ry of resuits of to-factor rep s for tre s)in cne-year old ht and tr ured for 5 tim a tree and tree-ring increment (measured for 3 years following the defoliation 2 ant for tree-rina)and no intera HTee Tree-ring growth following the defoliation Annual height growth following the defollation UiMHet a (in Gas exchange rate (luly 2003) Nitrogen in source of needles after the defoliation (1)At the shade site defolia ion led to a decrease in Ama At both sites,no defoliation effects on needle N contents for 2 years following defoliation MH et al.(ir LiMH et (in10 Nitrogen Sugars Starch NSC C-N ratio Height Tree-ring df1 F P F P F P F P F P df2 F P F P Between subjects Light (L) 1 21.003 <0.000 16.789 0.001 241.008 <0.000 106.931 <0.000 34.721 <0.000 1 74.994 <0.000 21.789 <0.000 Defoliation 4 0.667 n.s. 0.517 n.s. 1.385 n.s. 0.388 n.s. 0.637 n.s. 4 0.331 n.s. 2.851 0.05 Summary of results of two-factor repeated measures ANOVAs for tree￾physiological parameters (measured for 5 times during the experimental period of 3 years) in one-year old needles, annual height and tree-ring increment (measured for 3 years following the defoliation), Abies alba trees (D) L x D 4 0.592 n.s. 0.399 n.s. 1.375 n.s. 0.951 n.s. 0.152 n.s. 4 0.567 n.s. 2.644 n.s. Within subjects Time (T) 4 6.373 0.001 8.348 <0.000 142.098 <0.000 81.733 <0.000 71.110 <0.000 2 0.401 n.s. 6.386 <0.05 T x L 4 18.328 <0.000 3.672 <0.05 116.172 <0.000 46.626 <0.000 75.111 <0.000 2 9.446 <0.001 6.264 <0.05 T x D 16 1.414 n.s. 0.945 n.s. 1.064 n.s. 0.814 n.s. 1.618 n.s. 8 0.822 n.s. 4.243 <0.05 T x L x D 16 1.110 n.s. 0.744 n.s. 1.267 n.s. 0.689 n.s. 1.057 n.s. 8 1.226 n.s. 6.789 <0.001 Li MH et al. Tree Physiology (in preparation) No defoliation effects (except for tree-ring) and no interaction between L and D Low light High light Low light High light N NSC N NSC H D H D Summary of results of repeated measures ANOVAs for total nitrogen and NSC (non-structural carbohydrates) contents (measured for 5 times during the experimental period of 3 years) in one-year old needles, annual height and tree-ring increment (measured for 3 years following the defoliation) Source df1 F P F P F P F P df2 F P F P F P F P Defoliation (D) 4 0.761 n.s. 0.441 n.s. 0.582 n.s. 0.783 n.s. 4 0.343 n.s. 10.905 <0.001 0.644 n.s. 1.327 n.s. Time (T) 4 65.552 <0.000 46.250 <0.000 2.265 n.s. 74.120 <0.000 2 4.522 <0.05 5.389 <0.05 5.702 <0.05 8.074 <0.05 D x T 16 1.007 n.s. 1.029 n.s. 1.310 n.s. 0.598 n.s. 8 0.894 n.s. 7.986 <0.01 1.277 n.s. 0.900 n.s. Li MH et al. Tree Physiology (in preparation) Tree-ring growth following the defoliation 20 40 60 80 100 120 Relative growth rate of tree-ring (%) a a b b c a a b b c 30% of full light intensity 40 60 80 100 120 ive growth rate of tree-ring (%) a c b c c a ab b bc c 70% of full light intensity 0 Before defoliation 1yr following defoliation 2 yrs following defoliation Li MH et al. (in preparation) (1) Responses in tree-ring growth differed between the shade and gap site. (2) Severe defoliations reduced tree-ring growth at the shade site (3) Compensation growth of light defoliated trees was found at the gap site 0 20 Before defoliation 1yr following defoliation 2 yrs following defoliation Relat Annual height growth following the defoliation 20 40 60 80 100 120 140 Relative height growth rate (%) 0% -9% -27% -46% -71% a b b b c a b b b c 30% of sunlight 60 80 100 120 140 ght growth rate (%) a a a a b a ab b bc c 70% of sunlight 0 Before defoliation 1 yr following defoliation 2 yrs following defoliation Li MH et al. (in preparation) (1) At the shade site, defoliation led to a significant reduction in annual height growth. (2) At the gap site, light defoliations caused an increase, whereas a severe defoliation caused a decrease in height growth 0 20 40 60 Before defoliation 1 yr following defoliation 2 yrs following defoliation Relative heig Gas exchange rate (July 2003) of needles after the defoliation 2 3 4 5 6 (mmol CO2 m-2 s-1) Intact trees; Amax = 7.27 Shade site 2 3 4 5 6 7 8 Intact trees; Amax = 7.70 30% of full light intensity 70% of full light intensity Gap site 0 1 0 1000 2000 3000 4000 5000 Light (mmol m-2 s-1) Pn ( Intact trees; Amax 7.27 -27% of needle biomass; Amax = 5.74 -71% of needle biomass; Amax = 4.33 0 1 2 0 1000 2000 3000 4000 Light (mmol m-2 s-1) -27% of needle biomass; Amax = 9.35 -71% of needle biomass; Amax = 8.45 Li MH et al. (in preparation) (1) At the shade site defoliation led to a decrease in Amax. (2) But at the gap site, a compensation effect in photosynthesis has been detected Nitrogen in source 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Apr 02 July 02 Oct 02 Oct 03 Needle N contents (%) 0% -9% -27% -46% -71% D f li ti p>0.05 p>0.05 p>0.05 p>0.05 30% sunlight 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Needle N contents (%) 0% -9% -27% -46% -71% p>0.05 p>0.05 p>0.05 p>0.05 70% sunlight Defoliation Li MH et al. (in preparation) At both sites, no defoliation effects on needle N contents for 2 years following defoliation 0 0.2 Apr 02 July 02 Oct 02 Oct 03 Defoliation