The aim of this work was to assess the possible impacts on the forest soil and stand due to silvicultural treatment and forest operations in a beech high forest. Evenaged beech forests (Fagus sylvatica L.) in the Municipality of Cappadocia (AQ) and in the Municipality of Vallepietra (RM) were analyzed. The analysis on soil and stand were performed in order to assess the effects attributable to applied silviculture and forest logging. Two different logging methodologies (in particular for the extraction) were applied: mules were used in the areas with greater slopes and with obstacles, while for the areas with better accessibility, mechanical means were used, in this case tractors. In detail, the main objective was to assess the disturbs on the ground and on the stand, generated by the two different levels of mechanisation. In addition, it was also interesting to understand the possible effect on the soil specifically referred to the partial uncovering by removing part of the tree canopy. Only through an accurate cross-analysis of the studied parameters and indices, it was possible to highlight the anthropogenic impacts on the soil and stand due to forest operations in consideration of the different logging methodologies applied. The main results showed that the disturbs caused to the soil and stand were essentially caused in the bunching and extraction operations. The importance of avoiding or limiting the continuous passage of vehicles and animals on forest soil clearly emerges, especially in conditions of high soil moisture. It is also important to use correct technologies in fuction of the specific environmental characteristics and of the work planning. Finally, it is possible to state that, in substance, from the comparison carried out that a real disturbs difference did not exist referring to the two logging methodologies. Comparing the findings of this study with other researches, it was possible to highlight that substantial differences, in terms of improvement, can be obtained only applying different mechanisation in conjunction with a different logging system.

The restorers of degraded areas require high quality plants, with ideal morphological attributes to be able to establish successfully on the plantation sites, even if the site conditions are adverse. In order to know the plant quality of six pine species, that will be used for reforestation and restoration of forest lands in the state of México, we evaluated five morphological attributes based on the Mexican Norm NMX-AA-170-SCFI-2016 and Rodríguez-Ortiz et al. (2020). At the Heroes Bicentennial Forest Nursery of Tecámac, we measured seedling’s basal diameter (at the root neck (DC)), height, from the base to the apical bud (Alt), slenderness index (IE = Alt/DC), aerial dry biomass and dry root biomass ratio (BSA/BSR) and Dickson's quality index (ICD). For DC, the results showed that all species but Pinus ayacahuite, had high quality. In Alt, P. greggii and P. leiophylla had the best quality; while in IE, all the species but P. greggii, showed high quality. For the BSA/BSR ratio, P. cembroides, P. ayacahuite and P. hartwegii were the best, and for ICD, P. hartwegii had the highest quality value. Considering all the morphological indicators together, we determined that P. cembroides and P. greggii had the best plant quality. This information is key to analyze the seedling’s survival in the field and make timely decisions in land restoration management.

Forests represent both valuable and vulnerable natural resources because of the various ecosystem services they provide and their sensitivity to climate change and fires. In the Mediterranean region, the depth transformations in the rural land use with mass abandonment of traditional activities (farming, livestock-raising and forest utilisation) and an acceleration of urban sprawl, has affected the impact of fires on the territory and especially on the wildland-urban interface (WUI).

The objective of the present study is to generate maps of forest fire risks in the region of Provence-Alpes-Côte d'Azur (France) integrating natural factors (vegetation type, topography and meteorology conditions…) and human factors related to the closeness to causative elements that can potentially be the ignition point of fires (transport and power infrastructures, settlements and scattered buildings ...). GIS Spatial analyst has been used to combine single influence factors in risk maps to display the total fire risk map. These maps could be especially helpful in land management and emergency planning to minimize the effects of forest fire.

The presence of deadwood is undeniably essential in natural environments for its ecological role. In forest ecosystems, deadwood contributes to the protection of biodiversity, mitigation of climate change, soil protection against erosion, and playing an essential role within biogeochemical cycles, contributing to forest productivity by slowly releasing nutrients and moisture. We assessed the amount of deadwood in four macro-areas within two beech forests located on areas of public utility of Enciso (community of La Rioja, Spain). These areas were different in terms of silvicultural management and proximity to reforested stands of Pinus sylvestris. In each macro-area three circular sample plots were placed at an increasing distance from the access road to the forests: from 20 to 60 m, 60 to 100 m and 100 to 140 m. Dendrometric data and qualitative and quantitative characteristics of deadwood (snags, logs and dead stumps) were collected, and analyzed with respect to the degree of accessibility to the forest 1) to reconstruct past management history of the two stands, and 2) to determine the effect of different levels of forest accessibility on deadwood volume and carbon stocks, estimated using coefficients established by the Intergovernmental Panel on Climate Change (IPCC).
The amounts of deadwood and carbon stored per ha were higher than the values reported in the Spanish and Italian national forest inventories, including the one developed for the Riojan beech woods. Deadwood volume was on average 22.5 m³ ha^-1, showing an unequal distribution depending on the distance from the access roads. Deadwood volume decreased dramatically from the areas close to the access roads moving into the forest, passing from 31.6 m³ ha^-1 to 25.7 m³ ha^-1 to only 9.9 m³ ha^-1 (respectively in the first, second, and third class of accessibility). The decomposition classes were all present, indicating the development of natural degradation dynamics. Finally, the carbon sequestrated in the deadwood was 27.9 t ha^-1 in the first accessibility class, 22.7 t ha^-1 in the second accessibility class, and 9.7 t ha^-1 in the third accessibility class, for an average of 20.1 t ha^-1. The distribution patterns of deadwood in beech forests of La Rioja, apparently counterintuitive, were due to a combination of different factors, including slope, cattle grazing, and weather conditions which might have favoured downward movement of the deadwood. Furthermore, the presence of several standing dead trees near the access roads suggests a preference for removal of deadwood from local population in the more distant areas.

Point dendrometers have been widely used to monitor stem growth and phenology as well as tree drought response in forestry and to drive irrigation scheduling in woody crop species.

If the technical improvements of these tools has allowed to reduce costs and to manage them by remote control, the meaning of the signal (increase/decrease of the stem radius in the short-medium and long time) remains nowdays very difficult to interprete. For this reason a few algorithms were developed in recent years (Giovannelli et al., 2007, Cocozza et al., 2018; Zweifel et al., 2016; Deslauriers et al., 2010) allowing more reliable reading of the physiological meaning of the dendrometer signals. Thus stem shrinking, swelling and seasonal trends were associated to precise phenological phases, tree water status, cold acclimation, carbon storage, wood quality.

Although the dendrometer signals are commonly used to monitor stem increase, carbon accumulation and physiological status of entire forest stands, they could be ideally used as a proxy of the health/vitality of single trees. For this purpose, there is a need to set new algorithms to analyse the dendrometer signals able to match with the particular growth conditions of trees in urban contexts. As point dendrometers can be easily integrated in wireless system and remote control networks, they can ideally be used in complex system of environmental monitoring of the urban and periurban area in a view of smart cities development.

In this context, we installed point dendrometers on Pinus radiata trees growing in a semi-urban garden near Rome with the aim to verify if the dendrometer signals could be used as a proxy of tree vitality. We verify the hypothesis that through the decomposition of dendrometer signals in phase cycles (amplitude and duration of shrinkage and swelling, ratio between amplitude of cycles and duration) is possible to extrapolate reliable index to associate to tree vitality. These results could be used as basis to develop species related databases and new algorithms to analyse dendrodata of multiple woody species growing in urban areas.

Evenaged fifty years-old Pinus radiata individuals were selected and, based on their vitality score, assigned into three classes: alive, compromised and dead (five trees for each class respectively). In order to avoid artifact signals due to the internal stem wood degradation or knots, tomographic scanning were performed around each stem by an impulse tomography unit (Arbotom technology). On mid-June, point dendrometers were installed on the stem at breast height and data were recorded every 15 min with a CR 1000 data logger (Campbell Scientific, Inc. Logan, UT, USA). The stem radius increment, ∆R (mm) and amplitude and duration of stem shrinkage (∆w, mm and h respecitvely), were calculated following the stem cycle analyses approach (Giovannelli et al., 2007).

During July 2020, alive trees showed a positive trend of the stem radius. On the contrary compromise and dead trees had a constant decrease of the stem radius. Thus alive trees had higher positive growth cycle (when the maximum stem radius value of a cycle exceed the previous ones) than compromise and dead trees. The duration of the stem shrinkage were significantly lower in alive trees than in compromise and dead ones. Moreover in alive trees, the beginning of stem shrinkage was delayed with respect to the dead trees showing that in the latter, the stem radial variations were due mainly to the temperature effect rather than to the radial and longitudinal water fluxes adjustments.

Our preliminary data showed that point dendrometers signals could be used to define ripetible and valuable proxies of the tree vitality and health in Pinus radiata growing in the periurban areas. An increase in the number of trees monitored is however necessary to better understand the relationship between the change in the rhythm of stem water and the decline in tree health.

References

Giovannelli et al., (2007). Journal of experimental botany 58, No. 10, pp. 2673–2683

Cocozza et al., (2018). Forests 9, 134

Zweifel et al., (2016). New Phytologist 211, 839–849

Deslauriers et al., (2011). Dendrochronologia 29:151–161

Climate changes, also taking place in Poland, have a very negative impact on populations of many tree species. An example of a highly endangered and, at the same time, very valuable origin is the population of Norway spruce from Białowieża Primeval Forest. One of the protection methods a perishing population is to preserve its genetic pool in the form of seed orchards (ex situ method).

The genetic material of spruce mother trees from the Białowieża Primeval Forest has been preserved in a seed orchard with an area of 9.74 ha, established in 1996 in the Bielsk Forest District (approximately 35 km west of the Białowieża Primeval Forest). In December 2017, cones from all growing grafted trees were collected on a sample plot of 50 clones. An extensive analysis of the health of cones, seed yield from cones, parameters of cones and seeds was carried out, and the relationship between seed quality and position in the cone was determined. The number of cones on the analyzed trees ranged from 29 to 1766, with the average equal to 405 cones per clone. The greatest threat limiting seed production were insects that damaged seeds in cones. No dieback of grafted trees was recorded due to the presence of the spruce bark beetle. No dieback of grafted trees was detected as the effect of activity of European spruce bark beetle. The share of undamaged and poorly damaged cones amounted to about 88%. However, the average share of undamaged seeds is less than 50%.

Our surveys showed that the approximately 25-year-old plantation is able to give satisfying economic result and assure the preservation of the genetic pool of Norway spruce from the population of the Białowieża Forest.

The analysis of population variability usually concerns the adaptability of trees to changing climatic conditions and their timber production possibilities. It is already known that several phenotypic and genotypic features determine the adaptation possibilities of a population and every population of a given species may have different adaptability to climatic conditions. The assimilation apparatus is an important phenotypic feature that has a large impact on the functioning of tree organisms and their adaptability. Scots pine that covers vast areas of Europe, is a very important species in the context of ecosystems sustainability preservation in the era of global warming, especially. Therefore, in our research, the inter-population and individual variability of morpho-anatomical features of shoots and needles were analysed.

Nine national origins of Scots pine (3 populations each from northern, western, and central Poland), which are a part of a 50-year provenance plot, were compared. Fragments of one-year-old shoots (5 cm long) with needles were collected from the top parts of tree crowns. An extensive analysis of the morphological parameters of the needles (length and width, density, dry mass) and the anatomical features of the shoots (thickness, the share of bark, wood, and pith) was performed.

Our surveys showed that the differences between populations are much greater than between regions. The western pine populations, which have shown the highest volume of wood per ha, had the thickest shoots but the lowest dry mass. The northern populations, highly valued for the very good technical quality of wood, had thin shoots. Pine trees from Central Poland had the highest density and dry mass of needles and the highest share of wood in shoots.

Commiphora wightii (Arnott) is a critically endangered, dioecious plant and commonly known as Guggal. It has tremendous pharmaceutical and medicinal importance. The sex ratio is extremely skewed towards female plants and male plants are extremely rare. Slow growth, poor seed germination and extremely poor regeneration are some of the contributing factors causing decline in its population. The objective of the present work was to study the seed characters in different genotypes to establish the relationship amongst seed germination, seed colour and seed weight. Guggal plants produce seeds throughout the year but seed yield and viability are higher for seeds produced in winter. Total 1643 mature seeds were collected from nine genotypes (C1, C2, C3, P1, P2, P3, P4, P6 and P9) from Deesa (Gujarat, India) in November-December, 2017. The pooled seed weight data showed that seed weight of black seeds (41.89 gm) was higher than that of brown (30.57 gm) and white seeds (23.34 gm). Seed germination was also higher in black seeds (17.2%) than in brown seeds (5.5%) whereas white seeds failed to germinate. A significant positive correlation was also observed between seed germination and seed weight. The study on percentage of different seed lobes for each genotype revealed that four lobed seeds were found only in C2 (8.9%) and C3 (3.2%), whereas three lobed seeds were produced by C2 (1.1%), C3 (2.3%) and P9 (1.2%). Other six genotypes produced 100% two lobed seeds. The above results indicated that the seed colour and seed weight influence the seed viability as well as germination. Superior genotypes can be selected on the basis of the seed quality for establishing seed orchard and plantations as conservation strategy.

The correct measurement of harvested wood is economically seen one of the most important tasks in the wood supply chain. In the course of the fast digitalization process in forestry, several apps for mobile devices to facilitate measurement of wood piles using photo-optical approaches are now being used by large forest companies. However, detailed analysis on accuracy of these measurements is not yet available.

Therefore, three widespread apps were tested regarding the accuracy of their volume measurement of wood piles. These results were compared to the up to now used traditional manual wood pile measurement. In total, more than 150 piles of wood from different species and assortments, representing ca. 8,000 m³ of stacked wood, were measured manually and photo-optically in Northern Germany.

In dependency of the respective app, the photo-optical volume measurements of the wood piles deviated by -5.72 % to +4.46 % from the manually derived wood pile volumes in average. It was shown, that the quality of the pile (in terms of quality of piling) can influence both the deviation and the total volume of the pile. When looking at the piles’ dimensions, larger wood piles, with more than 60 m³ of stacked wood, showed a smaller deviation compared to piles with smaller volumes.

It was shown, that the manual measurement itself contains an inherent source of error as well: these volumes differed in average by 2,54 % in dependency of whether the measurement was done starting on the right or left side of the wood pile.

Timewise, the results give a first indication for faster wood pile measurement using photo-optical approaches as well. Based on these results, it can be said that photo-optical approaches can offer a meaningful solution for wood pile measurement. It can be an attractive alternative compared to manual measurement of wood piles, especially when marketing large volumes of wood piles of good quality.

The quality potential and possibilities of using beech logs and sawn wood has been investigated. Thirty beech logs, having 48 cm mean diameter, were cut from 10 trees from a Hacquetio epipactidis-Fagetum SE-site in Slovenia. Trees, with 28.2 m mean height, were pre-selected according to the national 5-grade quality scale of assessing forest stands. Beech logs were classified according to the EN 1316-1 and sawn afterwards into unedged boards of 35 mm nominal thickness. Altogether 250 boards were visually graded according to the EN 975-1 and European Organisation of the Sawmill Industry (EOS) rules. Longitudinal vibration of logs and boards with the determination of stress wave velocity and dynamic modulus of elasticity by MTG timber grader was additionally included into the quality assessment. This machine grading was used on logs and sawn timber – in the latter in green and air dried state. In the case of logs, we confirmed significance of the relationship between visually assessed log quality and stress wave velocity. The stress wave velocity in logs was also related to the stress wave velocity in boards, where it varied considerably, especially at low graded material. In the case of sawn wood, the relationship between sawn wood grade and stress wave velocity was insignificant. The research confirmed the possibility of determining the stiffness of air-dried sawn wood and its strength grade already in the green state.