Browsing by Author "HOFFMANN, A"

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    COMPARATIVE MORPHOLOGICAL AND ECOPHYSIOLOGICAL ASPECTS OF 2 SCLEROPHYLLOUS CHILEAN SHRUBS
    (1976) RIVEROS, F; HOFFMANN, A; AVILA, G; ALJARO, ME; ARAYA, S; HOFFMANN, AE; Montenegro Rizzardini, Gloria
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    ROOT STUDIES IN CHILEAN MATORRAL
    (1978) HOFFMANN, A; KUMMEROW, J
    The roots of matorral shrubs were excavated from an 18 m2 site of a mixed matorral stand located on a 27.degree. northeast facing slope at 1000 m elevation 40 km north northwest from Santiago (Chile). The climate in this area is similar to that of the southern Californian [USA] chaparral. The main species present were Lithraea caustica, Cryptocarya alba, Colliguaya odorifera, Mutisia retusa and Satureja gilliesii. After harvesting the above ground biomass, the soil was washed out in 20 cm layers down to a depth of 60 cm. The roots were harvested according to their position in the site, separated into species and root size classes. Soil analysis indicated a fertile and deep reaching, clayish soil. L. caustica was a deep rooting species with many thick roots growing deeper than 60 cm. This species had a massive burl of 67 kg dry wt in the excavation site. Cryptocarya was less deep rooting and C. odorifera had a shallow root system. The root:shoot biomass ratios of 4.9 and 1.4 for L. caustica and C. alba, respectively, are indicative of the forest character of this site in the past. This forest would have been destroyed by continuous charcoal manufacture. The bulk of the fine roots was found in the 20-40 cm soil layer. The average distance between fine roots was calculated as 1.9 cm. The results were compared with an earlier excavation in the Californian chaparral.
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    SHRUB CLUMPS OF THE CHILEAN MATORRAL VEGETATION - STRUCTURE AND POSSIBLE MAINTENANCE MECHANISMS
    (1984) FUENTES, ER; OTAIZA, RD; ALLIENDE, MC; HOFFMANN, A; POIANI, A
    Previous studies have claimed that the Chilean matorral is more open than the California [USA] chaparral and have attributed this dissimilarity largely to the role of man in Chile. The Chilean matorral has a structure better described as shrub clumps that merge to form a continuous vegetation matrix only in very mesic habitats, where it is comparable to the California chaparral. Evidence is presented that these clumps have been present for at least the last 26 yr and that even without human disturbance they are likely to maintain themselves. Evidence for the latter pertains to seed dispersal, seed germination and establishment, seedling survival and the diameter size structure of shrub clumps. Differences between the California chaparral and Chilean matorral may be more profound than previously thought and are due not only to different degrees of human disturbance, but also to the presence of periodical natural fires in California and not in Chile and to different shrub recruitment patterns and mammalian herbivore activity in the 2 areas.