Genetic diversity of Norway spruce [Picea abies (L.) Karst.] in Romanian Carpathians

The genetic diversity of Romanian most important coniferous tree species, the Norway spruce, was estimated by means of allozyme markers. A total of 695 adult trees sampled from eleven populations grouped in six mountainous areas in the Romanian Carpathians were analyzed. In three metapopulations (Maramureş, Postăvar and Parâng), to evaluate the influence of altitudinal gradient on genetic diversity, samples were collected from populations located at high and low altitude. At other location (ApuseniMountains) we compared the narrow-crown biotype (Picea abies var. columnaris) and the pyramidal crown biotype (Picea abies var. pyramidalis) and explored the genetic structure of peat bog ecotype. By analyzing 7 enzyme systems and 12 enzyme coding loci, a total of 38 allelic variants have been detected. The mean value of polymorphic loci for the six sites was 86.1%, ranging between 83.3% and 91.7% and the mean expected heterozygosity was 0.115, resulting in a moderate level of genetic diversity. The highest genetic diversity (He = 0.134) was found in the narrow-crown spruce population. Apuseni metapopulation showed the highest genetic diversity (He = 0.125), being the most valuable for conservation of genetic resources. The small value of fixation index (FST = 0.009) indicates a low genetic differentiation between the six sites and AMOVA test revealed a very high level of genetic diversity within population (99%). Comparative analysis of genetic parameters showed small differences between high and low altitude populations at each site, probably due to the neutral character of the markers analyzed and the effect of gene flow between gradiental populations.</p

Predicting Leaf Phenology in Forest Tree Species Using UAVs and Satellite Images: A Case Study for European Beech (Fagus sylvatica L.)

Understanding forest tree phenology is essential for assessing forest ecosystem responses to environmental changes. Observations of phenology using remote sensing devices, such as satellite imagery and Unmanned Aerial Vehicles (UAVs), along with machine learning, are promising techniques. They offer fast, accurate, and unbiased results linked to ground data to enable us to understand ecosystem processes. Here, we focused on European beech, one of Europe&rsquo;s most common forest tree species, along an altitudinal transect in the Carpathian Mountains. We performed ground observations of leaf phenology and collected aerial images using UAVs and satellite-based biophysical vegetation parameters. We studied the time series correlations between ground data and remote sensing observations (GLI r = 0.86 and FCover r = 0.91) and identified the most suitable vegetation indices (VIs). We trained linear and non-linear (random forest) models to predict the leaf phenology as a percentage of leaf cover on test datasets; the models had reasonable accuracy, RMSE percentages of 8% for individual trees, using UAV, and 12% as an average site value, using the Copernicus biophysical parameters. Our results suggest that the UAVs and satellite images can provide reliable data regarding leaf phenology in the European beech

Microenvironment Impact on Survival Rate, Growth and Stability Traits, in a Half-Sib Test of Pendula and Pyramidalis Varieties of Norway Spruce

Norway spruce (Picea abies) is a tree species with low resistance to wind storms and breakage from snow. In this study, we analyzed the microenvironmental impact on the survival rate (Sr), growth, and stability traits of 25-year-old narrow (pendula)- and normal-crowned (pyramidalis) spruce varieties in the M&#259;neciu half-sib trial. The replication factor had a highly significant influence (p &lt; 0.001) on the growth and stability traits and a significant influence (p &lt; 0.05) on the Sr, which confirms the microenvironmental impact. The average Sr was 85% and was 5% higher for the pendula variety (p &lt; 0.05). For normal-crowned trees, a negative correlation (r = &minus;0.26 ***) between the crown diameter and Sr was found, while for pendula trees, the correlations were 31% lower, suggesting the pendula variety&rsquo;s high adaptation potential to a denser planting scheme. The edge effect affected the Sr of both varieties almost equally, with a 3% superiority for pendula. The Sr variations in relation to the slope position indicated that the narrow-crowned variety was less affected by the slope position, while the normal variety showed significant slope variation. The pendula variety of Norway spruce could be promoted in afforestation because of its high adaptation plasticity to a denser planting scheme

Microenvironment Impact on Survival Rate, Growth and Stability Traits, in a Half-Sib Test of <i>Pendula</i> and <i>Pyramidalis</i> Varieties of Norway Spruce

Norway spruce (Picea abies) is a tree species with low resistance to wind storms and breakage from snow. In this study, we analyzed the microenvironmental impact on the survival rate (Sr), growth, and stability traits of 25-year-old narrow (pendula)- and normal-crowned (pyramidalis) spruce varieties in the Măneciu half-sib trial. The replication factor had a highly significant influence (p p pendula variety (p r = −0.26 ***) between the crown diameter and Sr was found, while for pendula trees, the correlations were 31% lower, suggesting the pendula variety’s high adaptation potential to a denser planting scheme. The edge effect affected the Sr of both varieties almost equally, with a 3% superiority for pendula. The Sr variations in relation to the slope position indicated that the narrow-crowned variety was less affected by the slope position, while the normal variety showed significant slope variation. The pendula variety of Norway spruce could be promoted in afforestation because of its high adaptation plasticity to a denser planting scheme

Predicting Leaf Phenology in Forest Tree Species Using UAVs and Satellite Images: A Case Study for European Beech (<i>Fagus sylvatica</i> L.)

Understanding forest tree phenology is essential for assessing forest ecosystem responses to environmental changes. Observations of phenology using remote sensing devices, such as satellite imagery and Unmanned Aerial Vehicles (UAVs), along with machine learning, are promising techniques. They offer fast, accurate, and unbiased results linked to ground data to enable us to understand ecosystem processes. Here, we focused on European beech, one of Europe’s most common forest tree species, along an altitudinal transect in the Carpathian Mountains. We performed ground observations of leaf phenology and collected aerial images using UAVs and satellite-based biophysical vegetation parameters. We studied the time series correlations between ground data and remote sensing observations (GLI r = 0.86 and FCover r = 0.91) and identified the most suitable vegetation indices (VIs). We trained linear and non-linear (random forest) models to predict the leaf phenology as a percentage of leaf cover on test datasets; the models had reasonable accuracy, RMSE percentages of 8% for individual trees, using UAV, and 12% as an average site value, using the Copernicus biophysical parameters. Our results suggest that the UAVs and satellite images can provide reliable data regarding leaf phenology in the European beech

Valuation of the Economic Benefits from Using Genetically Improved Forest Reproductive Materials in Afforestation

The research objective was to demonstrate the economic impact of using, in afforestation, forest reproductive materials (FRMs) obtained from seed trees selected in the most valuable Norway spruce populations of the FGRs&rsquo; (forest genetic resources&rsquo;) category. The values obtained for the main growth traits (diameter at breast height (Dbh), tree height (Th), and tree volume (Tv)), both in the FGR and in the closest population (with the same age and growth in similar environmental conditions), were compared. Three comparative trials were analyzed, each belonging to different breeding levels: Open-pollinated (Breţcu, 40 years old), half-sib (Măneciu, 25 years), and full-sib (Comandău, 23 years). The difference in volume/hectare between the FGR and an unimproved neighbor population was economically quantified (&euro;), based on the average price per cubic meter (m3) of spruce wood in Romania; the profit at the end of the rotation period (110 years) was projected taking into account the genetic gain that will result from the use of FRM collected from the FGRs. The average FGR growth results were superior to the unimproved neighbor populations, with 8%&ndash;13%, 14%&ndash;25%, and 26%&ndash;79% for Dbh, Th, and volume/ha, respectively, and the differences increased if the best 10% seed trees of the trials were used. For Th, a five times higher family mean heritability was registered for the pendula trees (compared to pyramidalis) in the half-sib trial, while in the full-sib experiment, the pendula trees (both full and half pendula) again registered higher heritability, but for Dbh, which recommends the pendula selection for different traits in the two trials. These results have led to a rate of profitability between 540 and 3366 &euro;/ha, a value that is predicted to increase until the end of the rotation period, when the genetic gain could generate a profit of 7560 &euro;/ha