Rainforest occurs in small patches throughout the park, mainly in sheltered, wet but reasonably well-drained gullies and on sheltered slopes.
Dry rainforest occurs on north-facing slopes and gully heads in the Coolangubra section. It's associated with large granitoid bedrock outcrops and sometimes with Ordovician metasediments. The canopy is dominated by Port Jackson fig (Ficus rubiginosa), often with Pittosporum undulatum and sometimes Alectryon subcinereus. Eucalyptus agglomerata is a common emergent. The understorey is generally very sparse. The vine Celastrus australis is characteristic of the ecosystem along with other vines, herbs, grasses and ferns.
Myanba eucalypt-fig forest can be found in the Coolangubra section on steep granitoid slopes at 500 m above sea level around Myanba Gorge. The indicator species of this ecosystem are in the shrubby understorey:
- Ficus rubiginosa
- Hymenanthera dentata
- the vine Celastrus australis
- the rock orchid Dendrodium speciosum.
The canopy usually contains various eucalypts, though these are not indicative.
Warm temperate rainforests are restricted to steep sheltered gullies, usually south-facing to east-facing on metasediments, and occasionally on granitoids.
Coastal warm temperate rainforests occur mainly below 300 m above sea level on coastal ranges in the Yowaka and Yurammie sections, while hinterland warm temperate rainforest is generally at higher elevations throughout the park. Common species include lilly pilly (Acmena smithii), pittosporum (Pittosporum undulatum) and sassafras (Doryphora sassafras) with pencil cedar (Polyscias murrayi).
Hinterland rainforest ecosystems can be distinguished by the presence of:
- Acacia melanoxylon
- Hedycarya angustifolia
- Eucryphia moorei
- Olearia argophylla
- Coprosma quadrifida
- Pomaderris aspera.
Cool temperate rainforest occurs in similar locations to the warm temperate rainforest but at higher elevations (generally above 700 m). This ecosystem is characterised by a canopy of black oliveberry (Elaeocarpus holopetalus), with blackwood (Acacia melanoxylon) and southern sassafras (Atherosperma moschatum) also occurring. The understorey is very sparse, containing mostly ferns. Occasional stands are dominated by pinkwood (Eucryphia moorei).
Wet eucalypt forests
Wet eucalypt forest ecosystems are generally found in the upper catchments, in gullies or on sheltered slopes, and cover about 42 per cent of the park.
Common canopy species include:
- monkey gum (Eucalyptus cypellocarpa)
- brown barrel (E. fastigata)
- messmate (E. obliqua)
- manna gum (E. viminalis)
- river peppermint (E. elata)
- shining gum (E. nitens).
Understoreys are characterised by the presence of:
- Bedfordia arborescens
- Blechnum nudum
- Clematis aristata
- Coprosma quadrifida
- Dicksonia antarctica
- Pomaderris aspera
- Poa meionectes
- Tylophora barbata
- Viola hederacea.
While some of the wetter forest ecosystems are typically tall, high rainfall wet eucalypt forests, most fall somewhere between the traditional wet to dry forest types.
Dry shrubby forest ecosystems prevail on the more infertile metasedimentary soils, exposed ridges and slopes and cover about 29 per cent of the park. Canopy species associated with the common types include:
- white stringybark (Eucalyptus globoidea)
- yellow stringybark (E. muelleriana)
- woollybutt (E. longifolia)
- coast grey box (E. bosistoana)
- silvertop ash (E. sieberi).
The understorey here tends to be dominated by shrubs with only a sparse or open groundcover of herbs and grasses. Some of the more common understorey species include:
- Acacia falciformis
- Allocasurina littoralis
- Cassinia longifolia
- Epacris impressa
- Monotoca scoparia
- Leucopogon lanceolatus
- Lomandra spp.
Dry grassy forest ecosystems are normally associated with the more fertile granitoid or basalt derived soils of the less steep hinterland and tablelands. They cover about 25 per cent of the park. Typical trees of the more common dry grassy forests are:
- maiden's gum (E. maidenii)
- coast grey box
- white stringybark
- Angophora floribunda
- Acacia mearnsii
- A. implexa.
Shrubs can be dense or patchy, typically including Bursaria lasiophylla, Cassinia and Ozothamnus spp. Groundcover consists of a wide range of herbs and grasses commonly including Danthonia longifolia, Microlaena stipoides and Themeda australis.
The typical canopy species of the rare dry forest ecosystems are Eucalyptus angophoroides, white stringybark, E. agglomerata and occasionally red box (E. polyanthemos ssp. Vestita). The understorey commonly contains some shrubs but always has a dense and diverse groundcover of grasses, herbs and sedges.
Freshwater swamps and riparian ecosystems are a diverse group that includes shrub and forest ecosystems along rivers and in poorly drained ephemeral or permanent wetlands.
Swamp forest is found along small drainage lines at 300-650 m above sea level in the Genoa section of the park. It occurs principally on granitoids in small stands with a widespread distribution. Soils are generally permanently waterlogged.
The dominant canopy species are swamp gum (E. ovata) and occasionally ribbon gum (E. viminalis). The understorey consists of a dense groundcover of Lomandra longifolia or various sedges (Carex appressa, Cyperus lucidus), grasses and herbs.
Subalpine bog occurs in patches along the escarpment at high elevations. It's found on waterlogged soils in broad flat valleys on the headwaters of mostly west-flowing streams. Subalpine bog consists of a mixture of wet heath (Baeckea utilis, Epacris paludosa, Hakea microcarpa) and wet grassland (Poa costiniana and numerous herbs), with various sedges (Empodisma minus, Restio australis).
Two riparian scrub types occur along rocky river beds and on the lower banks of major water courses in the park. Southern riparian scrub can be found along the Yowaka, Wallagaraugh and Towamba Rivers. Northern riparian scrubs are confined to rivers draining the drier slopes, such as parts of the Tantawangalo and Candelo Creeks and Bemboka River. Both riparian scrubs share some indicator species:
- Acacia floribunda
- Callistemon subulatus
- Lomatia myricoides
- Leptospermum emarginatum.
Additional indicator species of northern riparian scrub are:
- Melaleuca parvistaminea
- Hakea microcarpa
- Acacia elongata.
Indicator species specific to southern riparian scrub are:
- Melaleuca armillaris
- Calytrix tetragona
- Grevillea linearifolia
- Leptospermum scoparium.