Effects of open-field warming and precipitation manipulation on
leaf phenology of Pinus densiflora seedlings
Min Ji Park1, Soon Jin Yoon2, Saerom Han1, Seung Hyun Han1, Hyeon Min Yun1, Hanna Chang1, Yowhan Son1 *
1Department
of Environmental Science and Ecological Engineering, Graduate school, Korea University, Seoul 136-713, Korea
2Forest Ecology Division, Korea Forest Research Institute, Seoul 130-721, Korea
Introduction
•
•
•
•
In Korea, temperature and precipitation is expected to be increased by 3.3℃, and in a range of 2-24% in 2060, according to the RCP 8.5 scenario (CCIC, 2015).
With rising temperature and precipitation, negative impacts on the growth of Pinus densiflora are expected (Byun et al., 2010).
Plant phenology plays a dominant role in regulating species distribution and ecosystem productivity (Cleland et al., 2007).
This study was conducted to investigate the effects of open-field warming and precipitation manipulation on growth of P. densiflora seedlings.
Materials and Methods
 Study site and experimental design
 Measurements
• The experimental nursery was constructed at Korea University, Seoul, Korea. 18 plots
(1.5 m x 1.5 m) were established, with 6 different treatments (2 temperature levels x 3
precipitation levels) applied (Figure 1).
• 50 seedlings of 2-year-old P. densiflora were planted in each plot in April, 2013.
Almost all seedlings, except 2 to 5 per plot, were transplanted on April 12, 2014.
• The air temperature of warmed plots (W) had been set to be 3ºC higher than the
control plots (C) using infrared lamps. Precipitation was manipulated to be 30% lower
(P-) or higher (P+) than the control (P0), using transparent panels and drip irrigation.
• The leaf unfolding process of individual seedlings was
assessed based on a 5-stage system (Figure 2). Leaf
unfolding was monitored from March 28 to June 27 in a 57 day interval.
• The leaf fall of each plot was observed by collecting and
weighing the litter. Leaf fall was monitored at one-week
interval from October 23 to December 11, and
approximately at four-week interval until March, 2015.
Stage 0
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Figure 2. 5-stage system of the leaf unfolding process (0 = closed
bud; 1 = slight swelling; 2 = bud elongated over 2 cm; 3 = at least
one needle observed; 4 = needle grew to the top end of new shoot
and 5 = needle at the top end of new shoot elongated over 2 cm).
Figure 1. Open-field experimental warming and precipitation manipulation system.
Results and Discussion
 Leaf fall
• The leaf unfolding of seedlings in warmed plots, with all precipitation
manipulations, was advanced by 11.6, 13.1 and 4.5 days for stage 3, 4
and 5, respectively (Figure 3a).
• Timings of leaf unfolding tended to differ between transplanted
seedlings and non-transplanted seedlings, on average by 1.4, 5.4
and 21.9 days for stage 3, 4 and 5, respectively (Figure 3b).
• This result might be explained by the transplanting stress.
• In this study, effects of precipitation treatments were not observed.
Peñuelas et al. (2004) reported that some species advanced leaf
unfolding under increased precipitation, meanwhile other species
showed no significant changes.
• The cumulative weight of leaf fall was higher in the control plots than
in the warmed plots (Figure 4). On contrary, leaf biomass of 2014 (data
not shown) was higher in warmed plot than in the control.
• On the other hand, the effects of warming treatment on the leaf
longevity was observed. In March 2015, which was when the last
collection of litter fall was conducted, remaining 2-year-old green leaves
were observed in the half of the seedlings of the warmed plots, while it
was only in 10-20% seedlings in the control.
• This might indicate that the leaf longevity was increased and the leaf
fall was delayed with elevated temperature.
• Regarding precipitation manipulation, no distinct tendency was observed.
Non-transplanted seedlings
Transplanted seedlings
(a)
Leaf unfolding stage
5
(b)
Warmed
5
Warmed
4
4
3
Ambient
3
Ambient
P0W
P0C
P-W
P-C
P+W
P+C
2
Time of
transplanting
1
80
100
120
140
0
PW
P0C
P-W
P-C
P+W
P+C
2
Time of
transplanting
1
160
180
DOY
2014
80
100
120
140
160
180
DOY
2014
Figure 3. Leaf unfolding stage of transplanted seedlings (a) and non-transplanted seedlings (b) with
warming and precipitation manipulation in 2014.
Conclusions
• We might conclude that warming increases the growth period of P.
densiflora, with advanced leaf unfolding and delayed leaf fall.
• Provided level of precipitation in our experiment seemed to be
insufficient for any phenological changes occur.
• For a clear understanding of leaf phenology, disturbances on seedlings,
such as transplanting, should be minimized.
leaf weightof leaf fall (g)
Cumulative weight
 Leaf unfolding
18
16
14
12
Ambient
10
8
6
P0W
P0C
P-W
P-C
P+W
P+C
4
2
0
Warmed
280
300
280
300
320
340
320
340
DOY
2014
360
360
380
15
400
35
420
55
DOY
2015
440
75
460
95
Figure 4. Cumulative weight of leaf fall (g) with warming
and precipitation manipulation in 2014 and 2015.
References
• Byun, J-G., Lee, W-K., Nor, D-K., Kim, S-H., Choi. J-K., and Lee, Y-J. 2010. The relationship between tree radial
growth and topographic and climatic factors in red pine and oak in central regions of Korea. Journal of Korean
Forest Society, 99(6): 908-913. in Korean.
• Cleland, EE., Chuine, I., Menzel, A., Mooney, HA., Schwartz, MD. 2007. Shifting plant phenology in response to
global change. Trends in Ecology and Evolution. 22:357–365
• Climate Change Institute Center. 2015. http://www.climate.go.kr/
• Peñuelas, J., Filella, I., Zhang, X., Llorens, L., Ogaya, R., Lloret, F., Comas, P., Estiarte, M., Terradas, J. 2004.
Complex spatiotemporal phenological shifts as a response to rainfall changes. New Phytologist, 161(3): 837-846.
* Supported by National Research Foundation of Korea (NRF-2013R1A1A2012242)