Besides the field experiments, it is important to conduct complementary laboratory studies. In this study, laboratory studies demonstrated that additional N supply
can mitigate the effects of low VPD on cellular metabolism and leaf surface waxes in
silver birch. Concluding from above, rising air humidity has negative impact on
the productivity and functioning of forest trees, with a potential effect on species
composition in the future. Increasing temperature and atmospheric CO 2 concentration are expected to increase the forest productivity in northern Europe due to longer
growing season and higher carbon assimilation rate. However, the growth stimulation can be smaller than predicted if the climate change is accompanied by rising
atmospheric humidity.
Acknowledgements The authors thank Jaak Sõber and Priit Kupper for the technical constructions, coordination and management of the FAHM experiment.
References
Adams P, Holder R (1992) Effects of humidity, Ca and salinity on the accumulation of dry matter
and Ca by the leaves and fruit of tomato (Lycopersicon esculentum). J. Hortic Sci 67:137–142
Ainsworth EA, Long SP (2005) What have we learned from 15 years of free-air CO2 enrichment
(FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and
plant production to rising CO2. New Phytol 165(2):351–372
Aliniaeifard S, van Meeteren U (2013) Can prolonged exposure to low VPD disturb the ABA
signalling in stomatal guard cells? J Exp Bot 64:3551–3566
An P, Inanaga S, Lux A, Li XJ, Ali MEK, Matsui T, Sugimoto Y (2002) Effects of salinity and
relative humidity on two melon cultivars differing to salt tolerance. Biol Plant 45:409–415
Armstrong M, Kirkby E (1979) The influence of humidity on the mineral composition of tomato
plants with special reference to calcium distribution. Plant Soil 52:427–435
Arve LE, Kruse OMO, Tanino KK, Olsen JE, Futsæther C, Torre S (2017) Daily changes in VPD
during leaf development in high air humidity increase the stomatal responsiveness to darkness
and dry air. J Plant Physiol 211:63–69
Bakker JC (1991) Analysis of humidity effects on growth and production of glasshouse fruit
vegetables. Dissertation, Landbouwuniversiteit, Wageningen
Ball M, Cochrane M, Rawson H (1997) Growth and water use of the mangroves Rhizophora
apiculata and R. stylosa in response to salinity and humidity under ambient and elevated
concentrations of atmospheric CO 2 . Plant Cell Environ 20:1158–1166
Barber SA (1995) Soil nutrient bioavailability: a mechanistic approach. Wiley, Chichester
Boé J, Terray L (2014) Land–sea contrast, soil-atmosphere and cloud-temperature interactions:
interplays and roles in future summer European climate change. Clim Dyn 42:683–699
Carins Murphy MR, Jordan GJ, Brodribb TJ (2014) Acclimation to humidity modifies the link
between leaf size and the density of veins and stomata. Plant Cell Environ 37:124–131
Carlson RW (1979) Reduction in the photosynthetic rate of Acer, Quercus and Fraxinus species
caused by sulphur dioxide and ozone. Environ Pollut 18(2):159–170
Cernusak LA, Winter K, Turner BL (2011) Transpiration modulates phosphorus acquisition in
tropical tree seedlings. Tree Phys 31:878–885
Claverie E, Schoppach R, Sadok W (2016) Nighttime evaporative demand induces plasticity in leaf
and root hydraulic traits. Physiol Plant 158(4):402–413
Dai A (2006) Recent climatology, variability, and trends in global surface humidity. J Clim
19:3589–3606
Northern Forest Trees Under Increasing Atmospheric Humidity
331
can mitigate the effects of low VPD on cellular metabolism and leaf surface waxes in
silver birch. Concluding from above, rising air humidity has negative impact on
the productivity and functioning of forest trees, with a potential effect on species
composition in the future. Increasing temperature and atmospheric CO 2 concentration are expected to increase the forest productivity in northern Europe due to longer
growing season and higher carbon assimilation rate. However, the growth stimulation can be smaller than predicted if the climate change is accompanied by rising
atmospheric humidity.
Acknowledgements The authors thank Jaak Sõber and Priit Kupper for the technical constructions, coordination and management of the FAHM experiment.
References
Adams P, Holder R (1992) Effects of humidity, Ca and salinity on the accumulation of dry matter
and Ca by the leaves and fruit of tomato (Lycopersicon esculentum). J. Hortic Sci 67:137–142
Ainsworth EA, Long SP (2005) What have we learned from 15 years of free-air CO2 enrichment
(FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and
plant production to rising CO2. New Phytol 165(2):351–372
Aliniaeifard S, van Meeteren U (2013) Can prolonged exposure to low VPD disturb the ABA
signalling in stomatal guard cells? J Exp Bot 64:3551–3566
An P, Inanaga S, Lux A, Li XJ, Ali MEK, Matsui T, Sugimoto Y (2002) Effects of salinity and
relative humidity on two melon cultivars differing to salt tolerance. Biol Plant 45:409–415
Armstrong M, Kirkby E (1979) The influence of humidity on the mineral composition of tomato
plants with special reference to calcium distribution. Plant Soil 52:427–435
Arve LE, Kruse OMO, Tanino KK, Olsen JE, Futsæther C, Torre S (2017) Daily changes in VPD
during leaf development in high air humidity increase the stomatal responsiveness to darkness
and dry air. J Plant Physiol 211:63–69
Bakker JC (1991) Analysis of humidity effects on growth and production of glasshouse fruit
vegetables. Dissertation, Landbouwuniversiteit, Wageningen
Ball M, Cochrane M, Rawson H (1997) Growth and water use of the mangroves Rhizophora
apiculata and R. stylosa in response to salinity and humidity under ambient and elevated
concentrations of atmospheric CO 2 . Plant Cell Environ 20:1158–1166
Barber SA (1995) Soil nutrient bioavailability: a mechanistic approach. Wiley, Chichester
Boé J, Terray L (2014) Land–sea contrast, soil-atmosphere and cloud-temperature interactions:
interplays and roles in future summer European climate change. Clim Dyn 42:683–699
Carins Murphy MR, Jordan GJ, Brodribb TJ (2014) Acclimation to humidity modifies the link
between leaf size and the density of veins and stomata. Plant Cell Environ 37:124–131
Carlson RW (1979) Reduction in the photosynthetic rate of Acer, Quercus and Fraxinus species
caused by sulphur dioxide and ozone. Environ Pollut 18(2):159–170
Cernusak LA, Winter K, Turner BL (2011) Transpiration modulates phosphorus acquisition in
tropical tree seedlings. Tree Phys 31:878–885
Claverie E, Schoppach R, Sadok W (2016) Nighttime evaporative demand induces plasticity in leaf
and root hydraulic traits. Physiol Plant 158(4):402–413
Dai A (2006) Recent climatology, variability, and trends in global surface humidity. J Clim
19:3589–3606
Northern Forest Trees Under Increasing Atmospheric Humidity
331