Theory suggests that plant interactions at the neighbourhood scale play a fundamental role in regulating biodiversity–productivity relationships (BPRs) in tree communities. However, empirical evidence of this prediction is rare, as little is known about how neighbourhood interactions scale up to influence community BPRs. Here, using a biodiversity–ecosystem functioning experiment, we provide insights into processes underlying BPRs by demonstrating that diversity-mediated interactions among local neighbours are a strong regulator of productivity in species mixtures. Our results show that local neighbourhood interactions explain over half of the variation in observed community productivity along a diversity gradient. Overall, individual tree growth increased with neighbourhood species richness, leading to a positive BPR at the community scale. The importance of local-scale neighbourhood effects for regulating community productivity, however, distinctly increased with increasing community species richness. Preserving tree species diversity at the local neighbourhood scale, thus seems to be a promising way for promoting forest productivity.

Skogsägare, främst i Götaland, har stora problem med betesskador i tallföryngringar vilket kan bidra till minskad tillväxt och ekonomisk förlust. Studien undersökte huruvida trädslagssammansättning och fodertillgång påverkar betesskador på tall i ett fältförsök i Blekinge och i praktiska föryngringar i Östergötland. Studien visar att främst toppskottsbetning förekommer vid lägre höjder vilket påvisar vikten av att snabbt få upp föryngringen till en högre höjd. Att fastslå huruvida exempelvis trädslagssammansättning, vegetationstyp, höjdrelation och medelhöjd påverkar betesskador på tall är komplicerad då det finns många faktorer som har en betydande roll. Dessa kan exempelvis vara vikten av ståndortsanpassning, förädlat plantmaterial, markberedning samt tidpunkt för röjning. Skogsägare måste göra en avvägning i vad som är den mest effektiva metoden i varje enskilt fall för att föryngra tall utan en för stor andel betesskador.

Theory suggests that plant interactions at the neighbourhood scale play a fundamental role in regulating biodiversity–productivity relationships (BPRs) in tree communities. However, empirical evidence of this prediction is rare, as little is known about how neighbourhood interactions scale up to influence community BPRs. Here, using a biodiversity–ecosystem functioning experiment, we provide insights into processes underlying BPRs by demonstrating that diversity-mediated interactions among local neighbours are a strong regulator of productivity in species mixtures. Our results show that local neighbourhood interactions explain over half of the variation in observed community productivity along a diversity gradient. Overall, individual tree growth increased with neighbourhood species richness, leading to a positive BPR at the community scale. The importance of local-scale neighbourhood effects for regulating community productivity, however, distinctly increased with increasing community species richness. Preserving tree species diversity at the local neighbourhood scale, thus seems to be a promising way for promoting forest productivity.