Black locust (Robinia pseudoacacia L.) was the first forest tree species introduced from North America to Europe, at the beginning of the 17th century. Its unprecedented fast spread is due to its high-grade adaptability, drought-tolerance, abundant and frequent seed crop, excellent sprouting ability, fast growth and relatively high timber yield.... Other advantages are, that it has scarcely any fungi or insect pests. This review is a short summary on black locust improvement in Hungary, giving guidance for specialists who are interested in black locust management.
Black locust (Robinia pseudoacacia L.) is a valuable stand-forming tree species introduced to Europe approximately 400 years ago from North America. Today it is widely planted throughout the world, first of all for wood production. In Hungary, where black locust has great importance in the forest management, it is mainly propagated by...seeds. But since the seed-raised plants present a great genetic variation, this type of propagation can not be used for Robinia’s improved cultivars. In the Hungarian black locust clonal forestry, propagation from root cuttings can be used for reproduction of superior individuals or cultivars in large quantities. However, this method demands more care than raising seedlings from seeds and can be applied with success in well-equipped nurseries.
In Hungary black locust (Robinia pseudoacacia L.) is considered as an important exotic stand-forming tree species and due to climate change effects its importance is increasing in many other countries. It has some desirable characteristics from both the practical and research standpoints. As a result of a partly new black locust selection progr...amme new black locust clones were improved and a technology was developed for mass clonal micropropagation of juvenile trees. Clone trials with micropropagated plants were established in the country for evaluating the juvenile growth and the stem form of promising black locust clones under marginal site conditions. Significant differences (P<5%) were found for stem form value which partly verified the genetic gain of the selected clones against the common black locust. It was also proved that tissue culture could offer partly new prospects for the rapid mass cloning of selected genotypes.
The study on the diameter and volume increment of black locust (Robinia pseudoacacia L.) stand (age 10-27 years, yield class II) have shown that in comparison to the periodic annual increment of the breast height diameter of tree in height class I, trees in height class II have reached 83.3%, while in class III only 43.9. The same rela...tions for volume were found 59.0% and 24.5%, respectively. The mean values of the whole stand were close to those of height class II. According to the distribution of the periodic annual increment of volume between 10 and 27 years of age, 50% of the values were between 2.00 and13.88 dm3, 73% were between 2.00 and19.82 dm3, and 96% were between 2.00 and 37.64 dm3. The range of 13.88–19.82 dm3 had the highest occurrence (24.5%).
In Hungary, black locust (Robinia pseudoacacia L.) is one of the most important exotic stand-forming tree species, growing mostly under unfavourable ecological conditions. Considering the climate change effects its importance is increasing in many other countries. As a result of a selection programme, several black locust cult...ivars have been improved for setting up cultivar trials. In the paper four black locust cultivars were evaluated in Central Hungary under arid hydrological and brown forest soil conditions. Significant differences (P<5%) were found in height, DBH, mean tree volume and average stem form value (SFV). At the age of 35 the cultivar ‘R.p. Jászkiséri’ appeared to be the most promising one for yield production and ‘R.p. Zalai’ for SFV.
Black locust (Robinia pseudoacacia L.) is the most important fast growing stand-forming tree species in Hungary. Its importance is increasing in many other countries, too. As a result of a new selection programme 13 black locust clones have been improved for setting up clones trials and seed orchard. In 2003 five of them (R.p. ...>`Bácska', `Homoki', 'Szálas', `Oszlopos' and `Vacsi') were registered as cultivarcandidates. Tissue culture method has proved as a suitable mean of propagating superior individuals. The micropropagated plants have been growing successfully in the clone trials.
A more intensive integrated research and development approach to the work carried out on the growth on sandy soils of stands of black locust (Robinia pseudoacacia L.) has been adopted in recent years, revealing several factors influencing stand growth. The fact that certain ecological factors influencing fundamentally the growth of trees have b...ecome unfavourable in Hungary in recent years has led to the more extensive use of black locust in the course of afforestation and forest regeneration schemes. The study presents a new, simplified tending operation model for black locust stands and age, growing space and target diameter models suitable for qualitaty log production and for mass assortments. The simplicity of these practice-oriented
models may foster the qualitative development of black locust management in Hungary and in some other countries where this tree species may gain greater acceptance by landowners and the forest industry.
Honeybee races and ecotypes of different genetic background have different population development in spring. Some of them can reach the necessary population size by the beginning of Robinia pseudoacacia (black locust) blooming period. There were significant differences in the spring population development between the colonies of differ...ent genetic background. The Italian races (A. m. ligustica) and their cross-breeds over-wintered poorly in Hungary, their spring population was low and they collected small amount of Robinia honey. The Austrian improved Carniolan (A. m. carnica) colonies over-wintered well, they had the largest spring population in both years. There was no significant difference between the size of the spring population of the same colonies of different genetic background in 1995 and 1996. The rate of the population development of the colonies was different in the two examined years. There was strong correlation (r = 0.8) between the spring population size and the Robinia honey yield, and between the mid-April population size and the Robinia honey yield of the colony groups of different genetic background. Spring population size also important in the effective pollination of fruit tree species that bloom earlier than the black locust trees.
Establishment of short-rotation energy plantations for fuel production has been of international interest for many years. Energy plantation experiments in Hungary have been conducted for a longer time. In the country black locust ( Robinia ps eudoacacia L.) is one of the most important stand-forming tree species, covering approximately... 23% of the forested land (410 000 ha) and providing about 19% of the annual timber output of the country. This fast growing species seems to be suitable for energy plantations as well. So, in Helvecia (Central Hungary, sand-soil region) two energy plantation s were established u sing common black locust and its cultivars improved in Hungary. The spacing variations of the common black locust were: l.5x0.3 m, I .5x0.5 m and l.5x 1.0 m. At the age of 5 the closest spacing ( 1.5x0.3m) produced the greatest annual increment in oven-dry weight (6.5 t ha·1 yr- 1). In the trial with black locust cultivars planted in spacing of 1.5xl.0m, at the age of 7 the highest annual increment in oven-dry mass was produced by the cultivar ' Ulloi' (9.7 t ha-1 yr- 1) followed by the common black locust (8.4 t ha-1 yr- 1) and the cultivar 'J tiszkiseri (1.6 t ha·1 yr- 1). The trials have verified that in temperate climate the increment in oven dry dendromass of black locust energy plantation s has ranged from 6 to 12 t ha·1 yr·1. On the basis of the trials' evaluation the quantity of dendromass mostly depends on site quality, species and cultivars, as well as on the initial spacing (plants per hectare).
Black locust (Robinia pseudoacacia L.) can be considered as one of the most suitable tree species for establishing energy plantations due to its favourable growing characteristics such as vigorous growing potential in the juvenile phase, excellent coppicing ability, a relatively high resistance to pests. Based on national and international test... results the mean annual increment of oven-dry weight of energy plantations regenerated by coppicing generally exceeds the first cycle plantations established by seedlings.
The choice of the right initial spacing of stands is one of the most decisive operations of a successful afforestation. It is even more important in the case of fast growing tree species grown in plantations; it is expressed in their early phase of development and in wood quality. The results of a 5-year long experiment with four treatments wil...l be presented in this paper. They proved the priority of an initial spacing of 1.61.0 m in the majority of quality This treatment has been proved optimal exploitation of growing space by the young trees.