Research Highlights: This research provides a firm basis for understanding the improved aspen hybrid performance that aims at facilitating optimal clone selection for industrial application. Background and Objectives: Rapid growth and wood properties make aspen (Populus tremula L.) suitable for the production of pulp and paper. We assessed the potential of tree improvement through hybridization to enhance aspen productivity in northern Poland, and investigated the effects of Populus tremula hybridization with Populus tremuloides Michaux and Populus alba L. on the growth and cellulosic pulp properties for papermaking purposes. Materials and Methods: A common garden trial was utilized that included 15 hybrid aspen clones of P. tremula × P. tremuloides, four of P. tremula × P. alba, and one, previously tested P. tremula clone. Clones of P. tremula, plus trees from wild populations, were used as a reference. Tree height and diameter at breast height (DBH) were measured after growing seasons four through seven. At seven years of age, the three clones representing all species combinations were harvested, and their cellulosic pulp properties and paper sheet characteristics were assessed. Results: The clones from wild populations exhibited the poorest growth. In contrast, the clone ‘Wä 13′ (P. tremula × P. tremuloides) demonstrated the highest DBH, height, volume production, and mean annual increment (MAI) (25.4 m³ ha⁻¹ year⁻¹). The MAI ratio calculated for interspecific crosses ranged from 1.35- to 1.42-fold, higher than that for the P. tremula. Chemical properties of pulp, fiber morphology, and the physical properties of paper sheets were more desirable for interspecific hybrid clones than those for the pure P. tremula clone. Conclusions: The results indicated that plantations of hybrid aspen may constitute an important additional source of wood for pulp and paper products in Poland. Our findings further suggested that the standard rotation of these trees may be reduced from 40 to 20 years, increasing overall biomass yield and enhancing atmospheric carbon sequestration.

Renewable energy sources such as biomass are an important aspect of the energy policy of the European Union. As the use of ‘full-value wood’ for energy purposes has been restricted, short-rotation forestry may be an alternative source of woody biomass. In Poland, the most promising genus is poplar (Populus spp.). Ten poplar cultivars from the Aigeiros or Tacamahaca sections of the genus Populus were compared in 5- and 6-year rotations for biomass components and yields. Additional aims were to preliminarily (a) identify a suitable rotation length and (b) evaluate the sprouting capacity of various cultivars in the climate of northern Poland. The following variables were measured: diameter at breast height (DBH), height, survival rate, single-tree dry mass, crop biomass production, and sprouting ability. The cultivars ‘NE-42’ and ‘Fritzi Pauley’ showed the best growth characteristics (DBH and height) and highest biomass production (7.6 and 7.7 t ha−1 year−1, and 5.2 and 6.9 t ha−1 year−1, respectively, for cultivars in the 5- and 6-year cycles). These cultivars were also distinguished by a large number of coppice shoots and a high shoot length. Eight cultivars did well enough to produce worthwhile data, and five of these gave higher biomass production (t DM ha−1 year−1) during the 6-year, as opposed to the 5-year cycle. Of the eight cultivars analysed, ‘AF-8’ had the poorest growth parameters and produced two thirds less dry biomass than either the ‘NE-42’ or ‘Fritzi Pauley’ cultivars. Data for two Italian cultivars (‘AF-6’ and ‘MON’) were not analysed because of their cold tenderness and their high mortality. Rotation length is important for biomass production in energy plantations. Most of the tested poplar cultivars gave higher biomass productivity over an initial 6-year cycle than over a 5-year one. Our preliminary results suggest that the ‘NE-42’ and ‘Fritzi Pauley’ cultivars performed best among those tested. Both of these have been tested previously in Poland in medium and long rotations. The data indicate the importance of testing cultivars under local climatic conditions before planting on a commercial scale.

The aim of the paper is to present the results of a cost analysis for artificial and natural oak regeneration in selected forest districts in Poland. This research was conducted in six forest districts with a high share of natural oak regeneration, located in south-western and central Poland. Altogether 65 plots with artificial and 35 plots with natural regeneration were analysed based on the extent of silvicultural (weeding, blank-filling and pre-commercial thinning) and protective measures (chemical and mechanical wildlife damage control, fencing) performed on the regenerated areas for the six years following forest regeneration. An intensity ratio (i.e., a proportion of the area of measures to the area of forest regeneration) as well as the mean unit costs of the measures and mean costs of the measures per hectare of forest regeneration were calculated. The results show that the total costs of silvicultural and protective measures in natural oak regeneration were considerably lower as compared to artificial regeneration. The cumulative average costs during 6 years (without costs of fencing) amounted to 1216 PLN/ ha and 6543 PLN/ha for natural and artificial regeneration respectively. Lower costs of natural oak regeneration resulted from the complete lack of expenditures on seedlings and planting, a considerably lower weeding intensity, scarce blank-filling, and the absence of mechanical wildlife damage control measures. Nonetheless, natural regeneration generated higher costs for pre-commercial thinning due to its higher intensity, earlier initiation, and higher unit costs compared to artificial regeneration, as well as chemical wildlife damage control measures, for which the unit costs were higher by over 50%. However, the higher costs of pre-commercial thinning and chemical control measures did not significantly affect the measurable financial benefits of natural regeneration. In conclusion, the matter of financial viability of natural oak regeneration should be explored in more detail over longer time spans.

The aim of the present paper is to discuss the problems with attempts to increase forest area in Poland (with a focusing on afforestation in the last 30 years), to analyse the discrepancy between the afforested area and the recorded increase in forest area, and to identify solutions that could enable Poland to achieve the policy goal of 33% forest cover by 2050. The study is based on available official documents, statistical data, and the existing literature. It presents the results of a postal survey of key institutional actors involved in afforestation in Poland on the factors hindering the implementation of afforestation on private land. The study shows that the main factors influencing the collapse of afforestation are long-term, and it is unlikely that this trend will be reversed in the coming years. However, it appears possible to take steps to convert forested agricultural lands that meet national criteria for recognition as forest to forest. The urgent need to protect biodiversity and improve environmental quality in the face of climate change makes it necessary to develop and implement a new program to increase forest area and to provide coherent tools to support the conversion of forested agricultural land to forest.

Economic viability of forestry is one of the key pillars of sustainable forest management and a basis for maintaining forests and their multiple benefits for the society. It may be achieved by, inter alia, diversification of sources of income in forest management. The aim of the article is to analyse sources of revenues of state-owned forest enterprises (holdings) in selected European countries and ongoing changes in this respect in recent years. In the paper, we analyse the structure of revenues of state forest enterprises in Poland, Germany (with the examples of Bavaria and Lower Saxony) and Austria; however, particular attention is paid to the State Forests National Forest Holding in Poland, which is the largest state-owned forest holding in the European Union (EU) in terms of area of forests. The study is based on document content analysis methodology (desk research), including annual reports published by forest enterprises, statistical data and also legal regulations. The analysis shows that while revenues from the sale of wood are the main source of income of forest enterprises, some of them are seeking to diversify their sources of revenues. The Austrian Federal Forests can serve as an example of a good development strategy based on diversified sources of income. Also, the Lower Saxony State Forest company, which is approximately 60% dependent on the sale of wood, undertakes other activities, including real estate management, hunting and recreational services. Our study shows that both the State Forests National Forest Holding and the Bavarian State Forests Enterprise are based on timber harvest and sale to a large extent. We conclude that as regards the State Forests Holding in Poland, the possibility of expanding and diversifying commercial activities should become a subject of discussion among foresters, decision makers and politicians.