Artikkelit kirjoittajalta Seppo Kaunisto

The nutritional status of Scots pine (Pinus sylvestris L.) stands growing on a nitrogen-rich, drained pine mire in western Finland was studied after refertilization using needle analysis and the response of stand volume growth. The main aim was to find out if K-refertilization alone could maintain or increase the volume growth without causing a nutrient imbalance between K and P. The initial fertilization was carried out in 1961 - 62 using PK fertilizer and refertilized in 1976 and 1989 with different combinations of nitrogen (N), phosphorus (P), potassium (K) and boron (B). Needle samples were taken and the tree stands were measured in 1996 and 2001. Peat samples were taken in 2002. According to the needle analysis results, the concentration of P was above the deficiency level in all the treatments in 1995 and 2000. There was a clear shortage of K in the needles collected from the control treatment, but the concentration of K was still adequate 12 years after the latest K refertilization. The volume growth of the stands clearly responded to the 1976 refertilization with K alone, which was probably due to the fact that trees had been suffering from K deficiency before the first refertilization and 14-15 years thereafter. After the second refertilization, the combination of K and P increased the annual volume growth more than refertilization with K alone. This indicates that about 25 years after the initial fertilization, there was already some shortage of P. The highest stand volume was associated with the combined K (1976) and PK (1989) refertilization treatment. Refertilization with N did not increase stand volumes during the study period.

• Rautjärvi, The Finnish Forest Research Institute, Joensuu Research Centre, Box 68, FIN-80101 Joensuu Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo
• Tolonen, Sähköposti: ei.tietoa@nn.oo

The effects of refertilisation and growing density on the soil and tree nutrition, root penetration and growth of Scots pine stands were studied in a cutaway peatland area with deep peat layers. The fertilisation treatments were control, N1975+PKB1985 and PK1975+PKB1996 refertilisations and those of the growing density <1 300, 1 654 and 1 954 trees ha-1. The maximum root penetration varied between 26 and 34 cm independently of the treatments. The N/P ratios in pine needles were quite high even on the refertilised plots (11.6-15.7). The duration of P fertilisation seems to be shorter (about 15 years) on cutaway peatlands with deep peat layers than on drained peatland forests. The greatest yield without natural removal (239 m3 ha-1, on an average) in 35-years-old stands was measured on plots, which had the highest growing density and had been repeatedly fertilised with PK. The results show that quite a high yield of Scots pine can be reached on cutaway peatlands. However, pine has to be fertilised with PK at the afforestation stage and at least once later if the remaining peat layer is 40-60 cm, and possibly several broadcast fertilisations are needed on peat layers deeper than 60 cm. It seems that growing tree stands on cutaway peatlands in higher densities than in conventional forestry may improve nutrient cycling in stands and hence decrease leaching of nutrients from the site.

• Aro, Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

Wood production capacity on drained peatlands depends on the site type and temperature sum. Site type is closely related to the peat total nitrogen concentration. This study aims at clarifying the effect of peat nitrogen, fertilization and refertilization on the foliar nitrogen concentration of Scots pine in different temperature sum conditions (850, 950 and 1080 d.d.) on peatland sites with a wide peat nitrogen gradient (0.79- 2.80% in the 0-10 cm layer). In the coldest region, regardless of the peat total nitrogen concentrations in the 0-10 cm surface peat layer and PK- fertilization or PK-refertilization (37 and 26 years earlier respectively), the needle nitrogen concentrations were mostly below the severe deficiency limit (N = 1.2%) and also the arginine concentrations revealed a nitrogen shortage (<0.5 mg g-1). In the middle region the mean nitrogen concentrations in the needles were clearly higher and in the PK- fertilization and PK-refertilizations (32 and 22 years earlier respectively) surpassed the slight nitrogen deficiency limit (N = 1.3%). Also the arginine concentrations surpassed the deficiency limit (0.5 mg g-1 ) in both fertilization treatments although the mean arginine concentrations were near or under the deficiency limit. In the warmest region 25-26 years after the spot fertilization the mean nitrogen concentration was 1.84% and the arginine concentration was 3.04 mg g-1 revealing a surplus of nitrogen caused by phosphorus and potassium deficiencies. The PK-fertilization given 10 years later decreased the nitrogen concentration to 1.56% and the arginine concentration to 0.58 mg g-1. In the more favourable conditions the nitrogen and arginine in the needles increased when the nitrogen in the peat increased. In conclusion, tree growth in the middle and the warmest temperature sum region would respond to PK-refertilisation above a certain total peat nitrogen level but in the coldest temperature sum region tree growth would not respond to PK-refertilization in any of the studied peat total nitrogen conditions because of nitrogen deficiency.

• Pietiläinen, The Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

The aims of this study were 1) to get a better background for estimating limit values of potassium nutrition for Norway spruce (Picea abies L. Karst.) and 2) to find out if the needle potassium nutrition during dormancy could be estimated by analysing needles collected before the dormant period. Five groups of trees with different nutritional backgrounds were selected. One was on a shallow-peat (5–30 cm) mineral soil slope and four on a deep-peat site next to it. Needles were collected four times during the autumn months and twice during dormancy. The needle K concentration of a severe potassium deficiency limit indicated by the exponential accumulation of putrescine, was about 4.5 mg g–1. However, trees suffered from potassium shortage already at the potassium concentrations of about 5 mg g–1. The needle potassium concentrations during the autumn months from late August to early October were in very close correlation with the concentration during dormancy, y = 0.869x – 0.208 (r2 = 0.92), where y is the potassium concentration in the winter months and x that during the autumn months.

• Kaunisto, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, 39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Sarjala, Sähköposti: ei.tietoa@nn.oo

Relationships between the peat nutrient concentrations and the degree of humification, the ground vegetation and the botanical composition of the peat were studied on an afforested, originally treeless mire with a wide nitrogen gradient. The afforestation was carried out in 1971 using spot sowing and spot fertilisation. A broadcast fertilisation experiment that involved six replicates with four treatments, (i) a control, (ii) PK (rock phosphate and KCl), (iii) PK+ B, Cu and (iiii) wood ash was established in 1981–82. The surface peat layers were sampled for nutrient analyses in 1995 and for peat type determinations in 1997. The ground vegetation was inventoried in 1995. In 1995, the peat total nitrogen concentration varied from 8.7 to 29.1 mg g-1 in the 0–5 cm peat layer. The total nitrogen, phosphorus and iron concentrations and the degree of humification in the peat were all positively correlated with the proportion of Carex components and with each other. The frequency of Sphagnum mosses correlated negatively but that of forest mosses positively with the peat total nitrogen concentration. Broadcast fertilisation with wood ash increased the concentrations of phosphorus, potassium, calcium, magnesium, manganese, boron, copper and zinc especially in the 0–5 cm peat layer but did not affect other peat properties or the ground vegetation.

• Hartman, Finnish Forest Research Institute, Vantaa Reseach Centre, P.O. Box 18, 01301 Vantaa Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo
• Silfverberg, Sähköposti: ei.tietoa@nn.oo

The mycorrhizal infection of the roots of four-year-old Scots pine seedlings was stud ied by analysing root ergosterol, endogenous polyamines, nitrogen, phosphorus and potassium concentrations after two years in the field.The seedlings had been planted in a 25-year-old pine plantation on an originally treeless mire representing a wide peat nitrogen gradient.Common mycorrhizal types with Scots pine, such as Cenococcum Piloderma and Boletaceae types, and a number of unidentified types were found in the roots.The roots contained quite normal or a little lower levels of ergosterol than re ported elsewhere on tree roots in mineral soil forests.After two growing seasons in the field a positive correlation (r =0.584**)was found between the root ergosterol and peat nitrogen concentrations.The root ergosterol and spermidine concentrations correlated positively.This may be due to a more abundant physical presence of the fungal tissue which contains more spermidine than the other polyamines, or it may be due to a posi tive effect of the mycorrhizal fungi on the metabolic activity of the roots.

• Sarjala, Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

The effects of drainage maintenance on the nutrient contents in peat and Scots pine needles on drained pine mires were studied. The material consisted of twelve Finnish field experiments. Drainage maintenance (increasing ditching intensity; no treatment at all, mere ditch cleaning, mere complementary ditching, and both of them together) was carried out in 1982-1985. The needles were sampled in 1994-1995 and peat in 1996. There were great differences in the site types and consequently also in the peat and needle nutrient concentrations between the experiments. The needle Mn concentrations demonstrated a fairly good drainage status in all the treatments. Drainage maintenance had only minor effects on the nutrient status of peat and needles. Ditch cleaning decreased magnesium, manganese and zink amounts in the surface peat. Increasing the intensity of drainage maintenance increased the 100-needle dry mass, but decreased the needle boron concentrations. Peat and needle nitrogen concentrations increased slightly (not significantly) along with the increased intensity in drainage maintenance. The peat nutrients classified correctly 83.7% of the fertility classes for drained peatlands.

• Lauhanen, The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700, Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Kaunisto, Sähköposti: ei.tietoa@nn.oo

Pine nutrition was monitored after the application of phosphorus and potassium fertilisers of different solubility in 12 experiments on drained mires in northern Central Finland. Ten experiments involved the following three treatments: (i) control, (ii) fertilisation with rock phosphate and potassium chloride, and (iii) fertilisation with apatite ore or enriched apatite and phlogopite. Two experiments focused on the fertiliser amount. In seven experiments needle samples were collected three times: 3-7, 11-14 and 16-19 years after fertilisation and in the others once or twice (after 10-17 years). The stands suffered from phosphorus and potassium shortage on the unfertilised plots. Rock phosphate had raised the needle phosphorus concentrations slightly more than apatite by 5-7 and 11-14 years after fertilisation. By the last sampling apatite (16-19 years after) had raised the concentrations to about the same or to a higher level than rock phosphate. Potassium chloride raised the concentrations more than phlogopite during the first few years after fertilisation but the situation had reversed by 11-14 years. Five years later the change was even more pronounced. The needle potassium concentrations increased slightly with the increasing application amounts on the nitrogen-rich sites. Fertilisation with PK lowered the needle zinc, manganese, copper and boron concentrations especially on the nitrogen-rich sites.

• Kaunisto, The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Issakainen, Sähköposti: ei.tietoa@nn.oo

This paper is based on four experiments established in 1960-1969. There were four sources of potassium: potassium chloride, double salt of potassium and magnesium sulphates, cement potassium and potassium sulphate. The application rates of fertilizer potassium varied from 0 to 664 kg/ha as pure element. Nitrogen and phosphorus or phosphorus alone were also given at the beginning. The experiments were inventoried in 1988. The peat potassium amounts were independent of the application rate. On the other hand, the foliar potassium concentrations were the higher the higher the application rate. Yet, the effect of currently used potassium fertilizer rate, (about 80 kg/ha of K), on the foliar potassium concentrations did not significantly differ from the effect of the double rate. Fertilization increased the basal area growth for 8-22 years, after which the growth started to decline. The reason can at least partly be attributed to the shortage of potassium. The growth response was independent of the potassium source and rate on the potassium fertilized plots. Key words: Foliar nutrients, peatland, peat nutrients, Pinus sylvestris

• Kaunisto, The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

The authors visited Estonia and Latvia on 20-25.8.1990 in order to get acquainted with peatland forestry research and methods for increasing tree growth on cultivated peatlands, especially by using fertilization. The paper describes peatland forestry in general, paying special attention to the activities in the field of fertilization research on Estonian and Latvian peatlands. Keywords: Drainage, fertilization, peatland forestry

• Kaunisto, The Finnish Forest Research Institute, Parkano ResearchStation, SF-39700 Parkano, Finland. Sähköposti: ei.tietoa@nn.oo
• Ferm, Sähköposti: ei.tietoa@nn.oo
• Kokkonen, Sähköposti: ei.tietoa@nn.oo

The alder mixture and fertilization, both separately and especially together increased the growth of pine and the mass and length of roots, and decreased mortality of trees. Alder mixture increased the amounts of phosphorus and potassium in peat as compared to the alderless plots. The thickness of the peat layer (range 0.24-0.72 m) was negatively correlated with the growth of pine, the foliar P and K concentrations and the root mass and length. In no case were roots found in the peat layer closest to the subsoil. Obviously the peat layer should not be thicker than 30 cm, even if fertilized, for growing pine in a peat cutover area. Keywords: Foliar nutrients, peat nutrients, peat thickness, root penetration

• Kaunisto, The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo
• Viinamäki, Sähköposti: ei.tietoa@nn.oo

Generally in peat soils but especially in the old forest drainage areas the amount of potassium is low compared with that of nitrogen (ab. 1:100) and phosphorus (ab. 1:4). However, the amount of potassium fixed in tree biomass is about four times the amount of phosphorus. When estimating the future sufficiency of potassium for wood production in old drainage areas after one rotation (drainage 75 years earlier), it seems that on nitrogen-rich deep-peat pine mires potassium stores become exhausted during the second rotation after drainage if potassium is not applied. Key words: Fertilization, peat nutrient stores, potassium, transformed mires

• Kaunisto, The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland Sähköposti: ei.tietoa@nn.oo

Fertilization has had only a minor effect when carried out in conjunction with the reforestation of forest-covered peatlands, apart from in southern Finland where NPK fertilization has increased the growth of pine seedlings and transplants on oligotrophic pine swamps. On bogs phosphorus is the most important nutrient at the afforestation stage, but later on potassium deficiency may abruptly cause the deterioration and even death of the stands. Pine and birch can be grown on peat cutover areas without N fertilization. The mineral nutrition of trees can be satisfied either by the mineral nutrients in the subsoil, if the peat layer is thin or if mineral soil has been lifted onto the peat, or by fertilization. The refertilization of young stands with NPK instead of PK may lead to frost damage in pine, unless boron is simultaneously applied.

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

According to the Chinese Geographical Research Institute the definition of swamps include three criteria: - the area is waterlogged or under water - the area is dominated by hygrophytes - the area has either a peat or mud layer The area is classified as a swamp if two of the criteria are fulfilled simultaneously. Thus peat is not necessary. The entire China has a. 10 million ha of swamps that fit into this definition containing a 30 milliard cubic metres of peat. About 6 million ha are located in northern China. Usually the swamps have a rather shallow peat layer (less than 1 m). There is no nationwide swamp classification. A simple classification based on hydrological properties and draining techniques has been developed for the forestry use of swamps. Only open swamps are defined as swamps. The open swamps are divided into two main groups: seasonally waterlogged swamps and those waterlogged for the whole year. The area of such swamps is a. 1,8 million ha in Heilungkiang, a province in north-eastern China. It is estimated that 600 000 ha of these area suitable for growing forests. The afforestation of open swamps was started in the 1950's. So far 14 000 ha have been afforested. Most plantations, using Larix gmelini, are in seasonally waterlogged areas. Previously the sites were prepared mainly by manual mounding. The results have been highly encouraging. At the end of the 1970's a larger scale mechanical site preparation (by ploughing) was started.

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

A pine afforestation experiment was set up on a peat cut-away area at Aitoneva, Kihniö (62°12'N, 23°19'E, elev. a. 160 m) in the spring of 1979. By the autumn of the same year the area had been naturally stocked with a great number of Betula pendula and B. pubescens seedlings. In the spring of 1980 an inventory was carried out to find out the effect of the various fertilization and soil amelioration treatments on the number of Betula pendula and pubescens seedlings and on their growth during the first growing season. There were 96 sample plots (20 m x 15 m). On each plot 16 systematically chosen plots, sized 0.25 m2, were measured. The number of normal, leader damaged and dead seedlings were recorded on each circular plot as well as the height of the tallest Betula pendula and pubescens seedling. The various fertilization and soil amelioration treatments are presented in Table 1. The birch row along the road on the western side of the experimental field (Fig. 1 and Table 2) was the main seeding tree stand. The number of birch seedlings was very high near the seeding trees. Even 100 metres from the row there were far more seedlings than are required by practical forestry (Fig. 2, Table 3). By adding phosphorus, potassium, nitrogen and wood ash, the number of seedlings increased (Tables 4 and 5, Fig. 3). Liming had an adverse effect and the fertilization with micronutrients affected sometimes negatively, sometimes positively (Table 5). In their first growing season the seedlings grew the better, the more they received phosphorus and potassium (Table 6 and Fig. 4). Similarly, nitrogen fertilization improved the growth of, seedlings. The best growth was achieved on wood ash fertilized plots and the poorest on limed plots (Table 7). A very good Betula pendula and B. pubescens seedling stand was naturally reproduced with the aid of quite few seeding trees on a peat cut-over area. Such seedling reproduction, as it entails no costs, should be further studied and considered as one of the alternatives in producing wood material for energy production.

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

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