Kylmäoja spruce swamp and the Kylmäoja forest at its boundary are located in the Asola and Ilola districts, close to the border between Vantaa and Tuusula. The most essential part of the protected area is typical black alder swamp, which is a nature type to be protected in accordance with the Nature Conservation Act. The swamp area also includes lush grass swamps where there are several species of grass growing under the dense spruces, as well as wood horsetail swamps where the wood horsetail is…dominant. Among the different spruce swamps with dense woods, there is also a little open swamp. The eastern fork of the Kylmäoja brook flows through the protected area.
Thanks to the varying types of swamps, the vegetation in the area is also very diverse. In addition to various grasses and sedges, the Kylmäoja swamp and the surrounding areas include grasses typical of lush swamps, such as the meadowsweet, marsh skullcap, tufted loosestrife, yellow loosestrife and heath spotted orchid. In addition to the black alder, common trees in spruce swamps include spruce, white birch and grey alder. The undergrowth includes tea-leaved willows. You can easily identify them by their glimmering leaves. Marsh marigold and bog arum thrive by the stream.
The bird species encountered in the Kylmäoja protected area include the wood warbler, robin, goldcrest and willow tit. The forest area is also a suitable habitat for the northern goshawk, and this bird has indeed been seen nesting in the area's southern parts for years. Observations have been made that suggest that the Ural owl and the European honey buzzard also nest here. Elks and deer also move about the area. There are also badgers' nest caves in the forest hills to the west.
The Kylmäoja spruce swamp has been protected since 2001. In 2012, the protected area grew up to 37 hectares when surrounding forest areas were attached to it.