Uta Matthes-Sears

Rooting Characteristics of Trees in Rock: A Study of Thuja occidentalis on Cliff Faces

Sixty-two slow-growing Thuja occidentalis (eastern white cedar), 6-28 yr in age and 11-52 cm in size, were excavated from a vertical limestone cliff. Their root extension, distribution, biomass, and belowground allocation were investigated, as was the degree to which these rooting characteristics were influenced by substrate factors such as rock fracturing and the presence of soil pockets and ledges. Alson examined was the correlation between such microsite characteristics and individual tree growth rates. The results showed that the majority of trees grew in rock without soil or in very small soil pockets. Rooting was shallow, penetrating solid rock to an average of only 9 cm (maximum 30 cm). Roots were found almost exclusively in rock fissures of the softer, more weathered rock layers, penetrating harder layers only via crevices. Root competition was largely absent when trees grew in rock. The prescence of absence of soil had no effect on aboveground or belowground biomass, root: Shoot ratio, or growth rate but significantly affected the pattern of root deployment. Root: shoot ratios were within the normal range for temperature-zone trees (average 0.48). All microsite factors were poor predictors of individual plant growth rate. The likely availability of both water and nutrients near the rock surface may explain the lack of deep root penetration and a minimal need for soil. Plasticity of root deployment without a loss of uptake efficiency may be one of the characteristics that enable T. occidentalis to persist on cliff faces.

ABUNDANCE, BIOMASS, AND PRODUCTIVITY OF ENDOLITHIC AND EPILITHIC LOWER PLANTS ON THE TEMPERATE-ZONE CLIFFS OF THE NIAGARA ESCARPMENT, CANADA

To investigate the cover, frequency, biomass, and productivity of endolithic and epilithic lower plants on temperate-zone cliff faces, rock samples were randomly collected from the Niagara Escarpment in southern Ontario, Canada. Chlorophyll was extracted using dimethyl sulfoxide (DMSO), and CO2 gas exchange was measured in the laboratory using infrared gas analysis. Epilithic surface cover averaged 26% for cyanobacteria, 3% for green algae, and 20% for lichens. Endoliths were present below 6% of the surface area, with chasmoendoliths about twice as common as cryptoendoliths. Fungi were by far the most common organisms. The cliffs contained 73.0 mg chl a and 19.8 mg chl b per square meter; 15% and 23% of these, respectively, were in the endolithic zone. Biomass of primary producers (algae, cyanobacteria, and lichen photobionts) was 1.5-73 g dry mass m-2 total, and

Constrained Growth of Trees in a Hostile Environment: The Role of Water and Nutrient Availability for Thuja occidentalis on Cliff Faces

0.3-14\ {\rm g}\ {\rm m}^{-2}

Community structure of epilithic and endolithic algae and cyanobacteria on cliffs of the Niagara Escarpment

in the endolithic zone alone. Photosynthetic carbon uptake was 0.0021 mg

Growth and physiology of Thuja occidentalis L. from cliffs and swamps: is variation habitat or site specific?

{\rm CO}_{2}\ {\rm cm}^{-2}\ {\rm h}^{-1}

Patterns of Architectural Variation in Thuja occidentalis L. (Eastern White Cedar) from Upland and Lowland Sites

at 700 μ mol m-2 s-1 photosynthetically active radiation (PAR). At

The ecology of Ramalina menziesii. III: In situ diurnal field measurements at two sites on a coast-inland gradient

{\rm PAR}=130\ \mu {\rm mol}\ {\rm m}^{-2}\ {\rm s}^{-1}

The ecology of Ramalina menziesii. VI. Laboratory responses of net CO2 exchange to moisture, temperature, and light

, a small amount of carbon was released

The ecology of Ramalina menziesii. I. Geographical variation in form

(0.5\ {\rm mg}\ {\rm CO}_{2}\ {\rm m}^{-2}\ {\rm s}^{-1})

Cold Resistance of Lichens with Trentepohlia- or Trebouxia-Photobionts from the North American West Coast

; dark respiration was 0.0096 mg