Walking or biking through the forest the underlying landform of coastal dunes is often exposed. Dips and hollows near the coast provide homes for rare plants while a myriad of lower plants live under the canopy of pine trees.
The Bottle Lake Forest lagoons, wetlands and sand dunes were formed as silted stone was washed down the Waimakariri River from the Southern Alps. Soil and dust blown by the nor-westerly wind was deposited over the lagoons, wetlands and sand hills, providing an environment for scrub and grasses to grow. The original ‘Bottle Lake’ is now a wetland and is part of the golf course adjacent to the forest. Until the 1930s the lagoons and wetlands were frequently flooded with salt water washed in by high tides and storms from the sea. Fences along the sand dunes were constructed to trap the sand and increase the height of the dunes along the coastline, providing better protection to the land from coastal waves and storms.
The majority of land at Bottle Lake Forest is used as a commercial pine forest. Under the more mature stands of pine trees a dense carpet of moss and lichen can be found with regenerating native ferns, orchids, fungi, grasses and small trees and shrubs. Small communities of salt tolerant plants such as oioi, sedges and rushes occur within the wetland areas. On the edge of the wetland areas cabbage trees and flax can be found. Weeds, such as grey willow trees are a significant management problem within the remnant wetlands.
Blackbirds, sparrows, finches, silvereyes (tauhou) and thrushes can readily be seen around the edges of the forest. California quail are a common sight amongst the more established shrub areas in the forest. The occasional little owl, fantails (piwakawaka), plovers and grey warblers (riroriro) can be heard and sometimes seen around the forest.
The katipo spider, feared by some for its venomous bite, can be found in a few locations on the sand dunes. The spiders eat the hard-backed beetle, which feeds on the roots of sand dune grasses. The katipo spider lives amongst these grasses.