Dynamics of Carbon and Nutrient Accumulation in a Coppiced Chestnut (Castanea sativa Miller) Stand

1990

S. 413-444

8 Abb., 7 Tab., 33 Lit. Ang.

Unselbständiges Werk

200041187

The aim of the research on chestnut coppices was to gain data on the nutrient accumulation in the stands as a function of soil fertility, harvest intensity and rotation length. This research forms part of a more general programme on the effects of sylviculture intensification in the coppice system, on the export of nutrients from forest soils and consequently on the maintenance of soil fertility. Chestnut was used in this work to study the dynamics of carbon and nutrient accumulation during stand development. As the ideal method of studying a single stand was not possible, an age series of stands was used. The major constraints of this approach are related to soil heterogeneity and identity of the silvicultural treatments in all the stand. The construction of biomass and nutrient content tables applicable to the stands of different ages were tested. The results showed that for biomass measurements, it was necessary to use age as a parameter for the coefficients of regressions for all the stand components; for the nutrient component, the incorporation of age in the equations was very seldom necessary. It is clear that these differences are linked to the characteristics of carbon and nutrients in the vegetation: carbon is fixed definitively in the perennial components of trees while the nutrients are recycled from the old to the young tissues. Under the ecological conditions of the site studied (mesotrophic to eutrophic brown soil), the chestnut stand produced 7.2 of dry mater per ha per year at 15 yr old. This production is probably the greatest that can be found in coppices with numerous rotations. The study of stand dynamics showed that the nutrient incorporation rate decreased considerably with stand ageing; the current rate equals zero between 15 and 19 yr old. This means that the production is cost-free for the ecosystem at this stage of stand development. This approach allows us to evaluate the total return of litter to the soil (litter ss and tree mortality). For the stands, internal recyling, the importance of total return and the rate of humus, mineralization constituted an efficient strategy as regards independence from soil nutrient reserves, and permit a singificant growth in the content of soils with reduce fertility. Considering the production and the wood quality of chestnut stands, this species could be used for projected afforestation of land abandoned by agriculture.