Articles containing the keyword 'seedling damage'

The size, nutrient contents and terpene composition of needles of Scots pine (Pinus sylvestris L.) saplings untouched and repeatedly browsed by the moose (Alces alces L.) were compared. Material was collected from a 14-years old and 2.5 m high pine stand in Bromarv, Southern Finland. The average length and fresh and dry weight of the needles were measured, and nutrient content (N, P, K, Ca, Mg, B, Cu) was determined.

The needles of repeatedly browsed pines became long and robust. There was, however, no difference between the dry matter percentage between the needles. The average nitrogen content was higher in the rebrowsed trees. Nitrogen content is, however, not directly correlated with the palatability of pine needles. Even phosphorus and boron content were higher in the damaged trees. No difference was found in Ca, K, Mg and Cu contents of the browsed and control pine saplings.

The PDF includes a summary in Finnish.

• Löyttyniemi, E-mail: kl@mm.unknown

The aim of the present study was to survey the occurrence of Otiorrhynchus nodosus Müller weevils and their significance for the natural regeneration of Scots pine (Pinus sylvestris L.). The study was carried out during summer 1982 at Inari in northern Lapland.

There were two sample plots, one situated in a Scots pine seed-tree area and the other, the control sample plot, in an area with a coverage of mountain birch (Betula pubescens subsp. tortuosa, now subsp. czerepanovii). A total of 177 Otiorhynchus weevils were caught. Movement of the weevils reached its climax in July. There were 86% more individuals in the seed-tree area than in the mountain birch area. No damage to the pine germlings or seedlings was not observed, although the situation could be different during the peaks of the veewil populations.

The PDF includes a summary in English.

• Suoheimo, E-mail: js@mm.unknown

An inventory of Scots pine (Pinus sylvestris L.) graft collection in Kolari (67°15’ N, 23°45’ S) showed that severe damage by arctic hare (Lepus timidus L.), root and bank vole (Microtus oeconomus Pallas and M. agrestis L.) and moose (Alces alces L.) was done to grafts in size and in rather poor condition. Furthermore, the damage by arctic hare was dependent on the dry matter content of the needles. Another inventory in a fertilization experiment in a pine pole-stage forest showed that nitrogen fertilization increased the damage by arctic hare. On the basis of the present results, an assumption was made that the formation of repellent substances against herbivorous mammals is connected with wintering process of northern pines.

The PDF includes a summary in Finnish.

• Rousi, E-mail: mr@mm.unknown

In Finland the mite Nalepella is found in Norway spruce (Picea abies (L.) H. Karst.) in forests practically in every tree, and even in the nurseries. The paper reports on the occurrence of Nalepella Haarlovi var. picea-abietis Löyttyniemi in Finland in tree nurseries in Finland. The study is based on a large material, collected in connection with an investigation into spruce spider mites.

Nalepella lives vagrantly on the needles. Due to the sucking of the mites, the needles turn yellow, become dry an die. Single patches from sucking cannot be seen by the naked eye. They occur on all sides of the needles. The worst damage to spruce seedlings in nurseries is caused to the needles located in the top of the seedling. Sometimes the terminal bud dryes and the whole terminal shoot can die. However, the whole seedlings seldom die in consequence of the Nalepella mite alone. Subsequent damage to the injured needles is often caused by fungus Cladosporium herbarum.

The study shows that the mite causes economically significant damages only in the nurseries. In forests no such damages were observed in seedlings or in older trees. In 1965–68, significant damages occurred in 16 nurseries in Finland. About 600,000 four-year-old seedlings were destroyed in 1967. The damages were economically important only in the 4-year-old seedlings.

According to the study, seedlings damaged by Nalepella can be used for planting as they recover rather well after planting in the forest. Moreover, the damages end after planting, and density of the mite population decreases during the first summer.

The mite overwinters as egg on needles. The eggs hatch in Southern Finland in the end of April and in the beginning of May.

The PDF includes a summary in English.

• Löyttyniemi, E-mail: kl@mm.unknown

In early spring 1968 it was noticed that the black grouses (Lyrurus tetris L.) was eating terminal shoots of Scots pine (Pinus sylvestris L.) seedlings in a tree nursery in Luumäki, Southern Finland. The terminal shoots were picked 1–4 cm from the top of the seedlings. In total some thousands of two-year-old seedlings were damaged. The depth of the snow was 10–15 cm deep and only the tops of the seedlings could be seen above the surface of the snow.

The PDF includes a summary in English.

• Löyttyniemi, E-mail: kl@mm.unknown

When the seed harvest of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) are low, pine and spruce buds are among the secondary food items of squirrel (Sciurus vulgaris L.) in Finland. In this study, conducted in Nokia in Southern Finland in 1962-1963, eating of pine buds by squirrel is described. The eaten buds in 15-years old Scots pine seedlings were recorded in two seedling stands.

According to the results, the squirrels selected the largest buds of the best seedlings in the studied stands. In over 50% of the cases the squirrels chose only the buds of the leading shoot, especially the terminal bud. In half of the trees, a side bud of the leading shoot continued the growth, which causes form defects in the trees. In 35% of the damaged trees, a lateral branch continued the growth. Well-growing seedling stands may be especially susceptible for damages caused by, for instance, squirrels.

The PDF includes a summary in Finnish.

• Pulliainen, E-mail: ep@mm.unknown
• Salonen, E-mail: ks@mm.unknown

Since 1954 studies have been carried out by the Department of Plant Pathology of Agricultural Research Centre on occurrence of low-temperature parasitic fungi in nurseries in Finland. This paper reports analysis of the damage caused by the fungus to Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) seedlings.

In Southern and southwestern Finland, scarcely any damage caused by low-temperature parasitic fungi to coniferous seedlings was found. On the other hand, in Central, Eastern and Northern Finland, considerable injuries were present in the seedlings. The extent of damage varies between different localities and in a same location from year to year. The extent of damage is mostly dependent on snow cover which is heaviest in Central and Northern Finland. Damages are largest in wooded areas and in places where snow accumulates abundantly and remains until late in the spring.

The principal cause of winter damage to spruce seedlings is Hepotricia nigra (Hartig) which causes black snow mould. Depending on the amount of infestation, the damage can be limited to scattered groups or consist of large areas of dead seedlings. The fungus is unable to infect the plants during warm months of the growing season. The most damaging parasitic fungus in Scots pine is Phacidium infestans (Karst.) causing snow blight. The infestation varies from reddish-brown patches of infected seedlings to large areas of infected plants. Also, Botrytis cinerea has been determined from one- and two-year plants of pine and spruce.

In trials of chemical control by PCNB (pentachloronitrobenzene) gave nearly complete control of low-temperature parasitic fungi in one-year spruce seedlings. In addition, a compound of zineb (Dithane Z-78) gave similar results. Chemical control of the fungi is now common in the nurseries.

The PDF includes a summary in English.

• Jamalainen, E-mail: ej@mm.unknown

The aim of the study was to find out more about pine weevil (Hylobious abietis L.) injuries in Scots pine (Pinus sylvestris L.) seedling stands and their control by means of DDT. For this purpose, inventories were made of seedling stands established earlier. Control experiments were made on burnt areas by planting seedlings dipped in a DDT emulsion.

The results of the inventories show that injuries caused by pine weevils can, in certain circumstances, especially in seedling stands established by planting, cause the complete failure in artificial regeneration. The extent and quality of the injuries vary greatly according to planting method, treatment of the cutting area, age of the seedling stand, environmental factors, and weather conditions. The most extensive injuries occur in regeneration areas of old Norway spruce stands burnt after clear cutting and planted with Scots pine seedlings. Injuries are greater in seedling stands established by planting, especially after broadcast burning, than in seedling stands originating either from artificial or natural seeding. The quality of the patch for sowing or planting has a considerable effect on the quantity and character of the injuries: in a patch from which organic matter has been removed, injuries do not appear or they are slighter. Seedlings can be protected effectively and economically by dipping their tops up to the root collar, in a DDT emulsion before planting.

The PDF includes a summary in English.

• Nenonen, E-mail: mn@mm.unknown
• Jukola, E-mail: jj@mm.unknown

The article reviews the occurrence of damage causes by elk (Alces alces L.) in young Scots pine (Pinus sylvestris L.) stands established by direct seeding in the Ostrobothia region in Finland. The data was collected by random sampling, and consists of 110 sample plots in pine stands, established in 1930-1944.

Signs of elk damages could be observed in 20% of the stands. In more than half of the damaged stands pine seedlings were damaged by elk, on the rest of the stands the damage was targeted to hardwood saplings only. With the present density of elk population, the damage has an insignificant bearing upon the development of pine seedling stands in Ostrobothnia. The weaknesses of silvicultural state of the stands have been caused by other factors than elk.

Silviculturally weak stands were more liable to elk damage than strong ones. The occurrence of elk damage was more usual in stands with hardwood mixture than in pure pine stands. Especially goat willow, mountain ash and aspen, but also to some decree birch, seem to attract elk. Those factors that promote hardwood growth: fertility of the site, swampiness and the presence of seeding hardwoods in the area, increase the stand’s liability to elk damage.

The article includes an abstract in English and a summary in Swedish.

• Yli-Vakkuri, E-mail: py@mm.unknown

Increase in the elk (Alces alces L.) population and the problems of its grazing has called for detailed research. The present study concentrated on three observation areas representing northern, western and eastern parts of Finland. There were 28 field observers watching 68 elks.

Earlier investigations in Finland indicate that aspen (Populus tremula L.) is the staple diet of elk. This study reached different conclusions, probably largely because of aspen is gradually becoming an increasingly rare tree species in Finland. According to this study, the principal food of elk in the winter is willow (Salix sp.). In the whole country, willow accounts for about 70% of elk’s nutrition. In the Far North the percentage is approx. 90. Of the other tree species, the order of preference is: aspen, Scots pine, mountain ash, juniper and birch. In addition, in Western Finland where snow is less deep, lingonberry and blueberry shrubs are on the menu. Beard moss on the spruce was frequently eaten locally. Elk seems to have eaten mainly the last annual shoot of trees and bushes. In few cases it has gnawed the bark of Scots pine, aspen and willow. Elk consumes in average 340 twigs or terminal shoots per day in the winter. This corresponds to about 1.8 kg of food.

The problem of elks damaging Scots pine seedlings has been observed in Western Finland, were the elk population is higher. The article suggests that suitable feeding places would be left for elk in places that are unsuitable for agriculture or forestry. Leaving, for instance, birch seedlings in Scots pine stands has been noticed to attract elks and to increase the damage to pine.

The article includes an abstract in English and a summary in Swedish.

• Sainio, E-mail: ps@mm.unknown

Regeneration of large open areas in dry mineral soil forest sites that usually grow Scots pine (Pinus sylvestris L.) have several problems. For instance, soil frost, snow, ground vegetation and dryness can prevent germination and growth of seedlings. The damages caused by insects and fungi in seedlings of a large burned area in Siikakangas in Southern Finland was studied. A forest fire burned the area nearly completely in 1909, and 310 hectares have been sowed or planted with mostly Scots pine during the following years. Minor areas have been regenerated with Pinus montana Noll, Pinus excelsa Lamb., Pinus murrayana Balf. and Larix sibirica Ledeb.

No completely healthy pine seedling stands could be found in the area. About 41% of the seedlings in the sample plots were damaged. The most common causes for damage were Evetria resinella (now Retinia resinella L.), Luperus pinicola (now Calomicrus pinicola (Duft.)), Pissodes notatus (now Pissodes castaneus Degeer), Evetria turionana Hb. and Hylobious abietis L. The most usual fungal disease was Lophodermium sp. Evetria resinella caused damages in all the area. Evetria turionana, Pissodes notatus and Hylobius abietina were found in the older seedling stands. Other damages were more localized. The slacks in the terrain seemed to have most damages, the original cause being probably soil frost. Some damages, as Lophodermium, were related to the density of the seedlings, especially in the sown areas. Cleaning of seedling stands could decrease these damages. Planting seems to have succeeded better than patch sowing.

The PDF includes a summary in German.

• Kangas, E-mail: ek@mm.unknown

Germlings and small tree seedlings are exposed to extreme conditions in the forest floor. In this study the influence of climatic factors to seeds and seedlings were studied experimentally, and an attempt was made to estimate the importance of various factors in several sowing experiments in Finland.  

Seeds of Scots pine (Pinus sylvestris L.) were subjected to temperature variations which simulated those of exposed forest sites. The seeds lost some of their germinative capacity during the five-day treatments. Succulent seedlings died when subjected to immersion for 15 minutes at temperatures from 51.5 to 55 ºC. After a hardening pretreatments the seedlings tolerated 2-3 ºC higher temperatures. In artificial humus soil exposed to strong insolation for 15 minutes, temperatures in the range of 54-65 ºC proved to be critical for the seedlings. In natural conditions, also little lower temperatures may prove fatal. Exposure of succulent seedlings of Scots pine and Norway spruce (Picea abies (L.) Karst.) to insolation showed that most damage occurred on humus, quartz sand, and humus-sand mixture, due to rapid evaporation. Seeds of Scots pine, Norway spruce, Betula pendula and Betula pubescens tolerated poorly drought if germination had progressed to a 5–10 mm long radicle. Succulent seedlings tolerated 53-77 days long drought better in humus than in fine silty sand. Seedlings of Pinus sylvestris, Picea abies, Alnus incana and A. glutinosa tolerated cold variably. The developmental stage of the seedling affected cold resistance. Pine seeds sown in furrows germinated well after rain and the survival was high. Frost heaving, snail and insects caused some damages. Germination was lowest at the shallowest furrows. Sowing on natural surfaces gave poor results. Largest damages were caused by birds and ants. 

 The PDF includes a summary in Finnish.  

• Vaartaja, E-mail: ov@mm.unknown

The regeneration of forests in Hämeenkangas area in Southern Finland has been difficult due to various damages from the middle of the 1800s. Few seed trees were left in the area, and artificial regeneration has been used since 1880s. The area became an experimental area of the Forest Research Institute in 1924. The aim of the study was to survey the area before it was transferred to the Finnish Defense Forces.

The original Scots pine (Pinus sylvestris L.) forest of the esker area suffered from many forest fires. The total area is 13,000-14,000 ha, of which the experimental forests of Forest Research Institute cover 6,000 ha. The area is dry upland forest, and drought affects the survival of germlings. Soil frost is a major cause of loss of young seedlings. Sowing method affects the early development of the seedlings. Band sowing proved to be the best method regarding the soil frost. A total of 39 different harmful insect species, 8 pathogen species and 7 other causes of damages have been detected in the area.

The development of seedling stands follow a certain pattern, reported also in other studies. Many of the pine seedling stands develop well until they reach a certain height. After that seedlings begin to suffer from damages, but after reaching another stage develop normally. The damages affect the height growth of the seedlings. Some common damages are caused by Pissoides weevils, needle damages caused by certain beetles, shoot damages by Evetria resinella, and pine blister rust (Peridermium pini and Cronartium flaccidum).

• Kangas, E-mail: ek@mm.unknown

The utilization of available food resources by the moose (Alces alces L.) was studied in a Scots pine (Pinus sylvestris L.) plantation containing an admixture of deciduous species. Rowan (Sorbus aucuparia L.) and aspen (Populus tremula L.) were highly utilized compared to pine and both silver birch (Betula pendula Roth) and downy birch (B. pubescens Ehrh.). However, they were not capable of withstanding continuous browsing by moose owing to their diminished biomass. In total, the browsing intensity (number of browsed twigs/tree) on pine and birch was about double of that on rowan and aspen.

The number of browsed twigs per tree increased as the amount of available main branches increased. The number of bites per available branch, as well as the maximum diameter of the bites, decreased as the density of the plantation increased. Silver birch was more used by moose than pubescent birch as well as planted silver birch compared with naturally regenerated trees.

Main stem breakage was especially common in winter 1988, the average height of the pine and birch trees being over two meters. The tops of broken stems were commonly utilized as food. The increase in moose density and the relatively deep snow cover evidently promoted the incidence of serious damage. The number of undamaged trees/ha was greater in dense than in sparse parts of the stand.

The PDF includes a summary in Finnish.

• Heikkilä, E-mail: rh@mm.unknown

In Nordic countries, tree planting of seedlings is mainly performed during spring and early summer. Interest has increased in extending the planting window throughout the unfrozen growing season. This study compared the success of one-year-old spring, summer and autumn plantings in practical forestry in Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) in southern and central Finland. Planting success was based on the number of viable seedlings per hectare relative to a species-specific target density. The influence of different factors to poor planting results were determined, including quality of site preparation and planting, and sources of natural damage. Overall, in Norway spruce, 85, 69 and 84% and in Scots pine 53, 55 and 40% of spring, summer and autumn plantings succeeded. In Norway spruce, the planting results were consistent between the southern and central regions, whereas in Scots pine, the success was slightly lower in the south. The poor work quality and a low density of appropriate planting spots, contributed to poor planting results, regardless of planting season, region or tree species. Considering different damages, especially mammal damage contributed to the failure of Scots pine spring plantings, whereas in summer plantings, corresponding single failure reason could not be identified. Based on our findings, extending the planting season of Norway spruce could be recommended in both regions. For Scots pine, there is still significant uncertainty about the success of summer and autumn plantings, partially due to the limited number of plantings available for analyses.

• Pikkarainen, School of Forest Sciences, University of Eastern Finland, Yliopistonkatu 7, FI-80100 Joensuu, Finland E-mail: laura.pikkarainen@uef.fi
• Luoranen, Natural Resources Institute Finland (Luke), Production Systems, Neulaniementie 5, FI-70210 Kuopio, Finland E-mail: jaana.luoranen@luke.fi
• Kilpeläinen, School of Forest Sciences, University of Eastern Finland, Yliopistonkatu 7, FI-80100 Joensuu, Finland E-mail: antti.kilpelainen@uef.fi
• Oijala, Metsä Group, Metsä Forest, Kuormaajantie 7, FI-40320 Jyväskylä, Finland E-mail: teppo.oijala@metsagroup.com
• Peltola, School of Forest Sciences, University of Eastern Finland, Yliopistonkatu 7, FI-80100 Joensuu, Finland E-mail: heli.peltola@uef.fi

• Lukkarinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: antti.lukkarinen@pp.inet.fi
• Ruotsalainen, Finnish Forest Research Institute, FI-58450 Punkaharju, Finland E-mail: sn@nn.fi
• Nikkanen, Finnish Forest Research Institute, FI-58450 Punkaharju, Finland E-mail: tn@nn.fi
• Peltola, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: hp@nn.fi