James B. Heffernan. 2008. Wetlands as an alternative stable state in desert streams. Ecology 89:1261–1271.

Appendix D. Collection methods and analysis of height–biomass relationships used to estimate biomass.

Collection methods and analysis

For each species, samples for height-biomass relationships were collected from patches that were reasonably uniform in height during the growing seasons of 2005 and 2006. Prior to harvesting aboveground biomass from a 0.016-m² quadrat, I measured the height of four stems within the quadrat. Aboveground biomass was then removed from the quadrat area as thoroughly as possible and placed in a sealed plastic bag. Upon return to the laboratory, samples were dried at 60ºC and subsamples of dried material were ashed at 550 ºC for four hours to determine organic matter content. Power-law equations were used in regression analysis of relationships between mean plant height and total aboveground biomass (g AFDM/m²; Fig. D1). These relationships were generally very strong (Table D1).

FIG. D1. Lines are best-fit power-law relationships based on linear regression of log-transformed plant height and log-transformed aboveground biomass. Parameter values for relationships are given in Table D1.

TABLE D1. Results of linear-regression analysis of relationship between log-transformed mean plant height and log-transformed aboveground biomass for 12 taxa common to Sycamore Creek, Arizona, USA.