{"id":5045,"date":"2025-10-23T06:11:28","date_gmt":"2025-10-23T06:11:28","guid":{"rendered":"https:\/\/www.metsabiotalous.fi\/?page_id=5045"},"modified":"2025-10-24T07:18:55","modified_gmt":"2025-10-24T07:18:55","slug":"metsatuhot-muuttuvassa-ilmastossa","status":"publish","type":"page","link":"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/","title":{"rendered":"Forest damage in a changing climate"},"content":{"rendered":"
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Tree Damage Risks Due to Warming Climate<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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As the climate warms, the growing season lengthens, spring arrives earlier, and winter starts later. Winters become milder, and dry and hot spells become more common in summer. Although a longer growing season enhances tree growth, excessive drought and heat can limit it. Many tree-damaging pathogens and animals benefit from warming conditions. They, in turn, weaken trees' growth and carbon sequestration capacity.<\/p>

The ground freezes less often and for shorter periods than before. The winter-time anchoring of trees in the soil weakens, and the risk of overturning, especially for shallow-rooted spruce, increases. Fresh windfalls provide breeding grounds for bark beetles. Species like the European spruce bark beetle and the eight-toothed spruce bark beetle proliferate when given the opportunity. Simultaneous heat and drought periods increase the likelihood of bark beetle outbreaks and tree mortality.<\/p>

Warm and dry growing seasons can reduce diseases that thrive in moist and cool conditions. On the other\nhand, the same conditions facilitate the spread of other diseases by, for example, accelerating fungal\nmycelium growth and prolonging sporulation time. Root rots, significant decomposers of conifers, are\namong those that benefit from warming conditions.<\/p>

During the growing season, drought<\/strong> combined with heat increases tree transpiration. Trees close their stomata to curb water loss. At the same time, photosynthesis and carbon sequestration decline. Carbonbased resin is a defense substance for conifers: insects get stuck in it, and resin compounds repel insects and inhibit pathogen growth. Trees' defense capabilities weaken as photosynthesis declines, and trees stressed by water scarcity become more susceptible to insects and diseases.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Disturbances are interconnected<\/h3>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Wind<\/strong> is a significant cause of disturbances, ranking as the fourth largest contributor to damage in\nforestry. As the climate warms, extreme weather events are becoming more common, and storms are\nintensifying. Freshly wind-felled conifers cannot defend themselves against bark beetles and provide\nthem with breeding grounds.<\/p>

European spruce bark beetle <\/strong>(Ips typographus)<\/em> is the most well-known and economically significant\nspruce bark beetle (Figure 1). When present in small numbers, these beetles only infest weakened trees.\nHowever, if windfalls are abundant, bark beetle populations can proliferate. With enough numbers, they can even infest vigorous standing trees.<\/p>

In spring and summer, spruce trees infested by the European spruce bark beetle, which are still green,\ncan be identified by brown, coffee-ground-like frass accumulating at the base of the tree (Figure 2). As\nthe species reproduces, it leaves characteristic galleries under the bark (Figure 3).<\/p>

Removing already dead and\/or debarked spruce trees will not reduce the bark beetle population in the\nstand. These trees may host beneficial species that prey on or parasitize bark beetles. Instead, you should\nlook for infested but still green trees within the stand (Figure 4). Individual trees or small groups of trees\ninfested by the European spruce bark beetle usually do not develop into large outbreaks.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Figure 1.<\/strong> The European spruce bark beetle (4-5 mm)\nis one of the Finnish bark beetle species. Photo: Erkki\nOksanen, Natural Resources Institute Finland.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Figure 2.<\/strong> Brown frass collected at the base of the tree\nand in bark crevices is a sign of the European spruce\nbark beetle. Photo: Tiina Ylioja, Natural Resources\nInstitute Finland.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Figure 3.<\/strong> European spruce bark beetle gallery. Photo:\nErkki Oksanen, Natural Resources Institute Finland.<\/span><\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Figure 4.<\/strong> European spruce bark beetle life cycle.<\/span><\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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The impact of climate warming on the European spruce bark beetle<\/h3>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The European spruce bark beetle is found wherever spruce trees grow. It's less numerous\nin the north than in the south, but as the climate warms, its population is increasing further\nnorth than before. For timber production, the bark beetle is a pest, but in nature, its role is\nthat of a forest regenerator. Older spruce trees die and become decaying wood used and\nbroken down by other organisms, making space for new trees to grow.<\/p>

Poikilothermic (cold-blooded) insects are sensitive to environmental temperature\nfluctuations. Insect development from egg to adult is regulated by temperature. Insects also\nhave the capacity to produce multiple generations when the growing season warms and\nlengthens.<\/p>

The European spruce bark beetle's development from egg to adult accelerates, allowing it to\nreproduce more than once during the summer (graph). Overwintered adults reproduce twice,\nproducing what's known as a sister generation. If the late summer is favorable, the first\ngeneration that emerged during the summer can also reproduce and lay eggs for a second\ngeneration before winter. If this second generation doesn't reach adulthood before winter,\nthe larval and pupal stages will die. In late summer, decreasing temperatures and shorter\ndays signal to the beetle that winter is approaching and it's time to enter diapause.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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<\/div>\n\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"

Ilmaston l\u00e4mpenemisen tuomat puustotuhoriskit Ilmaston l\u00e4mmetess\u00e4 kasvukausi pitenee, kev\u00e4t aikaistuu ja talvi alkaa my\u00f6hemmin. Talvet leudontuvat ja kes\u00e4isin kuivuus- ja<\/p>","protected":false},"author":1,"featured_media":0,"parent":4999,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"acf":[],"yoast_head":"\nMets\u00e4tuhot muuttuvassa ilmastossa | Metsabiotalous<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Mets\u00e4tuhot muuttuvassa ilmastossa | Metsabiotalous\" \/>\n<meta property=\"og:description\" content=\"Ilmaston l\u00e4mpenemisen tuomat puustotuhoriskit Ilmaston l\u00e4mmetess\u00e4 kasvukausi pitenee, kev\u00e4t aikaistuu ja talvi alkaa my\u00f6hemmin. Talvet leudontuvat ja kes\u00e4isin kuivuus- ja\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/\" \/>\n<meta property=\"og:site_name\" content=\"Metsabiotalous\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-24T07:18:55+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.metsabiotalous.fi\/wp-content\/uploads\/2025\/10\/kirjanpainajatuhon-torjuntaopas-scaled.webp\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/#organization\",\"name\":\"Metsa Biotalous\",\"url\":\"https:\/\/www.metsabiotalous.fi\/en\/\",\"sameAs\":[],\"logo\":{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/#logo\",\"inLanguage\":\"en-US\",\"url\":\"\",\"caption\":\"Metsa Biotalous\"},\"image\":{\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/#logo\"}},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/#website\",\"url\":\"https:\/\/www.metsabiotalous.fi\/en\/\",\"name\":\"Metsabiotalous\",\"description\":\"Forest Economy\",\"publisher\":{\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":\"https:\/\/www.metsabiotalous.fi\/en\/?s={search_term_string}\",\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/#primaryimage\",\"inLanguage\":\"en-US\",\"url\":\"http:\/\/www.metsabiotalous.fi\/wp-content\/uploads\/2025\/10\/kirjanpainajatuhon-torjuntaopas-scaled.webp\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/#webpage\",\"url\":\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/\",\"name\":\"Mets\\u00e4tuhot muuttuvassa ilmastossa | Metsabiotalous\",\"isPartOf\":{\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/#primaryimage\"},\"datePublished\":\"2025-10-23T06:11:28+00:00\",\"dateModified\":\"2025-10-24T07:18:55+00:00\",\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.metsabiotalous.fi\/en\/punkaharjun-tutkimuspuisto\/metsatuhot-muuttuvassa-ilmastossa\/\"]}]}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","_links":{"self":[{"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/pages\/5045"}],"collection":[{"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/comments?post=5045"}],"version-history":[{"count":20,"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/pages\/5045\/revisions"}],"predecessor-version":[{"id":5157,"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/pages\/5045\/revisions\/5157"}],"up":[{"embeddable":true,"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/pages\/4999"}],"wp:attachment":[{"href":"https:\/\/www.metsabiotalous.fi\/en\/wp-json\/wp\/v2\/media?parent=5045"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}