The increase in moose (Alces alces) population of Finland in 2000th century has caused significant damages in agriculture and forestry. Amendment was made to the Game Law to compensate damage by moose to agricultural crops from state funds. It has been suggested already in 1936 that compensations should be paid for the damages caused to the forests as well. Finally, in 1956 the Government appointed a committee to study the quality and quantity of the damages caused by moose to the young stands. The committee carried out an inquiry about the extent of the damage in 1956–1957, in which 12,000 private forest holdings were studied.
According to the study, moose cause damage mainly to young Scots pine stands in Southwestern Finland and Western Finland, and the districts of Uusimaa-Häme, East Häme, South Karelia and East Savo. However, the number of forest holdings suffering from damage was relatively low, about 5.6% in the whole country in 1951–1956. The damage is concentrated on Scots pine-, aspen, and birch-dominated young stands. The study of the level of the damage showed, that only 14% of the pine and 17% of stands of other tree species should be reforested due to the damage.
The committee suggests that compensation is paid for those damages that require reforestation. Reforestation would be affected with the help of State relief funds under the provision of the Act on Forest Improvement. The owner would also receive a tax reduction for a lost growing season. In addition, attention to moose damages in the forests should be taken into account when moose hunting permissions are issued.
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The aim of this study was to investigate the ecophysiological and morphological characteristics of two salt-tolerant tree species, Eucalyptus camaldulensis Dehn. and Combretum quadrangulare Kurz. A greenhouse experiment with different levels of NaCl salinity (0, 0.5, 1.0, 1.5, and 2.0%) was set up and the results were compared with those of a field study on non-saline and saline soils. The determination of optimum gas exchange and the development and evaluation of photosynthetic models with and without water deficit were also included in this study.
Morphological characteristics under saline conditions showed that shoot height and diameter growth, shoot internode length, root length/biomass, leaf width and length, leaf area, number and biomass, and shoot/root and leaf/root ratios decreased with salinity, while leaf thickness increased with salinity. More growth was allocated to the roots than to the leaf canopy. Ecophysiological studies in laboratory showed that photosynthesis, stomatal conductance and water potential decreased with salinity, while the CO2 compensation point increased with salinity. Transpiration, dark respiration and photorespiration increased at low salinity but decreased at high salinity levels. In the field study, however, there were no significant differences in stomatal conductance and opening between saline and non-saline soils. Model predictions supported the results of the field measurements. Adaptation to salinity was reflected in an acclimatization of tree structure in the field study. There were both functioning and structural changes of seedlings in the greenhouse experiment
In terms of ecophysiological and morphological characteristics, E. Camaldulensis showed better salt tolerance than C. Quadragulare both in the greenhouse experiment and field study
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Genetic variation in the physiological characteristics and biomass accumulation of Acacia mangium Willd. was studied in both field and laboratory conditions. Variation in the growth characteristics, foliar nutrient concentration, phyllode anatomy and stomatal frequency was analysed in 16 different origins under field conditions in Central Thailand. Family variation and heritability of growth and flowering frequency were calculated using 20 open-pollinated families at the age of 28 months. The effect of environmental factors on diameter growth in different provenances is also discussed.
Under laboratory conditions, such physiological characteristics as transpiration rate, leaf conductance and leaf water potential were measured at varying soil moisture conditions. The responses of photosynthesis, photorespiration and dark respiration as well as the CO2 compensation point to temperature and irradiance were also investigated. All physiological characteristics indicated differences among provenances. An attempt was made to relate the results obtained in the laboratory to the growth performance in the field. Recommendations on provenance selection for the planting of A. mangium in Thailand are also given.
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