The enclosed files contain the questions (in Dutch, English & French) and the responses from tree surveys conducted under the Belgian Plant Sentinel Network. Background to the project Botanic gardens and arboreta possess outstanding scientific collections of a wide diversity of plants, frequently growing outside their natural geographical range. These can be used as sentinels for both early detection of emerging pests and for potentially invasive pests. This is why the International Plant Sentinel Network was launched by EUPHRESCO (EUropean PHytosanitary RESearch COordination), an international network of organisations funding research projects and coordinating national research programmes in the phytosanitary area. International Network developed a transnational network consisting of gardens, diagnostic laboratories and National Plant Protection Organisations, working together in order to provide an early warning system for new and emerging plant pests and diseases. It focused on developing tools and took place in a limited number of countries. Belgium did not participate in the first phase of International Plant Sentinel Network, even though there are many botanic gardens and arboreta in the country. The largest of them is Meise Botanic Garden, which is one of the largest botanic gardens in the world (92 ha). Besides Meise there are several gardens with diverse and unique collections spread all over the country. Among these gardens many have staff members with good knowledge of plant protection, which assure the control of pests and diseases in the collections of the gardens. On the other hand, up to now there have been only limited interactions between the gardens and the National Reference Laboratories for plant pests and diseases. It would be interesting to strengthen these interactions, both for the gardens and arboreta, for a better management and protection of their living collections, and for the Reference Laboratories, in order to gather more data on the presence of pests and diseases in the ...