Root density and root biomass in pure and mixed forest stands of Douglas-fir and beech

Authors

  • C.M.A. Hendriks
  • F.J.J.A. Bianchi

DOI:

https://doi.org/10.18174/njas.v43i3.570

Abstract

Below-ground interactions possibly play an important role in the success of mixed forests. Therefore, root density, root length, root biomass and rooting pattern were surveyed in representative pure and mixed stands of Douglas fir (Pseudotsuga menziesii) and beech (Fagus sylvatica) in the Veluwe area of central Netherlands. Each type of stand was represented by stands approximately 40 and 70 years old. The study was restricted to fine roots (<2 mm). The highest root length, 184x106 m/ha, was found in a 64-year-old pure beech stand. The smallest root length was 60x106 m/ha, found in a 60-year-old pure Douglas fir stand. In the mixed stands, the soil layers at 0.15-0.30 m and 0.30-0.45 m were more intensively rooted than in the pure stands. Beech was strongly suppressed by Douglas fir in mixed stands, although it developed an equal or even larger root length than Douglas fir. In mixed stands the specific root lengths of the fine roots of Douglas fir and beech were higher than in the pure stands, which may indicate below-ground competition; such below-ground competition between the different species appeared to lead to a different use of soil resources by fine roots. Furthermore, there were indications that in the mixed stands, as a reaction to the strong above-ground domination of Douglas fir, beech develops a rooting strategy which ensures the possibility of above-ground expansion when the growth of Douglas fir declines.

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Published

1995-09-01

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Section

Papers