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Decay and soundwood assessments made with the Resistograph® and the portable drill were compared with laboratory measurements of wood density. Sixteen Tasmanian blue gum (Eucalyptus globulus) and 5 Scotch elm (Ulmus glabra) were evaluated in the field, cut, sectioned along Resistograph and drill test paths, and measured for density. Resistograph measurements of soundwood depth agreed closely with density measurements in 85.5% of all cases for blue gum and 100% of all cases for elm. Portable drill measurements agreed closely with density measurements in 73% of cases for blue gum and 81% for elm. Drill evaluations varied considerably among operators. For both species, the Resistograph provided a higher level of consistency and reliability than the portable drill. For either method, familiarity with wood resistance patterns of the test species is critical for an accurate interpretation of decay presence or absence.

In November 2006, trees of Italian alder (Alnus cordata) were observed declining in association with bleeding trunk cankers in a commercial landscape in Foster City, CA. A species of Phytophthora was isolated on PARP selective medium from the leading edge of the cankers. The Phytophthora species was homothallic with primarily paragynous antheridia and had oospores that were mostly globose and aplerotic. Sporangia were produced from mycelia on plugs of carrot piece agar in soil extraction solution and were semi-papillate and ovoid to ellipsoid in shape. The intergenic transcribed spacer region of rDNA from an alder isolate matched with 100% identity to isolates in GenBank of Phytophthora siskiyouensis, a recently described species associated with tanoak and found in the soil and waterways of coastal Oregon. Pathogenicity was tested on young alder trees growing in pots. Pathogenicity was confirmed on Italian alder trees and potential pathogenicity was demonstrated on red and white alder trees. Accepted for publication 11 March 2009. Published 13 April 2009.

Since it is unlikely that crop coefficients will be established for landscape plantings, a method to estimate landscape water requirements is proposed. By evaluating three factors that significantly influence water use-species planted, vegetation density, and site microclimate-and assigning numerical values to each, an estimate of a landscape crop coefficient (or landscape coefficient, KL) can be calculated. An estimate of evapotranspirational water loss for landscapes is then the product of the landscape coefficient multiplied by the reference evapotranspiration. This paper presents values for the above three factors and discusses the rationale for each. Examples using the landscape coefficient formula are included, as well as a discussion of special considerations relative to its use.