Lisle – October 14, 2026 -- ArbNet, the accreditation program run by The Morton Arboretum, has reached 1,000 accredited arboreta after adding Kórnik Arboretum in Kórnik, Poland, and the network has doubled in the last five years alone.
Kórnik is the first ArbNet-accredited arboretum in Poland. ArbNet recognized it at level IV, the highest tier, at the Oct. 12 "Trees and Forests in a Changing Environment" conference. The Institute of Dendrology of the Polish Academy of Sciences, which oversees the arboretum, hosted the event. The program is now in its 15th year and describes itself as the only international accreditation scheme specific to arboreta.
Poland becomes one of 44 countries with an ArbNet-accredited arboretum
Newly welcomed countries this year include Bermuda, Denmark, Ecuador, Indonesia and Madagascar. Cayo Levantado Arboretum in Samaná Bay, Dominican Republic, was also recently accredited.
ArbNet also accredits parks, historical sites, college campuses and nature preserves that commit to tending tree collections. One example is Perkins Arboretum at Perkins School for the Blind in Watertown, Mass., which curated trees with varying bark textures, leaf shapes, sounds and smells for its students.
Kórnik holds Poland's oldest documented woody plant collection and 250+ lilac types
Kórnik Arboretum has the oldest collection of woody plants with documented origins in Poland. Some specimens are among the oldest of their species in greater Central and Eastern Europe. Its lilac collection is the country's largest, with more than 250 types forming a national collection.
Research plots in its Zwierzyniec Experimental Forest are now more than 50 years old, giving long-term observation data on native and introduced plants. The accreditation follows the arboretum's 200th anniversary.
Institute of Dendrology director Andrzej M. Jagodziński said joining at the highest accreditation level gives the arboretum's founding vision "a new, international dimension."
Chicago Park District partnership yields four accredited urban sites
ArbNet's partnership with the Chicago Park District has produced four accreditations:
- The Bloomingdale Trail, a nearly 3-mile path turned arboretum.
- Palmer Square Park Arboretum, which had 27 individual trees in the 1980s and now has 28 species.
- Richard Clark Park, a 22-acre site along the Chicago River that was once an amusement park.
- Wicker Park Gardens and Arboretum, maintained by a volunteer garden club.
ArbNet's collaborative model also informed The Morton Arboretum's "Green City Rising," a co-winning entry in World Business Chicago's "Horizon Lines: Visions for Chicago 250" urban design competition. The concept reimagines Chicago as a connected network of arboreta.
Funding and research directory target cross-border tree conservation
The Botanic Gardens Conservation International / ArbNet Partnership Programme funds collaborations between botanic gardens and arboreta to exchange skills, resources and expertise. ArbNet's Research Partner Directory, launched this year, lets accredited arboreta express interest in hosting or joining scientific and conservation projects at various scales. ArbNet also offers a free resource library with practical guidance for arboreta.