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  • Open access
  • 147 Reads
Comparing accuracy of three remote sensing methods to evaluate soil impact related to forest operations

The aim of the present work was the evaluation of the reliability of three different remote sensing tools to assess soil impact related to forest operations. Study area consisted in an oak coppice located in the Municipality of Castel Giorgio (Terni District, Central Italy). The different tested technologies were Sentinel-2, Google Earth and Unmanned Aerial vehicle equipped with RGB sensor. After the forest utilization, images of the study area were obtained from the mentioned above systems, and a photo-interpretation process allowed to identify the skid trails pattern opened by the operators to extract the wooden material. The three theoretical skid trails patterns were compared to the real one, obtained with field relief with GNSS technology. Obtained results showed that all these systems still need some improvements for a practical application in Italian forest sector, for what concerning soil impacts evaluation after forest operations.

  • Open access
  • 200 Reads
Long-term Sensitivity Analysis of Palmer Drought Severity Index (PDSI) Through Uncertainty and Error Estimation from Plant Productivity and Biophysical Parameters

The Palmer Drought Severity Index (PDSI) is the most effective and well-acknowledged drought severity index that particularly determines the long-term drought conditions over the forest and other terrestrial ecosystems. The PDSI is based on demand and supply concept of the water balance model, taking consideration not only precipitation deficit but also includes local temperature and soil moisture anomalies. However, the sensitivity of PDSI has not been explored yet based on productivity (i.e. Gross Primary Productivity or GPP), biophysical parameters (i.e. biomass- Leaf-area Index or LAI, Enhanced vegetation index or EVI; greenness content- Normalized difference vegetation index or NDVI) and solar radiation (i.e. fraction of absorbed solar radiation or fAPAR) over a humid-subtropical forest ecosystem. In this study, the sensitivity of PDSI has been analyzed through uncertainty and error estimation from long term (2015-2019) MODIS GPP and reflectance data using Google Earth Engine (GEE). The study was carried out over the humid-subtropical forest region of Arunachal Pradesh, India, the state that is enriched with the second largest forest cover. Most of the existing studies on drought severity showed a high sensitivity of GPP or NDVI during the drought period. However, in this study, it was experimentally observed that EVI was the most sensitive parameter to PDSI in a long-term observation based on low uncertainty and error. Besides, EVI had a strong agreement with PDSI compared to GPP, NDVI, LAI, and fAPAR where Pearson’s r was ranging from -0.87 to -0.63 except 2015. The estimated uncertainty (RMSE) and error (SE) between PDSI and EVI were also very low ranging from 1% to 2% and 0.07-0.12 respectively compared to the other parameters. So, based on the long-term analysis from this study, it is stated that EVI is the simple, effective, and most complementary indicator for assessing PDSI over forest regions of the tropical ecosystem. This study showed that EVI might be a promising tool for effectively evaluating long-term drought impacts on the forest ecosystem that indicates the actual water deficit induced stress conditions.

  • Open access
  • 46 Reads

Oak forests perform essential environmental, protective, recreational and health-improving functions as well as meet the needs of the national economy in valuable wood both at the local and regional levels. To determine the regime of use and provide effective forest management in the oak forests, it is advisable to improve the age structure of these stands, taking into account their functionality, which is determined by their belonging to a certain forest category. The data of the last forest inventory (as of 2011) were the basis for the calculations. In total, about 70,000 survey plots in oak stands within the Left-Bank Forest-Steppe were analysed. The area of the investigated stands was 284,094 hectares. The area of oak stands in Ukrainian Left-Bank Forest-Steppe was divided according to forest categories and age groups based on forest surveying data using the inventory subcompartment database. It was found that that oak stands are mainly concentrated in recreational, health-improving and protective forests, and therefore fulfill important water conservation and soil protection functions as well as provide recreational, sanitary, hygienic, aesthetic and other environmental services. The age distribution of oak stands was revealed to be imbalanced in all forest categories, with a significant predominance of middle-aged and maturing stands. Also, a very large proportion of mature and overmature stands and a small proportion of young stands were identified. This specificity is an important reason for forestry interventions aimed at optimizing the age structure, in particular, for complex felling, including conversion felling, in middle-aged understocked stands within forests fulfilling nature protection, scientific, historic, cultural, recreational and protective functions. This will contribute to the gradual transformation of even-aged stands to uneven-aged mixed multi-storeyed ones. The composition and structure of such new stands will meet the necessary criteria for those close to natural forests

  • Open access
  • 74 Reads
Sustainable forest management in radiata pine plantations: a study case in Sardinia (Italy)

Pinus radiata Don. (radiata pine) was planted in Italy mainly in Sardinia (11,000 ha), where it grows best on acidic soils, in medium mountain-Mediterranean conditions. Plantations were established about 50 years ago, in heavily grazed areas originally occupied by Mediterranean scrub vegetation, as part of extensive reforestation projects carried out with public funds and intended to deliver cellulose pulp to the paper industry. Since the request from the national paper industry ended, fewer exotic species were used, and plantations were often left without thinning and affected by wildfires.

We report a study case in central-eastern Sardinia (Ogliastra, Idòlo Mountain forest, belonging to the municipality of Arzana) where radiata pine stands, in about 45 years of growth, achieve an average production of 21 m3 ha-1 yr-1. Under these conditions, the regional forestry agency supports active forest management with the aim to produce timber (suitable as carpentry timber, for packaging industry, firewood and wood chips) and to start natural processes of regeneration. In order to regulate stand density, two thinning methods (production and crown thinning) and an expanding gap silvicultural system were compared. Traditional mechanization was used for felling and extraction (chainsaw and tractor with forest winch) as well as a harvester (for delimbing and bucking trees) and woodchipper.

The management of the fast-growing radiata pine, as observed in this study case, allows to achieve multiple benefits that are at the heart of forest sustainability: profitable and sustainable wood production (by activating the local economy linked to work timber, firewood and small packaging industry), biodiversity (restoring native forest species and natural regeneration processes), land degradation mitigation (improvement of soil conditions under continuous cover forest conditions), climate change (sequestration of atmospheric carbon and bioenergy production) and social aspects (local occupation).

  • Open access
  • 70 Reads
Manipulating mammal herbivory in South Patagonia forests: effects on plant species assemblage, survival and short-term growth response of Nothofagus antarctica seedlings

Livestock browsing and large wild herbivores in forested areas have been perceived as conflicting with silviculture and forest conservation for a long time. However, silvopastoral systems in native forests entail livestock manipulation in space and time, to reduce negative impacts on forest structure and dynamics. Competition from other vegetation and browsing by mammal herbivores are two factors that usually limit tree regeneration. In 2014, we established eight 15×15m fences (and the respective control plots with browsing) in four Nothofagus antarctica (ñire) silvopastoral sites in Tierra del Fuego Island, to protect tree seedlings and vegetation from cattle and guanaco browsing. In 2019, after five growing seasons, the exclusion treatment had favored regeneration of ñire by reducing browsing pressure while increasing seedling growth rate, though the effect on seedling survival was weak. Ñire regeneration was absent only in one of the fields (inside and outside of fences), probably due to the high coverage of the exotic fodder grass Holcus lanatus. Soil moisture increased while soil compaction decreased over years in all fields, though the fences effect was weak. Moreover, other plants, and especially palatable herbs (e.g., Taraxacum sp., Osmorhiza sp.) and grasses (e.g., Agrostis sp., Bromus unioloides) increased much more in abundance and height than ñire seedlings within fences. Thus, the use of exclusion treatments to manipulate browsing impact enhances the short-term growth of ñire regeneration in south Patagonia forests used for cattle production. However, a negative effect by competing for understory vegetation in fences probably also occur in the long term.

  • Open access
  • 79 Reads
Potential of Trichoderma sp. and Pinus sylvestris bark extracts as biocontrol agents against fungal pathogens residing in the Botryosphaeriales

Botryosphaeriales represents a diverse order of fungal pathogens of various woody plant species. In Serbia, these fungi are important pathogens of forest, ornamental and fruit trees causing die-back, cankers, leaf blights, fruit and root rot. The aim of this study was to evaluate the antifungal activity of Scots pine (Pinus sylvestris L.) bark extracts and Trichoderma sp. against Botryosphaeria dothidea, Neofusicoccum parvum and Dothiorella sarmentorum (Ascomycota: Botryosphaeriales) isolated from ornamental and forest trees. Bark extracts were prepared in water solution at two temperatures (80 and 120 ºC) and two pH levels (7 and 9). The extracts were tested using two concentrations (20 and 30%). Moreover, three isolates of Trichoderma sp. obtained from P. sylvestris bark were used against isolates of Botryosphaeriales and their antagonistic potential was estimated in vitro using a direct confrontation test. Mycelial growth of B. dothidea and D. sarmentorum in the presence of bark extracts was significantly inhibited while N. parvum showed no growth inhibition. B. dothidea growth was inhibited by 34 to 39% in case of 20% extracts and by 39 to 40% in case of 30% extracts. The growth inhibition of D. sarmentorum was between 48 to 60% in case of 20% extracts and 53 to 66% in case of 30% extracts.

All three isolates of Trichoderma sp. showed antifungal activity against selected pathogens. Isolate BK4G showed the highest inhibition level and it inhibited growth of B. dothidea, N. parvum and D. sarmentorum by 85, 62 and 75%, respectively.

Due to their ability to reside in wood, Botryosphaeriales are hard to manage. Moreover, environmentally safe pathogen control methods are preferred over classical fungicide treatments. This study suggested that both P. Sylvestris bark extracts and Trichoderma sp. could be used as biocontrol agents against Botryosphaeriales and that further evaluation of these agents in vivo is justified.

  • Open access
  • 42 Reads
Effect of Competition and Climatic conditions on the growth of beech in the mixed pine beech stand: Lithuanian case study

Climate change and warming will potentially have profound effect on forest growth and yield, especially for the pure stands in the near future. Thus, more and more attention is given to the mixed stands, for example pine and beech mixtures. Yet, interaction of tree species, growing in mixtures it is still remaining question to be answered.

Thus the aim of this study was to investigate the impact of the interspecific and intraspecific competition to diameter, height and crown width of pine and beech trees growing in mixtures and to evaluate the impact of climatic indicators to the beech radial diameter increment.

The data was collected in the mixed mature pine beech double layer stand, located in the western part of Lithuania in 2017. The sample plot of 1.2 hectare was established and tree species, diameter at the breast height, tree height, height to crown base and crown widths as well as position were measured for all 836 trees. Additionally, representative sample of radial diameter increments were estimated only for the beech trees, by taking out core discs at the height of 1 meter, when the stand was partially cut. Competition analysis was based on distance dependent competition index, based on crown parameters. Climatic effect was evaluated by using Classification and Regression Trees (CART) analysis.

It was found almost no intraspecific competition effect to diameter, height or crown width for both tree species. Yet, interspecific competition effect was important for pine as well as for beech trees.

These results show the possible coexistence of these tree species due to niche differentiation.

Analysis of climatic indicators revealed that higher than 48.5 mm precipitation during February-May of current year had very positive effect to radial growth of beech trees as well as mean temperatures from July to September being lover than 16.5 °C.

Contrary, temperatures lover than 5.2 °C during March and April as well as high precipitation during the January, more than 62.8 mm had negative effect to beech radial increment.

Generally, cool summers as well as higher precipitation during the June of current year had positive effect to the beech radial increment. It shows its sensitivity to high temperatures as well as droughts during the summer time under Lithuanian growth conditions.

  • Open access
  • 70 Reads
Connecting Indigenous and Scientific Ecological Knowledge in the Madidi National Park, Bolivia

Across the Amazonian basin, indigenous communities are part of the ecosystem functioning. They harbour a deep understanding of their surrounding ecosystem. Ethnobotany is the practice that aims for the preservation of the traditional botanical knowledge, wisdom, and reality. However, the extent to which humans depend on ecosystem services across different population groups and spatial scales prevail poorly understood. The purpose of this study is to understand the role of ecological processes and patterns in determining and responding to human use of plants of the Tacana people in Madidi National Park (Bolivia). Two different theories are tested (1) species availability influences plant use and (2) biodiversity shapes forest use. The data were compiled in a total of 44 plots (0.1 ha) within five different regions distributed among submontane and lowland forests. Results showed that 1) the availability of a resource plays a significant role in the human choice of plant species, 2) the maximal use of a forest is dependent on intermediate levels of plant diversity. Both ecological and ethnobotanical factors are intertwined shaping the human resources’ use. Therefore, the integration of indigenous perception in conservation strategies is crucial as the ecology of the Amazon basin is shaped by the long-lasting effects of its ancient and modern inhabitants.

  • Open access
  • 48 Reads
Carbon stock in forest stands of Ukrainian Eastern Forest-Steppe: forest monitoring data

In Ukraine carbon stocks in forests are assessed by gain-loss method, since the national forest inventory is under development now. For evaluation of main pools of oak and pine forest stands, typical for Forest-steppe of Ukraine, stock-difference method was used for data of repeated observations on 18 intensive forest monitoring plots.

The average carbon stock in the phytomass is 94.1 ± 10.5 tC ha-1 and 93.4 ± 12.6 tC · ha-1, in dead wood - 8.8 ± 3.8 tC · ha-1 and 5.3 ± 4.2 tC · ha-1 for oak and pine forest stands respectively. By age classes pine stands due to it higher productivity in general have higher C stock in phytomass comparing to oak.

C stock changes in trees phytomass is the highest in younger stands, and it decreases with age; while in dead wood it increases. At age 81-100 years oak forest stands have higher carbon storage capacity than pine (total stock in main pools (phytomass, mortmass and soils (30-cm layer)) is 191.7 t C ha-1 for oak and 175.4 t C ha-1 for pine stands). Trees phytomass carbon prevails among other pools (50.3 % in oak forests, and 57.6% in pine).

  • Open access
  • 64 Reads
Selected physical parameters and daily volume of silver birch sap collected from the cardinal directions of the tree trunk.

The collection, sale and processing of non-wood forest products are becoming a significant factor in stimulating regional development and improving the economic situation especially of poor rural communities. The fashion for a healthy lifestyle is also conducive to the growth of interest in such goods. Among them, birch sap is indicated as one of the most promising non-wood forest resources of central Europe, with very wide possibilities of its practical use, e.g. in the food and cosmetics industries.

The potential increase in birch sap use prompts to undertake research on both the principles of its collection and the impact of various factors on its use possibility and quality. In this presentation, we decided to investigate how the daily volume and selected sap parameters change depending on the location of the holes in relation to the cardinal directions.

The research was conducted in April 2018, in the eastern part of Poland, in a stand with a dominant share of silver birch (Betula pendula Roth) at the age of approx. 100 years, in a fresh broadleaved forest habitat. On each of the 6 selected trees, 4 holes were drilled at a height of 1 m, positioned according to the cardinal directions (N-E-S-W). Sap was collected twice, one week apart, always after 24 hours of leak. In each case, the daily volume of the obtained sap was determined, and then the selected properties of the sap were tested: electrolytic conductivity (proving, among others, the content of pro-health compounds), refractometric index (proving the approximate content of sugars), pH and the percent of dry matter.

The average daily volume of collected sap was 1.026 dm3/24h (the highest in the N direction - 1.397 dm3/24h, while the lowest in W - 880,58 dm3/24h, but the statistical analysis did not confirm the significance of this statement). Similar trend was observed concerning refractometric index (N: 0.74°Brix; W: 0.62°Brix; avg: 0.7°Brix, also not statistically proved). In other cases, the variability was small and multidirectional (for example: electrolytic conductivity: S – 654 µS/cm, N – 531 µS/cm, avg. – 577 µS/cm; pH: E- 5.6, W – 4.9, avg. – 5.3). This may mean that the location of the hole on the tree stump is of no practical importance for commercial sap harvesting. The obtained results may be important in the case of developing the principles of commercial collecting of birch sap.