Effects of soil water content, fertilization, light, weed competition and seedbed type on natural regeneration of beech ( Fagus sylvatica)

Abstract

Natural regeneration of beech ( Fagus sylvatica) is regarded as an inexpensive and generally satisfactory, though unreliable, method fo forest regeneration. In order to improve the understanding of the ecological conditions behind the growth and survival of beech seedlings, factorial experiments were carried out in each of two beech stands with different canopy openings. The effects of soil water content and nutrient supply in relation to light intensity, weed competition and seedbed type were studied. Under the open canopy (13% light) the seedling growth was increased three to four times when both fertilized and irrigated in a mineral soil seedbed compared with seedlings that were neither fertilized nor irrigated. The seedling response to treatments was small in the mixed soil seedbed under the open canopy and in both seedbed types under the closed canopy (5% light). Seedling growth was increased only with increased soil water content under the open canopy in fertilized plots. Weed competition did not reduce seedling growth significantly. Fertilization reduced soil water content up to about 20%. It was concluded that primary growth factors like light intensity, soil water content and nutrient supply should all be quantified or manipulated when the growth of beech seedlings is investigated. Otherwise, the correct interpretation of complex effects such as silvicultural treatments, soil types and weed competition must be regarded as very difficult or impossible to make.