Tom 68 (2022): Zeszyt 4 (December 2022)

The study focuses on the validation of the leaf unfolding (LU) onset of oak stands in the Western Carpathians in 2000–2021 derived from MODIS satellite data. LU onset was derived from the annual trajectories of the Normalised difference vegetation index (NDVI) fitted with a double sigmoid logistic function. The satellite metric Growing speed day (GSD) corresponding to the LU onset is represented by the first derivative of the sigmoid function. Ground-based observations from 22 phenological stations of the Slovak Hydrometeorological Institute (SHMI) were used to validate the date of GSD. The results showed a good agreement between the medians of ground- and satellite-based LU onset dates. In addition to the median, the LU onset at the 5th and 95th percentiles were compared. For both percentiles, we found differences in the onset from MODIS and SHMI. The 5th percentile of the LU onset derived from MODIS was determined later than the one from SHMI data. With the 95th percentile, it was the opposite. As a result, the range determining the duration of LU onset from MODIS was significantly shorter than from SHMI observations. The trend analyses over the period 2000–2021 revealed a shift to the earlier onset of LU ~ 0.33 day.year⁻¹ (p = 0.13) from satellite and ~ 0.32 day.year⁻¹ from ground-based observations (p = 0.08). The validated LU onset and trends using the median allow analysing of the oak stands response to changing environmental conditions. However, the differences at the 5th and 95th percentiles, i.e. at the beginning and the end of the LU onset duration, remained unexplained.

Forest management adaptation to climate change is a matter of forest type, disturbances regime, and forest owners’ behavior face the climate change issue. Knowing factors that determine people respond to climate change challenges is essential to explaining their perceptions of climate change adaptation. We have conducted astudy in North-Eastern Romania applying the Model of Private Proactive Adaptation to Climate Change. The aim was to identify private forest owners’ perceptions about climate change and forest management threats and constraints and to analyse what variables differentiate private forest owners’ adaptation behavior. The PFOs with higher education were aware of the forest regime regarding private management. They knew how to assess climate change risk, while those with secondary education were the only interest was obtaining wood. The PFOs’ risk experience played an important role in adaptation. The perceptions and beliefs of PFOs were strongly influenced by socio-economic status, and they believe in climate change effects on forests but not on theirs. Adaption has become less urgent because forest management problems blur climate change beliefs. Assuming that the Romanian PFOs’ perceptions and beliefs about climate change will follow the European trend, they will want to improve their knowledge about climate change impacts and adaptive measures. Therefore, aggregating the interested PFOs, creating suitable communication channels, and organizing trainings on forest management adaptation to climate change will be needed to prevent this need.

In this study, the fruit bodies (pycnidial) colonization and spore presence of Sphaeropsis sapinea (Fr.) Dyko & B. Sutton on Scots pine (Pinus sylvestris L.) trees in stands affected by long-term drought in the Czech Republic were evaluated. A total of 520 cones at four sites were evaluated every 1.5 months from June 2019 to December 2020. The pycnidia of S. sapinea in relation to colonization by subcortical insects in inner bark and wood, and wood-decaying fungi a total of 340 trunks at 17 sites during the autumn of 2020 were also evaluated. Pycnidial colonization of S. sapinea on cones was significantly higher at the site with the highest air humidity and significantly lower in the sampling periods of June 2019, August 2019, and November 2019, which were characterized by low precipitation levels. S. sapinea spore presence on cones was significantly higher at sites in Bohemia compared to those in Moravia, in sites with higher air humidity, and in three consecutive sampling periods in March 2020–June 2020. Pycnidial colonization of S. sapinea on trunks was significantly positively dependent on the colonization of subcortical insects in both inner bark and wood, but not with the colonization of wood-decaying fungi. The results of this study show a positive relationship between high humidity and colonization by subcortical insects in inner bark and wood with S. sapinea on Scots pine.

Airborne laser scanning (ALS) has emerged as a remote sensing technology capable of providing data suitable for deriving all types of elevation models. A canopy height model (CHM), which represents absolute height of objects above the ground in metres (e.g., trees), is the one most commonly used within the forest inventory. The aim of this study was to assess the accuracy of forest inventory performed for forest unit covered 17,583 ha (Slovakia, Central Europe) using the CHM derived from ALS data. This objective also included demonstrating the applicability of freely available data and software. Specifically, ALS data acquired during regular airborne survey, QGIS software, and packages for R environment were used for purpose of this study. A total of 180 testing plots (5.6 ha) were used for accuracy assessment. The differences between CHM-predicted and ground-observed forest stand attributes reached a relative root mean square error at 10.9%, 23.1%, and 34.5% for the mean height, mean diameter, and volume, respectively. Moreover, all predictions were unbiased (p-value < 0.05) and the strength of the relationships between CHM-predicted and ground-observed forest stand attributes were relative high (R² = 0.7 – 0.8).

Valuation of timber growing in commercial forests is a key issue for forest owners, forest enterprises, but also a starting point for long-term planning in the field of forest management. The subjective approach of the evaluator can, to a large extent, lead to inconsistencies in the area of wood qualitative evaluation. This paper aimed to perform an objective qualitative analysis on a selected set of 179 logs of hardwood raw-wood assortments in a selected Forest enterprise in Slovakia. Qualitative analysis, which was performed by the Technical Conditions used by Lesy SR, š.p. confirms the identical classification of raw-wood assortments, in comparison with the classification performed by the management of the forestry enterprise, in 65 logs (36.3% of logs). In 114 (63.7%) logs, the log assortment was classified in another quality class. Most of the logs, which were reclassified to lower quality classes, showed limiting qualitative features of multiple sweep (83 logs), resp. significant simple sweep over 8 cm/m (5 logs), soft rot over 20% of the end diameter area (10 logs), and decaved knots (19 logs). Our work confirmed that the qualitative evaluation of raw-wood assortments in forestry enterprises in Slovakia is not optimal and correct. The work should thus contribute to improving the setting of optimization processes in the timber production phase in forestry enterprises.

The paper presents the results of the solution defining the possible application of the adapter as a fire-fighting mobile device with a base machine of a forest wheeled skidder (LKT) in the fire protection of forests in the Slovak Republic. Following the challenging accessibility to fire-fighting machinery during any intervention in forestry operation, the main aim was formulated. It will be about basic technical parameters of the DATEFF fire-fighting adapter, resulting from operational measures and following specification of its tactical deployment in extinguishing forest fires. This fact also follows from based on statistically processed data on fire in state forests of the Slovak Republic in the last ten years. The greatest damage occurs mainly the forests at a slope gradient of 16%. Designed fire adapter is structurally designed mainly to these terrains. Regarding its design and technical parameters, the proposed DATEFF adapter can be employed tactically as fire-fighting mobile device. In the case of an unavailable water source without access to the forest transport network, the adapter can be used as a part of long-distance water transport or as a mobile device for emergency import of material. Another option is to use it as a water tank in inaccessible terrain with the possibility of refilling using a Bambi bag and a helicopter. This fire-fighting adapter DATEFF is designed for forest wheel tractors that reach 40% slope availability, are able to work on the stand area, overcome obstacles and are available in sufficient quantities in all Slovak forest owners.