Nutrient gain from wet and dry atmospheric deposition and rainfall acidity in southern California chaparral.

Ionic concentration and annual deposition of NO -N, NH -N, Ca, and Mg from bulk precipitation and dry atmospheric deposition were studied for one year in southern California. Data were collected from an inland chaparral site at 1,300 m elevation, 75 km from the coast. The annual depositions of NO -N and NH -N amounted to 96.

Temperature effect on growth rates of Eriophorum vaginatum roots.

Root growth rates of the sedge Eriophorum vaginatum L. were studied under controlled environmental conditions. The air temperature was maintained constant at 15°C while the root temperatures varied in 5°C intervals between 2° and 37° C (12° C excluded).

Seasonal root growth in the arctic tussock tundra.

The quantity of growing root tips per unit of soil volume was analyzed in a central Alaskan tussock tundra site. By June 10, the aboveground fraction of the vegetation had initiated the flush of spring growth and flowering while less than 5 active root tips cm were found. By June 25 this value had increased to 30 root tips cm.

Seasonal changes of fine root density in the Southern Californian chaparral.

Fine root extractions from soil cores of a south facing slope in the Southern Californian chaparral were used to study the dynamics of feeder root growth in a summer-dry area. The studies were concentrated on the root systems of Adenostoma fasciculatum, Arctostaphylos glauca, Ceanothus greggii, and Rhus ovata. The total fine root biomass of Adenostoma fasciculatum increased from 0.

Root studies in the Chilean matorral.

The roots of matorral shrubs were excavated from an 18 m site of a mixed matorral stand located on a 27° NE facing slope at 1000 m elevation 40 km NNW from Santiago de Chile. The climate in this area is similar to that of the Southern Californian chaparral. The main species present were Lithraea caustica, Cryptocarya alba, Colliguaya odorifera, Mutisia retusa, and Satureja gilliesii.

Root systems of chaparral shrubs.

Root systems of chaparral shrubs were excavated from a 70 m plot of a mixed chaparral stand located on a north-facing slope in San Diego County (32°54' N; 900 m above sea level). The main shrub species present were Adenostoma fasciculatum, Arctostaphylos pungens, Ceanothus greggii, Erigonum fasciculatum, and Haplopappus pinifolius. Shrubs were wired into their positions, and the soil was washed out beneath them down to a depth of approximately 60 cm, where impenetrable granite impeded further washing and root growth was severely restricted.