Vadakste Biodiversity forest in south-western Latvia is a partially fenced 50 hectares forested area in flat terrain on calcareous clay soils, surrounded by state-owned spruce monoculture plantations. This system contains several systems in different types of vegetation:
An alleycropping system with walnut (Juglans regia), chestnut trees (Castanea sativa), hazel bushes (Corylus avellana), and fruit trees with common/black alders (Alnus glutinosa) as nurse trees. Urine is used to water around the open field trees and on fence poles, in order to keep wild-life away.
A fenced polycyclic trial (with inspiration from this Italian system)
with a mix of fast and slow growing trees (aspen, alder, poplar,
willow, oak, beech and other hardwood species) supporting each other,
and intended for continuous timber harvest.
Several
thinned out stands of pioneer grey alder (Alnus incana) grown on arable
land with planted cherry (Prunus avium), linden (Tilia cordata), maple
(Acer platanoides), walnut (Juglans nigra), sweet chestnut (Castanea
sativa), larch (Larix decidua), wild pear (Pyrus pyraster), wild apple,
(Malus sylvestris), beech (Fagus sylvatica), oak (Quercus petrea,
palustris, rubra, robur) trees etc to provide nuts, timber, honey and
sap.
A
mixed pioneer forest on former forest pastures with silver birch and
weeping downy birch (Betula pendula, B. pubescens), spruce (Picea abies)
and patches of walnut trees in the understorey.
A
stand of spruce ready for felling, which is gradually being thinned out
to invite natural, broadleaf vegetation. Part of the thinned out areas
are planted with linden, maple, black alder and seeded with linden,
maple, sycamore maple (Acer pseudo-platanus), oak, beech, apple, rowan
(Sorbus aucuparia) and a bush layer seeded with barberry (Berberis
communis) and European buckthorn (Rhamnus cathartica).
Several
scattered, old “landmarks” of oak, wild apple, maple, linden, ash and
pine, with an undergrowth that includes bird cherry (Prunus padus),
hazel, gray willow (Salix cinerea) and bracken (Frangula alnus).
A plant nursery established in raised sand beds, inspired by Swedish gardener Peter Korn at Klinta trädgård, to enhance the plant robustness and to minimise the need for extensive maintenance.
Agnis Graudulis, a trained horticulturist and forester, began implementing his vision for his land in 2019; a seed source for biodiversity and trees for food and timber. The last three years were spent creating microhabitats in the forest, such as dead standing trunks, stone piles and ‘Mulmholks’ - a nest box filled with mulch resembling the conditions that can be found in hollow tree trunks, intended for insects, such as saproxylic beetles, that depend on dead and rotting wood for food and habitat.
Agnis’s ambition is to restore the vegetation to its original deciduous forest character, in combination with adopting the concept of PNV, “potentially natural vegetation”, in terms of reintroducing native vegetation and assisting the migration of new vegetation, as an increasingly warmer climate opens up new possibilities for planting nut trees.
Other experiments are underway such as a newly established “tiny-forest” trial and a breeding project for sweet chestnut and walnut trees.
PLANTING TREES IN THE FOREST
The trees planted in the forest are grown from seed and planted out with an earth auger, without fertilizers, wood chips or irrigation. Part of the forest plantings are done without fencing to compare possible browsing damage. Wildlife populations in the area are managed through agreements with local hunters.
Carefully establish a food and timber system in an existing forest has several advantages:
Nurse trees: taller trees around favor lower evaporation, resulting in higher soil moisture. Thanks to surrounding native trees, air movement is also more even, compared to grasslands, where the variation between day and night temperatures, sun and shade is greater. This reduction of heat and water stress seems to result in both stronger growth in an early stage and in better winter hardiness — the winters here can be really harsh. A late leaf-out and budding seems to favour young, frost sensitive nut trees.
A species rich vegetation with structural diversity and a variety of ages in different layers provides for habitats for beneficial animals that regulate the presence of insect pests. A diverse vegetation also extends the pollen and nectar season for honey-bees, compared to a monoculture landscape, and can offer a possible extra income. The trees provide a wind barrier for these hardworking pollinators and other insects.
Mycorrhiza collaborations with native trees efficiently help the planted trees find water and nutrients, while the constant production of organic matter from a diversity of roots, trunks and leaves contributes to a fertile soil, improving plant survival and stress tolerance.
Mimicking these principles into a commercial agroforestry system would result in a higher degree of resilience.
Social resilience; even though some of the work here is carried out with hired labor and small machinery, the group suggested opening up for collaborations, as one single person building a system of this size alone was perceived as potentially stressful to overall health.
From 2022, Vadakste is a demonstration site for privately owned, sustainable forest management in collaboration with WWF Latvia and LatViaNature.
“This is an interesting example of how former arable land can be transformed into a multi functional system. Instead of removing the native, pioneer, nitrogen-fixing grey alders they have been left to enrich the system. Vadakste can be an inspiration for southern Swedish forest and land owners who want to maintain the value of their forest investment by converting spruce plantations, which increasingly suffer from bark beetle infestations and storms, into a robust broadleaved forest with interplanted nut trees.” – Maja Lindström Kling.