How small forest owners can protect their spruce forests from bark beetles
Over the past decade, the bark beetle infestation has reached unprecedented levels. This can be attributed to a combination of natural and social factors, including extreme weather conditions, a shortage of manpower and organizational challenges in the forestry sector, as well as declining wood prices.
Photo: Extensive infestation of spruce stands by bark beetles (Morava, Třebíčsko – Horní Vilémovice; August 2018), VÚLHM archive, v. v. i., LOS
The issue of protecting spruce forests against bark beetles has been extensively researched, with a wide selection of publications available describing protection and defence methods in detail. However, there is still a need for a clear and concise publication tailored for small forest owners.
Small property owners have an advantage over larger properties because they are not financially dependent on the property and do not have to pay staff. However, they may struggle to ensure proper maintenance, unlike larger properties. They are unable to handle these situations themselves, leading to negative impacts, including societal ones. Additionally, the widespread and sudden death of mature trees due to extensive calamitous clearings and the long-term lack of afforestation is not desirable from ecological or socio-economic perspectives.
Photo: Windbreak material that supports the reproduction of bark beetles. VÚLHM archive, v. v. i., LOS.
The scientists from VÚLHM, v. v. i., Department of Forest Protection Services have developed a certified methodology for protecting spruce stands against bark beetles (Ochrana smrkových porostů před kůrovci pro drobné vlastníky lesa). This methodology is specifically designed for small forest owners. It is the outcome of the research project NAZV QK21020371 “Sustainable management in forests of small owners” funded by the Ministry of Agriculture of the Czech Republic.
The publication aims to provide forest owners with up to 50 hectares, who may not have professional forestry education or staff, with a clear summary of their legal responsibilities regarding the protection of spruce stands against bark beetles. It also aims to present the most important prevention, control, protection, and defence procedures and methods. The same information is intended for professional forest managers.
In the Czech Republic, forests owned by individual people make up 500,110 hectares (19.12%) of the total forest area. As of January 1, 2020, the real estate cadastre recorded almost 387,000 properties in the Czech Republic. Among the forest owners, over 346,000 individual owners (FO) possess approximately 17.5% of the forests, about 27,000 co-owning spouses (BSM) own another 1%, and over 13,000 legal entities (PO) own the remaining portion, with the state owning about 53.2% and other legal entities owning around 28.3%.
Photo: Feeding trace of an spruce bark beetle (above) and a shine bark beetle (below), VÚLHM archive, v. v. i., LOS
Around one-third of forest owners (FO) have forests smaller than 0.1 hectares, while approximately 104,000 owners have forests up to 0.5 hectares in size. The average sizes of forest properties are quite small, with FO averaging 1.34 hectares, co-owning spouses (BSM) averaging 1.01 hectares, and only private owners (PO), excluding the state, having a management-acceptable average size of 56 hectares. The greatest fragmentation is in the forest properties owned by FO individuals.
It is essential for forest owners to employ a professional forest manager (OLH) regardless of the size of their property. This manager ensures that the forest is professionally managed. As of 1st November 2023, forest owners have specific obligations to protect the forest from bark beetles in accordance with Act No. 289/1995 Coll., on forests. This law requires forest owners to take measures to prevent and mitigate the impact of harmful agents on the forest.
In case of unusual situations such as pest outbreaks, the forest owner must promptly take steps to eradicate them and minimize their impact. This includes accurately identifying and documenting the presence and severity of the pests, as well as taking preventive measures to stop their growth and spread.
Photo: Falling out of the bark at an advanced stage of the spruce bark beetle development or already during the arising of a new generation of beetles, VÚLHM archive, v. v. i., LOS
For instance, this refers to the special treatment of selective tree cutting and taking action to prevent an overgrowth of harmful organisms. In practical terms, this includes thorough inspection, timely action and proper treatment of trees and wood affected by bark beetles, following the principles of plant hygiene, and so on.
All fallen trees, uprooted trees, and wood that attract insect pests, which were created before March 31, must be processed or rehabilitated by May 31 at the latest. This applies to forest areas that extend to a position above 600 meters above sea level. For these areas, the deadline is June 30 of the current year. Only approved plant protection products may be used for forest protection.
Certain pests, known as bark beetles, such as the spruce bark beetle, northern bark beetle, and shine bark beetle, can cause significant damage. The spruce bark beetle primarily infests the stem of older spruce trees, but can also affect younger trees if they are overgrown. The shine bark beetle typically accompanies or replaces the spruce bark beetle in the upper trunk and crowns of spruce trees. In most areas, the northern bark beetle only attacks standing trees.
Photo: Wood chemically treated with insecticide and dye, VÚLHM archive, v. v. i., LOS
Bark beetles are currently the most significant harmful insects affecting spruce stands in the Czech Republic. The main advantage of the upcoming publication lies in its potential to reduce the risk of spruce trees being attacked by bark beetles, as well as providing a more effective solution to the bark beetle infestation in stands where it is already occurring.
Through proactive forest management to protect against bark beetles, owners can greatly minimize economic losses. This includes reducing the sale price of wood attacked by bark beetles, preventing premature felling of the stand, and avoiding the need for subsequent artificial regeneration and care of established stands. Effective management can help preserve the desired composition of tree species, ensure stand stability, and allow for appropriate silviculture treatments.
In locations and habitats where spruce is part of the natural tree species composition or is still considered a desirable economic tree species, the application of the methodology can help ensure the production of stands.
Photo: Pheromone trap of the Theysohn type (plate, impact, slot), VÚLHM archive, v. v. i., LOS
In regions where spruce is not native and experience prolonged decline, applying treatment can significantly delay the progression of decline and extend the time for recovery.
The methodology benefits the environment by, for instance, controlling the spread of bark beetles to neighbouring forest properties and reducing the need for plant protection products.
The economic benefit of implementing procedures from this methodology into practice is significant. The difference in the value of spruce wood that has not been attacked by bark beetles (e.g. from intentional logging) and wood that has been attacked by bark beetles (e.g. from accidental bark beetle harvesting) is in the order of tens of millions of CZK per year on a national scale.
The publication Protection of spruce stands against bark beetles for small forest owners (Ochrana smrkových porostů před kůrovci pro drobné vlastníky lesa) can be downloaded here.
Authors: Ing. Bc. Jan Lubojacký, Ph.D., Ing. Jan Liška, VÚLHM, v. v. i., e-mail: lubojacky@vulhm.cz
Prepared by: Ing. Jan Řezáč, VÚLHM, v. v. i., e-mail: rezac@vulhm.cz