For the regeneration and afforestation of Latvian forests, tree species listed in Annex No. 308 of the Cabinet of Ministers (CM) regulations can be used. The tree species included in it are suitable for various soil types and moisture conditions, providing forest owners with information on the best practices in forest cultivation.
The mentioned species are both domestic and some introduced tree species, such as red oak, European beech, larches, introduced species of aspen and poplar, as well as sweet cherry. These species have been tested in long-term experimental plantings in Latvia, and their suitability has been confirmed. For example, an aspen hybrid is grown industrially, which is obtained by crossing American aspen and common (European) aspen. In nature, you can also find hybrids that have arisen from crossing black alder and white alder.
Tree species name in Latvian and Latin:
Most native tree species are flexible and can grow in a variety of conditions. Exceptions are very poor sandy soils, where only pine can grow, and wet peat soils, where black alder or swamp birch grow. CM regulations No. 308 specify the forest types in which only pine can be used for forest regeneration, providing at least 80% of the stand composition for this species.
In different forest types, any of the tree species mentioned in the regulations appendix can be grown, but not everywhere they will grow equally well and form a quality stand. Pine grows well in poor forest types, but in more fertile forests it will grow branchy and of poor quality. Coniferous forests grow best in damaksnis, while spruce and birch, as well as various deciduous trees, grow well in vērī and gāršā. In excessively moist forests, pine grows in poorer types, but in wet damaksnis, spruce and deciduous trees can also be grown.
In forests with wet peat soils, the choice of suitable tree species is not as wide as in mineral soils or ameliorated forests. Pine or swamp birch can grow in swamps, and spruce can also grow in reed beds. In marshes and swamps, the stand will be formed by black alder and swamp birch. Only pine can be grown in ameliorated forest types (heather, mint and peatlands). In moderately fertile narrow-leaved heaths and peatlands, both coniferous and deciduous trees can be grown.
When establishing a forest on agricultural land, the area after establishment is classified according to the principles of forest typology, taking into account the soil composition, fertility and drainage system. Other characteristics of growing conditions, such as soil composition, pH level, aeration and lighting, are also important for tree species.
Forest reproductive material (seeds, seedlings, plants and plant parts) requires a certificate issued by the State Forest Service (SFS). The law stipulates that only material of suitable origin for a specific location may be used in forest regeneration and afforestation.
If the stand cross-sectional area has become smaller than the critical cross-sectional area, the forest must be regenerated within specified deadlines, depending on the forest type: within five calendar years in dry land forest types and within ten calendar years in wet forest types.