Understanding height-structured competition in forests: is there anR^*for light?

Abstract

Tree species differ from one another in, and display trade-offs among, a wide range of attributes, including canopy and understorey growth and mortality rates, fecundity, height and crown allometry, and crown transmissivity. But how does this variation affect the outcome of interspecific competition and hence community structure? We derive criteria for the outcome of competition among tree species competing for light, given their allometric and life-history parameters. These criteria are defined in terms of a new simple whole life-cycle measure of performance, which provides a simple way to organize and understand the many ways in which species differ. The general case, in which all parameters can differ between species, can produce coexistence, founder control or competitive exclusion: thus, competition for light need not be hierarchical as implied by R Ã theory. The special case in which species differ only in crown transmissivity produces neutral dynamics. The special case in which species differ in all parameters except crown transmissivity gives hierarchical competition, where the equivalent of R Ã isẐ Ã , the height at which trees enter the canopy in an equilibrium monoculture.

Reactions of N-arylsulfonylquinone imines with enamines

“…The characteristics of compound VIIa are consistent with the data in [16], of compounds VIIIa, VIIIb, in [27]. …”

“…1,4-Quinone monoimines IIIа, IIId-IIIp, IX were synthesized by procedure [26], 1,4-benzoquinone monoimines IIIb, IIIc, by procedure [27], N,N '-ditosyl-1,4-benzoquinone diimine (XIIIа), by method [28], N,N '-ditosyl-2-chloro-1,4-benzoquinone diimine (XIIIb), by method [29], acetylacetone p-tolylamine (IVа) and esters of 3-arylaminocrotonic acid IVb, IVc were obtained as described in [30].…”

Reaction of N-sulfonyl-1,4-benzoquinone imines with sodium azide

“…The addition of sodium azide to N-substituted 1,4-quinone imines generally proceeded in a way similar to the addition of HCl, i.e., according to the 1,4-addition path [4][5][6][7][8][9][10], while no reaction was observed with 2,6-dimethyl-1,4benzoquinone imine derivatives; this indicated that no other reaction paths were operative [8].…”

“…It was found that the addition products in boiling acetic acid may undergo intramolecular oxidation/reduction with formation of N-(3-amino-4-oxocyclohexa-2,5-dienylidene)arenesulfonamides [5,6,8,10], but the mechanism of this process was not studied. Analogous transformations of 1,4-benzo- [11,12] and 1,4-naphthoquinones [11] were also observed in chloroform in an inert atmosphere.…”

“…Yield 21%, mp 115-117°C.1 H NMR spectrum (DMSO-d6 ), δ, ppm: 1.14 d (6H, CHMe 2 , . Calculated, %: N 19.70; S 11.28.N-(3-Azido-4-hydroxy-2-isopropyl-5-methyl-phenyl)methanesulfonamide (6d).…”