Damage to Residual Trees in Thinning of Broadleaf Stand by Mechanised Harvesting System

This research was conducted to determine the cause, intensity and location of damage (stem, butt end, root collar, root) and the extent of damage to standing trees during felling and processing by an harvester and timber extraction by a forwarder (cut-to-length system). The research was conducted in the central part of the Republic of Croatia in the Management Unit (MU) “Bjelovarska Bilogora” during the thinning of Subcompartment 14b, area of 18.28 ha, in the stand of hornbeam (Carpino betuli—Quercetum roboris fagetosum Rauš 1975), age 70, and of Subcompartment 14c, area of 9.07 ha, in a stand of common beech (Carici pilosae—Fagetum Oberdorfer 1957) aged 79 years. The thinning intensity was 12.13% in Subcompartment 14b and 13.72% in Subcompartment 14c. Field measurements were carried out on sample plots—the first time in 2017 to determine the intensity and characteristics of the damage to standing trees with regard to the cause of the damage (harvester or forwarder), and the second time in 2018 to determine the overall intensity and features of the damage to standing trees after finishing harvesting operations. For all trees remaining in the stand after the harvesting operations, the following were determined: tree species, diameter at breast height (DBH), the position of the tree in the stand depending on the forest traffic infrastructure, and—if damaged—cause of damage, type of damage, the position of damage on the tree, and dimensions of damage. The intensity of the damage was expressed by the ratio of damaged and undamaged trees, with a detailed analysis of bark damage (squeezed-bark damage and peeled-bark injuries). The results of the research indicate the highest prevalence of peeled-bark injuries. In relation to the total number of standing trees, trees with peeled-bark injuries were more represented in Subcompartment 14c (39%) than in Subcompartment 14b (33%). In Subcompartment 14b, the harvester and the forwarder damaged an equal number of trees, while in Subcompartment 14c, the harvester damaged 59% of the damaged trees. In both subcompartments, an average of 83% of (peeled bark) injuries were up to 1.3 m above the ground. In both subcompartments, the most common (67%) were injuries up to 100 cm2 in size, for which many authors claim the tree can heal by itself. Given the increasing use of harvester-forwarder systems in deciduous stands and research results that indicate possible damage to standing trees, it is necessary to pay attention to all phases of planning and execution of timber harvesting operations, thus minimising negative effects.

Phenological variability and resistance to late spring frost of common beech in the international provenance test in Bosnia and Herzegovina

The research aimed to determine the start, end and duration of leafing phases, the degree of plant damage caused by late spring frost, and the retention of leaves in autumn. The research was conducted in the international common beech provenance test in Bosnia and Herzegovina. The test contains eight provenances from Bosnia and Herzegovina, four from Germany, three from Serbia, two each from Croatia, Romania and Switzerland, and one from Hungary. Leafing phenology, canopy damage caused by late spring frost, and leaf retention were assessed in 2019. Most provenances started opening buds on 17 April 2019. Complete canopy damage affected the highest percentage of plants in provenance BW Bad Wildbad, Germany (68 %), and the lowest in provenance Konjuh Kladanj, Bosnia and Herzegovina (3.2 %). Provenance Herzogenbuchsee from Switzerland had the highest percentage of winter leaf retention (37.5 % of plants). The results can be used in choosing provenances that are resistant to low temperatures in zones of late spring and early autumn frost.

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.

Biophysical Accounting of Forests’ Value under Different Management Regimes: Conservation vs. Exploitation

Forest ecosystems are important providers of ecosystem functions and services belonging to four categories: supporting, provisioning, regulating and cultural ecosystem services. Forest management, generally focused on timber production, has consequences on the ability of the system to keep providing services. Silviculture, in fact, may affect the ecological structures and processes from which services arise. In particular, the removal of biomass causes a radical change in the stocks and flows of energy characterizing the system. Aiming at the assessment of differences in stored natural capital and ecosystem functions and services provision, three differently managed temperate forests of common beech (Fagus sylvatica) were considered: (1) a forest in semi-natural condition, (2) a forest carefully managed to get timber in a sustainable way and (3) a forest exploited without management. Natural capital and ecosystem functions and services are here accounted in biophysical terms. Specifically, all the resources used up to create the biomass (stock) and maintain the production (flow) of the different components of the forest system were calculated. Both stored emergy and empower decrease with increasing human pressure on the forest, resulting in a loss of natural capital and a diminished ability of the natural system to contribute to human well-being in terms of ecosystem services provision.

Evaluating the effect of stand properties and site conditions on the forest reflectance from Sentinel-2 time series

Forest stand reflectance at the canopy level results from various factors, such as vegetation chemical properties, leaf morphology, canopy structure, and tree sizes. These factors are dependent on the species, age, and health statuses of trees, as well as the site conditions. Sentinel-2 imagery with the high spatial, spectral, and temporal resolution, has enabled analysis of the relationships between vegetation properties and their spectral responses at large spatial scales. A comprehensive study of these relationships is needed to understand the drivers of vegetation spectral patterns and is essential from the point of view of remote sensing data interpretation. Our study aimed to quantify the site and forest parameters affecting forest stands reflectance. The analysis was conducted for common beech-, silver fir- and Scots pine-dominated stands in a mountainous area of the Polish Carpathians. The effect of stands and site properties on reflectance in different parts of the growing season was captured using the dense time series provided by Sentinel-2 from 2018–2019. The results indicate that the reflectance of common beech stands is mainly influenced by elevation, particularly during spring and autumn. Other factors influencing beech stand reflectance include the share of the broadleaved understory, aspect, and, during summer, the age of stands. The reflectance of coniferous species, i.e., Scots pine and silver fir, is mainly influenced by the age and stand properties, namely the crown closure and stand density. The age is a primary driver for silver fir stands reflectance changes, while the stand properties have a large impact on Scots pine stands reflectance. Also, the understory influences Scots pine stands reflectance, while there appears to be no impact on silver fir stands. The influence of the abovementioned factors is highly diverse, depending on the used band and time of the season.

Biophysical Accounting of Forests’ Value Under Different Management Regimes: Conservation vs Exploitation

Forest ecosystems are important providers of ecosystem functions and services belonging to four categories: supporting, provisioning, regulating, and cultural ecosystem services. Forest management, generally focused on timber production, has consequences on the ability of the system to keep providing services. Silviculture, in fact, may affect ecological structures and processes from which services arise. In particular, the removal of biomass causes a radical change in the stocks and flows of energy characterizing the system. Aiming at the assessment of differences in stored natural capital and ecosystem functions and services provision, three differently managed temperate forests of common beech (Fagus sylvatica) were considered: (1) a forest in semi-natural condition, (2) a forest carefully managed to get timber in a sustainable way and (3) a forest exploited without management. Natural capital and ecosystem functions and services are here accounted in biophysical terms. Specifically, all the resources used up to create the biomass (stock) and maintain the production (flow) of the different components of the forest system were calculated. Both stored emergy and empower decrease at increasing human pressure on the forest, resulting in a loss of natural capital and a diminished ability of the natural system to contribute to human well-being in terms of ecosystem services provision.

Međuovisnost različitih indikatora vitaliteta stabala i njihov odziv na klimatske uvjete na plohi obične bukve (Fagus sylvatica L.)

Interrelations of various common beech vitality indicators (crown defoliation, foliar chemistry, radial growth) as well as their possible dependencies on climatic conditions were investigated over the course of 12 years in a mature and healthy beech stand. Our results confirm the importance of temperature variables for defoliation, as high temperatures during spring and summer months induce the increase of defoliation. The same negative influence was observed with high maximum temperatures and low precipitation during previous year summer months. Phosphorus, calcium and magnesium nutrition of beech trees suffers from high temperatures during current year summer and benefits from more precipitation. High temperatures in current year May positively influence beech radial growth, while a wide range of minimum temperatures during March and June has a negative effect. In summary, high summer temperatures and low precipitation were shown to have a negative effect on all vitality indicators, and for defoliation and nutrition this effect can last into the following year.

Monitoring fungus infestation of common beech wood using terahertz radiation

Wood is one of the most widely used materials for construction projects, in the furniture industry, as well as in the field of cultural property of valuable objects. Terahertz (THz) radiation has great potential for non-contact and non-destructive analysis of wooden materials. This article reports a study of the degree of growth of Trametes versicolor in wood samples, using THz radiation. The analysis compares the THz results to microscopic examinations of the samples, common beech incubated with T. versicolor, at different growth times. The results indicate a strong correlation between the parameters extracted from THz measurements and the progress of the fungal infestation, suggesting that THz imaging may be a valuable tool for non-contact inspection of wood.

Considerations Concerning the Oldest Stands from Banatului Mountains, Romania

The present study was realized in Banatului Mountains (Romanian Carpathians) within Nera, Caransebeș and Băile Herculane Forest Districts, based on forest management plans from 1991-2008 and has led to the identification of 394 stand elements older than 200 years. The purpose of this paper was to analyze the trees’ main qualitative characteristics (age), the stands’ structural characteristics (consistency, composition, average diameter and average height) as well as the stational characteristics (altitude, slope, soil type). The main focus was to identify the oldest stands from Banatului Mountains. The present paper presents the oldest 18 stands as well as their most representative characteristics: diameter, height, consistency, slope, altitude, soil, site and structure. The oldest stand identified in this area is a 260-year-old common beech stand from Nera with heights between 36-38 meters and a diameter of 98 meters. Furthermore, it has been observed that common beech stands have a normal consistency, while their structure is relatively uneven-age. The research has shown that the surface occupied by old common beech stands that have reached their exploitability age is of 60.978 ha, namely 13% of the total surface of these forests. The site conditions where they are spread are characterised by preponderantly Northeast and South-West expositions, fields with slopes of 21-30 degrees, average altitudes of 900-1000 m, eutric cambisol and luvisol soils and medium and superior reliability sites.