Separation of Dead and Live Material
The actual components of above-ground biomass that are considered during sampling depend upon the biomass property to sample. Biomass categories that may be identified include:
a. Living, actively growing material.
b. Recent dead - current year's growth which is no longer actively growing.
c. Old dead - produced during previous growing seasons.
d. Litter - detached plant material lying on the soil surface.
The accuracy and precision of data, whether acquired by harvesting to determine biomass or estimation approaches to determine biomass, are prejudiced by the observer's ability to identify current year's growth, and the level of care devoted to conscientiously and consistently separating components during sampling.
Other ground rules may be needed to describe the treatment of litter, flowers, fruit, etc.
References and Further Reading
(Note: pdf files require Adobe Acrobat (free) to view)
Bonham, C.D. 1989. Measurements of terrestrial vegetation. John Wiley Sons, New York, NY. pp 201-202.
Culley, M., Campbell, R.S., and R.H. Canfield. 1933. Values and limitations of clipped quadrats. Ecology 14:35-39.
Gillen, R.L., and K.W. Tate. 1993. The constituent differential method for determining live and dead herbage. Journal of Range Management 46:142-147. (pdf)
Johnson, M.K. 1986. Estimating ratios of live and dead plant material in clipped plots. Journal of Range Management 39:90. (pdf)
Lauenroth, W.K., Dodd, J.L., and C.E. Dickinson. 1980. Aboveground biomass dynamics of blue grama Bouteloua gracilis in a shortgrass steppe and evaluation of a method for separating live and dead. Journal of Range Management 33:210-212. (pdf)
Martin, M.H., Cox, J.R., and F.F. Ibarra. 1995. Climatic effects on buffelgrass productivity in the Sonoran Desert. Journal of Range Management 48:60-63.
Pieper, R.D. 1988. Rangeland vegetation productivity and biomass. In: P.T. Tueller. (ed). Vegetation science applications for rangeland analysis and management. Handbook of Vegetation Science, Volume 14. Kluwer Academic Publishers, Dordrecht. p 452.