ANPP.xlsx

Proper estimation of the herb layer annual net
primary production (ANPP) can help to appreciate the role of this layer in carbon
assimilation and nutrient cycling. Simple methods of ANPP estimation often
understate its value. More accurate methods take into account biomass
increments of individual species but are more laborious. We conducted our study
in an oak-hornbeam forest (site area 12 ha) dominated by beech in NW Poland during
two growing seasons (2010 and 2011). We collected herb layer biomass from 7 to
10 square frames (0.6×0.6 m). We collected plant biomass every week in April
and May and every two weeks for the rest of the growing season. We compared six
methods of calculating ANPP. The highest current year standing biomass (1st
method of ANPP calculation) was obtained on 15th May 2010 – 37.8 g m-2
and 7th May 2011 – 41.0 g m-2. The highest values of
ANPP were obtained by the 6th method based on the sum of the highest
products of shoot biomass and density for individual species: 74.3 g m‑2 year-1
in 2010 and 94.0 g m-2 year‑1 in 2011. The spring
ephemeral Anemone nemorosa had the highest share of ANPP with 50% of the
total ANPP. Two summer-greens, Galeobdolon luteum and Galium odoratum, each had a ca. 10% share of ANPP. The
best results of ANPP calculation resulted from laborious tracking of dynamics
of biomass and density of individual shoots.