Table 1.
Literature reviews for spatial elements

Classification Spatial elements Evaluation elements
Lee(2003) Vehicle accessibility, low tree density to secure the view, the diversity of forests according to location and season, own space for preschoolers

Securing the view

Flat land

Slope diversity

Vegetation diversity

Valley or ecological pond etc.

Forest trails

Ingredients for natural play

Kwon(2012) Topography where preschoolers can climb up, treesĀ·logs and rocks where preschoolers can climb up, surrounded space, a nearby forest, elements that can make sounds, ground and sand, a hideout, water play area, own space for preschoolers, resting stump, vacant land, shelter and material storage warehouse, vehicle accessibility, forest trail(1 to 2km), flat land(more than 10 people)
Korea Forest Service(2014) Flat land(more than 30 people, more than 2 places), vehicle accessibility, vegetation diversity, a place where there's no dangerous factors
Kang(2015) Biodiversity, accessibility, safety, slope diversity, connection with forest trails, space in the forest, low tree density to secure the view, a fixed stump, ingredients for natural play, soil and sand