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Black locust (Robinia pseudoacaciaL.) was introduced in Poland over 200 years ago, and its distribution area now covers the whole country, with the highest concentration of occurrence in the western part. Breeding of this species has been started in Poland for about 20 years, albeit on a limited scale, and two selected seed stands, 34 plus trees and two seed orchards have been registered. So far, selection efforts have not been coupled with the recognition of variation in the genetic structure of local populations. To fill the knowledge gap on genetic diversity, we selected the seven qualitatively best populations of R. pseudoacaciafor our study. To clarify the origin of the Polish population of R. pseudoacacia, a sample from a seed stand in eastern Germany and from a seed orchard with Hungarian clones from the Oborniki Śląskie Forest District was added. In this study, three microsatellites were used to evaluate genotypes: Rops15, Rops16 and Rops18, with the Rops15 locus (motif AG) showing hypermutability. Moderate or high variability was observed in all microsatellite loci examined, with a total of 27 alleles identified. In all stands, the average observed number of alleles per locus was higher than the average effective number of alleles per locus. Three main clusters have been identified in the genetic structure of the population, one of which is represented by the population from the Regional Directorate of State Forests in Zielona Góra. The second group comprised the populations from Mieszkowice, the populations Pińczów and Wołów, and the population from Germany. The last one included population from Strzelce and Oborniki Śląskie, where the population from Hungary is represented. This may be of great importance for practice. Perhaps it is worth postulating the separation of two seed regions. Under most scenarios, climate change is projected to change the distribution of forest types and tree species in all biomes. It can be assumed that the importance of black locust in times of climate change is likely to increase.

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 (Populusspp.). Ten poplar cultivars from the Aigeirosor Tacamahacasections of the genus Populuswere 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−1year−1, and 5.2 and 6.9 t ha−1year−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−1year−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 black locust (Robinia pseudoacaciaL.) has been present in Poland for more than 200 years now, its range coming to encompass the entire country, albeit with a particular concentration of occurrence in the west. Overall, it is present in 3.4% of the stands making up Poland’s “State Forests National Forest Holding” (Państwowe Gospodarstwo Leśne Lasy Państwowe), and is the dominant species in 0.1% of stands. Thanks to its producing durable wood of favourable energetic properties, this species is used in medium-rotation (≤ 40-year) plantations as well as in biomass energy plantations (where there is a 5–7-year rotation). In terms of its nectar production, the black locust is second only to lime as the Polish tree best serving the production of honey. While the species shows marked expansiveness in Poland, it has not thus far been placed on the list of aliens capable of threatening native species or natural habitats. Breeding of the species has been engaged in – if to only a limited extent – in Poland for some 20 years now, and 2 selected seed stands have been registered, as well as 34 plus trees and 2 seed orchards.