Regeneration of Pinus halepensis stands after partial cutting in southern France: Impacts of different ground vegetation, soil and logging slash treatments

Abstract

This study investigated the effects of different soil, ground vegetation and logging slash treatments on Aleppo pine recruitment in a mature stand after partial cut in southern France. An experimental design was assessed using five treatments: (1) chopping of the ground vegetation, (2) chopping followed by soil scarification in one or (3) in two directions, (4) controlled fire, (5) control—and two logging slash treatments: (1) presence or (2) absence of slash cover before the soil and ground vegetation treatments. Pine seedling emergence and survival were recorded on 580 one-square-meter plots at the end of spring and autumn from autumn 2005 to autumn 2007. Description of the soil surface conditions in cover classes was also established in each plot at the end of the year. Seedling emergence took place predominantly in autumn except for the last year of the experiment due to a severe drought period. Soil scarification treatments and controlled fire with slash present (i.e. intense fire) showed the highest seedling densities and bare soil cover was also the highest in these treatments. By contrast, a lower seedling density was recorded in the controlled fire without slash (i.e. moderate fire) where grass cover largely developed. Chopping also proved to be unfavorable to seedling emergence and survival. Seedling emergence was enhanced by the presence of logging slash in the moderate soil scarification treatment probably due to the additional seed source provided by the breakdown of the cones in the slash. The study showed the importance of mechanical treatments – in particular scarification – to favor pine recruitment. However a longer period of data recording is requested to analyze the response of pine seedlings to developing ground vegetation development in the coming years.