Growth and Nitrogen Retranslocation of Nutrient-Loaded Clonal Betula alnoides Transplanted with or without Fertilization

Nutrient loading can improve the growth and nutrient content of nursery-grown Betula alnoides Buch.-Ham. ex D. Don, but it is unknown whether nutrient loading enhances growth and nutrient uptake after transplanting. Plants were grown with three nutrient loading treatments (N100, N200, and N400; 100, 200, and 400 mg N per plant as 15N-urea) in nursery containers and then transplanted into plastic pots, with or without controlled-release fertilizer (F0 and F10, 0 and 10 g per plant). The N400 plants had a smaller size but higher nitrogen concentration relative to the N100 and N200 plants before transplanting. However, 180 days after transplanting, the N200 and N400 plants had superior root collar diameter, root length, and root area compared to the N100 plants, due to an increase in 15N retranslocation to new stems and new leaves. Moreover, transplant fertilization (F10) enhanced the height, root collar diameter, root length, and plant dry mass, but not nitrogen concentration or retranslocation, relative to F0. We recommend that medium- and high-dose nutrient loading is implemented in B. alnoides nurseries to optimize growth after transplanting. Additional fertilizer at transplanting may be advantageous in supporting growth, owing to the rapid depletion of nutrient reserves after planting out in the field.

Growth Dynamics and Tree Shape of Common Beech ( Fagus sylvatica L.) in the International Provenance Test

Provenance tests of forest tree species are important experiments in silviculture and tree breeding. Their results provide information about provenances' growth, adaptability, and other features. The research aimed to determine the dynamics of growth and tree shape of common beech plants per provenances in the international provenance test in Bosnia and Herzegovina to choose the best provenances considering wood production and quality. Research was conducted in the provenance test containing eight provenances from Bosnia and Herzegovina, four from Germany, three from Serbia, two each from Croatia, Romania, and Switzerland, and one from Hungary. Provenance test was established in 2007 by planting 2-year-old and 3-year old seedlings. Height and root collar diameter were measured, and tree shape was assessed in 2019. Data were processed in SPSS 26.0. Descriptive statistics, variance analysis, multiple Duncan's test for all traits, and Pearson's coefficient of corelation among morphological traits and tree shape were calculated. Variance for the height and root collar diameter showed statistically significant differences among different ages of plants and among provenances. Provenance from Croatia (Dilj Čaglinski) had the highest, and provenance from Romania (Alba-Iulia) had the lowest average height. The highest average value of root collar diameter had provenance Dilj Čaglinski, and the lowest value had provenance Sihlwald (Switzerland). The highest percentage of category 10 (ideal tree form) had provenance Bad Wildbad (Germany), and categories 1-4 (no silviculture value) had provenance Alba-Iulia (Romania). Pearson's coefficient showed that height, root collar diameter, and tree shape are highly correlated. Considering all the above, when planning forest-breeding works, it is recommended to continue the research and favor provenances with the best growth and tree shape.

Effect of Different Types of Mulching on Soil Properties and Tree Growth of Magnolia champaca Planted at the Montane Rainforest in Cameron Highlands, Pahang, Malaysia

Tropical Montane Cloud Forest (TMCF) is among the most vulnerable habitats to fragmentation, deforestation, and global climate change. A successful restoration program requires a comprehensive understanding of variables influencing seedling efficiency. This study was conducted on Sg. Terla Forest Reserve Cameron Highlands, Pahang, Malaysia. In this study, we used a randomized complete block design (RCBD) and measured the Magnolia champaca height, root collar diameter, diameter at breast height, plant survival, root diameter, main root length, lateral root length, root coiling, root direction, and chlorophyll content. The soil samples were taken to study the effect of different mulching materials on soil characteristics. We also measured soil compaction, soil texture, soil colour, soil moisture content, soil organic carbon, total nitrogen, total sulphur, available phosphorus, and exchanged potassium. This study indicates that mulching had no significant effect on plant height, diameter breast height, root collar diameter, and chlorophyll content between treatments. Although mulching had a significant effect on root diameter, main root length, and root distributions among treatments while for lateral root length and root:shoot ratio did not show a significant effect among treatments. However, oil palm mulching treatment had a greater effect on plant height, root collar diameter, and diameter at breast height growth, among treatments. Mulching significantly affected soil pH, soil moisture content, total sulphur, and potassium exchange. In contrast, mulching did not significantly affect soil organic carbon, total soil nitrogen, and soil available phosphorus between treatments.

Seedling Growth of Tectona grandis using Different Potting Mixture

Aims: This study evaluated the influence of 11 potting media compositions on seedling growth and development of Tectona grandis. Study Design: The experiment was set up in a completely randomized design involving ten replicates. Place and Duration of Study: The study was carried out at the Department of Forestry and Wildlife Management Nursery, University of Port Harcourt, Rivers State, Nigeria, between April 2019 and April 2020. Methodology: Ten (10) seedlings per sowing media including topsoil, topsoil and cow dung (2:1, 3:1), topsoil and poultry dung (2:1, 3:1), topsoil and pig dung (2.1, 3:1), topsoil and sawdust (2.1, 3:1), topsoil and mushroom substrate (2.1, 3:1) were selected and transplanted into polybags. Growth parameters (seedling height, root collar diameter, leaf number and biomass (shoot dry weight (SDW), root dry weight (RDW) and total dry weight (TDW)) were determined and subjected to analysis of variance. Results: Seedlings of T. grandis displayed significant differences (p ≤ 0.05) in height, root collar diameter, leaf number and biomass. Among treatments, tallest seedlings were observed in mixture of topsoil and poultry dung (3:1), at months 1 to 3 and in mixture of topsoil and cow dung (3:1) at months 4 and 5, highest root collar diameter was observed in mixture of topsoil and poultry dung (3:1) and highest leaf number was recorded in mixture of topsoil and poultry dung (2:1 and 3:1) and topsoil and cow dung (2:1 and 3:1) at months 1 to 5. The highest SDW was evident in mixture of topsoil and poultry dung (2:1) while highest RDW and TDW were observed in mixture of topsoil and cow dung (3:1). Lowest height, diameter, leaf number and biomass were recorded in topsoil (control) at months 1 to 5. Conclusion: The results revealed that among the tested mixtures, topsoil and poultry dung and topsoil and cow dung mixtures were the best for seedlings growth of T. grandis.

The Effect of Seed Size on Germination and Seedling Growth in Sweet Chestnut (Castanea sativa Mill.)

The quantity and quality of seedlings in the nursery has an impact on the success of re-establishment and later growth. High germination rates enable a sufficient number of seedlings, and their quality is assessed using a number of parameters, including seedling height and root collar diameter. These parameters are influenced in some species by seed size, but the correlation between them is species-specific. The model species in this research was sweet chestnut (Castanea sativa Mill.), and seeds from 12 populations from two distinct biogeographical regions of Croatia were collected. We examined the influence of seed size on four parameters: germination rate, seedling height, root collar diameter and sturdiness quotient. Seed size has been shown to have a positive influence on both seedling height and root collar diameter, whereas no such correlation was noted for germination rate and sturdiness quotient. Significant differences in nut size and seedling growth parameters were found between the Mediterranean and continental populations, with higher values observed in the coastal Mediterranean populations. We concluded that seed origin and seed size have a significant impact on seedling growth and are important factors to consider when choosing seed material. Further nursery operations should consider seed origin and local environmental conditions when choosing seedlings for reforestation efforts and general forest operations.

Responses of the Physiological and Biochemical Characteristics of Alfalfa Roots with Different Root Collar Diameters to Low Temperatures Under Simulated Winter Irrigation

Background: Due to the frequent occurrence of extremely low temperatures in northern China, the problem of alfalfa mortality during overwintering requires urgent solutions to support the development of large-scale alfalfa production in the region. Understanding the effects of winter irrigation and the alfalfa root collar diameter on physiological and biochemical cold resistance mechanisms in alfalfa will be of great significance to finding such solutions.Methods: In this study, alfalfa roots with different root collar diameters (3.50±0.10 mm, 5.25±0.10 mm, 7.00±0.10 mm) were subjected to simulated winter irrigation (0 ml, 20 ml, 40 ml) and different low-temperature stress treatments (4°C, -10°C, -15°C, -20°C) in the laboratory. The relationships between alfalfa root collar activity, relative conductivity and the nonstructural carbon and nitrogen contents and antioxidant enzyme activity in the collar were explored.Results: Low-temperature stress was the most important factor causing significant changes in the physiological and biochemical indexes of the alfalfa root collar, followed by the root collar diameter. Low-temperature stress and the root collar diameter had significant effects on nonstructural carbon and nitrogen levels and enzyme activity (except POD activity) in alfalfa root collars, and winter irrigation had extremely significant effects on the nonstructural nitrogen contents of alfalfa root collars. The larger the diameter of the root collar was, the higher the soluble protein content and the stronger the SOD activity. Simulated winter irrigation increased the C/N ratio in the alfalfa root collars. The increases in nonstructural carbon content, C/N ratio and SOD activity in alfalfa root collars helped improve alfalfa cold resistance.Conclusions: Alfalfa resists low-temperature stress by adjusting the proportions of nonstructural carbon and nitrogen as well as the SOD activity in the root collar. Therefore, fertilization, early sowing and other management measures should be adopted to ensure healthy alfalfa growth and thereby increase the root collar diameter of alfalfa grown in cold regions in northern China. Moreover, timely supplementary irrigation to reach soil saturation in winter can play an important role in improving cold resistance in alfalfa.

Influence of mycorrhizal preparation on seedling growth and Armillaria infestation

The influence of three types of treatment on seedling survival percentage, growth and Armillaria infestation of Fagus sylvatica L. (FAGUS), Abies alba Mill. (ABIES) and Picea abies (L.) H. Karst. (PICEA) seedlings were tested in this study: (i) inoculation with the Ectovit^® preparation containing ectomycorrhizal fungi (INOCUL), (ii) Ectovit^® preparation + Conavit^® fertilizer (INOCUL + FERTILIZ) and (iii) the untreated group (CONTROL). The selected sample contained 100 seedlings per each tree species and treatment type (900 seedlings in total). Besides that, 18 months after planting, 10 living seedlings per each species and treatment (90 seedlings in total) were sampled to evaluate root dry mass and Armillaria infestation. The data were statistically evaluated by frequency analysis, analysis of variance and Kruskal-Wallis test. The overall seedling survival percentage was very low, probably due to extreme drought and high temperatures, with significantly lower results for the ABIES INOCUL + FERTILIZ and PICEA INOCUL + FERTILIZ groups. All tested growth characteristics (seedling height increment, root collar diameter increment, seedling shoot dry weight, root dry mass) were significantly higher in PICEA seedlings. Root collar diameter increment showed significant differences within each species and inconsistent results. Armillaria was detected only in the PICEA CONTROL group as rhizomorphs identified as A. ostoyae. The results suggest that the artificial mycorrhizal preparation can be an efficient method of preventing Armillaria infestation, especially in spruce seedlings.

Mulch removal time did not have significant effects on Tuber melanosporum mycelium biomass

Aim of study: We aimed to i) evaluate the effects of mulching on Tuber melanosporum mycelium biomass and seedling growth (i.e. root collar diameter and seedling height) and ii) unravel the relationship between growth in root collar diameter and mycelium abundance, in a T. melanosporum plantation.Area of study: The experimental plantation is located in the Pre-Pyrenees mountains in Catalonia, Spain.Material and methods: The experimental plantation was established in 2010 using one-year-old T. melanosporum inoculated Quercus ilex seedlings. Double-layered mulch materials were placed around the seedlings. The mulch materials were removed from randomly selected seedlings in 2015 and 2018. Soil samples were collected in 2018 at 40 and 80 cm distances from seedlings that had mulching during five and eight years, and T. melanosporum mycelium biomass was estimated by quantitative Polymerase Chain Reaction (qPCR). Seedling root collar diameter and height were measured simultaneously when mulch materials were removed.Main results: Mulch removal time did not have significant effects on T. melanosporum mycelium biomass or seedling growth. However, mycelium biomass at 40 cm distance tended to be higher on seedlings after eight-year mulching with 0.9 mg/g soil whereas mycelium biomass was 0.4 mg/g soil after five-year mulching. A positive relationship between mycelium biomass and seedling root collar diameter was also found.Research highlights: Mulching seems to have a positive effect on truffle mycelium biomass, with nearly two times higher quantity of mycelium after eight-years compared with five-years mulching usage. Seedling root collar diameter is a good indicator of mycelium expansion in the plantation.Keywords: Black truffle; Quercus ilex; mulching; tree growth; truffle cultivation.

Allometric models for estimating aboveground biomass in tree sprouts of three dendroenergetic crops

Recurrent problems have been observed for biomass measurement in tree sprouts, mainly dueto differences in patterns of biomass distribution and the bias generated by using models for mature trees.The objective of this research was to evaluate models to estimate aboveground biomass in sprouts from two-year-old stumps of Short Rotation Woody Crops (SRWC) used for energetic purposes. The study was conducted in Central Chile (Bío-Bío region) under a complete block design and four replications.Three plant species were included: Eucalyptus globulus, E. denticulata, and Acacia dealbata, established in three population densities (5,000, 10,000 and 15,000 trees per ha). Two groups of nonlinear models wereused on three independent variables: root collar diameter (squared mean of two dominant stems), height (mean of two dominant stems) and number of epicormic stems. In the allometric model, the total aboveground biomass and the aboveground biomass by component were explained as the product of the mean square of the root collar diameter, mean height of the two dominant new sprouts and total number of epicormic sprouts as the predictive variable. Values of coefficient of determination (R2) ranged from 0.78 to 0.95 and RMSE ranged from 168 to 913 g. The species of E. globulus showed higher RMSE for biomass estimation in the all components except the branch component. The inclusion of dummy variables to identify the differences in each parameter of the models explained the seasonalityof the biomass accumulation in tree sprouts at 10, 21, and 31 months of age, improving the model goodness of fit RMSE by 27%. Accurate prediction of sprouts aboveground biomass was obtained by the models only evaluating the two dominant epicormic sprouts in the stump, avoiding the need of individual sprouts evaluation or using destructive methods for biomass measurement.