Our mökki is situated in the hazelnut zone and we are lucky enough to have masses of them in our forest. In the areas where we have cleared pine, spruce and birch, we have hazelnut growing quite vigorously. The trees produce nuts but I've never seen any ripe enough to eat. I assume that the season is too short, or maybe the squirrels eat them all.
Today we had some visitors and one young Finnish lad was really pleased to find a hazelnut tree for his summer school project. It is traditional in Finland for 7th graders to compile a specimen collection of native wild flowers and trees during their summer holidays. It usually involves parents and grandparents too because it is impossible to find all the plants in one location or indeed during the same week: some flower in late May, others in June, July or August. I think my boys had a list of about 100 plants and they had to collect a minimum of 40 from the list. Each plant has to be pressed and then stuck in a book, giving all the information concerning where it was found: location, date etc.
I remember bulrushes being very problematic. We had to use the canoe to reach them (we have some here in the pond). As pressing bulrushes is nigh impossible, we left them to dry before sticking them in the book (lots of sellotape). The teacher told Stefan that when she eventually got round to marking their projects, his bulrush had exploded and she had millions of seeds flying around her house for ages.