Aeshna subarctica (Bog Hawker, or Subarctic Darner in the USA) looks rather similar to Aeshna juncea (Moorland Hawker) but the colours are paler and less saturated. It’s a large hawker with a holarctic distribution.
Bog Hawkers oviposit in Sphagnum bogs where food is scarce. Therefore, it takes the nymphs up to four years to grow to final size and emerge.
Imagos are often seen perching on trees.
A female Bog Hawker ovipositing in a Sphagnum bog in the Netherlands, 2022