Artikkelit kirjoittajalta Heikki Veijalainen

The purpose of this study was to determine critical nutrient concentration values for interpreting foliar analysis of Norway spruce stands growing on drained peatlands. During 1987–91, a total of 162 spruce needle samples from various peatland sites in Finland were taken and analysed for N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn. The mean height growth of the two preceding growing seasons was used as the growth parameter for multiple and simple regression analyses. Foliar concentrations significantly explained height growth. Simple regression analysis was used to estimate the following critical values indicating severe to moderate nutrient deficiencies for the main nutrients: N 1.15–1.30%, P 1.70–2.30 mg g-1 and K 5.40–6.60 mg g-1. Also the following tentative critical concentrations are suggested: Cu 2.0 mg kg-1, Fe 13.0 mg kg-1, Mg 0.80 mg g-1 and Zn 16.0 mg kg-1. Results for B are in accordance with previous, but unsubstantiated, critical values (6–8 mg g-1).

• Veijalainen, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland Sähköposti: ei.tietoa@nn.oo

A granular calcium and wood ash mixture (Fyto-2H-fertilizer) increased foliar, K and B and decreased Zn after two growing periods in Pinus silvestris stands. It had also a positive effect on needle mass (d. m.), but not as pronounced one as the PK-fertilizer for peatland forests. It was concluded that Fyto-2H-product can increase the nutrient contents, which have been observed to be essential for the state of health in peatland forests. Further it contains slowly soluble portions of Ca and Mg, which have been proved to be very often the growth limiting factors e.g. in disturbed forests in Central Europe. Keywords: Fertilizer, liming, needle analysis, Pinus silvestris, wood ash

• Veijalainen, Department of Forest Ecology, The Finnish Forest Research Institute P.O. Box 18, FIN-01301, Vantaa Sähköposti: ei.tietoa@nn.oo

Biosludge from a biological waste-water treatment plant was tested in a greenhouse experiment on three substrates at 7 levels (0-240 m3/ha). The growth of birch seedlings was best on nitrogen poor substrate collected from a Vaccinium vitis-idaea (VT) forest site. NPK-fertilization was superior to sludge treatments on poor peat substrate. Biosludge increased the foliar nitrogen content on all three soils. Nutritional value of coal ash was tested at 17 levels (0.4-160 t/ha) on mineral soil from an afforested field. Low application levels of coal ash (400-1600 kg/ha) increased the growth of the birch seedlings more than other applications. However, even extremely high coal ash amounts (up to 160 t/ha) were not lethal for birch seedlings. Coal ash increased foliar boron contents two to three fold and with applications higher than 20 t/ha increase was five to seven fold. Birches planted in 1978 on a coal ash landfilling area showed good survival and growth, despite toxic boron contents and visual disturbances in the leaves. Key words: Boron toxicity, fertilization, peat substrate, recycling

• Veijalainen, The Finnish Forest Research Institute, Box 18, FIN-01301 Vantaa Sähköposti: ei.tietoa@nn.oo
• Silfverberg, Sähköposti: ei.tietoa@nn.oo
• Hytönen, Sähköposti: ei.tietoa@nn.oo

In Finland, determination of the fertilization requirements of freshly ditched peat-lands is generally based on the ground vegetation. Ground vegetation and site type are correlated rather well with the levels of certain nutrients in the peat. The large number of peatland site types have been grouped into three fertility categories on the basis of the fertilization requirements: 1. No fertilization needed 2. PK fertilization recommended 3. NPK fertilization recommended Fertility classification may be misleading in the case of old drainage areas and growth disturbance areas, especially in the refertilization stage. In order to avoid fruitless and erroneous fertilization treatments the following suplementary methods may be used: — fertilization experiments — identifying visible deficiency symptoms — chemical foliage analysis — chemical peat analysis Needle analysis is most suitable in pine stands. In treeless areas and in spruce and birch stands other methods are more applicable at the present time.

• Veijalainen, Sähköposti: ei.tietoa@nn.oo

Different kinds of boron and copper fertilizers were applied to pine seedlings planted in a flark (see table 1). Three growth periods after the fertilization copper oxide, fertilizer boron, fritted boron, micro-nutrient mixture and bark ash gave better height growth than the control (NPK, Ca). Poorest results were achieved with the following micronutrients; solubor, copper sulfate, copper chelate and PK with Cu and B. The height growth in years 1978 and 1979 of only those seedlings that were fertilized with solubor was poorer than that of the control. The height growtht of fritted boron and bark ash fertilized seedlings was statisticaly significantly better than that of the control. The best result was achieved with copper oxide (Table 2). The comparison between the copper fertilizers revealed that copper oxide was the best copper compound for pine seedlings in a flark (Fig. 1). Fritted boron appeared to be the best boron fertilizer (Fig. 2). Bark ash was best of the nutrient mixtures studied (Fig. 3). The experiment showed a positive trend in favor of slowly dissolving micronutrient compounds, including bark ash, on pine seedling growth in a flark. It is also evident, that the commercial micronutrient fertilizers are by no means biologically the most effective compounds for pine seedling fertilization on peatland. In forestry and research commonly used coppersulfate and fertilizer boron seemed to be rather questionable as peatland fertilizers.

• Pietiläinen, Sähköposti: ei.tietoa@nn.oo
• Veijalainen, Sähköposti: ei.tietoa@nn.oo

During the last five years a number of foresters and research workers in Finland have noticed the increasing occurrence of a growth distur-bance in 10—15 year old peatland stands. This phenomenon is referred to as "eskimosis" in this paper. The symptoms do not resemble those of any of the known nutrient deficiencies and as far as we know it does not appear to be caused by insects or fungi. The symptoms of eskimosis in Pinus silvestris are as follows; — young samplings have long branches — apical dominance is lost — lammas growth is common — terminal shoots may become branched — needle lenghts vary within wide limits — elongation growth is suppressed — dark green colouring and sturdy external appearance of saplings Apparently 1—2 years after these almost invisible symptoms first appear, eskimosis kills the apical parts of the "infected"" trees, usually from one to three whorls, during late winter (die back). Some trees develop 2—3 leaders without any additional symptoms, but usually eskimosis is repeated year after year causing cessation of height growth, giving the tree a flat-topped appearance with plenty of dead needles distributed throughout all parts of the trees. At this stage of eskimosis, resination of the buds, necrotic spots on the needles and browning inside the shoots proceeding from the apical parts, are typical secondary symptoms. After some years the cambial growth may also be suppressed as a result of the decreased amount of green needles. Eskimosis results in thick-stemmed and stunted trees which very often die. An investigation programme has been started by the Department of Peatland Forestry, the Finnish Forest Research Institute, and some preliminary results are published in this paper. Eskimosis may infect pines, spruces and birches on drained peatlands as well as on mineral soils. Phosphorus fertilization often increases the likelihood of eskimosis developing. The first attempt to cure eskimosis, was carried out in a drained spruce stand, by fertilizing with micro-and macro-nutrients. The greatest increase in radial growth was achieved with NP fertilization, although the spruces survived even without any fertilization. Boron had a slightly positive effect on visible symptoms. Eskimosis was apparently caused by P-rich litter from the previously felled pine stand which had been fertilized with phosphorus some years prior to felling. The young spruce stand lost its shelter stand and subsequently received much easily soluble phosphorus from the P-rich litter. The largest known eskimosis area lies at Kivi-suo Experimental Fields, Leivonmäki, in pine plantations established in 1959. Kivisuo, Exp. 1^ lay-out, 4x4x4 NPKwith two replications, planting spacing 2 m, ditch spacing 22 m, earlier used as a drying field for hydro peat, originally an open Sphagnum bog with rimpis, fertilization in 1959, refertilization 1968. During refertilization, the plots were divided into three parts; a = broadcast fertilization, PK(0-17-15) 500 kg/ha b =spot fertilization. PK(0-17-15) 50 g/ sq.m c = control A couple of years after refertilization was carried out, eskimosis appeared. It seems that eskimosis is largely a result of the original micro-relief of the bog and is further increased by the highest P and K levels (eg. Huikari and Paarlahti, 1973). Another investigation was carried out in 1975 with the following results: the elongation growth of the trees was decreased most on plots which received broadcast refertilization and least on the control plots (Fig. 1.). The situation was about the same in Experiment V which was spot fertilized in 1959 (spot size 0,25 sq.m) and refertilized in 1966 in a similar way as exp. 1. Eskimosis also appeared soon after refertilization. A decrease in tree heights induced by eskimosis was observed (Fig- 2). Experiments under greenhouse conditions using substrate taken from sites where eskimosis is prevalent have shown that this Scheuchzeria-rich peat is deficient in N, K and B even after previous site treatments with NPK and PK at high levels. This may be the solution to the problem at Kivisuo. It will require perhaps another 2—3 years to confirm this before our micronutrient experiments will provide us with the final details. "

• Veijalainen, Sähköposti: ei.tietoa@nn.oo

The study deals with the trampling tolerance of a drained pine swamp type, very common in Finland. Measurements of the sinking and wearing of peat and vegetation were performed at Jaakkoinsuo near Vilppula (62°04'N, 24° 34'E) on a thick (1—2 m) peat layer drained in 1909 (Fig 1). An assistant, weighing 70 kg made the trampling along the 5 meter long lines at the following levels: 0, 1, 2, 4, 8, 15, 30 and 50 times per week during 12 weeks (experiment a) and 0 or 100 times in June, July or august (experiment b). Measurements were carried out with ten replications. The main results of the study were as follows: All trampling levels differed significantly from 0 level. Trampling levels 1-8 did not differ significantly from each other. Trampling levels 30 and 50 differed from all the other levels significantly (Fig 2). This means that trampling 12 times per summer makes a visible path into the peat surface. Trampling 180—360 times per summer makes almost all living parts of the vegetation to die, small roots to crack and thicker roots to denude resulting obvious damages in rhizosphere. The monthly trampling experiment revealed that the august trampling produced the deepest pathway in the peat (Fig 3). A year after the trampling was carried out, another measurement at experiment a was conducted. No significant development was observed (Fig 4). It means that pathways, on peat-land types in question, take several years to recover after the trampling. Even the lowest levels of trampling were measurable and visible after one summer without trampling. All this calls our attention to the question about pathway construction on our experimental areas, along the excursion routes everywhere with more than 200 visitors per year.

• Veijalainen, Sähköposti: ei.tietoa@nn.oo

• Veijalainen, Sähköposti: ei.tietoa@nn.oo