Habitat management works in the Nature Park “Piejura” are planned also in the year 2019. In order for residents and visitors of the park to understand why and what works are done, we will tell in this article about one of the greatest values of the Nature Park and about methods of its management.

According to the habitat mapping data obtained within the LIFE-Nature project “Protection and Management of Coastal Habitats in Latvia” in 2003, the percentage distribution of forest habitats across the Nature Park “Piejura” reaches in total up to 79%. This allows us to conclude that among the habitats found in the park, forest habitats are the most common in the whole territory of the Nature Park “Piejura”.

What makes the wooded seaside dunes so special and how should one manage them? Read more about it here:

The wooded seaside dunes are a protected habitat of the European Union importance. The wooded dunes are natural or semi-natural forests on the seaside dunes with well-developed woodlands and a set of species characteristic to forests. The habitat is found only in the Seaside lowland, which is separated from the inland by an ancient slope of the Baltic Ice Lake. The places of concentration of the habitat coincide with the location of the largest dune massifs of the Baltic Sea in Bernati, Kolka surroundings, between Engure and Ragaciems, in the southern part of the Gulf of Riga, in Saulkrasti. According to the habitat mapping data obtained within the LIFE-Nature project “Protection and Management of Coastal Habitats in Latvia” in 2003, the average age of all nature park forests in the Natural Park “Piejura” is 80 years. The oldest pine groves reach the age of up to 140 years. The habitat includes both separate forest-covered dunes and compact dune groups, extensive dune massifs, where the dunes are connected by flat and wavy wind-blast areas of various widths and inter-dune hollows of various shapes.

Wooded dunes are almost completely entrenched dunes, in which the movement of sand can be caused only by particularly strong storms. Their influence can be enhanced by various anthropogenic factors – harvesting, recreation or construction of varying intensity, which, by complete or partial destruction of the vegetation, can lead to local erosion. Sand is the determining creator of the environment, so dry, nutrient-poor growth conditions always prevail on the coast. The difference in humidity conditions and relatively large diversity is determined by the different height of the dunes, as well as the humidity conditions of the inter-dune delves. Pine forests are light, with coniferous trees and shrubs. The relief of the dunes creates different surfaces exposed to the sun, which in a relatively small area create different lighting and temperature conditions, as well as different wind effects.

Overall, the wooded seaside dunes are a rare habitat – it occupies 0.9% of the land area of Latvia, or about 60,000 ha. The wooded seaside dunes are an important habitat for rare and protected plant species Sand Pink, Pasque Flower, Small Pasque Flower, club moss, etc. This habitat is significant also for specially protected invertebrates - Nothorhina Muricata, Ergates Faber, and Tragosoma Depsarium. It is also a very important habitat for several species of Jewel Beetles (Buprestidae) and Sand Vasp, as well as for birds – Stock Dove and Woodlark. Typical species are Scots Pine, Juniper, Cowberry, Bearberry, Black Crowberry, Heather, Blueberry, Umbellate Wintergreen, Sheep and Dune Fescue, Grey-Blue Koeleria, Nottingham Catchfly, Wavy Hair-Gras, Red-Stemmed Feather-moss, Cup Lichens, and Reindeer moss.

Latvia is one of the few countries of the European Union where natural forest-covered dunes are found, as well as one of the few countries where most of the wooded seaside dunes have not been significantly transformed.

The wooded seaside dunes in Latvia account for about 6.5% of the total area of the habitat in the boreal biogeographical region, which is considered to be a very high indicator for such a small country as Latvia. The relatively high incidence of habitats is determined by historical geomorphological conditions in Latvia, in particular – the historical development of the Baltic Sea. The habitat forms a visually high-value seaside landscape characteristic to Latvia. It plays a high and diverse social and economic role in recreation, sports, and tourism.

Interestingly: the wooded seaside dunes are an important object in the Latvian art of the XX and XXI centuries. The habitat is described in written sources of various historical stages, including legends and chronicles. In wartime, dunes were important in observation and installation of combat positions. Today, individual dunes are used in military training. Fishing villages, cemeteries, and other objects are of high aesthetic and cultural and historical value.

Both historically and nowadays, the wooded seaside dunes are threatened by a number of factors, mainly caused by human activity. Also, the latest results of the nature census show a decrease in the quality of forest habitats. At the end of the second season of field works on gathering information about the habitats of European Union importance or nature counting, experts estimate that the quality of forest habitats in Latvia is lower than originally expected.

What affects the Natural Park? The Nature Park “Piejura” is a relatively young and sensitive coastal area, exposed to the strong influence of sea and winds, as well as human activity.

Both historically and nowadays, the wooded seaside dunes are threatened by a number of factors caused both by nature and human activity. An example of the influence of human activities is the loss of forest structure diversity, which contributes to the dead-wood removal from the old pine forests, as well as the natural vegetation destruction and pollution with domestic waste, and damaging of the valuable habitat with vehicles.

Intensive logging has a significant negative impact, incl. formation of flat clearings and afforestation with spruce, as well as inappropriate soil preparation. On the direct sea coast, the habitat is negatively affected by recreation, which often also contributes to eutrophication of the environment, resulting in a significant change in the structure and composition of plant societies. Over the past 200 years, the area of the habitat has decreased and the quality has reduced mainly due to the development of populated areas such as Riga, Saulkrasti, Ventspils, Liepaja, Kolka, and many small seaside towns that have developed on dune massifs.

The influence of wind and overflowing sand is one of the main factors in the functioning of both open and wooded dunes' habitats and the provision of habitats for characteristic species. In some places of the Nature Park “Piejura”, the influence of the load created by humans on the forest and dune vegetation is too excessive just as the formation of too dense forest stands in the wooded and grey dunes where a dense layer of litter is formed, that prevents the renewal of lichens and characteristic caulescent plants, which gradually disappear. In addition, in densely overgrown forest massifs, sunlight and warms are also insufficiently supplied to the ground cover, which is one of the determining factors for the existence of healthy pine forests and habitats characteristic here. In osier clamps in the grey dunes, where the accumulation of humus and sand is more passive than in the open dunes, pines have been sown, and they are already beginning to form closed groves, thus reducing the desired habitat structure and species composition. Also, the glades in the pine forests of the Seashore lowland begin to overgrow, thereby disappears the vegetation of Small Pasque Flower and other rare plant species. Openings in the crown deck (including glades) are of great importance in pine forests, the biodiversity of which depends on sunlight and warms. In dry forests, 3-5 openings per hectare are required to maintain structural diversity.

An additional negative factor is the tendency of the last decade to use species and varieties of alien plants in greenery. Alien species are often more ecologically flexible; they do not require specific growth conditions. When getting outside the greenery, they quickly spread, easily adapt to the conditions of growth and suppress local species thus reducing the biodiversity. In the Nature Park “Piejura” such invasive species as Rugosa Rose, Blue Lettuce, Canada Goldenrod, and Himalayan balsam have been found.

Restoration of wooded seaside dunes. The existence of the habitat depends on the understanding of the coastal nature processes and the use of appropriate management techniques and, in this respect, the wooded seaside dunes are relatively well renewable.

The most appropriate management method to ensure the favourable conservation status of the wooded seaside dunes is the smooth development of the habitat, the preservation of the natural hydrological regime and the control of anthropogenic load. When restoring the habitat, it is necessary to take into account the possible movement of sand, and also the amount of nutrients. The long-term existence of wooded seaside dunes requires natural disturbances characteristic to coniferous forests, for example, storms, etc. In the absence of the necessary amount of beneficial interference, they should be replaced by appropriate biotechnical measures, such as:

The natural improvement of the forest stands to upgrade the natural structure of the habitat is carried out by means of special felling. The performance of felling varies slightly depending on the target habitat, in how many old stands and under what growing conditions it is carried out, the previous forest stands; depending on the stand age, thickness and specific location, both forestry “grooming cuttings” and “other cuttings” can be performed.

Formation of openings: they can be of irregular shape. Perhaps, to make an opening, it is necessary to cut off (or ring bark) several trees growing near each other. The formation of openings can be combined with the formation of additional dead wood by leaving the decayed trees on the ground. Depending on the nature of the habitat, removal or incineration of felling residues may be required. Depending on the age, thickness and specific location of the stand, both forestry “grooming cuttings” and “other cuttings” can be performed.

Formation of dead wood (possible for all habitats). The continuity of the emergence of dead wood can be ensured by creating openings in the crown of the forest for improving light conditions, as well as by maintaining groups of dense overgrown trees. Part of the trees left will die out in the process of self-destruction, and there will no longer be a need to artificially increase the number of crests and trunks repeatedly.

The use of “other cuttings” is recommended for this measure. In the countries of Northern Europe, other methods are also used, such as tipping trees with tractor machinery or blasting trunks. Another method is the ring barking of trees ‒ in the form of a ring, at a depth of 2-3 cm around the trunk, the bark and cambium layer is removed. The formation of scars on the root neck of the tree has a similar effect.

Imitation of natural disturbances: a complex of measures involving the formation of dead wood and openings, the naturalization of the structure, as well as the controlled burning or burning of felling residues in medium-sized piles.

The wooded seaside dunes are a complex habitat, which can also include deciduous and mixed tree forests in dry and wet mineral soils and peat soils, shrubs, as well as burn areas, clearings, nurseries, and degraded areas. It is necessary to ensure the leaving of dry and fallen trees in the habitat since it serves as a habitat for many species. Deciduous groves in the inter-footed hollows need to be saved.

When planning management works, it should be taken into consideration that forest habitat management in the Nature Park must be carried out in accordance with the Nature Park individual protection and use regulations (MoC Regulation No 204 of the Republic of Latvia adopted on 14.03.2006) as well as in accordance with the forest management legislation of the Republic of Latvia.

Forest stand management measures for the formation of habitats and biodiversity-relevant structures related to tree felling should be carried out during the winter season, preferably in conditions of soil freezing, in order to leave as little impact on the soil as possible; thus, the planned work under the LIFE CoHaBit project will take place during these periods. It is planned to use small-scale tractor machinery or other mechanisms that leave as little impact as possible on the soil and do not form trace.

Similar works have already been carried out in other places, and the Langervalde Forest in Jelgava serves as a good example, which demonstrates how the habitat management work has improved the habitat quality and the forest has been was made available to citizens. Previously, the forest was overgrown with thick undergrowth, but in the framework of the project, a part of the wood has been removed, openings have been created and, thus, the amount of light on the ground cover has been increased providing the existing plants with the possibility to grow.