Hannu Raitio

Promoting human health through forests: overview and major challenges.

This review aims to contribute to the ongoing discussion about human health, global change, and biodiversity by concentrating on the relationships between forests and human health. This review gives a short overview of the most important health benefits that forests provide to humans, and the risks that forests may pose to human health. Furthermore, it discusses the future challenges for the research on the links between forests and human health, and for delivering health through forests in practice. Forests provide enormous possibilities to improve human health conditions. The results of a vast amount of research show that forest visits promote both physical and mental health by reducing stress. Forests represent rich natural pharmacies by virtue of being enormous sources of plant and microbial material with known or potential medicinal or nutritional value. Forest food offers a safety net for the most vulnerable population groups in developing countries, and healthy forest ecosystems may also help in regulation of infectious diseases. Utilizing forests effectively in health promotion could reduce public health care budgets and create new sources of income. Main challenges to delivering health through forests are due to ecosystem and biodiversity degradation, deforestation, and climate change. In addition, major implementation of research results into practice is still lacking. Inadequate implementation is partly caused by insufficient evidence base and partly due to the lack of policy-makers’ and practitioners’ awareness of the potential of forests for improving human health. This calls for strong cooperation among researchers, policy-makers, and practitioners as well as between different sectors, especially between health and environmental professionals.

Comparison of Two Wet Digestion Procedures for Multi‐element Analysis of Plant Samples

Two microwave digestion systems for multi‐element analysis of leaves and fruits were compared. Samples were digested by two different methods: 1) with HNO3 (8 mL) and HClO4 (6 mL) using an open microwave system and 2) with HNO3 (5 mL) and H2O2 (3 mL) in a closed microwave system. Total concentrations of aluminum (Al), cadmium (Cd), copper (Cu), chromium (Cr), iron (Fe), leaf (Pb), magnesium (Mg), manganese (Mn), nickel (Ni), and zinc (Zn) were determined in 22 samples by inductively coupled plasma atomic emission spectrometry and by simultaneous inductively coupled plasma mass spectrometry (ICP/AES and ICP/MS). Not statistical differences for Cu, Mn, Mg, Pb, and Zn concentration between the two methods were observed. Trace elements, whose concentration is low, such as Cr and Cd, have to be determinate by ICP/MS. The accuracy of the procedures was acceptable, except for Al, Fe, and Mg using the open microwave system, as the results from certified reference materials were in agreement with certified values.

Evaluation of forest nutrition based on large-scale foliar surveys: are nutrition profiles the way of the future?

This paper introduces the use of nutrition profiles as a first step in the development of a concept that is suitable for evaluating forest nutrition on the basis of large-scale foliar surveys. Nutrition profiles of a tree or stand were defined as the nutrient status, which accounts for all element concentrations, contents and interactions between two or more elements. Therefore a nutrition profile overcomes the shortcomings associated with the commonly used concepts for evaluating forest nutrition. Nutrition profiles can be calculated by means of a neural network, i.e. a self-organizing map, and an agglomerative clustering algorithm with pruning. As an example, nutrition profiles were calculated to describe the temporal variation in the mineral composition of Scots pine and Norway spruce needles in Finland between 1987 and 2000. The temporal trends in the frequency distribution of the nutrition profiles of Scots pine indicated that, between 1987 and 2000, the N, S, P, K, Ca, Mg and Al decreased, whereas the needle mass (NM) increased or remained unchanged. As there were no temporal trends in the frequency distribution of the nutrition profiles of Norway spruce, the mineral composition of the needles of Norway spruce needles subsequently did not change. Interpretation of the (lack of) temporal trends was outside the scope of this example. However, nutrition profiles prove to be a new and better concept for the evaluation of the mineral composition of large-scale surveys only when a biological interpretation of the nutrition profiles can be provided.

Relation between sulphur concentrations in the Scots pine needles and the air in northernmost Europe

The SO2 emissions from the Kola Peninsula in Arctic Russia (totalling around 600 Gg(SO2) yr−1 at the beginning of the 1990s) produce an atmospheric SO2 concentration gradient to the northernmost Europe. This gradient covers the range from >50 μg m−3 in the vicinity of the sources to 1 μg m−3 in Finnish Lapland. In the present study, the measured sulphur concentrations in Scots pine needles were compared with the estimated distribution of atmospheric SO2. The total sulphur concentrations in the needles ranged from 741 to 2017 mg kg−1. Strongly elevated concentrations (> 1200 mg kg−1) were found within 40 km from the smelters corresponding to an area where the annual mean atmospheric SO2 concentration exceeded 10 μg m−3. The foliar sulphur concentrations (total, organic and inorganic) show a high correlation with the estimated mean SO2 concentration distribution in the air. Consequently the foliar sulphur concentrations reflected the atmospheric sulphur load well. The data presented here show that uptake via stomata is an important deposition pathway also in the arctic conditions with a short growing season.

Site elevation differences in frost damage to scots pine (Pinus sylvestris)

Abstract This investigation deals with the external symptoms and occurrence of frost damage in Scots pine seedlings (Pinus sylvestris) growing on a dry, barren mineral soil site. The results suggest that the annual shoots of pine are sensitive to frost at the end of their height growth period. The mosaic-like occurrence of the damage indicated that even a slight variation in topography gives quite significant differences under extreme growing conditions. The difference in height between the highest and lowest sample plot was 244 cm. The largest number of seedlings grew on the flat areas and the smallest on the slope. The tallest seedlings grew on the upper part of the slope. Severe frost damage in live seedlings occurred more frequently on low-lying sites. Moreover, the results show that low temperatures during the growing season may be part of the cause of multiple leaders.

Effects of emissions from copper‐nickel smelters on the frost hardiness of Finns sylvestris needles in the subarctic region

It has been proposed that freezing injuries play an important role in the forest decline phenomenon. In this study, the effect of emissions from the copper-nickel smelters in Monchegorsk and Nikel-Zapolyarnyi in the Kola Peninsula, south-west Russia, on seasonal changes in the frost hardiness of Pinus sylvestris L. needles were studied. The frost hardiness of current-year needles during autumn, winter, spring and early summer in 1991-1993 was estimated by the electrolyte leakage method and by visual estimation of the proportion of damaged needles at nine sites in Finnish Lapland, at five sites in the vicinity of Monchegorsk and at two sites in Norway, in the vicinity of Nikel. The foliar S, Cu, and Ni concentrations also analysed. There were no significant differences at any time of the year between the frost hardiness of pine needles at the sites in Norway and Finnish Lapland. However, in the winter, the degree of visual damage at -45 °C, the temperature close to the lowest recorded temperature in this area, was slightly higher at the sites near to Nikel than at the sites in Finnish Lapland. In the Kola Peninsula the frost hardiness was consistently lower at the sites located 10 km to the south and 36 km to the south-west of Monchegorsk than at the other sites (48-110 km to the south-west). The differences were greatest in early June, 1991, when frost hardiness was -2 °C and -8°C at the sites closest to Monchegorsk. At the same time, the frost hardiness at the other sites was e.-20 °C. There were slight differences between years, but the trends were the same. A clearly increasing gradient in the S, Cu and Ni concentrations was observed on moving towards the emission point source at Monchegorsk. Highly elevated concentrations were found within 40 km of the smelter. The results suggest that air pollutants from the copper-nickel smelter have predisposed the pines to freezing injuries, rhus contributing to forest decline in the Kola Peninsula.

Airborne radiocesium in Scots pine and Norway spruce needles

This paper presents the activity of radiocesium (134Cs and 137Cs) and chemical composition of Scots pine and Norway spruce needles in southern Finland during the years 1987–1991. In 1991, contents and vertical distribution of radiocesium in soil have been determined both under and between canopies. The total 134Cs content per square meter in soil layers varied within the range of 470–9500 Bq/m2 in stands of Norway spruce and 1200–2300 Bq/m2 in stands of Scots pine; the corresponding figures for 137Cs were 5000–88000 and 11 100–28600 Bq/m2. About 80–90% of the radiocesium was located in the humus and in the first 3 cm of mineral soil. There were no statistically significant differences in the contents of 134Cs and 137Cs in the soil under and between the tree crowns. Most of the 137Cs which originated from nuclear weapons fallout, was in the top mineral soil layers. The radiocesium concentrations in the needles varied considerably from stand to stand. In 1987, with the exception of a few forests, the radiocesium concentrations in the 2-year-old (C + 1) needles were higher than those in the current (C) needles. In the other years, the situation was the opposite. The regression between 137Cs concentration in current needles and the year was linear for pine needles and polynomial for spruce needles.

The Foliar Chemical Composition of Young Pines (Pinus sylvestris L.) with or without Decline

Tree decline and death have been observed recently among 20–30-year-old pine stands in dry heath forests in the Hameenkangas and Pohjankangas areas of southwestern Finland. Typical symptoms of affected trees include dieback of leading shoots and bright yellow colour in needles in the upper parts of the crowns in spring.

Concentrations of persistent organochlorine compounds in spruce needles from Western Finland

Abstract Persistent organochlorine compounds in spruce needles from Western Finland, altogether 60 samples, were analyzed by GC/ECD and GC/MS. The distribution of α-HCH, lindane and hexachlorobenzene in the spruce needles was found to be uniform all over the area investigated. The concentrations of α-HCH were higher than the concentrations of lindane. In the PCB profiles, PCB-153 and PCB-138 dominated in all samples, the concentration of PCB-153 being remarkably higher than that of PCB-138. As a rule, the needles from the year 1991 contained these compounds in larger amounts than the needles from the year 1992. TeCDFs, PeCDFs, HexaCDFs, TeCDDs and PeCDDs in very low (pg/g) concentrations were detected in the pooled samples. The concentrations of the PCDFs were higher than the concentrations of PCDDs. The effect of the tree age on the concentrations of organochlorine compounds was riot observed.

Resistance of Scots pine wood to Brown-rot fungi after long-term forest fertilization

The susceptibility of Scots pine (Pinus sylvestris L.) sap- and heartwood against the wood decaying brown-rot fungus (Coniophora puteana) was investigated after long-term forest fertilization at three different sites in central Finland. Different wood properties: wood extractives, wood chemistry, and wood anatomy were used to explain sap- and heartwood decay. Scots pine sapwood was more susceptible to decay than its heartwood. In one site, sapwood seemed to be more resistant to wood decay after forest fertilization whereas the susceptibility of heartwood increased. Significant changes in the sapwood chemistry were found between treatment and sites, however, no relationship between wood chemistry and wood decay was observed in the factor analysis. The results of this study show that there was an inconsistent relationship between decay susceptibility and fertilization and the measured physical and chemical attributes of the wood were not consistently correlated with the decay rate.