Of hedges, copses and timber cultivation in the region of Wurzen near Leipzig

Review of the field day on 21.06.2024


© Anke Hahn

The field day on 21 June 2024 in the region of Wurzen near Leipzig focused on the combination of environmental services and regional value creation aspects with the growth of agroforestry systems with fast growing trees together with hedges and other landscape elements of nature conservation interest. Three different agroforestry structures on the land of farmer Frank Uhlemann between Zschorna, Hohburg and Thammenhain were the centre of interest for around 40 participants on this day. The reason for the plantings at the time were research trials carried out by the Saxony Forest Service (Staatsbetrieb Sachsenforst) on behalf of the Agency for Renewable Resources (FNR), with the harvested wood being sold to regional energy suppliers and the pulp industry.

The OLGA research project and the ongoing activities of the Competence Centre of Organic Farming as part of the Saxon State Office for Environment, Agriculture and Geology to promote agroforestry in Saxony were presented at the beginning. During the look at a field copse structure with different tree and shrub species between Zschorna and Hohburg at the first location, the main focus was on its importance for the restoration of a species-rich and structurally diverse agricultural landscapes. This is because such landscape elements primarily organise the landscape, protect it from wind and erosion and can be components of the local biotope network. Unfortunately, one farmer complained that the promotion of hedges and the willingness to authorise these structures in the Free State of Saxony was rather poor. Here, agriculture and nature conservation need to cooperate more closely, develop joint objectives and translate them into funding programmes. Agroforestry, with its diverse and multifunctional approaches to land use, is still treated with too many kid gloves in the environmental and agricultural administration in this country. As a result, the current fundings are not yet very lucrative. 

After travelling to the next system planted as part of the FastWOOD project in 2014, the colleagues of Sachsenforst presented their research work on the cultivation of aspen. In this trial, the aspen clones planted by hand in a 2 m x 1 m formation were compared with ten other trial areas with aspen in Saxony in terms of their biomass growth in short rotation. This is because the productivity of these agricultural timber structures can be increased by breeding more productive varieties. The diameter of the breast height and biomass growth after 10 years differ depending on the plantation area. The differences are not dependent on the location of the trees within the plantation, but on the respective test link (in this case: in each case as the offspring of two defined parents).

At the third location, a poplar trial area with cuttings was established in 1999 with the aim of selling the harvested wood biomass to the pulp industry. In particular, the biomass growth was compared with different soil pre-treatments, plant associations and rotation times. The trial area was pre-treated with herbicides in a test variant. This resulted in better initial growth because there was no competition from the lack of accompanying vegetation. The same effect could also be achieved with mechanical weed control, but this was not investigated in this case. The wider the plantation, the less biomass is produced per hectare, as the wide spacing between the trees means that a relatively large amount of sunlight initially falls on the ground and is not absorbed by the trees. However, the growth of the individual trees is promoted by extending the plantation. If the aim is to maximise the tree dimensions and not to maximise the yield per unit area, it is therefore advisable to choose wider planting strips. This plot trial showed that the potential is far from fully utilised in the first rotation due to the necessary establishment of the plants, so that the biomass yield increases significantly in subsequent rotations (regardless of their duration).

Ever heard of Tordis, Inger and Max1? These are not Swedish national football players, but the names of different willow clones that were planted in the immediate vicinity at the fourth location of the field day near Thammenhain. The site was one of 42 other test sites that were established between 2012 and 2015 as part of the ProLoc breeding project to record clone-site interactions in poplar and willow in three- and ten-year rotations. 

The agroforestry field day in Wurzener Land was a collaboration between the Uhlemann farm, the Competence Centre for Organic Farming of the Free State of Saxony, the German Agroforestry Association DeFAF, the Saxony Forestry Service (SBS) and the OLGA research project.