Modelling the Tree Height, Crown Base Height, and Effective Crown Height of Pinus koraiensis Plantations Based on Knot Analysis

Taking 1735 Pinus koraiensis knots in Mengjiagang Forest Farm plantations in Jiamusi City, Heilongjiang Province as the research object, a dynamic tree height, effective crown height, and crown base height growth model was developed using 349 screened knots. The Richards equation was selected as the basic model to develop a crown base height and effective crown height nonlinear mixed-effects model considering random tree-level effects. Model parameters were estimated with the non-liner mixed effect model (NLMIXED) Statistical Analysis System (SAS) module. The akaike information criterion (AIC), bayesian information criterion (BIC), −2 Log likelihood (−2LL), adjusted coefficient (Ra2), root mean square error (RMSE), and residual squared sum (RSS) values were used for the optimal model selection and performance evaluation. When tested with independent sample data, the mixed-effects model tree effects-considering outperformed the traditional model regarding their goodness of fit and validation; the two-parameter mixed-effects model outperformed the one-parameter model. Pinus koraiensis pruning times and intensities were calculated using the developed model. The difference between the effective crown and crown base heights was 1.01 m at the 15th year; thus, artificial pruning could occur. Initial pruning was performed with a 1.01 m intensity in the 15th year. Five pruning were required throughout the young forest period; the average pruning intensity was 1.46 m. The pruning interval did not differ extensively in the half-mature forest period, while the intensity decreased significantly. The final pruning intensity was only 0.34 m.

Mandibular incisor inclination and gingival recession after treatment with the Jasper Jumper: a 10-year follow-up

Objective To evaluate the long-term outcomes of Class II treatment with the Jasper Jumper appliance and comprehensive orthodontic treatment concerning inclination of the mandibular incisors and gingival recession. Methods Sixteen patients with Class II malocclusion at a mean age of 12.54y (SD = 1.17) were treated with the Jasper Jumper appliance and comprehensive orthodontic treatment. The mean treatment time was 2.05y (SD = 0.21). Dental records were taken before (T1), after treatment (T2) and 11.90y (SD = 0.48) after debonding (T3). The frequency of gingival recession, clinical crown height and mandibular incisor position were evaluated using intraoral photographs, digital models and lateral cephalograms. Interphase changes were evaluated using dependent t and McNemar’s tests. Correlation between clinical crown height and final position of the mandibular incisors was evaluated using Pearson correlation test (P < 0.05). Results The frequency of gingival recessions increased over time and was observed in 6 (9.4%), 12 (18.8%) and 24 (37.5%) of the mandibular incisors at T1, T2 and T3, respectively. A significant increase in labial inclination and protrusion of the mandibular incisors was observed between T1 and T2 interval. The clinical crown height significantly increased in the follow-up period (T3–T2) and in the complete observation time (T3–T1). There was no correlation between the amount of labial inclination and protrusion of the mandibular incisors and clinical crown height for all time intervals. Conclusion No significant correlation between the amount of labial movement of the mandibular incisor and clinical crown height increase was found.

Extracting Crown Morphology with a Low-Cost Mobile Lidar Scanning System in the Natural Environment

To meet the demand for intelligent measurements of canopy morphological parameters, a mobile LiDAR scanning system with LiDAR and IMU as the main sensors was constructed. The system uses a LiDAR-IMU tight coupling odometry method to reconstruct a point cloud map of the area surveyed. After using the RANSAC algorithm to remove the map ground, the European clustering algorithm is used for point cloud segmentation. Finally, morphological parameters of the canopy, such as crown height, crown diameter, and crown volume, are extracted using statistical and voxel methods. To verify the algorithm, a total of 43 trees in multiple plots of the campus were tested and compared. The algorithm defined in this study was evaluated with manual measurements as reference, and the morphological parameters of the canopy obtained using the LOAM and LeGO-LOAM algorithms as the basic framework were compared. Experiments show that this method can be used to easily obtain the crown height, crown diameter, and crown volume of the area; the correlation coefficients of these parameters were 0.91, 0.87, and 0.83, respectively. Compared with the LOAM and LeGO-LOAM methods, they were increased by 0.004, 0.12, and 0.13 and 0.07, 0.15, and 0.04, respectively. The test results for this new system are positive and meet the requirements of horticulture and orchard measurements, indicating that it will have significant value as an application.

Evaluation of the Morphological Quality of Hybrid Seeds and the Vegetative Development of Plants from the Two Reproductive Systems of Elite Dura Genitors from Oil Palm (Elaeisguineensis Jacq) Seed Fields in Côte d'Ivoire

The production of quality oil palm plant material (Elaeisguineensis Jacq.) necessarily involves the creation of seed fields made up of elite Dura parents. Two methods of reproduction of these elite Duragenitors were adopted for the establishment of current seed fields by the National Center for Agronomic Research (CNRA). The first group is made up of elite first-cycle parents who have undergone two successive generations of [(G1) AF] AF type self-fertilization, noted AFAF. The second group is composed of genitors having undergone a prior self-fertilization followed by AFSIB-type recombination cycle of recombination between genitors of the type (G1 × G2) AF, noted AFSIB. This study involves evaluation of morphological quality of seeds from the two breeding systems of the parents and their quality of vegetative development. For this, the seeds from 553 Dura parents distributed among eight (8) descendants and grouped within the category C1001 F were used.The resultsderived from this study have shown that the seeds obtained from the parents through double self-fertilization of AFAF-type parents are characterized by a thin shell and a high percentage of germination. After the elimination of the abnormal plants at the end of the nursery, various traits viz.circumference at the crown, height of the plants and the number of leaves emitted from the plants on the healthy plants showed that the plants resulting from the seeds obtained from self-fertilization followed by AFSIB-type recombination showed good vegetative development and vigor compared to those of AFAF type respectively.

Tree form morphometrics of Agathis dammara and Acacia mangium in the IPB’s Dramaga Landscape Campus, Bogor

Tree growth comprises diverse tree forms and crown shapes that are influenced by the growing space and are related to biomechanical responses. Due to the complex structures of tree forms and crown architecture, more understanding of their functions is necessary. The study aimed to evaluate the morphometrics of two tree species of contrasting tree forms. Each represents excurrent and decurrent crown architectures located in the Dramaga Campus Landscape, Bogor. Morphometric analysis was conducted on those two species, namely excurrent agathis (n=23 trees) and decurrent mangium (n= 15 trees). The morphometric analysis was carried out for several basic growth variables such as diameter at breast height, total height, and crown height. In addition, other variables and parameters were also assessed, namely live crown ratio, slenderness ratio, crown diameter, crown projection area, crown index, and coefficient of space for growth. The results showed that the average diameters of agathis and mangium trees in this study were 0.49 and 0.48 m, respectively, while the average heights were 24.63 m and 18.23 m, respectively. The live crown ratio of both trees was more than 80%. The average slenderness ratio for agathis trees was 50.66 higher than that of mangium trees (40.64). The crown projection areas for agathis and mangium were 37.60 m2 and 69.69 m2, respectively. On the other hand, the crown index of agathis was 3.20, and mangium was 1.84. The coefficient of space for the growth of agathis and mangium was 0.14. and 0.19. The information related to tree morphometry is important for tree management, especially in evaluating healthy and steady tree stands.

Dynamics of an apple tree yield after rejuvenation pruning

The studies were carried out in the apple orchard planted in 1987. The layout of trees was 7x5 m, the stock was vigorous (seedlings of cultivated varieties). In the first experiment, the influence of the crown cut on fruit yield was studied. The object of research was an apple tree of the Sinap Orlovsky variety. The following options were considered: 1. Without reduction in the crown height (control); 2. Cutting the tree height to 5.0-5.5 m; 3. Cutting the tree height to 4.0-4.5 m; 4. Cutting the tree height to 3.0-3.5 m. The trees were pruned in the spring of 2015. In the second experiment, perennial wood was removed and the yield was compared. The object of the study was an apple tree of the Antonovka Ordinary variety. The following options were considered: 1. Sanitary pruning (control); 2. Pruning for 3-4 year old wood; 3. Pruning for 5-6 year old wood; 4. Pruning for 7-8 year old wood. The trees were pruned in the spring of 2016. The experiments were repeated 4 times, each option used 6 trees, the placement of the plots was randomized. In the first experiment, on the sixth year, the highest yield (15.8 t/ha) was observed for the option with a crown cut to 4.0-4.5 m. This option also showed the highest total yield for 6 years (55.1 t/ha). In the second experiment for options with rejuvenation pruning, the total yield over 5 years exceeded the control option by 9.9-36.3%. The highest yield (52.2 t/ha) was obtained for the option with pruning for 5-6 year old wood.

Effect of crown-to-implant ratio and crown height space on marginal bone stress: a finite element analysis

Background Crown-to-implant ratio and crown height space, associated with the use of short implants, have been related with marginal bone loss. However, it is unclear which of the two entities would play the most important role on the bone remodelling process. Using a finite element analysis, the present work aims to help clarifying how those two factors contribute for the stress generation at the marginal bone level. A numerical model (reference model), with a crown-to-implant ratio of 4, was double validated and submitted to a numerical calculation. Then, it was modified in two different ways: (a) by decreasing the prosthetic height obtaining crown-to-implant ratios of 3, 2.5 and 2 and (b) by increasing the implants length obtaining a crown-to-implant ratio of 2.08. The new models were also submitted to numerical calculations. Results The reference model showed a marginal bone stress of 96.9 MPa. The increase in the implants’ length did not show statistically significant differences in the marginal bone stress (p-value = 0.2364). The decrease in the prosthetic height was accompanied with a statistically significant decrease in the marginal bone stresses (p-value = 2.2e− 16). Conclusions The results represent a paradigm change as the crown height space appears to be more responsible for marginal bone stress than the high crown-to-implant ratios or the implants’ length. New prosthetic designs should be attempted to decrease the stress generated at the marginal bone level.

Quantification of dwarfing effect of different rootstocks in ‘Picual’ olive cultivar using UAV-photogrammetry

Hedgerow orchard is an olive growing system where trees are planted at a super high-density higher than 20-fold (i.e., 1200–2500 trees ha−1) compared to the traditional density of olive orchards (usually 50 to 160 trees ha−1). It is dominating a great proportion of new plantations because harvesting can be fully mechanized, it is early bearing and has a relatively constant high productivity. However, there are a limited number of cultivars with sufficiently low vigour to be suitable for such plantation densities. For that reason, a set of low vigour cultivars and breeding selections has been used in a field experiment as rootstocks for reducing the vigour of “Picual”, the most frequent cultivar planted in Spain. Tree vigour was characterized by measuring crown height, projected and side areas, and volume through the analysis of photogrammetric point clouds created from images acquired with an unmanned aerial vehicle. A significant reduction of the ‘Picual’ vigour was observed in most of the rootstocks tested, with canopy volume reduced up to one half. High variability on vigour, first harvesting and their relative relationship was observed between the different rootstocks used. This indicates there might be enough genetic variability to perform breeding selection for dwarfing rootstocks on ‘Picual’ olive cultivar.

Marginal Adaptation of Implant Prostheses Fabricated by Different Materials in Excessive Crown Height Space Before and After Veneering

Objectives: This study aimed to investigate the marginal adaptation of implant-supported three-unit fixed restorations fabricated in excessive crown height by various frameworks namely zirconia, nickel-chromium (Ni-Cr) alloy, and Polyetheretherketone (PEEK) before and after veneering. Materials and Methods: A basic model with two implant fixtures was made to receive posterior three-unit fixed partial dentures (second premolar to second molar) in 15 mm crown height. A total of 30 frameworks were fabricated using Ni-Cr, zirconia, and PEEK (n=10). All specimens were veneered and vertical marginal discrepancy was evaluated before and after veneering using a stereomicroscope (×75). The effect of framework material and veneering on marginal discrepancy was evaluated by repeated-measures and one-way ANOVA, and paired t test (α=0.05). Results: There was a significant difference between the groups (P<0.001) before and after veneering. The vertical marginal discrepancy of zirconia frameworks was significantly lower than that of other groups both before and after veneering (P<0.001). Statistical analysis revealed that the veneering process had a significant effect on marginal adaptation (P<0.001). Conclusion: In implant prostheses with excessive crown height, zirconia had the greatest marginal adaptaion significantly, followed by Ni-Cr. Veneering caused a significant increase in marginal discrepancy of all the materials.