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The solvolytic reactions of the neutral esters p-nitrophenyl acetate and p-nitrophenyl heptanoate catalyzed by poly[4(5)-vinylimidazole] and by imidazole have been investigated in solutions containing varying compositions of ethanol and water. Temperature and pH have been investigated as the perturbing variable in order to elucidate the roles of the effects of nonpolar polymer-substrate interactions and bifunctional catalysis in the synthetic polymeric catalyses. Further, the solution properties of poly[4(5)-vinylimidazole] were investigated in varying ethanol-water compositions and at varying pH values. It was found that the conformation of the polymer chain of poly[4(5)-vinylimidazole] in an ethanol-water mixture is dramatically affected by the ethanol-water composition and by the degree of neutralization of the pendent imidazole groups. The polymeric, catalytic enhancement for the solvolyses of neutral substrates in low and high ethanol compositions at pH ca. 8 was attributed to increased bifunctional catalysis which increases with the shrinkage of the macromolecules in solution. The solvolysis of PNPH at low ethanol concentration by poly[4(5)-vinylimidazole] appeared to involve an increased accumulation of the substrate in the polymer domain because of nonpolar polymer-substrate interactions.sphere with stirring by using a microburet and a Beckman pH meter.

a b s t r a c tAll or a part of a sequence of forest practices (i.e., salvage logging, site preparation, planting crop trees, and weeding) has been implemented after natural disturbances for the rapid re-establishment of tree cover. Forest policies in Japan have recently changed from monocultural planting of coniferous crop trees to planting native broadleaved trees to restore forests and nurture local biodiversity following large windthrows. However, the effects of this new practice on preserving biodiversity, as well as the effects of legacy retention, have never been verified in Asia. Thus, the objective of our research was to compare the effects of legacy retention with plantation after salvaging on the initial stage of vegetation recovery in a blowdown area, specifically focusing on plant species diversity, the occurrence of alien species, and the composition of plant species. Following the analysis of our results, we finally describe appropriate practices to alter disturbed coniferous plantations to bring the species composition closer to that of the original natural mixed forests.A control (A, legacy retention) and three experimental treatment sites (B, salvage logged, site prepared, and Quercus crispula seedlings planted; C, same as B, but weeded once during the summer; and D, residual rows that emerged after establishing sites for planting) were prepared, and quadrats were set. Eleven indicators of the ground condition and the number of vascular plant species, including ferns, were quantified, and the number and abundance of residual and newly colonized plants of the main woody species were estimated.Our main findings were as follows: (1) in unsalvaged sites and residual rows, the diversity of plant species was poor, but a variety of plant species compositions were observed due to the heterogeneous conditions of the ground and ample residual plants; (2) in the planting site, many species appeared, but little variety of the species composition was observed due to the homogeneous condition of the ground and the destruction of residual plants; (3) a large number of alien species emerged in broad, unvegetated areas; (4) the impact of site preparation overwhelmed the impact of salvage logging on the initial recovery of plant species; and (5) to restore a natural mixed forest, a combination of legacy retention and plantation after salvaging would be the most appropriate.

Abstract.C6HI2Se 2 +.2BFa.CH3CN, Mr = 456.74, monoclinic, P21/a, a = 24.053 (6), b = 6.955 (2), c =

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