The rugged and diverse terrain, the altitude range from 144m to 2,429m and the striking presence of water contribute to the formation of a variety of natural habitats.
17 different types of habitats have already been registered, the most interesting of which, due to their rarity, are: a) the forests of foetid juniper (Juniperus foetidissima), growing at an altitude of 1000m-1500m, b) the forests of black pine (Pinus nigra) and c) the mountain or sub-alpine fields located in relatively wet areas above the upper limit of the forest. The forest habitats, such as those of fir and oak, are also remarkable. Those of evergreen and hardwood deciduous trees, such as oaks, kermes oaks, arbutus, heathers, and of plane-trees, Holm oak and laurel are particularly important for the National Park.
The habitats recorded inside the National Park of Tzoumerka, Peristeri and Arachthos are outlined in the table below.
| CODE | Habitat types Annex I |
| 3280 | Constantly flowing Mediterranean rivers with PaspaloAgrostidion species and hanging curtains of Salix and Populus alba |
| 3290 | Intermittently flowing Mediterranean rivers of the Paspalo-Agrostidion |
| 4090 | Endemic oro-Mediterranean heaths with gorse |
| 5210 | Arborescent matorral with Juniperus spp. |
| 6230* | Species-rich Nardus grasslands, on siliceous substrates in mountain areas (and submountain areas, in Continental Europe) |
| 8140 | Eastern Mediterranean screes |
| 8210 | Calcareous rocky slopes with chasmophytic vegetation |
| 9130 | Asperulo-Fagetum beech forests |
| 9270 | Hellenic beech forests with Abies borisii-regis |
| 92C0 | Platanus orientalis and Liquidambar orientalis woods (Plantanion orientalis) |
| 9530* | (Sub-)Mediterranean pine forests with endemic black pines |
| 9560* | Endemic forests with Juniperus spp. |
| 9340h | Quercus ilex and Quercus rotundifolia forests |
| 9280h | Quercus frainetto woods |
