More than £10,000 of damage has been caused to trees in Oak Hill Park, Barnet, by dogs being prepared for fighting.
The worst damage has been caused to two mature silver maple trees. Six Indian bean trees, planted two years ago, have also been damaged.
Safer Neighbourhoods Team officers in East Barnet are stepping up patrols around the park in a bid to deter the practice. Police arrested a 22-year-old man on 14 July on suspicion of causing criminal damage and animal cruelty.
The problem has been on the increase across London, and Horticulture Week forum members have been reporting their own concerns on the Fighting Dogs Damaging Trees thread.
Liverpool-based Gary Williams said it was a "worryingly increasing trend".
He added that this year alone more than 50 newly planted extra-heavy standards and semi-mature trees have been attacked in one park.
Subscribe to Horticulture Week for more news, more in-depth features and more technical and market info.