Experiment 1 Needle age-dependent LMA Experiment 1 Needle ongevity and age-dependentneede blomass 生deb .1.)and the lowlands (570 m)in Switz 214士2234士152 11k士6170士14523士m LI MH ot al 2006.Troos 20.8t in order to periment2 ents e exposure within crown 。Experimen 13814.3143 Stom xylem+ 66 Needle age Current year 1 year 2 years 3 years 4 years >4 years Total† Needle biomass (kg; mean values ± SD) per age class and total needle biomass (kg) in old and young Pinus cembra trees growing in the high￾lands (2100 – 2300 m a.s.l.) and the lowlands (570 m) in Switzerland* Needle longevity longevity and age-dependent dependent needle biomass biomass Old lowland trees 9.298±1.14 5.555±1.25 + + + 14.853 Young lowland trees 2.016±0.42 1.292±0.47 0.311±0.06 + + 3.619 Old highland trees 18.745±2.32 16.213±2.1 12.227±1.2 5.656±1.01 1.023±0.04 + 53.864 Young highland trees 2.304±0.37 1.887±0.24 1.295±0.35 0.400±0.04 0.084±0.01 + 5.970 * “+” in the table means that few needles still remained † Total needle biomass (kg) of a tree crown Li MH et al. 2006. Trees 20, 611-618 Highland Lowland Young trees Old trees Young trees Old trees Current year needles 214.59±2.61 223.41±15.2 205.50±13.6 212.88±15.4 Leaf mass per unit area (LMA, g m-2; mean values ± SD) of old and young Pinus cembra trees growing in the highlands (2100 – 2300 m a.s.l.) and the lowlands (570 m) in Switzerland Needle age-dependent dependent LMA 1-year-old needles 218.12±6.70 227.90±14.5 213.68±10.5 220.73±18.7 2-year-old needles 221.41±26.26 222.53±16.6 No needles No needles 3-year-old needles 218.90±5.17 225.32±10.1 No needles No needles 4-year-old needles 215.98±18.61 223.52±7.40 No needles No needles Li MH et al. 2006. Trees 20, 611-618 Experiments 2 & 3 are to understand the needle age-related physiology within a crown, in order to develop an accuracy sampling strategy. Hypotheses: 1) concentrations of N, NSC and its components, and δ13C are needle-age dependent, and higher in current dl th i t year needles than in one-year old dl nee es, since the former is physiologically more active than the latter; 2) these concentrations in needles at the south crown side or top crown level are higher than those at the north side or lower crown level, respectively, due to the differences in sunlight exposure within a crown. May July September Sugars Starch NSC Sugars Starch NSC Sugars Starch NSC Current-yr. needles no needle no needle no needle 3.8±0.3a 7.2±0.2a 11.0±0.5a 9.1±0.4a 5.7±0.3a 14.8±0.4 Sugar, starch and NSC concentrations (% d. m., mean value ± SE) of needles of different age-classes needles needle 1-year-old needles 7.3±0.2a 16.4±0.5ab 23.7±0.3a 5.9±0.3b 17.5±0.5b 23.4±0.4b 8.7±0.5a 6.7±0.3ab 15.4±0.3 2-year-old needles 6.7±0.3ab 16.3±0.5ab 23.0±0.4a 5.5±0.2bd 16.5±0.3b 22.0±0.5c 7.3±0.4b 6.5±0.4ab 13.8±0.3 3-year-old needles 6.7±0.4ab 16.5±0.3a 23.2±0.4a 5.0±0.2cd 16.3±0.4b 21.3±0.4c 7.0±0.2b 7.6±0.6b 14.6±0.7 4-year-old needles 5.8±0.3b 15.5±0.4ab 21.3±0.5b 4.7±0.2c 16.2±0.4b 20.9±0.4c 6.3±0.3b 8.3±0.4b 14.6±0.6 5-year-old needles 6.0±0.3b 14.6±0.3b 20.6±0.2b 4.8±0.2c 16.5±0.3b 21.3±0.4c 6.8±0.3b 7.4±0.3ab 14.2±0.3 Li MH et al. 2001. Phyton 41, 203-213 0.0 5.0 10.0 15.0 20.0 25.0 30.0 May July Sept May July Sept May July Sept TNC (% d.m.) N-slope S-slope 2-yr.-old needles Buds Stem wood * 5.0 10.0 15.0 20.0 25.0 TNC (% d.m.) S-side N-side North-facing slope vs. South-facing slope North crown side vs. 0.0 S th id 5.0 May July Sept May July Sept May July Sept T Current yr. needles 2 yr. old needles Buds 0.0 5.0 10.0 15.0 20.0 25.0 30.0 May July Sept May July Sept May July Sept TNC (% d.m.) Lower section Mid-section Upper section 2 yr. old needles Buds Stem xylem South crown side Vertical crown levels: Lower – Middle - Upper Li MH et al. 2001. Phyton 41, 203-213 TNC within a crown Pinus cembra Li MH et al. 2001. Phyton 41, 203-213