It will be more greenery for Lalbagh Botanical Gardens as the horticulture department has embarked upon a special tree exchange programme, to add to the parks existing diversity on the lines of animal exchange plans undertaken by zoos of the country. Though the City's lung space is shrinking, the silver lining is that under this programme, the park will get over 3,000 trees from every nook and corner of the world. "We already have about 7,500 trees of 1,854 species. Now another 850 species will arrive,' Dr M Jagadish, Deputy Director, Lalbagh Botanical Gardens told Deccan Herald.