Åter till Brämsand, med funderingar på rylens dynamik, krav och tolerans

A complete survey of Chimaphila umbellata was done during 21 days in 2021–2022 in a 40-hectare coastal pine-dominated forest on calcium-rich sand at Brämsand, northern Uppland. The result was almost 50 000 shoots at 565 separate co-ordinates which thus is by far the largest population in Sweden. The pine trees were actively planted during the early 1900s, so the Chimaphila population is established rather recently. A comparison with a pioneer survey performed in 2002, indicates a strong increase since then. The central part of the area consists of a 2-hectare flat-blown-sand field that had been planted also with alien Pinus mugo which were cut down in the early 2000s and was burnt in 2017. Surprisingly, most of the Chimaphila clones survived the fire, probably through deep-rooted rhizomes. Hence, this observation suggests that Chimaphila is tolerant and partly favoured by fire, which thus contradicts the opposite conclusion by Delin (2013). Chimaphila is generally considered sensitive to exposed situations but has survived in many places on open sand, probably because of little competition from other plants in the harsh environment. Chimaphila flourishes along north- and east-facing forest edges and in small glades (max 25 metres across). The area is also well-known for its many rare species of fungi connected to calcareous forests. Chimaphila is frequently accompanied by Pyrola chlorantha, sometimes by Antennaria dioica and Monotropa hypophegea (while M. hypopitys is rare). Also, Goodyera repens occurs sparsely but becomes more common towards the south of the area where Norway spruce replaces Scots pine.