalibrated and validated the increment models and the mortality model within MOSES using the latest large and holistic dataset based on monitoring and permanent inventory plots for seven of the most common tree species in Europe (five for the mortality model). These plots were mainly from Austria and Switzerland, as well as Germany. In addition, we calibrated sets of coefficients for the “species groups” (i) other broadleaf and (ii) other conifer trees. The total dataset comprises 278,979 repeated tree measurements, 56,312 of them were used for calibration and 222,667 for validation. The validation of the newly parameterized growth and mortality models exhibit consistent and unbiased estimates for tree growth in central European forests using the MOSES simulator.
Objective
This study aimed to investigate the contribution of body composition including skeletal muscle mass (SMM) and body fat mass (BFM) to longitudinal growth among children and adolescents aged ...6–11 years old.
Methods
This cohort study was conducted from the annual health examination between 2019 and 2020. Annual height gain and weight gain and changes in SMM and BFM were calculated and compared between sexes, different nutritional status, and growth curve shifting mode. Spearman analyses and multiple linear regression analysis were performed to identify the impact of SMM, BFM, or body mass index (BMI) on height gain.
Results
Of the 584 subjects, the annual height gains of boys (4.76 cm in the 6–9-year group and 4.63 cm in the 10–11-year group) were significantly lower than those of girls (5.48 and 5.74 cm, respectively). Spearman analysis showed that SMM gain and height gain were positively and significantly correlated in each examination of all children (
r
= 0.535 for boys and 0.734 for girls,
p
< 0.001). Conversely, BFM and height gains were negatively (
r
= -0.5240 for boys and -0.232 for girls,
p
< 0.001) correlated. Multiple linear regression analysis identified SMM gain as an independent predictor (95% CI: 1.20,1.44) of height gain after adjusting for age, gender, BMI, BFM gain, and percentage of body fat (PBF).
Conclusion
SMM gains, rather than BFM gains, were associated with height gains in children and adolescents aged 6–11 years. Monitoring SMM changes in routine healthcare might motivate children and adolescents to achieve dietary and exercise recommendations, thereby growing taller without gaining excessive weight.
Growth dynamics of pachycaulous stems of arborescent cycad plants are not well understood, and most observations have been made in cultivated garden plants. We studied Cycas micronesica plants in ...Guam, Tinian, and Yap to understand the influences of geography, plant size, sex, and herbivory on stem growth. We also determined the changes in demography of Guam's population after 15 years of damage by non-native insect herbivores. The height increment (HI) was similar for plants within the height range from 100 cm to more than 600 cm, so the relative growth rate declined with height. Female tree HI was 68% of male tree HI, and Yap tree HI was 87% of Guam tree HI. Chronic herbivory by non-native insect herbivores caused a mean 44% decline in HI. Plants in managed gardens grew more rapidly than plants in a wild habitat. The HI was used to estimate that Guam has experienced a complete loss of ≈70 y of demographic depth resulting from the selective mortality of small plants since 2005. When future conservation interventions successfully mitigate the ubiquitous biological threats, our HI may be useful for empirically quantifying recovery of plant health.
In forest management in Poland, there are no standards for the quality and suitability for planting seedlings produced in nursery containers; therefore, research contributing to the development of ...such guidelines is important. We investigated the growth reaction of European beech and Norway spruce seedlings growing in container technology one year after planting on an experimental forest plantation. The seedlings used in the study were three experimental variants grown in a container nursery differing in fertilization. Two heights of seedlings were measured, i.e., after the first growing season on the experimental plantation and the initial (obtained in the forest nursery), and the annual (AHI, cm) and relative height increments (RHI, %) were calculated. The regression of the RHI of seedlings to their initial height was calculated, and the equations obtained were used to determine the optimal range of seedling height at the stage of nursery growth at which they will achieve the maximum increment in the first year of growth on the plantation. The change from foliar fertilization to a mixed one affected beech and spruce seedling parameters; however, it did not affect the diversity of their survival on the experimental plantation. Higher seedlings planted on the experimental plantation were characterized by a smaller RHI. The optimal range for the height of seedlings obtained at the nursery stage of growing, which determined the maximum value of the AHI after the first year of growth after planting, was 18–36 cm for beech and 14–25 cm for spruce.
Combining nine tree growth proxies from four sites, from the west coast of Norway to the Kola Peninsula of NW Russia, provides a well replicated (> 100 annual measurements per year) mean index of ...tree growth over the last 1200 years that represents the growth of much of the northern pine timberline forests of northern Fennoscandia. The simple mean of the nine series, z-scored over their common period, correlates strongly with mean June to August temperature averaged over this region (r = 0.81), allowing reconstructions of summer temperature based on regression and variance scaling. The reconstructions correlate significantly with gridded summer temperatures across the whole of Fennoscandia, extending north across Svalbard and south into Denmark. Uncertainty in the reconstructions is estimated by combining the uncertainty in mean tree growth with the uncertainty in the regression models. Over the last seven centuries the uncertainty is < 4.5% higher than in the 20th century, and reaches a maximum of 12% above recent levels during the 10th century. The results suggest that the 20th century was the warmest of the last 1200 years, but that it was not significantly different from the 11th century. The coldest century was the 17th. The impact of volcanic eruptions is clear, and a delayed recovery from pairs or multiple eruptions suggests the presence of some positive feedback mechanism. There is no clear and consistent link between northern Fennoscandian summer temperatures and solar forcing.
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