Just found this
Interesting discussion. So I was just doing a search on this subject and found this:
Title
Effects of artificial defoliation on the growth of Cork Oak.
Authors
Magnoler, A.; Cambini, A.
Journal
Forest Science 1970 Vol. 16 No. 3 pp. 364-6
ISSN
0015-749X
Record Number
19700602894
Abstract
Thirty trees of Quercus suber, aged 22 years, in Sardinia were studied to assess the effect on growth of artificial defoliation (simulating defoliation by Lymantria dispar and Malacosoma neustria larvae). In mid-June, 1965, 10 trees were completely defoliated, 10 were half defoliated (by removing alternate leaves) and 10 were left as controls. All defoliated trees produced a new crop of leaves within 30 to 40 days of the treatment, but total foliar dry-weight production was less than before defoliation in both 1965 and 1966. The immediate response to complete defoliation was a reduction of 63% in height growth and 45% in xylem ring width. The corresponding figures for 50% defoliation were respectively 19% and 26%. Reduction in the width of cork growth rings was 36% after complete and 20% after 50% defoliation in 1965, but in the next year the cork ring width did not differ significantly from that of controls. However, cork production depends also on the generating area, which is reduced by the reduction in xylem growth: with complete defoliation the combined loss of cork production was ca. 60% in the first and 32% in the second year after treatment; and with 50% defoliation the losses were respectively 42 and 10%.
Bnut, did you ever defoliate??