Health of spruce groves remaining a key concern of forestry professionals2016-04-01
Forestry professionals in charge of maintenance of State forests are now mostly concerned with the health of spruce groves of young, medium, and mature age. According to Virgilijus Vasiliauskas, head of the Division of Sanitary Protection of Forests at the State Forest Service under the Ministry of Environment, these spruce groves are expected to demonstrate, in the first semester 2016, a most unfavourable situation in sanitary terms, due to increasing population of the bark beetles, forest pests. Risk is most predominant in those spruce groves with primary sources of pests left unaddressed in 2015, as well as forests previously exposed to strong winds, as well as spruce groves of mature age. Where wind fallen trees are not removed, sources of bark beetles can spread to new places.
As the overview of sanitary status of the State forests in Lithuania 2015, compiled by the State Forest Service suggests, in 2015, national forests were mostly exposed to tree diseases (30% of the entire source area), abiotic factors (29%), wild animal-caused damage (21%) and pests (20%). Violations in question were recorded in area of 10,200 thousand hectares in 2015, i.e. as much as 2.2 times less compared to 2014.
In 2015, infection tree diseases affected area of 3,048 hectares of forests, i.e. almost 1.6 times less compared to 2014. Forestry professionals are glad to see the total area of disease source diminishing since 2006. Last year, ash groves (1,578 hectares) and aspen groves (1,269 hectares) were most exposed. Any trees damaged by diseases were cut down for sanitary purposes in the area of 1,191 hectares.
Harm caused by abiotic factors (wind, draught, and cold) as well as other factors of inanimate nature was recorded in the area of 2,892 hectares, i.e. 4.2 times less compared to 2014. In 2015, beasts and other animals affected forests in the area of 2,160 hectares. Damage was mostly caused by ungulate wild animals (roe-deer, deer, and moose), abundant in Lithuanian forests. Last year, they have damaged sprouts in the area of 963 hectares, while damaged bark was found in 862 hectares. Since the population of moose in the forest on the increase, this presents a growing concern for the forestry professionals. In 2015, moose have damaged 140 hectares of young forest plantation. Protection of State forests from wild animals regularly requires considerable effort and funding. For instance, in 2015, areas of plantations were protected by a cover of over 100 tons of repellent in the area of 17,500 hectares, fencing over 880 hectares of young plantations, etc.
In 2015, insects damaged 2,062 hectares of forest, i.e. a drop of almost 3 times compared to 2014. Most damage was caused by pests affecting tree trunks (1,488 hectares), with bark beetle topping the list (1,445 hectares). Compared to 2014, sources of this type of pest were recorded in an area that was almost 3,000 hectares smaller than before. Spreading of sources was mitigated by spring weather unfavourable spread of pests in the post-hibernation period, and rather cool and rainy July, when the newly developed second generation of bark beetle takes flight. This largely was due to preventive measures of sanitary protection, put in place by forestry enterprises, including pheromone traps, insect-trapping trees, insecticides for protection of processed timber, etc.