Presseinformation: Smart use of trees and crops brings best yield

Nr. 157 - 05.11.2026

Researchers show selecting winter or spring crops based on tree age maximises benefits in agroforestry

Cultivating crops – such as wheat, barley and rye – alongside rows of trees is a system of agroforestry that is known as “alley-cropping”. It serves many functions: in addition to enhancing ecosystems and biodiversity, it can also counteract the negative effects of growing crops in treeless open land. The advantages of alley-cropping come from the interaction between trees and crops, resulting in improved soil quality, reduced wind erosion, enhanced nutrient cycling, and climate change mitigation through increased carbon capture. However, rows of trees can create competition for resources such as water, sunlight and nutrients, which negatively affects crop yield. A research team led by the University of Göttingen has now shown that, in systems with rows of fast-growing poplar trees, choosing between winter and spring crops based on the age of the trees can cancel out competition, creating opportunities for farmers to optimise their harvests. The results were published in the journal Agronomy for Sustainable Development.

The study was conducted over six years at four different areas in Germany. Crop yields were measured at various distances from the tree rows. The trees were managed as “short-rotation coppice” – meaning trees are planted and cut down to near ground level every three to nine years before being allowed to regrow. The results showed that spring crops in agroforestry had between 10 and 35 percent lower yields compared to treeless open farmland when the trees were five years or older. The greatest reduction in yield occurred to crops growing within four metres of the tree rows and was primarily due to limited light caused by the shade from the trees. However, this effect was not observed in winter crops, where researchers found similar yields to those in treeless open land across the nine years of tree growth. In addition, annual wood production was three times higher after the second tree harvest compared to the first two tree harvests.

“It has been known for decades that planting crops near rows of trees can negatively affect their growth and harvests. Conversely, we know that rows of trees can sometimes have a positive effect on crop growth and yields when planted further from the trees. The benefit of trees is that they can protect against high wind and this reduces moisture loss from the crop growing a bit further away from the trees. This can, in fact, sometimes make up for the losses in harvest close to the tree rows. Until now, we didn’t know how to explain these seemingly contradictory observations and this made finding a strategy for optimizing yields difficult,” said Professor Edzo Veldkamp, who led the research at Göttingen University’s Faculty of Forest Sciences and Forest Ecology. Dr Sarah Choe, who conducted the research as part of her PhD, adds, “Our study shows that farmers can counteract the negative effects that the shade from trees has on crops by growing spring crops only during the first three years following the harvest of trees, whereas winter crops can be grown throughout the entire rotation because they are less affected by tree shade. We were also able to show that there was increased wood production from the poplar trees after the second tree harvest. This means that with the right choice of winter or spring crops, alley cropping agroforestry outperforms open farmland in terms of productivity.”

Original publication: Choe S et al (2026). “Optimizing crop types in temperate alley-cropping agroforestry depends on tree age” Agronomy for sustainable development 2026. DOI: 10.1007/s13593-026-01149-z

Contact:

Professor Edzo Veldkamp

University of Göttingen

Faculty of Forest Sciences and Forest Ecology

Göttingen 37077, Germany

Tel: +49 (0) 551- 3927339

Email: eveldka@gwdg.de

www.uni-goettingen.de/en/67070.html

Dr Sarah Choe

University of Göttingen

Faculty of Forest Sciences and Forest Ecology

Göttingen 37077, Germany

Email: sarah.choe@uni-goettingen.de