Lazdiņš Andis, PhD.

The forestry and timber industry are strong sectors in the economies of European countries. The current trend of introducing forestry management that respects the various functions of the forest has created new challenges. However, forestry itself, as well as those challenges, varies in different regions in Europe. The aim of this review paper was to describe forest resources and their potential as well to define challenges in forestry and forest engineering in regions of East Europe. Case studies were selected from four countries: Croatia, Latvia, Poland and Romania. The background data and information of the forest-based sector included: forest resources and forest productivity, forest utilisation, development of forest operations and difficulties in forest management. In the analysed countries, state-owned forestry was represented by at least 45%. Forestry is an important sector in all four countries and future challenges are observed in forest management and forest engineering mainly including: an increase in timber resources, improvement in species composition for better productivity and the introduction of effective mechanised forest operations in pre-commercial thinning. Further improvement of harvester heads is expected for the harvesting of broadleaved species and for young stands. Issues linked to the environment were also recognised as challenging factors: mild winters make it difficult to use CTL technology on wet and sensitive sites. Additionally, dry seasons have a high impact on forest fire frequency, but this can be controlled by effective monitoring systems. Improvement in IT systems used in forest operations should limit the carbon footprint by optimising transport, machine use and limiting fuel use. Finally, innovations are recognised as key issues in the improvement of forest management and forest engineering; therefore, special budgets have been allocated to support science and development.

The aim of the study was to provide a comprehensive overview of global long-distance road transportation of industrial roundwood. The study focused on the maximum gross vehicle weight (GVW) limits allowed with different timber truck configurations, typical payloads in timber trucking, the road transportation share of the total industrial roundwood long-distance transportation volume, and the average long-distance transportation distances and costs of industrial roundwood. The study was carried out as a questionnaire survey. The questionnaire was sent to timber transportation logistics experts and research scientists in the 30 countries with the largest industrial roundwood removals in Europe, as well as selected major forestry countries in the world (Argentina, Australia, Brazil, Canada, Chile, China, Japan, New Zealand, South Africa, Türkiye, the United States of America and Uruguay) in February 2022, and closed in May 2022. A total of 31 countries took part in the survey. The survey illustrated that timber trucking was the main long-distance transportation method of industrial roundwood in almost every country surveyed. Road transportation averaged 89% of the total industrial roundwood long-distance transportation volume. Timber truck configurations of 4 to 9 axles with GVW limits of around 30 tonnes to over 70 tonnes were most commonly used. The results indicated that higher GVW limits allowed significantly higher payloads in timber trucking, with the lowest payloads at less than 25 tonnes, and the highest payloads more than 45 tonnes. The average road transportation distance with industrial roundwood was 128 km, and the average long-distance transportation cost in timber trucking was €11.1 per tonne of timber transported. In the entire survey material, there was a direct relationship between transportation distance and transportation costs and an inverse relationship between maximum GVW limits and transportation costs. Consequently, in order to reduce transportation costs, it is essential to maximise payloads (within legal limits) and minimise haul distances. Several measures to increase cost- and energy-efficiency, and to reduce greenhouse gas emissions in road transportation logistics, are discussed in the paper. On the basis of the survey, it is recommended that up-to-date statistical data and novel research studies on the long-distance transportation of industrial roundwood be conducted in some countries in the future.

Determining forest stand characteristics after thinning, in order to assess the quality of the work and update the inventory data of the thinned stand, is one of the few forest management tasks for which an efficient and accurate automation solution has not yet been developed. Currently, forest stand characteristics are determined by a certified inventory expert using manual instruments such as a range finder, digital or manual calliper, and a Bitterlich gauge. Manual measurements add a significant cost to forest management, and automating this process could increase the competitiveness of forest owners in the global timber market, helping reduce human error and providing more detailed information on the condition of stands and the distribution of trees of different dimensions in a stand.

The aim of the study is to adapt a method developed in Sweden for the automated estimation of forest stand characteristics after thinning using the HprGallring software to Latvian conditions and to determine accuracy of the modelling-based prediction of stand characteristics.

In the study, the height, number, diameter, and species of individual trees after thinning were determined using the sample plot method (according to methods applied in forest resources monitoring) and using photogrammetry as reference data for the study. In some felling areas, the diameters of all trees were measured before and after felling. The data obtained using different methods were compared with updated stand characteristics in the Forest resource database updated by certified inventory experts using plot measurement method.

According to the results of the study, HprGallring can provide the data necessary for updating the forest inventory database after thinning, but the accuracy of the modelled projections, as compared to manual measurements, are not yet within the uncertainty range as required by the forest inventory regulations. The average tree height, as indicated in the State Forest Register, matches the HprGallring estimates within the regulatory uncertainty limits in 67% of Scots pine (Pinus sylvestris L.) stands, 65% of Norway spruce (Picea abies (L.) H.Karst.) stands, and 48% of Birch (Betula sp.) stands. The diameter of an average tree after thinning estimated by the HprGallring is larger than that according to the manual measurement. The average diameter estimated using HprGallring in pine stands matches the data in State Forest Register in 40% of the assessed areas, in 47% for spruce stands, and 35% of birch stands. The accuracy of the predictions needs to be improved to make HprGallring usable in forest inventory, but even now it provides valuable spatial information about the distribution of trees of different dimensions and species within stands, enabling more accurate planning of management methods and spatial redesigning of the forest compartments.