Current issue: 55(2)
We investigated the causative agent of a disease outbreak affecting small-leaved limes (Tilia cordata Mill.) and resulting in darkening of the leaf petioles and excessive defoliation during summer 2016 in southern Finland. The fungal species composition of the symptomatic petioles was examined by culture isolation and molecular identification using ITS rDNA sequences, which revealed the most prevalent fungal species present in the petioles as Apiognomonia errabunda (Roberge) Höhn. Based on reviewing curated herbarium specimens deposited at the Universities of Helsinki and Turku, A. errabunda is native and widely distributed in small-leaved limes in Finland, and occasionally infects also other broadleaved trees, including Quercus robur L. and ornamental species of Tilia L. and Fagus L. The ITS sequence analysis conducted during this study revealed minor within-species polymorphisms similar to those observed earlier in the Central European and Russian populations of A. errabunda, and reports the first nucleotide sequences of this species from the Nordic countries.
Half-deciduous woodlands are the combination of deciduous forests and heath forests from their vegetation. The article describes three half-deciduous forest types from the commune of Hager, 40 kilometers south form Tallinn.
The occurrence of half-deciduous forests depends on the soil conditions, especially on lime content of the soil, when the occurrence of other forest types is more a question of climate. They are important as an original site for many continental plant species.
The PDF contains a summary in Finnish.
The article is a literature review focusing on the reaction of soil respiration, litter decomposition and microflora of forest soils to various pollutants like acidic deposition, heavy metals and unusual high amounts of basic cations. There is a great deal of evidence indicating that environmental pollution affects soil microbial activity and community structure. Much of the data originates from experimental designs where high levels of pollutants were applied to the soil under field or laboratory conditions. Furthermore, many were short-term experiments designed to look for large effects. These experiments have an indicative value, but it has to be kept in mind that environmental pollution is a combination of many pollutants, mostly at low concentrations, acting over long periods of time. There is therefore consequently a demand for research performed in natural forest environments polluted with anthropogenic compounds.
The study is based on the results of the soil studies by Valmari (1921) and the growth inventories of respective areas. The aim is to show the connection of soil fertility (nutrient content) and forest growth with means of correlation calculations. The examined nutrients were nitrogen, calcium and phosphorus, also the electrolyte content was studied.The results show that with increase of nitrogen content of the soil the growth of pine stand increases as well. The correlation is clearly identified. The number of birch and spruce stands is too small for systematic review. For calcium there is a similar kind of relation. With phosphorus content or amount of electrolytes the correlation with doesn’t exist. Also the loss on ignition test was conducted. The relation found is somewhat weak.
Length of the regeneration period is a criterion commonly used for comparing different reforestation methods. The time factor should be evaluated using a realistic system for long-term planning. In this paper the preliminary evaluation is made by simplified calculations based on the development series. The slow regeneration method is assumed to be otherwise equal to the rapid one but it has a 5- or 10-years delay at the beginning, and the rotation is thus the final cutting age plus 5- or 10-years delay. Cost of the time delay is taken to be the difference in reforestation costs that makes the rapid and the slow methods equivalent. Calculations are made using zero costs for the slow method; but if the cost of the slow method increases, the critical cost difference decreases very slowly. The final cutting age and the regeneration method must be decided simultaneously. Therefore, the cost of the time delay is presented as a function of final cutting age. By maximizing the average annual revenue, rotation can be even increased if more rapid but more expensive regeneration method is used.
The PDF includes a summary in English.
During the summer and fall of 1966 changes brought about by urea, calcium ammonium nitrate, nitrate of lime, and ammonium sulphate were observed. Application of the fertilizers corresponded to 100 kg/N per hectare.
The effect of urea was immediate. The pH rose and the bacterial density increased to 20–30 times more than determined in the spring, while the microfungal density decreased to one third of the spring density. In the ammonium sulphate plot opposite changes occurred almost as rapidly as in the previous case. A gradually increasing biological activity observed after application of calcium ammonium nitrate and of lime fertilizers seemed almost the same for bacteria and microfungi. Both microbe groups displayed consistent quantitative growth. pH 4.3 was the limit of acidity below which the bacteria showed a tendency to decline and the microfungi to increase, while the opposite was true above this limit.
The PDF includes a summary in Finnish.
The aim of the study was to update knowledge of natural range of English oak (Quercus robur L.), European ash (Fraxinus exelsior L.), Norway maple (Acer platanoides L.), small-leaved lime (Tilia cordata Miller), wych elm (Ulmus glabra Mill.) and European white elm (Ulmus laevis Pall.) in Finland, and estimate how far north they could be grown as forest trees or as park trees. The study is based on literature and questionnaires sent to cities and towns, District Forestry Boards, districts of Forest Service, Forestry Management Associations and railway stations.
The northern borders in the natural range of the species succeed one another from south to north as follows: English oak, European ash, Norway maple, wych elm, and small-leaved lime. Occurrence of European white elm is sporadic. The English oak forms forests in the southernmost Finland, while the other species grow only as small stands, groups or solitary trees. According to experiences of planted stands or trees, the northern limits of the species succeed one another from south to north as follows: European ash, English oak, Norway maple, European white elm, wych elm and small-leaved lime. All the species are grown in parks fairly generally up to the district of Kuopio-Vaasa (63 °). The northern limits where the species can be grown as park trees reach considerably further north in the western part of the country than in the east.
The article includes a summary in English.